Date: 14/12/2013 | By: Mathieu
The Quest for Full Frame: Is it worth it? – Part I
Full Frame: these two words put together make lots of photographers happy. Immediately we think of gorgeous image quality, beautiful shallow depth of field, exceptional dynamic range and great low-light performance. But technical specifications aside, what are the real benefits of using a Full Frame camera and what are the reasons to choose one?
To begin, let’s explain what we mean by a Full Frame camera for those unfamiliar with the term. Full frame terminology refers to the 35mm film that we were used to on most film cameras. A full frame digital sensor matches the same dimensions of a 35mm film frame. As with digital today, back in the days of film there were already different sizes. The 35mm format was the most common, then there was also the medium format and the half frame used by the original Olympus Pen. Without digging into all the film formats available, we can simplify by saying that sensor size is today what film size was back then.
When the first digital cameras were released, sensors were smaller than the 35mm format. The first full frame DSLRs were the Contax N and the Canon EOS 1Ds, which were released in 2002. On the “mirrorless” side, the first interchangeable-lens full frame camera came from Leica, the M9. Later in 2012, Sony released the first fixed lens compact camera with a full frame sensor, the RX1.
Late this year, the announcement of the Sony A7 and A7r opened a door to a more consistent full frame market in the mirrorless segment, a sensor which was mainly present in the DSLR market. The M series by Leica was the only alternative, but its prohibitive price placed it in a niche. But now everything is about to change…
My experience with a full frame camera is mostly related to the Nikon D700. Since its release, many new cameras with improved sensors have come out, and today the low-light capabilities of a Nikon D4 or the dynamic range and resolution of a Nikon D800 are without a doubt a big reference in the high-end digital camera market. My goal here isn’t to write an in-depth technical analysis of full frame capabilities, as it would require lots of tests and comparisons, but rather to share a more personal thought about sensor size and up to what point it matters.
Let’s take the three topics we are most likely to see in a discussion about full frame cameras: dynamic range, depth of field and low-light performance. There are also other aspects I will purposely skip, like sensor technology, resolution (or megapixels) and other important things such as printing. I don’t skip them because they are less important, but because I want to concentrate on the aspects mentioned above. This is why this article is just a first part. More episodes will likely follow in the future.
Shallow depth of field
… or the right lens makes the difference
Let’s be honest, this is the first and perhaps the most appealing aspect of full frame cameras, as with the right lenses, they can truly give you what other systems (with smaller sensors) cannot. Below, you can see some shots I took with the D700 in Canada during the summer of 2012. They probably best represent what you can do with a full frame sensor and shallow depth of field. These images were taken with a Nikkor 24mm f/1.4, so we are talking about a very fast wide angle lens on a full frame format – quite a rare combo that can deliver pictures like the ones below.
So yes, a shallow depth of field and especially a “bokehlicious” depth of field may depend on the lens. Certainly, the sensor size helps. But why? Well, put in simple terms, comparison to a smaller sensor, a full frame sensor will require you to be closer to a determined subject or to use a longer focal length in order to fill the frame with the subject in. If you get closer to the subject or use a longer focal length, your depth of field will be shallower. If you want to maintain a DoF equal to the one obtained with an APS-C sensor, you will have to close the aperture.
Explained in a concrete manner, a f/2.8 lens aperture used on a APS-C sensor would gave me a corresponding result of f/4 on a full frame sensor. On a MFT sensor, it would gave me a corresponding result of f/5.6. This can explain why even without using a super fast lens on a full frame sensor, you can achieve a good DoF.
If I wanted to have the same DoF of my full frame shot, let’s say, on my MFT camera, I would need to use a f/1.4 aperture. This is why a full frame sensor to me makes a bigger difference with short focal lengths than with APS-C and MFT sensors (and I won’t go a step further and talk about medium format). To replicate the same DoF as my D700 shots with the Nikkor 24mm f/1.4, I would need an equivalent focal length lens on MFT with a f/0.7 aperture, which simply doesn’t exist. The fastest lens you can get for MFT is the Voigtlaender f/0.95, and perhaps the upcoming Ibelux 40mm f/0.85.
But let’s put aside technical comparisons. If I want a shallow depth of field at these focal lengths with a MFT camera, things certainly become more complicated but not impossible. Again, it depends on the lenses, the focus distance and how you use your knowledge of the camera to compose your shot and achieve that desired DoF.
With an APS-C sensor, the difference can become less noticeable, as there is a smaller gap between it and a full frame sensor. Put that wonderful 23mm f/1.4 on an X-Pro1 or X-E2 and you might get very similar results
Certainly the difference on MFT is more pronounced. Let’s say that what you can do with a 24mm or a 35mm lens on a full frame, you are likely to get with a fast 50mm equivalent on a MFT sensor. This theory is not scientific and it of course depends on the aperture the lens has. But the point is that, in the end, there exists a beautiful shallow depth of field for each system if you know how to reproduce it and more importantly, which lens to choose. And since you probably won’t shoot the same scene three times with three different cameras just to pick the best DoF, you will do what you have to do with the right lens to get achieve right composition.
With portrait lenses and telephoto lenses, the difference is less noticeable as the shallow depth of field is dependant on the focal length itself. Certainly there will be a difference in bokeh depending on the lens type, aperture and focal length but in this case the advantages of a full frame format are less important to me.
The most important thing to take home from this chapter is that a full frame sensor will give you more control over depth of field even with short focal lengths, something that is harder to achieve with MFT sensors, and slightly less difficult with APS-C. What is also in favour of full frame cameras is a wider variety of fast aperture lenses. You will very rarely find a 24mm equivalent designed for APS-C or MFT cameras capable of a f/1.4 aperture or less.
Some photographers choose their favourite system and then pick the right lenses to achieve a shallow depth of field. Others might choose the lenses first and then the system that mounts them. One way isn’t better than the other, as long as you remember that DoF isn’t the only element of importance in photography. Certainly, if you want a super sharp wide-open 50mm f/0.95, there is only one system to choose and it will cost you money!
A full frame sensor has a bigger surface, therefore it has bigger pixels which also means bigger photodiodes (although there are some exceptions). Not only should it be able to give better performance in low light (with less noise) but also capture a more rich range of tones.
With digital cameras, one of the easiest ways to see how far you can push the dynamic range of your image is to post process the RAW file and see how much detail it hides in the shadows and highlighted areas. This could result in a HDR-like photograph with an unnatural look if you push the settings too far, but despite the look, it helps you understand how far you can go in post-processing an image.
With my D700, the furthest I went in post-processing a photograph was during the Venice Carnival in 2012. We woke up at dawn and went to San Marco’s Square where people with masks were already flooding the canals, ready to be photographed as the sun began to rise. I wanted to make those wonderful colours pop. Since HDR was impossible because there were too many moving elements in the frame, I shot the RAW with the maximum possible quality (14 bit). Though I noticed some slight deterioration in the files, this is surely an example how far I could go in processing a RAW file coming from a full frame camera, something that I could probably replicate with a very good APS-C sensor, but less so with a MFT sensor.
Dynamic range isn’t only about opening shadows and recovering highlights. It is also about having lots of information in every area of the exposure, as it helps with the richness of details, accuracy in the rendition and tonal transitions. But what are the situations where you would require a better dynamic range?
Certainly situations with a high contrast or sunrise/sunset are good situations to test the dynamic range of a camera. I’ve personally found that the latest generation of sensors are all capable of handling dynamic range pretty well, even though they are smaller.
In a real world situation, if the camera has a good sensor and you shoot RAW, you will have little difficulty recovering what you need. Certainly, the bigger the sensor, the more you will retain detail especially in the highlights. A full frame sensor or the Fuji X-Trans sensor are very good with highlights. MFT sensors are stronger with shadows.
In the end, it is a question of knowing the strengths and limits of your system and using the settings accordingly. Even with MFT, I’ve never come across a photograph that has given me a headache in post-production. Of course if you accidentally overexpose a picture, you will recover it more with a full frame sensor than with a MFT sensor. But let’s not forget that an overexposed picture is almost always a bad picture (unless there is a specific intention behind it).
This is the part where I do envy the performance of certain full frame cameras. The native ISO range of a Nikon D4 or a Canon 5d mark III are nothing short of impressive. Knowing that I could shoot at 6400 ISO and achieve the same quality of 800 ISO on my E-M5 would certainly be a huge benefit for some of my shooting, but for my kind of work, the higher costs, weight and size remain strong arguments against the system.
As I explained before, a full frame sensor has bigger pixels, meaning that each one can capture more light with less noise. In my case, the switch from my D700 to the E-M5 was not very painful as I rarely went over 3200 ISO with my Nikon camera. Moreover, the D700 has an old generation sensor. The E-M5’s sensor is more recent and while I’ve never made a direct comparison, I found the amount of noise very similar. Probably at 6400 ISO, the D700 would retain more detail. As for my X100s, I’ve found the X-trans sensor II even better than the other two.
I must say that I’ve never worried too much about high ISO. Certainly, I would be careful for work assignments and try to keep the values as low as possible, but otherwise I’ve never disliked a little bit of grain in my images. If the photograph is powerful enough, 6400 or 200 ISO become irrelevant. If the photograph is bad or just boring, we might become more sensitive to its technical aspects.
As I wrote in the introduction, there are other aspects that would be worth analysing such as resolution, printing or colours. The first two are for me more specific. Printing is a world of its own and if it is a primary aspect of your photography, then it can certainly influence your choice of camera. Resolution is also related to printing. I have never been a huge fan of counting megapixels. The D700 had 12, the E-M5 and the X100s that I am currently using have 16, which is more than enough for me. Certainly, the 36 megapixels of a D800 or a Sony A7r can be useful for large prints and you may achieve what you could only do with medium format before. But these are specific situations. If I don’t need large prints, I don’t need 36 MP sensor that will fill my hard drive in one fell swoop.
In my opinion, a full frame format is not essential in this day in age. Don’t get me wrong, I really love the image quality and completely understand why it remains the first choice of professionals. But at the same time, I’ve never missed my D700 for one second since I sold it months ago. I adapted my photography style to the new gear I was using and little by little I actually updated it. That minor loss of overall image quality was compensated with many advantages.
Now, the question is: could the Sony A7 & A7r reunite the amazing image quality of a full frame sensor with the joy of using light and compact gear? Well, I will be able to say more about that tomorrow so stay tuned!
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