Tuesday, November 17, 2009

Finder comparison - 6x6 versus Digital 1.5 crop format (DX) and 135 Film Cameras

Usually your equipment does not give you to get better images, but sometimes it can really help. One of the major advantages of medium format SLR or TLR photography is the larger finder compared to both, 136 format and DX format digital photography. First I would like to show you the resulting Velvia slide, which was shot with an 80mm lens at EV 10.5 = 1/4 s at f/19, focussed to about 10 meters which should yield almost optimum depth of field.


I should have shot more wide open (for example at f/8) and I should have focussed closer because the image is not very sharp in 100% view scanned at 4000dpi (because of f/19 and focus distance of 10m). Anyway, the following image shows a medium format 99% finder image of 55mm x 55mm at 200 dpi (not really shot from the finder but scaled down from a scanned Velvia slide) - if you do not own the latest, brightest and most expensive focusing screen - less colorful, less contrast - less sharp (image is simulated, I did not include the crosshairs):


But I do not consider this to be a problem. It is not too bad if it appears worse in the finder than it really is - it might even help you to get better pictures. And it looks a little better with a modern focusing screen. The same subject in a DSLR with a crop factor of 1.5 (16mm sensor size, 95% finder, AF sensors not included) will look about like this:


I took the original image and only scaled it but did not alter color, contrast, or sharpness because modern finder usually look bright and clear. Of course the aspect ratio would be 3:2 instead of 1:1 as shown here, but if you want to end up with an aspect ratio of 1:1 (a square), you would need to crop. It is really shocking how much smaller the DSLR image is! The finder image will be larger if you plan to crop it or if you use a 135 film camera or an FX sensor (24mm image height = 24mm sensor size in portrait format = 135 film in landscape format):
Another large advantage is you usually use both of your eyes for focusing and composing. The image thus appears three dimensional. Moreover, you see detracting elements much easier in the frame because they are larger. With 6x6 you also do not need to rotate the camera - you can chose between square, landscape or portrait format after the image has been made.
As zoom lenses are much less common with medium format photography, you need to move in order to compose which also helps to find the best perspective. With zoom lenses, one often becomes lazy and does not try different perspectives in order to find the best one. But of course you can also use prime lenses with digital cameras and 135 SLRs.

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