Trying to Choose New Camera and Lenses: Olympus OM-D vs Sony NEX

NO DOF depends on three major things:

1. Focal length
2. Apperture
3. Distance

And although you are technicly right here, you forget a very importaant part of photography: how to frame a picture. When you take a picture with your 50mm lens on a FF camera the perceived DOF will be exactly the same as when you take the picture from the same distance with the same lens on a m43 camera, as long as you enlarge the picture by the same number, only the FF camera will show a bigger picture, with a wider view. You have to enlarge the same to compare apples with apples...

And they are right you know. When you take a picture with a FF camera with an 50 mm lens at F2.8 and you wan t to recreate the same looking picture (same FOV and DOF) you can do two things: move farther away from the subject and use a wider apperture, or use a lens with a smaller Focal length and a wider apperture. As you see, in both cases you need a larger apperture to recreate a picture with the same FOV and DOF. And that is what the Apperture equivalent is all about.