A quick tip for DSLR users who add 35mm film or digital full-frame photography to their repertoire; don’t forget that there will be a depth of field difference in your final shot.
The amount of difference will be determined by several factors, including the focal length of your lens, the distance to the desired focus point, and aperture settings.
This past weekend I finished a roll of film on a nearby park that I shoot fairly often. I decided to shoot the porch of an old historic house that is on the property, and compare it to digital shots I had of the same angle.
This is what the photo looked like from my Canon 60D DSLR (1.6x crop factor); I shot with a 24mm 1.8 lens (which is equivalent to 80mm on a full-frame digital or 35mm film camera), at f/3.2. I focused about 3 feet into the scene, near the wooden column on the right:
And here is the same shot from my Canon AE-1 35mm film camera, using a 50mm 1.8 lens shot at f/5.6, focused in around the same area:
Small differences in composition and other factors changed the depth of field quite considerably. When shooting a film camera, remember that you won’t see this exact difference until your develop the negatives and have a print or scan made. If your camera has a depth of field preview button, you can see an approximation, but will lose a huge portion of light coming in to the preview, so it will be difficult to tell exactly what you’re working with.
In short, remember to allow yourself a bit more leeway when composing based on expected sharpness; you’ll usually find a scene that will render in a favorable way at f/4 on your crop-factor DSLR will have too thin of an area of focus at that same aperture on your 35mm film camera. Always take note of your camera settings for your film shots, and adjust your aperture accordingly when shooting to get the depth of field you’re looking for.
You can find a much more in-depth explanation here of how depth of field works on different sized sensors and what factors come into play: