Which one of these has shallower dof?

[Epimetheus]

Here is a stupid question. I would like to know which of these camera lens combinations is able to produce a shallower depth of field when using the widest aperture.

1. Olympus OM-2 with Zuiko 55mm F1.2
2. Pentax 67 with 105mm F2.4

There is not much difference in the numbers on depth of field calculators but I don’t think that’s the whole truth.

Format FL f/No Object dist. Depth of Field
35 55 1.2 3 0.210 m
6x7 105 2.4 3 0.246 m

 

[rxmd]

That's not much of a difference in the numbers; in depth of field alone you wouldn't notice too much of a difference. Nevertheless the pictures would probably look rather different; in this kind of comparison the results depend much more on the OOF rendering characteristics of the lens than on the maximum aperture number alone. That's also where it begins to be somewhat subjective. For example, I like the look of the 105/2.4 a lot 🙂

A print from the medium format lens is quite likely to have nicer tonality, given the lower enlargement factor and larger negative area. (We had a rather interesting thread on that some time ago.)

Incidentally, which DOF calculator did you use?

Philipp

 

[Epimetheus]

I used this one: http://www.bobatkins.com/photography/technical/dofcalc.html