The pros and cons of m4/3

Started Jul 11, 2011 | Discussions thread
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drwho9437 Senior Member • Posts: 1,992
The pros and cons of m4/3

I have had a m4/3 camera for a few months now so I think I am in a good position to give a useful view on the system.

I have historically shot classic MF SLRs (70s/80s), digital P+S, and the Canon 1.6x system.

For this discussion I will put aside the aspect ratio differences and focus on the pros and cons verse an entry level DSLR.

Photography for me is about the basics. To take a good photograph you need to compose a picture you wish to take. Use a light meter to determine what settings are available, set them, focus the camera and take the photo.

In the end there are only 4 settings on a camera: ISO, aperture, shutter speed and focus.

One of the great disappointments of all digital cameras up to m4/3 has been: focus.

This is a great strength of m4/3. In particular the cameras with a quality eye level finder allow for excellent ability to check focus. I have not felt this confident in my focus since I had a split prism. Even then that confidence could have been misplaced as there could be a path difference between the focusing screen and the film plane.

I cannot overstate how annoying it is to have to rely AF and how much I have wanted to have the simple ability to turn knob and know my subject is in focus.

Liveview without the EVF is significantly less useful. As much as I like the GF1 styling it is not usable in normal outdoor conditions for checking critical focus.

I have not had the opportunity to use the recent Canon and other make cameras with Liveview. It should be a boon to check focus at least in the studio case.

The EVF on the G2 has other upsides as well. The largest of which is seeing both white balance and aberrations in real time. Blooming for instance off a metallic object is a sensor/lens interaction and far easier to notice with the EVF than an optical finder. White balance can be horribly off and this makes looking through the EVF disturbing, but at the same time affords the opportunity to make sure a photo of a gray card is taken or custom white balance is set at the time, rather than assuming it can be corrected for later.

The principle downside to the EVF is lag and noise. With a slower lens these both become significant downsides. While a optical finder may be dim with such an optic it is at least not laggy and noisy. Although the normalized gain of the EVF might be preferred by some over a dark scene, it is not to me. My eyes adjust to the dark. And mostly compensate in the optical case.

Overall noise of a GF1 and G2 is certainly worse than the 400D that I currently own. It is not a huge margin but it is clearly worse.

As the majority of my subjects are shot in bright light this is only an issue in dark shadows where there is clear shadow noise. I hope Panasonic and Olympus resist the urge to increase anything but dynamic range and noise performance in this system.

The lenses in the system are nothing to complain about at all. The build quality is just where it should be: good without being overbuilt. The point of m4/3 is largely portability and so a lead brick of a lens is not a wise design choice.

Ergonomically the controls on the G series are quite good. The click wheel is without any doubt superior to the rebel button + wheel approach for changing a secondary setting. It is perhaps superior to even a two wheel camera as it does not require movement of the hand.

So in summary so far the G2 has an excellent viewfinder, and excellent control system. This allows you to easily set: focus, aperture, and shutter speeds. ISO has a dedicated button and thus is only slightly more awkward to change.

In short it does the basics very well indeed!

Taking a step back it is useful to think which approach is better optical or the EVF. Consider why the SLR was introduced. People wanted to see what they would get on the film. The best way to do this was to have the reflex design and a second film plane at 90 degrees to the first. It is a great design. But fundamentally a liveview EVF achieves what the SLR wanted to achieve even better: exactly what is on the film (now sensor).

That isn't to say an optical design doesn't have advantages. The advantages are clear: a real time lag free view of the subject. Phase detect AF has advantages also, but if it wasn't clear from my comment earlier, I couldn't care less about AF systems if I am given the ability to use MF cleanly.

The other place where m4/3 and DSLRs differ is the sensor size. m4/3 is 1/4 the size of FF. This means that there should be a 2 stop disadvantage for fundamental noise performance (limited by Poisson statistics, in reality there are other limits as well). The difference between APS and m4/3 is about 1/2 a stop.

The other place m4/3 is at a disadvantage is subject isolation. (IE DOF). Control of this in photography is important, and a while generation of photographers is no growing up without it for the most part. This is sad.

In the end though it is a question of how much is enough? You can make the same argument against FF as you can about APS or m4/3 with medium format. There is also the flip side of the issue. In low light sometimes you can want more DOF than you have light for. This was certainly an issue in film days, but this problem is mostly eliminated with adjustable ISO. So a principle issue with m4/3 is getting low DOF.

How low is enough? For me a human head being all that is in focus is probably the standard to have. The question then is one of distance and focal length. The more obvious choice for this are short telephotos and standard lengths. (IE 50-100 mm in 35 mm terms). A human head is about perhaps a 6-8 inch target.

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