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

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.

Bokeh comparison @ 20mm

I have two lenses that can do 20mm, so I thought it would be interesting to compare their bokeh. Both the Panasonic Lumix 20mm f/1.7, and the Panasonic Lumix 14-140mm f/4-5.8 zoom comprise the 20mm focal length. Apart from this, they are of course very different. At f=20mm, the superzoom has a maximum aperture of f/4.4, which is quite a bit smaller than the f/1.7 that the fixed 20mm prime can do.

To compare the lenses, I have taken the same picture with various apertures. The centre region is in focus, and the focus distance is around 60cm, just above the minimum focus distance for the 14-140mm superzoom lens.

First the picture with the Lumix 20mm f/1.7 at maximum aperture. The picture is rescaled and sharpened a bit.

Second, the same image taken with the Lumix 14-140mm at 20mm f/4.4:

Click for larger images.

The make the comparison more sensible, I have looked at 100% crops from the image at various apertures with both lenses (click for larger image):

And here are 100% crops from another region of the image. It was a bit more windy in the second series, so the leaves were not always in the same spot.

Conclusion

It is not surprising that the bokeh for the 20mm prime lens is the best. For out of focus highlights, the bokeh is pretty even, but has hard edges. On the other hand, it is not entirely round, especially when stopping down. All in all, the bokeh is pleasant, and has no significant ringing. The superzoom bokeh is a bit "dirty".

You'll also note some differences in sharpness. Note, however, that a higher ISO value was used for the f/8 and f/11 images for the 20mm prime lens. So some lack of sharpness could be due to using a higher ISO. It can still be noted that the superzoom lens appears very sharp.

The 14-140mm also has more flare, which is due to it's more complicated construction. The 14-140mm lens has 17 lens elements in 13 groups, while the 20mm pancake only has 7 elements in 5 groups. Generally speaking, the less number of lens elements, the less problems with flare you're likely to see. Of course, many other factors also affect flare.

Using the Lumix 20mm as portrait lens

A portrait lens has two main properties. First, the focal length is fairly long, so that you can take a picture of a face at sufficient distance to avoid distortion. Second, the aperture is large, so that you can focus on a face and have the background out of focus.

Typical high end portrait lenses for film based cameras are 85mm f/1.4. The focal length corresponds to around 42-45mm for Micro Four Thirds. Many zoom lenses available for Micro Four Thirds will give you this focal length option. However, the largest aperture of these zoom lenses is generally much smaller than f/1.4.

One prime lens which comes close is the Lumix Leica 45mm f/2.8 macro. However, while this lens has a larger aperture than the zoom lenses, it is still far from f/1.4, and I am sure some will find it limiting for portrait usage.

Another lens comes close in the aperture department. It is the Panasonic Lumix 20mm f/1.7 pancake. However, this lens is quite a bit wider than most portrait lenses. So can you use it for portraits?



Let's take a look. When talking about portraits, let's say that we mean a picture in which the face fills the majority of the frame. When using the Lumix 20mm pancake lens, this is what we get, when going close enough to fill the face into the frame:



As you can see, the face is distorted. The nose and chin looks too large. This is due to getting very close to the face. The distortion is not a property of the wide lens. The distortion is related to the distance to the face. The closer the distance, the more distortion. With a longer focal length, you can stand at a longer distance when photographing, to avoid distortion.

So let's try a longer focal length. Here is the same face filled into the frame using the Lumix 45-200mm f/4-5.6 at 45mm:



The effect is very clear: 45mm is sufficient to get a proper perspective. The nose and chin now looks natural, and not artificially large, like in the picture taken at 20mm.

This picture was taken at 1m (3.3 feet) distance, which is the closest you can get with the 45-200mm lens. This is probably no coincidence. I'm guessing Panasonic designed the lens so that it could be used to take a headshot at the shortest focal length.

It is also interesting to see that the out of focus discs (bokeh) are about similar sizes in the two images. This means that f/4 at 45mm gives about the same background blur as f/1.7 at 20mm, when filling a face into the entire frame. Of course, the 20mm image was taken at a closer focus distance.

In a previous paragraph, I said that the distortion is related to the distance to the subject. So the solution is very simple: When using the Lumix 20mm pancake lens, take a step backwards. With the same distance as in the 45mm image above, the perspective should also be the same. Here is the outcome when using the 20mm lens at 1m (3.3 feet) distance:



In this example, there is no apparent distortion. However, the downside is of course that the face only fills a part of the frame. Also, the background is less blurred, since the focus length was larger.

The Lumix 20mm lens is very sharp. Especially in the centre region. So what you can do, is to crop the centre out of the image. Here is what I get using that method:



Of course, you might want to include a bit of background, and not crop as tightly as I have done here.

Conclusion

So can you use the Lumix 20mm lens for portraits? Yes, but don't stick the camera in the face of the subject. At a distance of about 0.7m (2 feet) or more, the face distortion should not be noticeable. If you need to, you can crop off a bit of the borders, to get a closer portrait.

Of course, you could take a so called "environmental portrait", in which you don't just shoot the face, but include some more of the person, and some elements around him or her. In that case, it makes good sense to use the 20mm lens. In fact, I'd say the Panasonic Lumix 20mm f/1.7 pancake is a perfect lens for environmental portraits.

Here is an example environmental portrait taken with the GH2 and the 20mm f/1.7 lens.  The image parameters are: f/2, 1/60 second, ISO 1600.

You could even use the Lumix 14mm f/2.5 wide angle prime lens for environmental portraits. As long as you keep a distance to the face of around 2 feet or more, you should not get any excessive distortion. On the other hand, if you photograph a sitting person head on, his knees will look abnormally large this way, due to the perspective.

Lumix 20mm distortion correction

One of the key features that separates quality optics from the cheaper variants, especially for wide angle lenses, is the the handling of distortion. In this respect, the Panasonic Lumix 20mm f/1.7 pancake lens is special, since in fact it features quite a bit of barrel distortion. However, this distortion is corrected by software inside the camera, so the user will never notice the fact in the first place.

However, the RAW files can be opened with third party software, to reveal the true image as captured by the sensor. In this case, I used UFRaw to convert the image to JPEG. Below is the original JPEG out of camera (left) and the RAW image with distortion uncorrected (right). The images were rescaled and sharpened. Click for larger images.

Out of camera JPEG	Uncorrected, from the RAW file

For these images, I used the 3:2 aspect ratio feature of the Lumix GH1 camera.

As you can see, there is some distortion in the right image. To correct it in The Gimp image processing software, around -13.5 Lens Distortion adjustment is needed.

Due to the distortion correction, all of the sensor surface is not used in the final image. Hence, the image area from the border is lost, as the image is adjusted and rescaled back to 12 megapixels.

In the image below, the area outside the white box corresponds roughly to the pixels lost during the distortion correction:



This means that when using the Lumix 20mm lens, about 7% of the sensor area is lost. The 12 megapixel sensor becomes 11 megapixels using the automatic distortion correction. The end user may never notice, however, as the output image is converted back to 12 megapixels anyway.

The upside of this is that when photographing non-straight shapes, you can probably get away with using the uncorrected image. This means that you gain some details in the borders, and a wider effective angle. For example, if you are photographing nature, flowers, people, animals, etc.

Most Micro Four Thirds lenses employ software distortion correction. Kit lenses like the Panasonic Lumix G 45-200mm f/4-5.6 and the Panasonic Lumix G HD 14-140mm f/4-5.8 do. One notable exception is the Panasonic Leica Lumix DG Macro-Elmarit 45mm f/2.8 1:1 Macro, which has all the distortion correction done optically.

Rolling shutter

The "rolling shutter" concept is related to the shutter not reading out the exposure values at once, but rather scanning across the sensor vertically or horizontally. This implementation could be mechanical, as with the shutter curtain on the Micro Four Thirds cameras, or electronical, as when the sensor output is read during a video recording.

This is not strictly related only to digital cameras. Older film based cameras often feature a focal plane curtain shutter, which "rolls" across the film plane and exposes the film horizontally or vertically. A very famous example of this is the racing car picture taken in 1913 by Jacques Henri Lartigue using a 4x5 Speed Graphic camera.


The shutter moves relatively slowly on this camera, when compared with modern SLRs, which gives the distortion of the racing car. The distortion is especially visible in the wheels, which appear to be leaning forward. This effect was later copied by cartoonists when they wanted to give the impression of speed.

Example video capture, GH1+Lumix 20mm

Here is an example video recorded without using a tripod, using the Panasonic Lumix GH1, and the Lumix 20mm f/1.7 pancake lens.



And a larger version of the same video:



As you can see in the video, the focus is hunting a bit back and forth. This could be due to selecting spot autofocus and the smallest focus area. Perhaps it would have been more calm using multi area focus.

Also, in this case I am using the camera firmware v1.2. The new firmware v1.3 available on May 10th, 2010 is said to improve autofocus performance during video recording, and may have solved this focus hunt problem.

When using video mode on the GH1, the camera will focus continuously, even if the focus selector is set in AFS. According to my knowledge, there is no mode that allows for autofocus when starting the recording, but keeps the focus constant when filming. I think this is a drawback with the camera. It is of course possible to select AFS, pre-focus, and then set MF before starting the video recording. But this is a somewhat awkward procedure.

The recording was done with the AVCHD format, at 720p and 50fps. My version of the camera is PAL, hence I am not able to record in 60fps. I used HandBrake to convert the stream to H.264, which is better suited for uploading.

The image is also a bit jerky, but I can only blame myself for not keeping the camera stable.

The video was recorded in Gamla Stan, Stockholm, Sweden. The musicians are singing "Dina ögon är som knivar", a Vladimir Vysotskij song translated to Swedish. The band is called Carl Oscar Nygrens kalas och nöjesorkester.

"Home made" hood for the Lumix 20mm f/1.7 pancake

The Panasonic Lumix 20mm f/1.7 pancake is a brilliant lens, but it does not come with a lens hood. Flare is not a big issue with this lens, but a lens hood is still good for protecting the front element. Some people use UV protection filters for the same effect, however, adding another glass layer will reduce the image quality to some degree.

One option is to get a cheap third party hood designed for the Leica Summilux lens, to screw into the front 46mm filter thread. However, this hood adds some bulk to the lens, making it less compact. The compactness is one of the desirable features of the Lumix 20mm pancake in the first place.

In an attempt to find a low profile hood that looks more like the hood for the Pentax 40mm f/2.8 pancake lens, I bought a cheap 46mm to 37mm step down ring. The ring is essentially a short cylinder with 46mm threads on the outside, and 37mm threads on the inside.

The ring is made out of light metal, and is extruded on the rear side to save some weight:


Step up and step down rings should be used with care with the Lumix 20mm pancake. When powering down, the lens retracts the front assembly slightly into the chassis, which will jam and possibly damage the focus mechanism if you attach a ring which is too wide. The following picture shows that this step down ring is not too wide, and can be safely used with the Lumix 20mm pancake lens:


Looking at hoods, you will note that they are usually ribbed and matte on the inside. This is to avoid having light reflected into the lens. Since the inside of the step down ring is threaded, it already has the right shape. However, the metal is still a bit shiny. To make it more matte, I applied some matte black enamel paint on the inside threads. Wanting to retain the stealthy look of the lens, I also painted the front and the side of the ring:


Here is the lens with the "home made" hood attached. This hood does not cause any additional vignetting.


You will probably want to have a front lens cap as well, and you can get a 37mm cap which fits into the front threads of the step down ring. Both the step down ring and the front lens cap can be found on various auction sites.

Portrait lens

Traditionally, a portrait lens is one that has around 85-105mm focal length (35mm equvivalent), and a fast aperture to allow shallow depth of field to blur the background. The closest we have at the moment in the Micro Four Thirds lens lineup is the Olympus M.Zuiko Digital 45mm f/1.8 prime lens.

The fast aperture is easy to understand. At a small, slow aperture, the background will be less blurred, and will distract the viewer from the main focus of the image: The face. So you will want a fast, large aperture to blur the background and avoid distracting elements in the background.

But how about the focal length? To study this, I have photographed the same face with various focal lengths from 9 to 70mm with the Panasonic Lumix GH1 and the Lumix HD 14-140mm lens. I also used the Olympus Four Thirds 9-18mm wide angle zoom lens for the first picture. This corresponds to 18mm-140mm on traditional film based 35mm cameras. The distance from the camera to the face was shortest with the shortest focal length. As I zoomed in, I needed to step backwards.

Here is the series of photos:

9mm

14mm

18mm

25mm

35mm

50mm

70mm

As you can see, in the first pictures, the perspective is distorted. The nose appears much too large. This is not due to any flaw in the lens, or due to the camera, but due to the fact that I needed to get very close to make the face fill the entire frame at 9mm focal length.

So close, in fact, that the lens was not able to focus close enough. To get the face reasonably in focus, I focused as close as possible, and used a small aperture to make the depth of field wide. The bicycle in the background is almost in focus in the first images, due to the small aperture.

The distorted perspective is due to being close to the subject, to fill the face into the entire frame. You would get the same distorted image if you looked at the face with your own eyes, given the same distance. But you don't normally get so close to someone's face.

The first frame is obviously distorted. The last one looks normal. I would say that the one taken with 35mm focal length also looks slightly distorted. So to achieve enough distance to the subject to avoid a distorted perspective, you need approximately 50mm focal length on Micro Four Thirds.

You could use a smaller focal length as well. If you still keep some more distance to the subject, you could get the face to fill just some part of the image, and be distortion free. But such a picture would not be a portrait.

This is exactly the reason why traditional portrait lenses are around 85-105mm, corresponding to about 42-53mm of Micro Four Thirds.

Panasonic Leica 45mm f/2.8 1:1 macro

Based on this, you will understand that the choice of focal length for the Panasonic Leica DG Macro-Elmarit 45mm f/2.8 1:1 Macro Mega O.I.S. was no coincidence. 45mm corresponds to a portrait lens for Micro Four Thirds, and gives you enough distance to the subject for taking distortion free portraits. However, the aperture size, at f/2.8, is not really large enough to isolate the background from the face. f/2 or larger would have been desirable.


Olympus 45mm f/1.8

In the summer 2011, Olympus launched a true portrait prime lens for the Micro Four Thirds system, the Olympus M.Zuiko Digital 45mm f/1.8. While I'm sure some will still be disappointed with the maximum apeture, it could have been even larger at f/1.4, for example, I think this is the best portrait lens for the format at the moment.


Panasonic 20mm f/1.7

The Panasonic Lumix 20mm f/1.7 is a popular lens for taking available light pictures of people, but it is not a portrait lens. You cannot fill the subject's face in the entire frame and avoid distortion with this lens. With that said, the lens is very sharp, and you should be able to get away with stepping back a bit, and cropping the picture later. This is not an optimal solution, but it should work well in many cases.

The Panasonic Lumix 20mm f/1.7 lens is also good for taking environmental portraits.


Olympus 50mm f/2 1:2 macro

On the other hand, the Four Thirds lens Olympus 50mm f/2 macro can be considered a portrait lens. The focal length is in the correct range, and the aperture is large enough to blur the background sufficiently.


All kit lenses include the typical portrait focal length area. Both the Olympus 14-42mm and the Panasonic 14-45mm extend to around 85-90mm in 35mm film equivalent. However, at the maximum tele, the aperture is not very impressive at f/5.6. With this aperture, you need to check the background, and try to make sure it does not distract too much from the main subject, the person.

Panasonic 45-200mm f/4-5.6

The Panasonic Lumix 45-200mm f/4-5.6 Mega O.I.S. does cover the typical portrait field of view. However, with a maximum aperture of f/4 at 45mm, it can not really be considered a genuine portrait zoom. With f/4, you need to watch the background to make sure it does not distract too much. If the background is even, though, I see no reason why you should not use it for portraits.

Other tele zooms can be used in the same way, e.g., the Lumix X 45-175mm f/4-5.6, Lumix G 45-150mm f/4-5.6 and the Olympus 40-150mm f/4-5.6. Normally, one would want to pair tele zoom lenses with cameras of the same brand, i.e., use a Panasonic lens on a Panasonic camera. The reason is that Panasonic cameras don't have built in in-camera image stabilization, like the Olympus cameras do.


Panasonic Leica 25mm f/1.4

The Panasonic Leica DG Summilux 25mm f/1.4 Asph lens corresponds to a "normal" lens on a traditional film camera. While it is longer than the 20mm pancake lens, it is still not a portrait lens. If you go close enough to fill the face of the subject into the entire frame, then you are too close to get a distortion free image. On the other hand, with the slightly longer focal length, it is certainly better suited for low light photos of a person's face and shoulders.


On 35mm film based cameras, a portrait zoom is typically 70-200mm f/2.8. This lens allows portraits at various distances, with a minimum of distortion, and reasonably blurred background. In the Four Thirds system for DSLR cameras, the Olympus 35-100mm f/2 is a typical portrait zoom. For the Micro Four Thirds system, there is the Lumix X 35-100mm f/2.8, which can be called a portrait zoom.



For APS-C DSLR cameras, portrait zooms typically have 50-135mm f/2.8 specifications. Pentax, Tokina and Sigma have lenses in that category.