diffraction limits...again

[Kirk Gittings]

In the middle of contemplating the rapture last night, a thought struck me (why then I have no idea-but that is another thread perhaps).

I am well acquainted with how diffraction limits effect my negatives when shooting (and plan accordingly-I have tested this on many of my lenses and know where it strarts to influence sharpness).

But I have never noticed its effect when enlarging and sometimes I stop way down purposely to get long exposures to give me time to do complicated burning and dodging. Hmmmmm.....

[Mark Woods]

Hello Kirk, what is the smallest stop on your enlarging lens?

[Greg Blank]

I have to tell you that my opinion is that: On all modern lenses I have used diffraction,... I don't see the so called problems these limits impose. I also firmly believe these issuses that are upon by hand wringing people that can't find enough reasonable excuses for not being able to make pictures. I have used my 4x5 enlarger lens wide open an stopped all they way down- wide open can certainly effect sharpness if your enlarger is not aligned well....stopped down effects sharpness sometimes "in a positive way". You might be able to see the problems through a microscope between f16 and f45

In the middle of contemplating the rapture last night, a thought struck me (why then I have no idea-but that is another thread perhaps).

I am well acquainted with how diffraction limits effect my negatives when shooting (and plan accordingly-I have tested this on many of my lenses and know where it strarts to influence sharpness).

But I have never noticed its effect when enlarging and sometimes I stop way down purposely to get long exposures to give me time to do complicated burning and dodging. Hmmmmm.....

[Noah A]

I haven't used an enlarger in years, but it seems to me that when you shoot a negative, any diffraction-related sharpness loss will be magnified when you later enlarge that negative (or inspect it with a powerful loupe).

When you make a print, it's possible that any sharpness loss is just not noticed since you're probably not further magnifying the print or even inspecting it under a loupe for that matter.

[ic-racer]

But I have never noticed its effect when enlarging and sometimes I stop way down purposely to get long exposures to give me time to do complicated burning and dodging. Hmmmmm.....

???
Very noticable with rollfilm. Perhaps your LF negatives have magnification ratios too small to see the effects on the grain.

With a grain magnifier, throw a 35mm TRIX negative in your enlarger with a 50mm lens. It is very informative. The grain in the center is sharpest wide open (usually, depending on your lens) and keeps getting worse as you stop down. Most usually F8 will be the farthest you can go without being annoyed by it. At f16 it is just a blurry mess.

With an 8x10 negative making a 11x14 print, indeed, the above effects are very hard to see because the magnification ratio is so small and the grain is so small.

What exactly is your setup?
Grain magnifier type?
Lens?
Format?
Enlargement size?

[Henry Ambrose]

It'll only matter if the resolution that the paper and negative are capable of is greater than the output ability of your lens at a given aperture and reproduction size. At 1:1 you may never see any loss no matter the aperture, at 1:10 you may.

Also consider your ability to see at the viewing distance to the print. Across the room from the 1:10 you may not see any loss.

Some really smart person will, no doubt, calculate this for us. Otherwise if your prints look great, they look great!

[rdenney]

Hmmmmm.....

Hmmmm indeed. In my Peak grain focuser, I could clearly see where the crispness of the grain improved as I stopped down from wide open, and then degraded again as I kept stopping it down. Maybe you need a better grain focuser.

Rick "wondering what penance in Hell is reserved for being presumptuous with the likes of Kirk" Denney

[Oren Grad]

It depends...

It's easy to see the effect of stopping down through my Micromega. But some years back I also did an experiment in which I made a modest enlargement from a half-frame 35mm negative made on Tri-X with my Pen FT and 40/1.4 Zuiko - I think the final image size was around 3x4", which is about a 4x enlargement. I made a series of prints, bracketing through the entire aperture range of my EL-Nikkor. I think I used the 50/2.8, though it may have been the 80/5.6.

I have the prints buried away somewhere. But as I recall, even with my nose in the prints it was very difficult to see any degradation in image clarity until I got down toward the tail end of the aperture scale - I think it was f/16. But at that point it was clearly apparent. With a greater degree of enlargement, I expect the degradation would have been visible sooner.

[GPS]

Diffraction is the same for all lenses for the same aperture number given a light wavelength. Everything else you can ascribe to the alchemy of perceived sharpness - there lies your hidden answer.

[Greg Blank]

That would equate to all lenses being made from the same materials. Which they are not. Differing materials produce differing degrees of diffraction, an example would be a Flourite lens versus a standard. Or an HM lens versus a standard.

Diffraction is the same for all lenses for the same aperture number given a light wavelength. Everything else you can ascribe to the alchemy of perceived sharpness - there lies your hidden answer.