All the DOF calculators I looked at were - and probably still are - based on the laws of optics of an ideal, infinitely thin lens. Within this theoretical model and the cases we’re talking about in this part of the forum, the distance between sensor and film should be 400mm when a 100mm lens is used to capture e negative with a scale of 1:1.
The usual camera lens is everything but infinitely short, which suggests that calculations based on theoretical models might still apply, but in a completely different way. Let’s take a look at this lens:
At 1:1, I measured the distance between sensor and negative to be 300mm, which - according to “ideal optics” - makes the focal length of this lens shrink to 75mm and move the “ideal lens” from position A to position B. With additional measurements, I get this:
Does any of the above matter in respect to DOF? I don’t know yet, I’ll post results as soon as I get them. Meanwhile, you can check DOF here, it’s the only site I found so far that even considers the macro situation.
Anyone any ideas or manufacturer info regarding DOF @ macro?