Tuesday, 16 December 2014

Bokeh part 3

In part 1, I discussed what bokeh is (the nature of out of focus rendering). I also illustrated that the larger the aperture, the more selective focus. In part 2, I compared the bokeh between some different lenses.

Here, I am going to illustrate how the sensor size affects the degree of selective focus. Some would say "the amount of bokeh", but that is the wrong use of the term. I'll stick to the correct nomenclature in this article, to avoid angering people.

First off, here is a comparison of common sensor sizes:


The full frame sensor size is derived from the common 135 film format, commonly used in SLR and compact cameras. At this time, there is only one mirrorless camera system which uses a full frame sensor, the Sony A7 series. You'll also find full frame sensors in Nikon D810 and Canon 5D III DSLR cameras, to name a couple.

APS-C sensor size sensors are found in a vast number of DSLR and mirrorless cameras. This is pretty much the norm size for consumer system cameras. The crop factor is found by calculating the ratio of the full frame diameter (43.3mm) to the APS-C sensor diameter (28.3mm), which is 1.5.

The Four Thirds sensor size was introduced by Olympus with the E-1 DSLR camera in 2003. It has a crop factor of 2, and was later reused for Micro Four Thirds in 2008.

In 2011, Nikon launched the CX format, which uses a so-called 1 inch sensor. The sensor size is also used in the Sony RX100 camera line as well, and is becoming the norm size for premium compact cameras. The crop factor is 2.7.

Many smaller sizes of sensors are used in compact cameras, and 1/3.2'' is just one example. It is used in the Iphone. The crop factor is 7.6.

Here are some example images taken with a normal lens, using sensor crop factors from 1.5 to 7.6, and using apertures f/1.4, f/1.8 and f/2.5. The focus was set on the tree in the left foreground.

Crop factor
APS-C, 1.5x
Four Thirds, 2.0x
1 inch, 2.7x
1/3.2'', 7.6x
f/1.4
f/1.8

f/2.5
Camera
Pentax K10D with Sigma 30mm f/1.4

To more easily compare the amount of selective focus, please see these 100% crops from the images. The Iphone picture was not entirely similar, but the point is that with the small sensor, most of the image is in focus.


What we see here, is that the larger the aperture (smaller f-stop number), the more selective focus (top row has f/1.4). Also, the larger the sensor, the more selective focus effect (left column has 1.5x crop factor).

So, does this mean that you'll always want the biggest possible sensor size? Everybody should buy Sony A7 cameras?

It depends on what you want with your images. If you want to use selective focus as an effect, then yes, the bigger sensor, the better. Personally, I don't think that a very selective focus is always preferable, so I am perfectly happy with the Micro Four Thirds and Nikon 1 camera systems.

Also, when selecting smaller sensor camera systems, you get smaller lenses and smaller cameras. Here are the systems I used for the image series above:


From left to right: Pentax K10D with Sigma 30mm f/1.4, Lumix GM1 with Leica 25mm f/1.4, Nikon 1 V3 with Nikkor 18.5mm f/1.8, and an Iphone for scale.

Generally speaking, the larger the sensor, the larger the camera and the lens. And a compact camera system is often favoured.

Conclusion


If you want to use selective focus (and bokeh) as an effect, then go for a camera system with a reasonably large sensor. However, larger sensor systems are often larger, heavier, and more costly.

If you go for a camera with a moderate sensor size, like Micro Four Thirds or Nikon 1, then you need a fairly large aperture lens to get a significant selective focus effect.

Example lenses to achieve this are, for Micro Four Thirds: Leica 42.5mm f/1.2 and Leica 15mm f/1.7. And for Nikon 1: Nikkor 32mm f/1.2.

Saturday, 13 December 2014

Old bag, new bag

Camera bags are very personal things. A bag that works well for me, might be totally wrong for someone else.

For the last seven years, I have used the Tamrac Velocity 6x sling bag. I have used it extensively, so much that I needed to replace it with a new bag. And what better bag to buy than exactly the same model? Here they are, the new to the left, and the old to the right:


The bag comes with two internal dividers, which can be placed wherever you want with velcro:

Normally, I only use one of these dividers, to make one big and one slightly smaller room:


That way, I can carry one camera with a lens mounted, and an additional 1-3 lenses, depending on their sizes. In this example, I have the Lumix GH3 with the Lumix X 35-100mm f/2.8 mounted, and the Lumix X 12-35mm f/2.8 as a spare (click to see my lens reviews):


It is also possible to use the front pocket to store some pancake lenses. The front pocket can be used to carry memory cards and batteries, and has a clever system to recall which one is full, and which one is used.

The bag is to be carried diagonally across the torso. When in the rear position, it is reasonably level, so you don't need to worry about stuff falling out, even if you don't close the top. The wide band helps keep the bag in place, so that it does not slip around while walking or even cycling:


The bag slides under the right hand to the front position, where you can access the contents. It is also quite level here:


After seven years of heavy use, one of the lower corners have become quite worn:


Also, the zipper doesn't always close perfectly around the second turn:


To prevent the zipper problem, I guess you can avoid closing the bag completely unless absolutely needed. The extra friction around the second turn appears to wear the zipper.

Conclusion


I think the Tamrac Velocity 6x sling bag is very good for mirrorless camera use, where it easily takes one camera with 2-5 lenses, depending on the size of them. The sling design means that the camera is always easy to get, and the bag is reasonably weatherproof. It has proven to be very durable for me, and I expect to continue to use this type of bag for another decade.

Tuesday, 9 December 2014

Is metal better?

The last years, there has been a clear trend within consumer electronics: The devices must have a smooth metal surface. This is perceived as a mark of quality: Metal means solidity for the general public.

One example is the Lumix G 12-32mm f/3.5-5.6 (my review) pancake zoom lens, seen below (to the left) compared with the older Lumix X PZ 14-42mm f/3.5-5.6 (my review):



The older black lens has a plastic body, while the newer silver lens has a bare metal surface.

But is the new lens better, with the external aluminium body? In terms of handling, I certainly like the old lens the best. It has a ribbed ring around the base, which is good for gripping when mounting the lens. The new lens has nothing of the kind, and is quite slippery to handle.

There is, however, a textured ring around the front, which is used for extending the lens and zooming. The older, black lens does not have a zoom ring, as the motorized zoom is operated with a lever.

I guess the purpose of the metal surface is to make people think that this is a high quality metal lens. However, is it really a metal lens?

Some people have reported that the front metal surface has come off, revealing a plastic construction below. For me, the rear ring came off, and you can see clearly below that it is just a very thin layer of aluminium, which is glued to the plastic chassis of the lens:


Personally, I don't mind the plastic construction at all, in fact, I think an all plastic design would have been superior: It could have been textured for a better grip, and the surface would not come off accidentally, as it could have been part of the chassis.

Now, I am sure that if I had taken the lens back to the retailer, they would have sent it for repair at no extra cost to me. But this is a hassle, and I would much have preferred a design which does not put a thin, fragile metal surface on the outside of the lens.

By the way, here we see that the metal ring is prevented from rotating by a small "tap":


Not only Panasonic is doing this, of course. Some people have been angered by the fact that the pro grade Olympus 12-40mm f/2.8 has a plastic construction beneath the metal surface.

And the new Samsung Mini-NX system has metal clad camera bodies and lenses:


Just to mention a few. I think to put a thin metal surface on all consumer electronic devices is a strong, and, sadly, dysfunctional, trend.



Sunday, 23 November 2014

Product news, sensor size is the new megapixel race

The camera industry is in a crisis. People have more or less stopped buying basic compact cameras, since mobile phones take good enough pictures anyway. Also DSLRs are seeing less sales.

There are two areas which still see good sales: Premium compacts and mirrorless cameras.

Panasonic used to be king of the premium compact line, with the Lumix LX7, and the Leica rebranded version. However, Sony raised the bar significantly with the RX100 series of cameras with a larger 1 inch sensor.

Panasonic's answer was the Lumix LX100, with an even larger sensor, however, now the camera is getting worringly larger than the predecessor. Also Canon wants to take part in this segment, with their Canon G7 X, also sporting a 1 inch sensor. Both of these cameras have significant issues, though: The Lumix camera lacks an articulated LCD screen, and the Canon lacks an EVF.

4K video


When the Lumix GH4 camera (my review) was launched this spring, it was a game changer. It was the first affordable interchangeable lens camera to feature 4K video recording. Since this time, we have seen some competition.

Sony have released their Sony A7s (s for "sensitivity") full frame camera. It can record 4K video without cropping, unlike the Lumix GH4. On the other hand, it needs an external HDMI recorder for 4K. One such option is the Atomos Shogun 4k, costing a whopping US$2000.

Samsung have been quite innovative with their lines of mirrorless cameras, the APS-C sized NX mount, and the 1 inch sized Mini-NX mount. Still, their impact have been limited, with no super interesting options.

They recently released their flagship camera, the Samsung NX1, which aims to change this. It is priced similarly as the Lumix GH4, and gives you 4k recording without an additional crop.

It also sports 28MP resolution, the highest yet for an APS-C sensor. Finally, it has the H.265 codec, which promises better video quality. However, some would say it is still untested.

Beyond these expensive and rather large cameras, we have not yet seen 4k video trickle down into smaller volume cameras in the mirrorless segment.

Camera
System crop
4k crop
Native resolution
Weight
Price
Native lens selection
2x
2.6x
16MP
560g
US$1500
1.5x
1.5x
28MP
550g
US$1500
Moderate
None
None
12MP
489g
US$2500
Limited

With the ability to record 4k video without cropping makes the Samsung NX1 a good option. It also comes with the Samsung 16-50mm f/2-2.8 pro grade zoom lens.

Sony


With the Sony A6000, they finally did get the on-sensor PDAF technology right, and it performs very well in terms of continuous autofocus with moving subjects. However, it comes with the 16-50mm f/3.5-5.6 pancake zoom lens, which is not very good. See my test here.

They also announced a new version of their A7 full frame camera, the Mark II. It comes with better ergonomics, and, more importantly, it has built in sensor shift image stabilization, quite impressive. It still has the well known 24MP sensor, and does not feature 4k video recording.


Canon


Even if a manager said in an interview that they are committed to mirrorless, they still only have the rather poor EOS M camera out. To stay in the game, they need to release some proper gear, and fast.

Nikon


With the Nikon CX 70-300mm lens (my review), there is a renewed interest in the mirrorless Nikon 1 line. The lens is very good for anyone who wants a long reach at a small size, for example birders.

The Nikon 1 system is good for those who need very fast PDAF performance with moving subjects, also during video recording. It is also interesting for the ability to take a very quick series of images, up to 60 frames per second at full resolution. But beyond these specialty uses, other systems, like Micro Four Thirds, are mostly better.

And Nikon's position on this system is hard to understand. Do they want it to be for the fashion conscious who want glossy, pastel coloured camera kits?

Or for serious amateurs who might want to buy the premium Nikon 1 32mm f/1.2 portrait lens? Too bad that they don't have any sensible pro camera to match it. They have the Nikon 1 V3 camera, but it has some serious issues which will annoy the typical serious amateur, for example, you cannot use an external flash and the EVF at the same time.

Are Nikon really committed to continue the Nikon One line? I think that remains to be seen.

Conclusion


With the camera market in crisis, what is going to happen? Are we going to see some mirrorless camera systems being discontinued?

If Canon wants to be in the game, they need to release a proper mirrorless camera, probably one with the new 20MP sensor with PDAF capabilities, used in Canon EOS 70D and Canon EOS 7D II. They also need more lenses. At this time, they only have two lenses for mirrorless cameras, three including a wide angle zoom lens only available in Japan. I'd say Canon EOS M is closest to being stopped at this time.

The Nikon 1 system also has a foot in the grave, in the sense that no significant new product have been announced for some time. Nikon has an ok lineup of cameras and lenses, but they could do with some exciting news. For example, a macro lens is missing. Some choose to use the Nikon 40mm f/2.8 DSLR lens on a Nikon 1 camera, using the FT-1 adapter. And it works fine, but a dedicated Nikon 1 macro lens could have been more compact.

Nikon 1 have gotten some attention lately with the Nikon CX 70-300mm lens for birds, wildlife, sports, and so on. But can this lens alone float the system?

Nikon's problem with Nikon 1 now is sensor size. While the megapixel race was very important in the last decade, we now have a sensor size race. The general public is more aware that a big sensor is good for selective focus and image quality, and we see the camera makers trying to tap into this by offering large sensor enthusiast cameras.

Sony was an early mover with the RX100 series of compact cameras, offering the same sensor size as Nikon 1, but with a better specified zoom lens built in. After the first RX100 camera, it is harder for competitors to release a premium camera with a smaller sensor.

Nikon launched the Coolpix A in early 2013, with a 28mm equivalent f/2.8 prime lens and an APS-C sensor size, but it was not very popular, due to a steep price, no eye level viewfinder, and no zoom.

The market is more demanding now, and wants: A large sensor compact camera, with a wide angle zoom lens, that has a large maximum aperture, and a tilting LCD touch screen, as well as an EVF. Canon have tried to answer this by launching the Canon G7 X, however it misses out on the EVF (not having an electronic eye level viewfinder).

Nikon don't have any camera which matches this, while Panasonic is all in with the Lumix GM5 for those who want an interchangeable lens camera, and the Lumix LX100 for those who don't. However, with the sensors topping out at 16MP resolution, the specifications are starting to look a bit dated for the general public.

It seems that the winner is going to be those who combine a compact camera with a large sensor and a bright zoom lens, including an EVF. Sony and Panasonic are the closest now, while Nikon and Canon have not succeeded in winning this market.

Thursday, 6 November 2014

One concert, two cameras

I had the chance to bring two different cameras to a concert, to see how they compare. I brought the Lumix GH4 with the Leica 25mm f/1.4, and the Nikon 1 V3 with the Nikon 18.5mm f/1.8. Both systems are shown below:


Even if the lenses have different focal lengths, they still have the same field of view, because of the different crop factors of the cameras systems. Both are what we usually call "normal lenses", with the classic 50mm equivalent field of view.

Also, both lenses are quite fast, in the sense that they have a large maximum aperture. This makes them well suited for use in dark venues. And the concert venue was very dark indeed, also having oddly coloured artificial stage lights which makes the exposure very tricky.

Lumix GH4


The exposure parameters used were: f/1.4, 1/120s, ISO 3200. The exposure was set by using the A-mode without any exposure compensation. The video was recorded in 1080p, 60FPS:



I left autofocus on during the video recording. Most of the time, the camera highlighted the face of the artist, making sure it was in focus. And the focus was kept pretty well during the recording. When the face was obscured too much, e.g., by the microphone, the focus was lost for some short while.

It would probably have been better to prefocus, and then switch to manual focus during the recording, but this was a nice test.

Nikon 1 V3


The Nikon lens has a smaller maximum aperture. However, using the A-mode, it exposed somewhat less, still using similar exposure parameters as the Lumix system: f/1.8, 1/100s, ISO 3200. It was also recorded in 1080p, 60FPS



Even if the Nikon systems uses on sensor PDAF for the best autofocus during video, I doubt that it can utilize this in the dark concert venue. So it probably has to resort to using CDAF, just like the Lumix camera. And just like the Lumix system, it was able to identify the face of the artist most of the time, and kept the focus on him.

The Nikon 1 V3 appears to find the better colour balance, in this very challenging lightning. I left both cameras on auto white balance.

Sound


I used the built in microphone on both cameras. They are a bit different: The sound of the Nikon system is a bit thinner, with less base. With a bit of mixing, though, one could probably eliminate most of the difference.

Friday, 31 October 2014

Basic tele lenses compared

All camera systems have a cheap tele zoom lens available. Here are two such lenses, the Lumix G 45-200mm f/4-5.6 for Micro Four Thirds, and the Nikon 1 30-110mm f/3.8-5.6 for the Nikon 1 system:


The Nikon lens is seen here in a glossy orange finish. I guess it could have been worse, it could have been pink. Yes, this lens also exists in pink!

Both lenses cover a fairly wide range of tele focal lengths, useful for daily use. The range of the lenses is illustrated in the diagram below, in 135 film equivalent terms. You can also compare the maximum aperture as a function of the field of view:

Even when extended, the Nikon lens is impressively small:


Both lenses have rubberized zoom rings, which are nice to handle. The Nikon lens does not have a focus ring at all. I don't see this as a problem. The autofocus works well anyway, and I rarely see the need to focus manually.

Specifiations


Lens
AnnouncedSept 12th, 2008Sept 21st, 2011
Equivalent focal length90-400mm81-300mm
Lens elements/groups16/1318/12
Minimum focus1m1m
Weight380g180g
Diameter70mm60mm
Length100mm61mm
Filter thread52mm40.5mm
Focus ringYesNo
Image stabilizationOpticalOptical

Image quality


To compare the image quality, I have taken the same pictures with both lenses. The images were taken with the Lumix GH4 (my review), and Nikon 1 V3, respectively. The images were taken with the cameras safely mounted on a tripod, with the self timer to avoid camera shake, and at base ISO.

Lumix 45-200mm @ 45mm f/4
Nikon 30-110mm @ 30mm f/3.8

Here are some 100% crops from the centre:


From the right side:


And finally 100% crops from the top left corner:


In the centre, both lenses perform very well. However, in the corner, the Nikon lens is clearly a lot better. It renders the corners more sharply, and also handles the high contrast between the sky and the leaves better. This situation is quite challenging to render for most lenses.

Here is another comparison at the long end of the lenses:

Lumix 45-200mm @ 200mm f/5.6
Nikon 30-110mm @ 110mm f/5.6

Now, the Lumix lens has some advantage here, as it is used at a longer reach. True, on the other hand, this is how people use these lenses: They are often used in the most extreme setting. So that is why I test them like this.

Here are 100% crops from the centre:


And from the top left corner:


In this setting, the Lumix lens appears to show more details. However, it also has slightly more magnification. The Nikon system suffers from somewhat more diffraction effects when stopped down, that is why you see more dullness at f/9.

Bokeh


At long focal lengths, the depth of focus is thinner, and you tend to get the foreground and/or the background out of focus. Hence, the nature of the out of focus rendering, the bokeh. Therefore, it is important that the bokeh does look nice, and effectively blurs the out of focus areas.

To illustrate the bokeh, here are a couple of pictures taken wide open, at the short end of the lenses. I focused on the bicycle light in the top left part of the image:

Lumix 45-200mm @ 45mm f/4
Nikon 30-110mm @ 30mm f/3.8

Here is a magnification from both lenses:


Both lenses have perfectly fine bokeh in this example. The Lumix lens does feature slightly "dirty" out of focus highlights, but it is hardly a problem.

Autofocus during video


Panasonic and Nikon are taking different approaches to autofocus. Panasonic relies entirely on contrast detection (CDAF), and the most recent model Lumix GH4 adding DFD (depth from defocus), which attempts to find out in what way the image is out of focus by analysing the bokeh.

Nikon, on the other hand, has relied on phase detection sensors on the imaging chip (PDAF). This approach leads to very fast AF performance, even with moving subjects, and while recording video. However, the performance can be sub-par in darkness.

To test the autofocus performance during video recording, I recorded two sequences with the Lumix GH4 and the Nikon 1 V3. The first sequence was recorded inside an artificially lit shopping centre while riding an escalator, to get the same movement speed in both sequences.

The second sequence was recorded in darkness while watching an approaching bus:



All of it was recorded in 1080p, 60FPS. The settings were 150mm f/5.6 for the Lumix lens, and 110mm f/5.6 for the Nikon lens.

In the first sequence, the Nikon system certainly keeps the focus up better. Even in darkness, it does retain a good focus.

Conclusion


Generally, I am more convinced by the image quality of the Nikon 30-110mm lens. It is not as long, and, hence does not provide as much details in the tele end as the Lumix 45-200mm.

With the Nikon lens, I feel more confident using it wide open at all focal lengths, and I think it handles challenging contrasts better. While, with the Lumix lens, I more often feel the need to stop it down for better image quality.

The Nikon system also keeps the focus better up while recording video, and with moving subjects. However, as the image processing improves, future Micro Four Thirds cameras may very well be able to perform as good.


Alternative lenses


For Micro Four Thirds, there are a lot of alternative lenses. If you have an Olympus camera, with built in image stabilization, you could go for the affordable and great Olympus 40-150mm f/4-5.6.

For use on Panasonic cameras, you could go for the very compact and reasonably priced Lumix G 45-150mm f/4-5.6. Another alternative is the more expensive and very good Lumix X PZ 45-175mm f/4-5.6 (my review).

From Nikon, there are not any alternative lenses in the same price range. For a bit more money, you can get the Nikon 1 10-100mm f/4-5.6. It is not as long, but with the added wide angle range, it is very flexible, and covers most focal range needs in one lens.

Tuesday, 28 October 2014

Third party grip for the GM1, LB-GM1

The Lumix GM1 is a fascinating camera: Very small, nicely designed, has good external controls despite the size, and offers top image and video quality.


The only problem I have with it, is the lack of a proper grip. It is awkward to hold.

There is the official grip, which I reviewed here. However, it is quite expensive, and it blocks the tripod mount, and the battery and SD card compartment. Which makes it less than optimal, to say the least.

However, there is an interesting third party alternative grip, which fixes these issues. Both the grips are laid out below (the official grip behind on the left):


The black third party grip comes with two hex keys, and in addition to the grip, it also adds an Arca-Swiss mounting plate on the right side, for setting the camera up in portrait layout.

Mounted to the camera, it looks like this:


The side Arca-Swiss grip can be disassembled using the hex key:


As you see, there are two tabs in the side mount, which makes sure it is aligned correctly. It fits tightly, and there is no wobbling when attached. Using the side mount, the camera can be put on an Arca Swiss compatible tripod head in either landscape or portrait position:


In the pictures above, I used an Induro BHD1 ball head with an Arca-Swiss compatible clamp. But there are many, many ball heads available which are Arca-Swiss compatible.

With the grip mounted, you can still access the battery and SD card. Behind the open battery door, you can see the extra tripod attachment:


Here is what it looks like in the hand. The grip part is a bit glossy and slippery, compared with the original grip. Also, the grip is wider, which leaves less space for your finger between it and the lens:


The whole front grip can also be removed, in case you want to use only the tripod attachment functionality of the grip.

Conclusion


I like the third party grip better. It adds a lot of functionality, at a lower price.

It is unclear to me if you can also use the grip with the Lumix GM5 camera. Based on the pictures I have seen, both cameras appear to have the same footprint, so it may be possible. But I have not tested them physically.

Pros:Light, very nicely finished, good finger grip.Pros: Adds two Arca-Swiss compatible tripod mounts, a second tripod screw hole, access to battery and SD card possible.
Cons:Expensive, blocks battery, SD card door and tripod hole.Cons:Heavy, grip is glossy, with little grip texture. Not much space between grip and lens.