Comparing sensors

How much does size matter in today's digital cameras (Feb 2017)

Curious about the differences between a crop frame and a full frame sensor? Are you worried that you are missing out on something by using a crop frame sensor instead of a full frame?

I am probably in the minority, but I think that the latest "crop" of crop frame sensors, such as the Canon EOS 80D or even the Canon EOS M5 mirrorless camera compare favorably with full frame sensors, such as in the Canon EOS 6D, especially for studio work.

Here is a pair of images made with a 6D and an M5. The subject and the lens (Canon 70-200L f/4 IS) remained stationary between the images, but the lens was zoomed to approximate the same angle of view/framing. The lens was attached to the tripod via its tripod color and then I simply switched out camera bodies to make the two exposures. The image with the 6D was taken at 200mm and the image with the M5 was taken at 121mm to account for the 1.6x crop factor (yes, it should have been 125mm, but the lens doesn't have a marking between 100mm and 135mm, so I had to guess at mark, and came up a few mm short). Lighting is a single Einstein head with a 35" octabank about 20" from the subject with no fill card.

In creating this, I noticed a slight change in the shape of the mannequin's face between the two images. My best guess on this is that there is a different amount of distortion (barrel vs pincusion) at the 121mm and 200mm focal length settings on this lens. Additionally, this is an internal focus/zoom lens that doesn't change physical size when focusing or zooming, so the magnification math (1.6x between the two cameras) might not be exact when the lens is focused closer than infinity. 

Anyway, I think you will see that the two images are very similar in quality. As expected, the depth of field is slightly shallower in the full frame (6D) image because the image is magnified more vs the small sensor. You can see this around the hair and the earring hole in the ear of the mannequin. But other than that, I think that you would be hard pressed to be able to see a difference between these two images if they were printed side by side in a magazine.

If you are just getting started in digital photography, or if you are sitting on the fence trying to decide if you should trade in your crop frame camera to buy a new full frame, I think I would opt for keeping the crop frame and using the savings on better glass or on lighting gear in the studio.

I have not made a comparison of images made in low light situations, such as stage performances. There might be, and probably is, a small advantage to the full frame sensors in those situations. I will see if I can do a comparison at the next event I photograph. 

Until then, keep enjoying the camera that you have now.