Sensor Size

posted on 3rd of april, 2012

Some of us pay more attention to aspect ratio than others. Some prefer to shoot at the camera's native aspect ratio and crop later while others prefer to compose in the final aspect ratio. At least that is what we have been telling ourselves since the dSLRs we're used to only have one option :)

One of the things I love about my Panasonic GH2 is the ability to view and compose in the final aspect ratio, including square! [An interesting side note is that I occasionally find myself still rotating the camera into 'portrait' orientation when I'm shooting in square format - which says something about how much my years of shooting 3:2 aspect has influenced my habits...]

Whatever your take on the subject, with a dSLR it just isn't an option to compose in your desired aspect ratio using an optical finder. My Canon 7D, for example, doesn't offer an option to do this even in live view where it could, nor does it offer framing in its dynamic LCD screen in the optical finder. The GH2 (and GH1 before it) offer a unique (thus far, anyways) feature on their sensor in that it is larger than the image circle in the horizontal direction, thus giving you more physical sensor areas when you go to a wider format such as 3:2 or 16:9. Thus you actually get more horizontal field of view, as well as locking in the aspect ratio choice. The point here is that this isn't a case where you can take it in 16:9 but still use the full image later - you actually lock it into the RAW file and discard the top and bottom (which would not have covered the whole width anyways).

For me, it turns out that I like composing and shooting in a slightly more square format than 3:2. 4:3 is more my style, and thus I never shoot in 3:2 with the GH2. I do go to 16:9 where I'm getting more width and less blue sky, or to square. But 3:2 simply isn't my preference. So the question I wondered was if you compared an APS-C camera to MFT in 4:3, what is the actual difference in area? My guess was that they were a lot closer than the typical stated 50% difference we're used to hearing.

A quick bit of spreadsheet math, and here are the numbers:

MFT: 13mm x 17.3mm, total area is 225 mm2.
Canon APS-C: 14.9mm x 19.9mm, total area is 296 mm2 (normally the full width is 22.3mm)

and just for fun, here is the new Canon GX1:

18.7mm x 14mm, total area is 261.8mm2 (a case in point, DPReview says it is 20% smaller than its APS-C cousins ignoring aspect ratio - using 4:3 on both would bring it to more like a 12% difference)

There is a nice image of this http://2.s.img-dpreview.com/reviews/canong1x/images/Sensorsizes.png?v=1440.

Thus, if you are cropping to 4:3 or 'squarer', the sensor size area difference is only 1.3x or less. The height difference is a mere 15%. I think it is safe to say that most discussions about the sensor size differences ignore the discussion on aspect ratio, to the detriment of MFT. Of course, if you are using Olympus or any of the non GH series Panasonic bodies you don't get the slight bump in resolution when you go to 3:2 or 16:9, but you still see the 4:3 versus 3:2 advantage - unless of course you prefer to shoot in 3:2 :) If you do actually shoot 3:2 as a preference, then the argument goes the other way!

If you look at typical portrait sizes, like an 8x10, or 16x20, then the height of the sensor is the limiting side, and the extra area of a 3:2 sensor is wasted. Worse, you typically have to compose with the extra space in the viewfinder, too.

MFT is only as good as it really is, and discovering that the sensor area difference is smaller than you thought doesn't mean the image you weren't happy with last week is any better - but when you read about people talking about the 'huge' sensor size difference, take it with a grain of salt... More and more, MFT is good enough for me - certainly for my personal photos!

How does this relate to stock? Well, 4:3 gives you a bigger overall thumbnail on Dreamstime :) I'm not sure how aspect ratio helps or hurts for stock - I think buyers are savvy enough to know they can crop, and usually appreciate a bit of extra room to crop either way.

Here are a couple of shots of the kids on my personal blog taken in 4:3 ratio: http://mftadventures.blogspot.com/2012/04/mft-and-kids-portraits-action.html. What is your preferred aspect ratio?

Tags: area aspect mft ratio sensor

Comments (11)

	Posted by Alvera on April 05, 2012 I think that with 4:3 you will lose buyers who just buy&drag&drop images on 3:2 "preformated" websites.
	Posted by Bradcalkins on April 04, 2012 Brad, thanks for including my photo of Mass MoCA - only one small detail - that photo was taken with a Panasonic DMC-LX5. Whoops :) I was intended to grab an MFT image, but to be honest my article is more about aspect ratio, and I looked for an image that was 4:3 without paying enough attention to the camera!
	Posted by Peanutroaster on April 04, 2012 I think I'm going to write a little blog on M4/3 lens. Maybe club members can chime in...
	Posted by Peanutroaster on April 04, 2012 Brad, thanks for including my photo of Mass MoCA - only one small detail - that photo was taken with a Panasonic DMC-LX5.
	Posted by Elifranssens on April 04, 2012 I think I have to read this again... I got lost somewhere in the middle of all the math... :-)
	Posted by Bradcalkins on April 03, 2012 @Gmargittai - the thing i love about m4/3 is the EVF and rear screen being identical in use. My Canon is really two completely different cameras when you switch to live view. Video, as well, is so much nicer from the viewfinder. The EVF has all kinds of cool features, like shooting in an aspect ratio, low light, and even black and white! The fact that AF is on par with dSLRs for static subject and the frame rates are up to 5-9 fps means there is little you can't do with M4/3 if you have some fast primes to go with it. I'm very excited about the new OM-D. I don't see the image quality being much different than the GH2, but the optional grip means I can have a comfortable studio camera in the portrait position OR a small and compact travel camera. If I can do it all with one camera, I will !
	Posted by Gmargittai on April 03, 2012 I'm also in the club! I am using a GH1, previously a G1. Prior to that I had an FZ50. By about the time I switched to G1 I stopped getting the refusals on lens frindgeing and low quality lens, distorted pixel stuff. Which means that quality wise the m4/3 is there, meeting DT standard. What is missing in my case is the dedication of taking it to the next level. But regarding m4/3 in my mind the biggest advantage is the live view and the tilting LCD which gives me the possibility of shooting from very low, without lying in the mud and conversely way above my head in a crowd. Also waist level shooting is not only a medium format thing. All this and when I need it there is the viewfinder with all the things overlayed.
	Posted by Bradcalkins on April 03, 2012 @Peanutroaster - there you go, just for being someone who shoots stock with a G2/G3 I've added an image :) Between my GH2 and old GF1 I've got close to 700 downloads from micro four thirds shots!
	Posted by Littlemacproductions on April 03, 2012 Thanks Brad.. great info as always!
	Posted by Androniques on April 03, 2012 Interesting point of view and analysis of sensors. Never thought in that direction, maybe because my D5000 only allows shooting in 3:2 ratio. Would be interesting to try other formats "in the field", although in my case I am afraid that would have a potential of doubling or trebling my home-stock volume. Too many choices are overwhelming sometimes, but good to have to start with. :)
	Posted by Peanutroaster on April 03, 2012 Thanks for the info. I shot my first 800 portfolio images with a Panasonic Lumix G2 and now moved up to a G3. Have felt camera envy for those bigger, more expensive cameras but then again a lot of them stay at home because they are too bulky and heavy.