Depth of Field

[Krzys]

I seem to have fallen in love with f/4 on my Canon 50mm f/1.4 FD. My question is that what aperture on my (medium format) Mamiya Sekor C 80mm will give the same depth of field as the (small format) 50mm at f/4 and what is the sharpest point for the lens?

 

[Herzeleid]

I find this site quite useful for DOF, www.dofmaster.com
No idea with Mamiya Sekor.

 

[Rolleijoe]

Those lenses are totally different. So their bokeh won't exactly be the same. Experience is the best teacher, just shoot a roll and see if it gives you want you're looking for.

 

[elekm]

I agree. It might be f/5.6 or f/8, but either way, different lens designs will yield different characteristics. It's one of those things that you'll only learn through experience -- often known as trial and error (or in my case, just error).

 

[Nicholas Lindan]

The same DOF at ~f6.8, but experiment with a roll of film and find the one you like the best.

Optimum resolution should be around f11 +/- 1 stop. Print out a resolution chart and put it in the test roll you shoot, above. Finding the best aperture doesn't require anything fancy in a resolution chart, it's pretty obvious where the sharpest apertures are.

 

[mweintraub]

Plus the distance from the subject changes the DOF.

 

[ic-racer]

A good rule of thumb is to match absolute aperture size; ie around 12mm. You can look in the lenses side-by-side and get a rough guide. You can also calculate it as others have indicated (around f6 to f7 on your 80mm).