To further reduce the overall size, it comes with new slim line, low profile front and rear lens caps:
Saturday, 13 November 2010
Panasonic Lumix G 14mm f/2.5
The Panasonic Lumix G 14mm pancake lens is the long awaited miniature standard wide prime. Some people have been disappointed by the aperture: The max aperture is f/2.5, which is a tad slow for primes. On the other hand, it is clear that size was important when designing this lens, and a moderate max aperture is needed to design a small lens.
To further reduce the overall size, it comes with new slim line, low profile front and rear lens caps:
To further reduce the overall size, it comes with new slim line, low profile front and rear lens caps:
Example video capture, GH1+Lumix 45-200mm
This recording was done in Union Square Park using a Panasonic GH1 and a Panasonic Lumix G 45-200mm f/4-5.6 zoom lens.
In this example capture, you can see that the camera jogs the focus back and forth now and then, probably to verify the correctness of the focus. Also, while zooming, the focus is lost for a short period. The newer Lumix G 100-300mm f/4-5.6 lens is said to have some technology to prevent the loss of focus during zooming.
The recording was done in 720p, and converted/edited using HandBrake and Kdenlive.
Of course, one should be very careful with zooming during video recording. It is almost impossible to get the zooming smooth and undistracting. When zooming is done by professional videographers, the usually use a dedicated zoom motor, which attaches to the zoom ring and rotates it smoothly.
This video example illustrates how you can achieve a nice background blur using one of the cheapest lenses available. The possibility to blur the background to enhance the foreground subject is one of the reasons why some people like using Micro Four Thirds for filming.
Here is another example video capture:
This was filmed using 720p, 50 fps. I set the focal length to 120mm, which corresponds to 240mm on a traditional 35mm film camera.
The camera was not on a tripod, but I rested it against a fence for extra stability. Still, it was difficult to keep it entirely stable. You can see that there is some camera shake.
In this example capture, you can see that the camera jogs the focus back and forth now and then, probably to verify the correctness of the focus. Also, while zooming, the focus is lost for a short period. The newer Lumix G 100-300mm f/4-5.6 lens is said to have some technology to prevent the loss of focus during zooming.
The recording was done in 720p, and converted/edited using HandBrake and Kdenlive.
Of course, one should be very careful with zooming during video recording. It is almost impossible to get the zooming smooth and undistracting. When zooming is done by professional videographers, the usually use a dedicated zoom motor, which attaches to the zoom ring and rotates it smoothly.
This video example illustrates how you can achieve a nice background blur using one of the cheapest lenses available. The possibility to blur the background to enhance the foreground subject is one of the reasons why some people like using Micro Four Thirds for filming.
Here is another example video capture:
This was filmed using 720p, 50 fps. I set the focal length to 120mm, which corresponds to 240mm on a traditional 35mm film camera.
The camera was not on a tripod, but I rested it against a fence for extra stability. Still, it was difficult to keep it entirely stable. You can see that there is some camera shake.
Tuesday, 9 November 2010
Lumix G 8mm f/3.5 Fisheye
The 8mm fisheye lens is a specialized lens, meaning that it is not a lens that most people would use a lot. One can imagine several reasons why Panasonic still chose to develop this lens, e.g.:
Anyway, the user is of course free to choose what to use this lens for, and does not need to be restricted by the items above.
I have made a comparison of the sharpness and other aspects of the Lumix 8mm fisheye lens compared with the Olympus Zuiko 9-18mm f/4-5.6.
In 2011, the Samyang 7.5mm f/3.5 fisheye lens was announced. It is a fisheye lens with fairly similar specifications as the Lumix G 8mm f/3.5. The Samyang is a manual focus lens, with a manually operated aperture ring. My study has shown that it has remarkably good optics, in terms of sharpness and CAs. It also has somewhat less distortion than the Lumix G 8mm lens.
Type of fisheye lens
Most fisheye lenses fall into two categories: Circular fisheye lenses, and full frame fisheye lenses. Circular fisheye lenses cover the field of view of 180° in all directions, and only expose a disc in the centre of the frame. Full frame fisheye lenses, on the other hand, expose the whole sensor area, but only cover 180° in the diagonal.
The Lumix G 8mm fisheye lens is a full frame fisheye lens. A circular fisheye lens on the Four Thirds format sensor would probably have a focal length of around 3-4mm.
Physical appearance
The lens comes with a built in, non removable, hood. The hood also protects the front lens element against objects touching it accidentally. Due to the hood, you can place the lens upside down on a table without the glass touching anything.
The front lens cap is unusual. Rather than the pinch centre caps that we are used to, this one is more like a lid which slides onto the outside of the hood. It is held in place by friction. The outside of the hood is around 61mm wide. You better take good care of the lens cap, since replacing it can cost around US$40.
Comparing the fisheye lens with the Lumix 20mm f/1.7 Pancake lens, reveals that it's size is small:
The Lumix 20mm is seen here with a "home made" low profile hood.
Quality wise, the lens gives a very good impression. There are no moving parts on the outside (beyond the focus ring), due to the internal focus mechanism.
The aperture can be set from f/3.5 to f/22. Changing the aperture gives a small "click" sound. It is not as silent as the Lumix G HD 14-140mm superzoom lens, but still, I hardly think anyone will find this problematic.
There is no geometric distortion correction in software when using this lens. As opposed to most Micro Four Thirds lenses, which utilize geometric correction in post processing, e.g., the Lumix G 20mm and Lumix G 14mm pancake lenses.
Autofocus
This lens has a very quick autofocus system. Except when photographing very close objects, you barely notice the focus at all: It appears to be in focus instantly when half pressing the shutter.
Here is a comparison of the focus speed for various lenses on a GH2. In this study, the 8mm fisheye lens has a very quick timing.
Moreover, the autofocus is virtually inaudible. It is barely noticeable in use.
I would recommend using multi point AF with this lens. The spot autofocus can be a bit awkward, with the very wide angle of view.
The closest focus distance possible is very short, specified to 0.1m. Keep in mind, though, that this is measured from the sensor, meaning that the minimum focus distance is very close to the front lens element. At this distance, it is ineviteable that the lens casts some shadow on the subject.
Here is an example use of the lens for macro purposes.
Manual focus is possible by using the focus ring. It is made of ribbed plastic, and for that reason it is not as easy to operate as a rubber ring would have been. On the other hand, the plastic ring is probably much more solid, and will not wear out any time soon. The ring feels fairly dampened and smooth, about the same as the Lumix 20mm focus ring.
Sharpness
My experience so far indicates that the sharpness is very good, even at f/3.5.
The typical way to evaluate the sharpness and artifacts of a wide angle lens, is to take a picture of foliage with the sky in the background. So here they are:
To better evaluate the sharpness, let's look at some 100% crops from certain areas in the image (click for a larger image):
As we see from these crops, the image is very sharp from f/3.5, even in the corners. When stopping down the aperture to f/5.6, the corners sharpen up even more.
I have made a comparison of the sharpness and other aspects of the Lumix 8mm fisheye lens compared with the Olympus Zuiko 9-18mm f/4-5.6.
Here is another sharpness comparison with the Samyang 7.5mm f/3.5 fisheye lens.
My study of the chromatic aberrations (CA) artifacts reveals that the lens has around 2-3 pixels wide red/green fringing in the corners of the frame, caused by high contrast areas. This is corrected by post processing software in the camera, and by some RAW converters. There is still some residual purple fringing in the corners after this in camera image processing, but it's mostly not a problem.
Flare
The Lumix G 8mm fisheye lens covers a very wide field of view. For this reason, it can be difficult not to have a strong light source in the frame, e.g., the sun. Hence, it is important that the lens handles flare well. Otherwise, one strong light source could ruin your shot.
I have included an extreme example below. Here, the sun is in the centre of the frame, just behind the figures.
And here is an enlargement of the persons, who has the sun just behind them. This is a 100% crop, meaning that it has not been resized:
Here we see that the sun does indeed reduce the contrast. However, considering how difficult this scene is to render, given the very high contrast, I think the lens does a good job. So flare is not a big problem with this lens, I would say.
Example images
This specific fisheye lens is the full frame type, meaning that the image fills the entire rectangular frame. The diagonal coverage is stated to be 180°.
A fisheye lens generates images that are not rectilinear, as we are used to, but rather hemispherical. This looks like an excessive amount of barrel distortion.
This distortion is very apparent when photographing rectangular shapes, like, for example, the Apple store in New York:
However, when photographing organic forms, the distortion might not be a huge problem. Here is the sled dog Balto, the only one to get a statue in Central Park while still being alive:
It is easy to see that the head is too large, and that the hind part of the dog is too small. This is due to the fisheye distortion. But on first glance, the shapes do not look very wrong. Only when the intention is an anatomically correct image, would the distortion be a problem.
Fisheye lenses can be defished, i.e., transformed to a rectilinear projection. In this example, I used the program Hugin to do the transformation. The original picture of the Tourneau store was taken with a 16:9 aspect ratio:
The diagonal field of view is 180°. In the 16:9 aspect ratio, the ratio of field of view becomes even more narrow, due to the curvature of the projection. The field of view is 136° horizontally, and 76° vertically. Here's how the defished image looks:
You'll note that there is some residual barrel distortion even after the defishing process. This is because the Lumix G 8mm f/3.5 fisheye lens gives somewhat more distortion than what is common for a fisheye lens. Here is a distortion comparison with the Samyang 7.5mm f/3.5 fisheye lens.
Example video
Here's an example video, filmed at 720p with the Panasonic Lumix GH1. It was filmed while holding the camera above my head at arms length, so it is a tad shaky. Doubleclick on the video to go to the YouTube view, which may work better than this embedded view.
Compared with the Lumix G 7-14mm f/4
It is natural to compare this fisheye lens with the Panasonic Lumix G 7-14mm f/4 ultra wide zoom lens. They are both extremely wide lenses, and their pricing are fairly similar.
When it comes to the lens construction, the 8mm fisheye lens is a much simpler design. It features 10 lens elements in 9 groups, while the 7-14mm zoom has 16 lens elements in 12 groups. In terms of exotic elements, it is also simpler: 1 ED glass element (4 in the 7-14mm), and no aspherical elements (2 in the 7-14mm).
There's no significant difference in the speed. The wide angle zoom has a maximum aperture of f/4, which is only slightly smaller than f/3.5. While the fisheye wins in this respect, the difference is hardly significant.
The fisheye lens has a close focusing distance of 0.1 meter, which is very, very close. The corresponding distance is 0.25 meter for the 7-14mm zoom, which is also close, but still not comparable. While you may not use this close focusing distance a lot with the fisheye, the front lens element is less than an inch from the subject at this distance, it can still be used for some interesting effects.
In terms of overall usefulness, the 7-14mm zoom wins, no question about it. In the longer end, it becomes a "normal" wide angle lens, useful for a lot of shooting situations. The fisheye lens, on the other hand, remains an exotic, specialized lens all the time.
The 8mm fisheye lens is still attractive due to it's very wide angle of view, and the small size (37% shorter and 45% lighter).
Conclusion
This is a very good and compact lens. But it's usefulness is a bit limited for most people, and it is expensive.
Due to its lower cost and good optics, the Samyang 7.5mm f/3.5 fisheye lens can be a good alternative to the Lumix G 8mm f/3.5 fisheye lens.
The Samyang lens also has a more common fisheye projection model, and is easier defished, in my experience. If you plan on doing that, then the Samyang may be a better choice.
- The short flange distance for the Micro Four Thirds system means that wide angle lenses can be made very compact, illustrating the strengths of the M4/3 concept.
- Videographers commonly use fisheye lenses for skateboard, BMX and other types of sports events.
- When panning with a rectilinear wide angle lens, the objects can appear as if they change size as they move across the frame. With a fisheye lens, this can look more natural. Hence, some videographers prefer fisheye for wide angle videos, as opposed to traditional wide angle lenses.
- Fisheye lenses can be used to make "cute" images and videos, e.g., novelty images of animals where the nose appears very large.
Anyway, the user is of course free to choose what to use this lens for, and does not need to be restricted by the items above.
I have made a comparison of the sharpness and other aspects of the Lumix 8mm fisheye lens compared with the Olympus Zuiko 9-18mm f/4-5.6.
In 2011, the Samyang 7.5mm f/3.5 fisheye lens was announced. It is a fisheye lens with fairly similar specifications as the Lumix G 8mm f/3.5. The Samyang is a manual focus lens, with a manually operated aperture ring. My study has shown that it has remarkably good optics, in terms of sharpness and CAs. It also has somewhat less distortion than the Lumix G 8mm lens.
Type of fisheye lens
Most fisheye lenses fall into two categories: Circular fisheye lenses, and full frame fisheye lenses. Circular fisheye lenses cover the field of view of 180° in all directions, and only expose a disc in the centre of the frame. Full frame fisheye lenses, on the other hand, expose the whole sensor area, but only cover 180° in the diagonal.
The Lumix G 8mm fisheye lens is a full frame fisheye lens. A circular fisheye lens on the Four Thirds format sensor would probably have a focal length of around 3-4mm.
Physical appearance
The lens comes with a built in, non removable, hood. The hood also protects the front lens element against objects touching it accidentally. Due to the hood, you can place the lens upside down on a table without the glass touching anything.
The front lens cap is unusual. Rather than the pinch centre caps that we are used to, this one is more like a lid which slides onto the outside of the hood. It is held in place by friction. The outside of the hood is around 61mm wide. You better take good care of the lens cap, since replacing it can cost around US$40.
Comparing the fisheye lens with the Lumix 20mm f/1.7 Pancake lens, reveals that it's size is small:
The Lumix 20mm is seen here with a "home made" low profile hood.
Quality wise, the lens gives a very good impression. There are no moving parts on the outside (beyond the focus ring), due to the internal focus mechanism.
The aperture can be set from f/3.5 to f/22. Changing the aperture gives a small "click" sound. It is not as silent as the Lumix G HD 14-140mm superzoom lens, but still, I hardly think anyone will find this problematic.
There is no geometric distortion correction in software when using this lens. As opposed to most Micro Four Thirds lenses, which utilize geometric correction in post processing, e.g., the Lumix G 20mm and Lumix G 14mm pancake lenses.
Autofocus
This lens has a very quick autofocus system. Except when photographing very close objects, you barely notice the focus at all: It appears to be in focus instantly when half pressing the shutter.
Here is a comparison of the focus speed for various lenses on a GH2. In this study, the 8mm fisheye lens has a very quick timing.
Moreover, the autofocus is virtually inaudible. It is barely noticeable in use.
I would recommend using multi point AF with this lens. The spot autofocus can be a bit awkward, with the very wide angle of view.
The closest focus distance possible is very short, specified to 0.1m. Keep in mind, though, that this is measured from the sensor, meaning that the minimum focus distance is very close to the front lens element. At this distance, it is ineviteable that the lens casts some shadow on the subject.
Here is an example use of the lens for macro purposes.
Manual focus is possible by using the focus ring. It is made of ribbed plastic, and for that reason it is not as easy to operate as a rubber ring would have been. On the other hand, the plastic ring is probably much more solid, and will not wear out any time soon. The ring feels fairly dampened and smooth, about the same as the Lumix 20mm focus ring.
Sharpness
My experience so far indicates that the sharpness is very good, even at f/3.5.
The typical way to evaluate the sharpness and artifacts of a wide angle lens, is to take a picture of foliage with the sky in the background. So here they are:
 |  |
f/3.5, 1/13000, ISO 200 | f/5.6, 1/500, ISO 200 |
To better evaluate the sharpness, let's look at some 100% crops from certain areas in the image (click for a larger image):
As we see from these crops, the image is very sharp from f/3.5, even in the corners. When stopping down the aperture to f/5.6, the corners sharpen up even more.
I have made a comparison of the sharpness and other aspects of the Lumix 8mm fisheye lens compared with the Olympus Zuiko 9-18mm f/4-5.6.
Here is another sharpness comparison with the Samyang 7.5mm f/3.5 fisheye lens.
My study of the chromatic aberrations (CA) artifacts reveals that the lens has around 2-3 pixels wide red/green fringing in the corners of the frame, caused by high contrast areas. This is corrected by post processing software in the camera, and by some RAW converters. There is still some residual purple fringing in the corners after this in camera image processing, but it's mostly not a problem.
Flare
The Lumix G 8mm fisheye lens covers a very wide field of view. For this reason, it can be difficult not to have a strong light source in the frame, e.g., the sun. Hence, it is important that the lens handles flare well. Otherwise, one strong light source could ruin your shot.
I have included an extreme example below. Here, the sun is in the centre of the frame, just behind the figures.
And here is an enlargement of the persons, who has the sun just behind them. This is a 100% crop, meaning that it has not been resized:
Here we see that the sun does indeed reduce the contrast. However, considering how difficult this scene is to render, given the very high contrast, I think the lens does a good job. So flare is not a big problem with this lens, I would say.
Example images
This specific fisheye lens is the full frame type, meaning that the image fills the entire rectangular frame. The diagonal coverage is stated to be 180°.
A fisheye lens generates images that are not rectilinear, as we are used to, but rather hemispherical. This looks like an excessive amount of barrel distortion.
This distortion is very apparent when photographing rectangular shapes, like, for example, the Apple store in New York:
However, when photographing organic forms, the distortion might not be a huge problem. Here is the sled dog Balto, the only one to get a statue in Central Park while still being alive:
It is easy to see that the head is too large, and that the hind part of the dog is too small. This is due to the fisheye distortion. But on first glance, the shapes do not look very wrong. Only when the intention is an anatomically correct image, would the distortion be a problem.
Fisheye lenses can be defished, i.e., transformed to a rectilinear projection. In this example, I used the program Hugin to do the transformation. The original picture of the Tourneau store was taken with a 16:9 aspect ratio:
The diagonal field of view is 180°. In the 16:9 aspect ratio, the ratio of field of view becomes even more narrow, due to the curvature of the projection. The field of view is 136° horizontally, and 76° vertically. Here's how the defished image looks:
You'll note that there is some residual barrel distortion even after the defishing process. This is because the Lumix G 8mm f/3.5 fisheye lens gives somewhat more distortion than what is common for a fisheye lens. Here is a distortion comparison with the Samyang 7.5mm f/3.5 fisheye lens.
Example video
Here's an example video, filmed at 720p with the Panasonic Lumix GH1. It was filmed while holding the camera above my head at arms length, so it is a tad shaky. Doubleclick on the video to go to the YouTube view, which may work better than this embedded view.
Compared with the Lumix G 7-14mm f/4
It is natural to compare this fisheye lens with the Panasonic Lumix G 7-14mm f/4 ultra wide zoom lens. They are both extremely wide lenses, and their pricing are fairly similar.
When it comes to the lens construction, the 8mm fisheye lens is a much simpler design. It features 10 lens elements in 9 groups, while the 7-14mm zoom has 16 lens elements in 12 groups. In terms of exotic elements, it is also simpler: 1 ED glass element (4 in the 7-14mm), and no aspherical elements (2 in the 7-14mm).
There's no significant difference in the speed. The wide angle zoom has a maximum aperture of f/4, which is only slightly smaller than f/3.5. While the fisheye wins in this respect, the difference is hardly significant.
The fisheye lens has a close focusing distance of 0.1 meter, which is very, very close. The corresponding distance is 0.25 meter for the 7-14mm zoom, which is also close, but still not comparable. While you may not use this close focusing distance a lot with the fisheye, the front lens element is less than an inch from the subject at this distance, it can still be used for some interesting effects.
In terms of overall usefulness, the 7-14mm zoom wins, no question about it. In the longer end, it becomes a "normal" wide angle lens, useful for a lot of shooting situations. The fisheye lens, on the other hand, remains an exotic, specialized lens all the time.
The 8mm fisheye lens is still attractive due to it's very wide angle of view, and the small size (37% shorter and 45% lighter).
Conclusion
This is a very good and compact lens. But it's usefulness is a bit limited for most people, and it is expensive.
Due to its lower cost and good optics, the Samyang 7.5mm f/3.5 fisheye lens can be a good alternative to the Lumix G 8mm f/3.5 fisheye lens.
The Samyang lens also has a more common fisheye projection model, and is easier defished, in my experience. If you plan on doing that, then the Samyang may be a better choice.
Lensbaby Tilt Transformer and Composer: First impressions
For Photokina 2010, Lensbaby introduced their newest product: The Tilt Transformer. It can be had for Micro Four Thirds cameras, and for Sony NEX E-mount. It can be bought stand alone, or with a Composer lens element.
Below are both products: The Composer (left) and the Tilt Transformer (right):
The Tilt Transformer (right) can be mounted to a Micro Four Thirds camera. This device acts as an adapter for Nikon F lenses, and also as a tilting platform.
The Composer (left) is a very simple lens. Turning the black ring around the lens pushes the lens elements back and forth, thus giving manual focus capability. To change the aperture, you need to disassemble the lens, and change the aperture plate. The lens comes with round plates with curcular holes, corresponding to apertures from f/1.8 to f/22.
One would perhaps think that the Composer can also be used as a lens on Nikon cameras, since the Tilt Transformer accepts Nikon lenses. However, this does not appear to be true. It is probably not a good idea to try to mount the Composer to a Nikon camera, since the lens element protrudes far into the camera, possibly interfering with the mirror.
The next picture shows the two devices mounted together:
In this configuration, it acts as a standalone lens for Micro Four Thirds cameras, with tilt capability built in. Loosening the ribbed metal ring allows you to rotate and tilt the adapter and Composer lens element. You can tighten the ring to fix the rotation and tilt in place.
Build quality
Unlike most native Micro Four Thirds lenses, the chassis of this lens is composed largely of metal. Still, it does not have a very good quality feeling: For example, the finish of extruded parts is somewhat rough. Also, what annoyed me, was that when mounted on a camera, the connection is a bit loose. Even the cheapest adapters fit the camera well, in my experience, but when mounting the Tilt Transformer on the camera, there is some play in the connection. It can be jerked a bit back and forth, unlike any other lenses I have tried on a Micro Four Thirds camera.
In use
When loosening the ribbed metal ring, you can adjust the amount of tilt. This adjustment is not dampened well. The tilting adapter moves quite jerkily. Again, I think this is a bit disappointing. Tightening the locking ring fixes the position of the adapter, and this functions well.
Manual focusing is pretty easy. The focus ring is very light to operate, and there is a lot of rotation, meaning that fine tuning is easy.
Changing the aperture is, of course, a bit of a hassle. You must unscrew the front section of the lens, remove the aperture disc with the supplied magnet tool, and then insert a new disc with the aperture of your choice, before putting back the front lens section.
Example image
This is the very first image I took using this adapter/lens combination. I used the f/4 aperture plate, and tilted the lens a bit to the side. Then I rotated the focus ring so that the middle part of the image was in focus, and pushed the shutter release. That's it. The picture was taken with a Panasonic Lumix GH1. (Click for a larger image.)
So is this image interesting? Well, it does have a "miniature" look to it, due to the selective focus. With some practice, the effect can be made much better.
Below are both products: The Composer (left) and the Tilt Transformer (right):
The Tilt Transformer (right) can be mounted to a Micro Four Thirds camera. This device acts as an adapter for Nikon F lenses, and also as a tilting platform.
The Composer (left) is a very simple lens. Turning the black ring around the lens pushes the lens elements back and forth, thus giving manual focus capability. To change the aperture, you need to disassemble the lens, and change the aperture plate. The lens comes with round plates with curcular holes, corresponding to apertures from f/1.8 to f/22.
One would perhaps think that the Composer can also be used as a lens on Nikon cameras, since the Tilt Transformer accepts Nikon lenses. However, this does not appear to be true. It is probably not a good idea to try to mount the Composer to a Nikon camera, since the lens element protrudes far into the camera, possibly interfering with the mirror.
The next picture shows the two devices mounted together:
In this configuration, it acts as a standalone lens for Micro Four Thirds cameras, with tilt capability built in. Loosening the ribbed metal ring allows you to rotate and tilt the adapter and Composer lens element. You can tighten the ring to fix the rotation and tilt in place.
Build quality
Unlike most native Micro Four Thirds lenses, the chassis of this lens is composed largely of metal. Still, it does not have a very good quality feeling: For example, the finish of extruded parts is somewhat rough. Also, what annoyed me, was that when mounted on a camera, the connection is a bit loose. Even the cheapest adapters fit the camera well, in my experience, but when mounting the Tilt Transformer on the camera, there is some play in the connection. It can be jerked a bit back and forth, unlike any other lenses I have tried on a Micro Four Thirds camera.
In use
When loosening the ribbed metal ring, you can adjust the amount of tilt. This adjustment is not dampened well. The tilting adapter moves quite jerkily. Again, I think this is a bit disappointing. Tightening the locking ring fixes the position of the adapter, and this functions well.
Manual focusing is pretty easy. The focus ring is very light to operate, and there is a lot of rotation, meaning that fine tuning is easy.
Changing the aperture is, of course, a bit of a hassle. You must unscrew the front section of the lens, remove the aperture disc with the supplied magnet tool, and then insert a new disc with the aperture of your choice, before putting back the front lens section.
Example image
This is the very first image I took using this adapter/lens combination. I used the f/4 aperture plate, and tilted the lens a bit to the side. Then I rotated the focus ring so that the middle part of the image was in focus, and pushed the shutter release. That's it. The picture was taken with a Panasonic Lumix GH1. (Click for a larger image.)
So is this image interesting? Well, it does have a "miniature" look to it, due to the selective focus. With some practice, the effect can be made much better.
Saturday, 6 November 2010
Index of lens related articles
Here is an index of lens related articles on this blog, sorted by lens:
Panasonic Lumix X 12-35mm f/2.8
Review
Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro
Review
A study of the bokeh at various apertures
Bokeh comparison with Lumix G HD 14-140mm and Lumix G 45-200mm, all at 45mm
Bokeh comparison with the Olympus Zuiko 50mm f/2 1:2 Macro
A study of the diffraction effects when using smaller apertures
A verification that the enlargement is actually 1:1
Example use of the touch screen AF with Panasonic GH2
A sharpness comparison with the Olympus Zuiko 50mm f/2 1:2 Macro at a long focus distance
A very simple sharpness comparison with the Olympus Zuiko 50mm f/2 1:2 Macro at a close focus distance
Autofocus speed
Olymus M.Zuiko Digital 45mm f/1.8
Review
Optical performance comparison with the Panasonic Leica 45mm f/2.8 macro
Panasonic Lumix G 20mm f/1.7 Pancake
Review
Autofocus speed comparison
Using a third party screw in 46mm metal hood, Leica Summicron type
Using a 46mm to 37mm step down ring as an alternative, low profile hood
An example video capture with the Panasonic Lumix GH1
Bokeh comparison with the Lumix G HD 14-140mm
Using the Lumix 20mm as a portrait lens
Distortion correction
Compared with the Lumix G 14mm f/2.5 pancake lens
A comparison with the Sigma 30mm f/1.4 lens on an APS-C camera. This is a lens that, in my opinion, does more or less the same job, and has around the same price point.
Panasonic Lumix G 14mm f/2.5 Pancake
Review
Compared with the Lumix G 20mm f/1.7 pancake lens
Comparison with the Lumix G 14-42mm and Lumix G HD 14-140mm zoom lenses at 14mm focal length
Autofocus speed comparison
Distortion correction
Measuring the field of view
Lumix G 100-300mm f/4-5.6
Review
Sharpness comparison with the Lumix G 45-200mm and the Lumix G HD 14-140mm
Lumix G 45-200mm f/4-5.6
Review
Bokeh comparison with Lumix G HD 14-140mm and Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro, all at 45mm
A bokeh comparison with the Nikkor 200mm f/4 AIS, not conclusive
Autofocus speed comparison
A look at the relation between the focus distance and field of view
An example video capture
Lumix G X PZ 45-175mm f/4-5.6
Review
Sharpness comparison with Lumix G 45-200mm
Lumix G HD 14-140mm f/4-5.8
Review
Autofocus speed comparison
Bokeh comparison with Lumix G 45-200mm and Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro, all at 45mm
Bokeh comparison with the Lumix 20mm f/1.7, both at 20mm
Example use of the touch screen AF using Panasonic GH2
Lumix G 8mm f/3.5 Fisheye
Review
Autofocus speed
Using the fisheye lens as a macro lens
Sigma 19mm f/2.8 EX DN
Autofocus speed comparison with the Lumix G 20mm f/1.7.
Sharpness comparison with the Lumix G 20mm f/1.7.
Sigma 30mm f/2.8 EX DN
Review
Samyang 7.5mm f/3.5 Fisheye
Review
Field of view comparison with the Lumix G 7-14mm f/4 wide angle zoom
Projection comparison with the Lumix G 8mm f/3.5 fisheye lens
Olympus Zuiko Digital 50mm f/2 1:2 Macro (Four Thirds lens)
Review
Manual focus with the Panasonic Lumix GH1
Bokeh comparison with the Panasonic Leica Lumix 45mm f/2.8 Macro
A simple sharpness comparison with the Panasonic Leica Lumix 45mm f/2.8 Macro
Using a cheap and simple macro soft box
Lumix G 7-14mm f/4 wide angle zoom lens
Short review
Field of view comparison with the Samyang 7.5mm f/3.5 fisheye lens
Panasonic Lumix X 12-35mm f/2.8
Review
Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro
Review
A study of the bokeh at various apertures
Bokeh comparison with Lumix G HD 14-140mm and Lumix G 45-200mm, all at 45mm
Bokeh comparison with the Olympus Zuiko 50mm f/2 1:2 Macro
A study of the diffraction effects when using smaller apertures
A verification that the enlargement is actually 1:1
Example use of the touch screen AF with Panasonic GH2
A sharpness comparison with the Olympus Zuiko 50mm f/2 1:2 Macro at a long focus distance
A very simple sharpness comparison with the Olympus Zuiko 50mm f/2 1:2 Macro at a close focus distance
Autofocus speed
Olymus M.Zuiko Digital 45mm f/1.8
Review
Optical performance comparison with the Panasonic Leica 45mm f/2.8 macro
Panasonic Lumix G 20mm f/1.7 Pancake
Review
Autofocus speed comparison
Using a third party screw in 46mm metal hood, Leica Summicron type
Using a 46mm to 37mm step down ring as an alternative, low profile hood
An example video capture with the Panasonic Lumix GH1
Bokeh comparison with the Lumix G HD 14-140mm
Using the Lumix 20mm as a portrait lens
Distortion correction
Compared with the Lumix G 14mm f/2.5 pancake lens
A comparison with the Sigma 30mm f/1.4 lens on an APS-C camera. This is a lens that, in my opinion, does more or less the same job, and has around the same price point.
Panasonic Lumix G 14mm f/2.5 Pancake
Review
Compared with the Lumix G 20mm f/1.7 pancake lens
Comparison with the Lumix G 14-42mm and Lumix G HD 14-140mm zoom lenses at 14mm focal length
Autofocus speed comparison
Distortion correction
Measuring the field of view
Lumix G 100-300mm f/4-5.6
Review
Sharpness comparison with the Lumix G 45-200mm and the Lumix G HD 14-140mm
Lumix G 45-200mm f/4-5.6
Review
Bokeh comparison with Lumix G HD 14-140mm and Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro, all at 45mm
A bokeh comparison with the Nikkor 200mm f/4 AIS, not conclusive
Autofocus speed comparison
A look at the relation between the focus distance and field of view
An example video capture
Lumix G X PZ 45-175mm f/4-5.6
Review
Sharpness comparison with Lumix G 45-200mm
Lumix G HD 14-140mm f/4-5.8
Review
Autofocus speed comparison
Bokeh comparison with Lumix G 45-200mm and Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro, all at 45mm
Bokeh comparison with the Lumix 20mm f/1.7, both at 20mm
Example use of the touch screen AF using Panasonic GH2
Lumix G 8mm f/3.5 Fisheye
Review
Autofocus speed
Using the fisheye lens as a macro lens
Sigma 19mm f/2.8 EX DN
Autofocus speed comparison with the Lumix G 20mm f/1.7.
Sharpness comparison with the Lumix G 20mm f/1.7.
Sigma 30mm f/2.8 EX DN
Review
Samyang 7.5mm f/3.5 Fisheye
Review
Field of view comparison with the Lumix G 7-14mm f/4 wide angle zoom
Projection comparison with the Lumix G 8mm f/3.5 fisheye lens
Olympus Zuiko Digital 50mm f/2 1:2 Macro (Four Thirds lens)
Review
Manual focus with the Panasonic Lumix GH1
Bokeh comparison with the Panasonic Leica Lumix 45mm f/2.8 Macro
A simple sharpness comparison with the Panasonic Leica Lumix 45mm f/2.8 Macro
Using a cheap and simple macro soft box
Lumix G 7-14mm f/4 wide angle zoom lens
Short review
Field of view comparison with the Samyang 7.5mm f/3.5 fisheye lens
Sunday, 24 October 2010
Focal length and focus distance
You'll notice that the focal length of most lenses is specified at infinity focus. It turns out that some lens designs imply a change of focal length, as the focus distance changes.
Here's a comparison of two quite different lenses. The Nikkor 200mm f/4 AIS is a traditional fixed focal tele lens. Compact, light, and reasonably fast, it is a classic lens. It is also rather simple from a mechanical point of view. If features "only" five lens elements.
The other lens is the Panasonic Lumix G 45-200mm f/4-5.6. Since it is a zoom lens, and it also has special lens groups for the OIS, it features a whopping 16 lens elements.
They are both shown here, the Nikkor 200mm lens with the Nikon-M43 adapter mounted. The 45-200mm lens is shown zoomed to maximum tele, to be comparable with the Nikon lens:
They are also quite different when it comes to focusing. The Nikkor has a traditional focus mechanism, which simply moves the entire lens assembly forward when going from infinity to close distance focus. In the picture below, it is shown focusing at infinity (left) and just below 2 meters (right).
The Panasonic Lumix G 45-200mm f/4-5.6, on the other hand, features internal focusing. This is very practical, since it means that the length of the lens stays the same regardless of the focus.
Also, the internal lenses moving around are much smaller, and faster to move about. This makes the focus faster, and requires less juice from the batteries. And the 45-200mm does focus very fast indeed!
The negative side of internal focusing, is that it can affect the focal length when changing focus. Let's compare the two lenses when focused far and near. The upper and lower images are taken at exactly the same place, but with the focus placed at the parked car (upper), and the foreground flower (lower).
What we see here, is that when focused far away, the field of view of the lenses are mostly the same. The Lumix has a slightly wider field of view, but there is hardly any significant difference. When focused at 2 meter distance, however, the field of view is significantly wider with the Lumix lens.
Mostly, this is not any problem at all. When recording video, however, it can be annoying if the field of view changes significantly during focus. This feature is usually referred to as "focus breathing", as the objects recorded will pulse in size as the focus moves back and forth.
With contrast detection autofocus (CDAF), this can in fact be a big problem during video recording, as the camera must jog the lens focus back and forth to verify that the focus is correct. You can see these focus movements in a video recorded using the Lumix 20mm f/1.7 pancake lens. The Lumix 20mm f/1.7 lens features a traditional moving lens assembly, and does not suffer from focus breathing. This is good, since the continuous autofocus operation is not very visible in the video, but on the other hand, the lens is probably not as solid and weather resistant with this construction.
I first noticed this change of focal length when examining the bokeh of the 45-200mm at 200mm, compared with the Nikkor 200mm lens.
Here's a comparison of two quite different lenses. The Nikkor 200mm f/4 AIS is a traditional fixed focal tele lens. Compact, light, and reasonably fast, it is a classic lens. It is also rather simple from a mechanical point of view. If features "only" five lens elements.
The other lens is the Panasonic Lumix G 45-200mm f/4-5.6. Since it is a zoom lens, and it also has special lens groups for the OIS, it features a whopping 16 lens elements.
They are both shown here, the Nikkor 200mm lens with the Nikon-M43 adapter mounted. The 45-200mm lens is shown zoomed to maximum tele, to be comparable with the Nikon lens:
They are also quite different when it comes to focusing. The Nikkor has a traditional focus mechanism, which simply moves the entire lens assembly forward when going from infinity to close distance focus. In the picture below, it is shown focusing at infinity (left) and just below 2 meters (right).
The Panasonic Lumix G 45-200mm f/4-5.6, on the other hand, features internal focusing. This is very practical, since it means that the length of the lens stays the same regardless of the focus.
Also, the internal lenses moving around are much smaller, and faster to move about. This makes the focus faster, and requires less juice from the batteries. And the 45-200mm does focus very fast indeed!
The negative side of internal focusing, is that it can affect the focal length when changing focus. Let's compare the two lenses when focused far and near. The upper and lower images are taken at exactly the same place, but with the focus placed at the parked car (upper), and the foreground flower (lower).
What we see here, is that when focused far away, the field of view of the lenses are mostly the same. The Lumix has a slightly wider field of view, but there is hardly any significant difference. When focused at 2 meter distance, however, the field of view is significantly wider with the Lumix lens.
Mostly, this is not any problem at all. When recording video, however, it can be annoying if the field of view changes significantly during focus. This feature is usually referred to as "focus breathing", as the objects recorded will pulse in size as the focus moves back and forth.
With contrast detection autofocus (CDAF), this can in fact be a big problem during video recording, as the camera must jog the lens focus back and forth to verify that the focus is correct. You can see these focus movements in a video recorded using the Lumix 20mm f/1.7 pancake lens. The Lumix 20mm f/1.7 lens features a traditional moving lens assembly, and does not suffer from focus breathing. This is good, since the continuous autofocus operation is not very visible in the video, but on the other hand, the lens is probably not as solid and weather resistant with this construction.
I first noticed this change of focal length when examining the bokeh of the 45-200mm at 200mm, compared with the Nikkor 200mm lens.
Lumix G 14-42, new kit zoom
For the introduction of the Panasonic Lumix G2 and G10 cameras, a new kit zoom was launched. Much to the dismay of Micro Four Thirds users, since on first sight it looks like a dumbed down version of the old kit zoom.
First of all, it has slightly worse technical specifications: The long end of the zoom is 42mm, while the old had 45mm. Next, the new kit lens has got a plastic mount, while the older has a metal mount. The new zoom also lost the OIS switch: Switching OIS on or off is now done through the menus.
In terms of ergonomy, the new lens also lost the rubber zoom ring. It now features a plastic zoom ring, which gives somewhat less friction when operating it with your fingers. Some users of the old lens experienced that the rubber zoom ring came loose. This will not be a problem with the new lens, since there is no rubber ring.
Now, the change of the long end focal length doesn't bother me. 42mm and 45mm is basically the same field of view, there is no significant difference here. Also, the plastic mount, if done properly with good quality materials, is probably solid enough. After all, this is a very light weight lens, and in normal use, it doesn't need as strong support as larger lenses.
What about other aspects? Some reports indicate that the sharpness of the new lens is not as good as the original Lumix G 14-45mm lens. I cannot comment this, since I haven't used both.
Here's an analysis of the sharpness and bokeh of the lens.
The GH1 kit lens, the Lumix G HD 14-140mm, is specified with an aperture range from f/4 to f/5.8. However, while zooming from wide to tele, it closes down very quickly. So it is fair to say that this is essentially an "around f/5.6" lens, with a bonus brightness in the short end.
What about the other kit lenses? This diagram shows the relationship between the focal length and the maximum aperture for the three kit lenses:
For the 14-42mm and 14-140mm kit lenses, these values were sampled by using the actual lens. For the 14-45mm lens, I took the values from various reviews off the Internet.
It looks like the new kit lens has slightly better speed at f=25mm: f/4.6, compared with f/4.9 for the old kit lens.
I also added the aperture data for the premium Olympus standard zoom, the Olympus M.Zuiko Digital ED 12-50mm F3.5-6.3 EZ power zoom. This lens is comparable with the other kit lenses in the short end, but the aperture closes down very quickly as the focal length increases. I think this is consistent with the Olympus M 4/3 design philosophy, which generally puts compactness ahead of maximum aperture.
The main purpose of the kit lens, is to be cheap and good enough for most beginners. I'm guessing that the size and number of the glass lens elements is an important contributor to the price.
The diameter of the front element of the 14-42mm lens is 13% smaller than that of the 14-45mm lens. And that means the area is 25% smaller:
It is quite remarkable that Panasonic has essentially retained the specifications, while shrinking the front element so much. Of course, reducing the front lens diameter is not necessarily good for the image quality. It could lead to more vignetting at max aperture, for example.
All in all, I think this will be a pretty successful lens. Some early reports indicate slightly worse sharpness, however, for the target audience that may not be a problem. The cheaper construction means that Panasonic can sell them in kits at a lower price point, which they will need now that the competition has gotten their systems launched.
The autofocus speed of the newer 14-42mm lens is very good.
First of all, it has slightly worse technical specifications: The long end of the zoom is 42mm, while the old had 45mm. Next, the new kit lens has got a plastic mount, while the older has a metal mount. The new zoom also lost the OIS switch: Switching OIS on or off is now done through the menus.
In terms of ergonomy, the new lens also lost the rubber zoom ring. It now features a plastic zoom ring, which gives somewhat less friction when operating it with your fingers. Some users of the old lens experienced that the rubber zoom ring came loose. This will not be a problem with the new lens, since there is no rubber ring.
Now, the change of the long end focal length doesn't bother me. 42mm and 45mm is basically the same field of view, there is no significant difference here. Also, the plastic mount, if done properly with good quality materials, is probably solid enough. After all, this is a very light weight lens, and in normal use, it doesn't need as strong support as larger lenses.
What about other aspects? Some reports indicate that the sharpness of the new lens is not as good as the original Lumix G 14-45mm lens. I cannot comment this, since I haven't used both.
Here's an analysis of the sharpness and bokeh of the lens.
The GH1 kit lens, the Lumix G HD 14-140mm, is specified with an aperture range from f/4 to f/5.8. However, while zooming from wide to tele, it closes down very quickly. So it is fair to say that this is essentially an "around f/5.6" lens, with a bonus brightness in the short end.
What about the other kit lenses? This diagram shows the relationship between the focal length and the maximum aperture for the three kit lenses:
For the 14-42mm and 14-140mm kit lenses, these values were sampled by using the actual lens. For the 14-45mm lens, I took the values from various reviews off the Internet.
It looks like the new kit lens has slightly better speed at f=25mm: f/4.6, compared with f/4.9 for the old kit lens.
I also added the aperture data for the premium Olympus standard zoom, the Olympus M.Zuiko Digital ED 12-50mm F3.5-6.3 EZ power zoom. This lens is comparable with the other kit lenses in the short end, but the aperture closes down very quickly as the focal length increases. I think this is consistent with the Olympus M 4/3 design philosophy, which generally puts compactness ahead of maximum aperture.
The main purpose of the kit lens, is to be cheap and good enough for most beginners. I'm guessing that the size and number of the glass lens elements is an important contributor to the price.
The diameter of the front element of the 14-42mm lens is 13% smaller than that of the 14-45mm lens. And that means the area is 25% smaller:
It is quite remarkable that Panasonic has essentially retained the specifications, while shrinking the front element so much. Of course, reducing the front lens diameter is not necessarily good for the image quality. It could lead to more vignetting at max aperture, for example.
All in all, I think this will be a pretty successful lens. Some early reports indicate slightly worse sharpness, however, for the target audience that may not be a problem. The cheaper construction means that Panasonic can sell them in kits at a lower price point, which they will need now that the competition has gotten their systems launched.
The autofocus speed of the newer 14-42mm lens is very good.
Sunday, 17 October 2010
Lumix 20mm compared with Sigma 30mm
A lot of people have complained that the Panasonic Lumix 20mm f/1.7 pancake lens is overpriced. To have a look at this statement, let's compare it with a lens in the same price range, the Sigma 30mm f/1.4.
The lenses have a lot in common. They share the same price tag in my market, and they do essentially the same job. The Lumix 20mm lens has a slightly wider field of view, and the Sigma 30mm has half a stop larger aperture. But these differences are not very significant. When I compare their fields of view, I refer to the Sigma 30mm being used on an APS-C camera, for which is was designed.
Here they are both:
The Sigma 30mm lens is shown with the supplied lens hood, which is very nicely designed. Sadly, the Lumix 20mm does not come with a hood, but I have put a step down ring on it, which acts as a compact hood.
As is apparent from the image, these lenses are very different in size. The Sigma (left) is 77x59mm, 430g. To the right, the Lumix is 25.5x63mm, 100g. Adding the supplied hood to the Sigma lens will make the difference even larger, of course.
When mounting the lenses to cameras, they look like this:
To the left is the Panasonic Lumix GH1 with the Lumix 20mm lens, and to the right is the Pentax K10D with the Sigma 30mm lens.
Image quality
What about the image quality? I tried to take the same picture with both setups, to see how they compare.
GH1 + Lumix 20mm @ f/1.7, 1/60 second, ISO 100 (click for larger image)
K10D + Sigma 30mm @ f/1.7, 1/45 second, ISO 100 (click for larger image)
Note that I used the same aperture on both lenses. The Sigma lens was stopped down from f/1.4 to f/1.7 to be comparable with the Lumix 20mm, which was used at the maximum aperture.
What we see straight away, is that the Lumix provides a wider field of view. I also think that the Pentax colours are more pleasing straight from the camera. Of course, using the RAW files you are free to adjust the colours of either images as you want.
To make the images easier to compare, I also added 100% crops from two sections of the images (click for larger image):
Here it is quite apparent that the Lumix lens is the sharpest. Also, there are less purple fringing artifacts in the Lumix image.
Now, we know that Chromatic Apperation (CA) artifacts are corrected for in software in the Panasonic Lumix G-series cameras. So the Lumix lens has an advantage here, in that these artifacts are automatically removed. Still, as a user of the systems, I care about the end result, not how it was achieved. And the end result is most certainly a lot better using the Lumix lens.
The Pentax setup uses phase detection autofocus (PDAF). With a large aperture lens like the Sigma 30mm f/1.4, this means that you can worry about the precision of the autofocus. Some camera body/lens combinations suffer from front-focus or back-focus. The setup might need expensive calibration to avoid these problems and achieve the best focus.
With the GH1 and Lumix 20mm lens, though, you get contrast detection autofocus (CDAF). With this system, you are ensured the best focus every time, as long as you set the focus region to suit your needs.
Size
The Lumix lens is a lot smaller and lighter. For me personally, that is a huge advantage. It could be a disadvantage for some users, though. Some customers might not take you seriously if you show up at a photography job with a small lens like this. When they pay for a photographer's services, some expect to get a person with a big camera and lens. For most users, though, this is not an issue.
Conclusion
From my point of view, these lenses, which do more or less the same job and are priced similarly, do not have an equal value. I much prefer the Lumix 20mm lens, which gives me better images, and is easier to lug around. I like the hood supplied with the Sigma 30mm lens. And having the option of using half a stop larger aperture is nice. However, you're not very likely to use the Sigma 30mm lens at f/1.4, since it is not very sharp wide open.
One could argue that my example image is not the most relevant for this type of lenses. These lenses are made for low light images of people, in which the corner sharpness doesn't matter too much. Also, while I haven't studied it carefully, I have a feeling that the bokeh from the Sigma 30mm lens is better. The Lumix 20mm bokeh is certainly very adequate, though.
I have also tested the autofocus of these two camera/lens combinations. The Pentax/Sigma combination is pretty fast in terms of autofocus, but not as fast as the Lumix. Also, the Pentax/Sigma makes much more noise when focusing.
The lenses have a lot in common. They share the same price tag in my market, and they do essentially the same job. The Lumix 20mm lens has a slightly wider field of view, and the Sigma 30mm has half a stop larger aperture. But these differences are not very significant. When I compare their fields of view, I refer to the Sigma 30mm being used on an APS-C camera, for which is was designed.
Here they are both:
The Sigma 30mm lens is shown with the supplied lens hood, which is very nicely designed. Sadly, the Lumix 20mm does not come with a hood, but I have put a step down ring on it, which acts as a compact hood.
As is apparent from the image, these lenses are very different in size. The Sigma (left) is 77x59mm, 430g. To the right, the Lumix is 25.5x63mm, 100g. Adding the supplied hood to the Sigma lens will make the difference even larger, of course.
When mounting the lenses to cameras, they look like this:
To the left is the Panasonic Lumix GH1 with the Lumix 20mm lens, and to the right is the Pentax K10D with the Sigma 30mm lens.
Image quality
What about the image quality? I tried to take the same picture with both setups, to see how they compare.
GH1 + Lumix 20mm @ f/1.7, 1/60 second, ISO 100 (click for larger image)
K10D + Sigma 30mm @ f/1.7, 1/45 second, ISO 100 (click for larger image)
Note that I used the same aperture on both lenses. The Sigma lens was stopped down from f/1.4 to f/1.7 to be comparable with the Lumix 20mm, which was used at the maximum aperture.
What we see straight away, is that the Lumix provides a wider field of view. I also think that the Pentax colours are more pleasing straight from the camera. Of course, using the RAW files you are free to adjust the colours of either images as you want.
To make the images easier to compare, I also added 100% crops from two sections of the images (click for larger image):
Here it is quite apparent that the Lumix lens is the sharpest. Also, there are less purple fringing artifacts in the Lumix image.
Now, we know that Chromatic Apperation (CA) artifacts are corrected for in software in the Panasonic Lumix G-series cameras. So the Lumix lens has an advantage here, in that these artifacts are automatically removed. Still, as a user of the systems, I care about the end result, not how it was achieved. And the end result is most certainly a lot better using the Lumix lens.
The Pentax setup uses phase detection autofocus (PDAF). With a large aperture lens like the Sigma 30mm f/1.4, this means that you can worry about the precision of the autofocus. Some camera body/lens combinations suffer from front-focus or back-focus. The setup might need expensive calibration to avoid these problems and achieve the best focus.
With the GH1 and Lumix 20mm lens, though, you get contrast detection autofocus (CDAF). With this system, you are ensured the best focus every time, as long as you set the focus region to suit your needs.
Size
The Lumix lens is a lot smaller and lighter. For me personally, that is a huge advantage. It could be a disadvantage for some users, though. Some customers might not take you seriously if you show up at a photography job with a small lens like this. When they pay for a photographer's services, some expect to get a person with a big camera and lens. For most users, though, this is not an issue.
Conclusion
From my point of view, these lenses, which do more or less the same job and are priced similarly, do not have an equal value. I much prefer the Lumix 20mm lens, which gives me better images, and is easier to lug around. I like the hood supplied with the Sigma 30mm lens. And having the option of using half a stop larger aperture is nice. However, you're not very likely to use the Sigma 30mm lens at f/1.4, since it is not very sharp wide open.
One could argue that my example image is not the most relevant for this type of lenses. These lenses are made for low light images of people, in which the corner sharpness doesn't matter too much. Also, while I haven't studied it carefully, I have a feeling that the bokeh from the Sigma 30mm lens is better. The Lumix 20mm bokeh is certainly very adequate, though.
I have also tested the autofocus of these two camera/lens combinations. The Pentax/Sigma combination is pretty fast in terms of autofocus, but not as fast as the Lumix. Also, the Pentax/Sigma makes much more noise when focusing.
Wednesday, 13 October 2010
Firmware v1.3 for Lumix 14-140 and AF speed
In the beginning of October 2010, a new firmware version 1.3 became available for the Panasonic Lumix 14-140mm f/4-5.8 superzoom lens. The new version is said to give faster AF speed, as well as faster startup time.
I have previously tested the AF speed of the Lumix 14-140mm. My conclusion was that the AF speed was very fast, albeit with some hunting in the longer end of the zoom, at close to the minimum focus distance. So I wanted to see if the new version improved the focus speed.
Again I used the same setup, with a LEGO figure as object to be photographed. The LEGO figure was placed at a distance of 0.5 meters, which is the minimum focus distance for the lens. After turning on the camera, I pressed the shutter release button, and measured the time until focus was achieved. The lightning was dull, about 6 EV.
I used the Panasonic Lumix GH1. Here's the experiment using firmware version 1.2:
And using the firmware version 1.3:
The time until focus was 0.76 seconds with firmware version 1.2, and 0.68 seconds with the latest firmware version. This is hardly any significant difference, but there is still some improvement.
I was not able to reproduce the focus hunting at 140mm that I experienced in my first comparison. The first test was done using firmware 1.1, so I guess this was fixed already in the version 1.2.
I have previously tested the AF speed of the Lumix 14-140mm. My conclusion was that the AF speed was very fast, albeit with some hunting in the longer end of the zoom, at close to the minimum focus distance. So I wanted to see if the new version improved the focus speed.
Again I used the same setup, with a LEGO figure as object to be photographed. The LEGO figure was placed at a distance of 0.5 meters, which is the minimum focus distance for the lens. After turning on the camera, I pressed the shutter release button, and measured the time until focus was achieved. The lightning was dull, about 6 EV.
I used the Panasonic Lumix GH1. Here's the experiment using firmware version 1.2:
And using the firmware version 1.3:
The time until focus was 0.76 seconds with firmware version 1.2, and 0.68 seconds with the latest firmware version. This is hardly any significant difference, but there is still some improvement.
I was not able to reproduce the focus hunting at 140mm that I experienced in my first comparison. The first test was done using firmware 1.1, so I guess this was fixed already in the version 1.2.
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