Originally posted by fejker I'm all in for [...] and dof control.
Originally posted by ftpaddict I don't need the resolution, just the DOF control.
Because this is stated so many times, let me make my comment on this once in while...
Available DoF (at a given FoV) is
only determined by the physical lens aperture in mm. So, I had a look at the available Pentax 645 prime lens lineup [source: pentax.de]:
- 35/3.5 -> 10 mm -> 20/2.0 -> FA 20/2.8, FA24/2.0
- 45/2.8 -> 16 mm -> 26/1.6 -> A 28/2, Sigma 30/1.4
- 75/2.8 -> 27 mm -> 43/1.6 -> FA 43/1.9, A50/1.2
- 120/4.0 Makro -> 30 mm -> 69/2.3 Makro -> FA77/1.8, FA50/2.8 Macro, FA100/2.8 Macro
- 150/2.8 -> 54 mm -> 87/1.6 -> FA85/1.4
- 200/4.0 -> 50 mm -> 116/2.3 -> FA100/2.8 Macro
- 300/4.0 -> 75 mm -> 173/2.3 -> FA135/2.8, FA200/2.8, A135/1.8
- 300/5.6
- 400/5.6 -> 71 mm -> 231/3.3 -> FA300/2.8, FA200/2.8
How to read:
#. 645 lens focal/aperture -> physical diameter -> FF lens/aperture with same DoF -> closest FF lens in Dimitrov's lens archive (dropping '*'-designations).
(Here, I assumed that FF is a 1.73x crop from MF. Where I used a MF size of 60x45mm which is wrong. The correct value is 56x41.5mm. Fortunately, the argument doesn't depend on this.)
Where the corresponding FF glass actually has wider aperture, I've put it in boldface. I.e., the FA*85/1.4 or A50/1.2 offer DoF control unparalleled in the MF range.
Overall, medium format offers a
slight advantage with respect to DoF control over FF. Much less significant than most people would believe w/o going through this exercise. And some lenses at the very short and very long end simply don't exist for MF. The advantages of MF are elsewhere (brighter VF, less noise, potentially much more headroom for digital crop, etc.). Therefore, I never would give up a "high-megapixel"
option when going MF.
Last edited by falconeye; 04-01-2009 at 03:12 AM.
Reason: added the A*135/1.8 and FA*24/2.0, added 56x41.5 comment