Aperture for nice skies

[NedL]

I've been finding myself opening up my aperture more often lately when there are nice clouds. A year ago, many of my landscape shots were f/11 or smaller for 35mm, f/22 or smaller for 120, and often f/32 or f/45 for my old antique cameras.

These days, I often choose f/5.6 or even f/4 on 35mm and f/11 or f/8 for MF, and f/16 on my old kodak folders. In other words I'm making a choice that the sky looks enough better to frame my picture differently or accept some foreground softness. I've seen this effect in all of these film formats, on contact prints as well as enlarged prints.

My question is why? There are lots of related threads on APUG, e.g. (there was a url link here which no longer exists) but what's actually going on? I can see that not everyone stops way down for landscape shots, but not the WHY of it!

When people say a lens has a "sweet spot" at f/4 or f/5.6, what exactly is better than at f/16? I've heard the term "micro-contrast" but I don't know what it means... is that it? I'm not seeing any obvious difference in the range of tones in my prints, and all are in focus if you look closely.

Honestly, I look at the prints, and I know I like the skies in one better, but I can't say what's different. I don't think it's my imagination.

I suppose in the end it doesn't matter why... I'll keep doing what I like, but it's curious and it seems like it goes against the "common f/64 wisdom" for landscapes...

 

[Chris G]

There is a loss in sharpness due to diffraction at smaller apertures. Its a bit of a balancing act between depth of field and this loss of sharpness due to diffraction. That's why the sweet spot is somewhere like 5.6 or 8 (35 mm).

 

[NedL]

There is a loss in sharpness due to diffraction at smaller apertures. Its a bit of a balancing act between depth of field and this loss of sharpness due to diffraction. That's why the sweet spot is somewhere like 5.6 or 8 (35 mm).

That makes sense. It may be that I'm only now learning what sharpness really means in different parts of my photos.

 

[Chris G]

There is only a very tiny slice in the depth of field that is truly in focus (sharp), everything else on the depth of field scale is deemed acceptably in focus, acceptably being subjective, ie. the circle of confusion.

As you stop down, this range or depth increases... but past a certain point the light starts to diffract and the image suffers a loss of sharpness ... a balancing act..

 

[NedL]

Thanks! I get that. My subjective impression is that the difference is not focus but it could be other aspects of perceived sharpness like edge effects or contrast or something else. It's hard to find anything that looks out of focus ( blurred ) on prints of more stopped down photos. The effect is hard to see when you look at little details in the print, but more of an overall impression. But I can imagine a tiny bit of blurry could be hard to spot in a detail, but give an overall impression of "less sharp". Also, these are not big prints ( mostly 5x7 and about ~6x9 prints ).

 

[Chris G]

Ahh... a certain "je ne sais quoi"


Always nice to contemplate...