Diffraction Limit Discussion Continuation

Started 9 months ago | Discussions thread
Great Bustard
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Re: It seems odd to me...
In reply to cmpatti, 9 months ago

cmpatti wrote:

Great Bustard wrote:

cmpatti wrote:

Great Bustard wrote:

cmpatti wrote:

Jonny Boyd wrote:

I get the impression that some people see the words 'diffraction' and 'limit(ed)' in close proximity and freak out without reading what I've written.

I think you've put your finger on it. It seems that a number of your interlocutors have become so invested in (correctly) debunking claims that peak resolution depends on sensor resolution or that lower sensor resolution can combat the effects of diffraction that they can't admit that sensor resolution can have any impact on our ability to perceive the effects of diffraction in actual photographs. If I understand you, you're saying merely that higher resolution sensors will enable us to see more subtle diffraction effects than lower resolution sensors will; a suggestion which I wouldn't have thought to be controversial.

...that the system that is "diffraction limited" at the wider aperture is the higher resolving system. For example, if System A is "diffraction limited" at f/4 and System B is "diffraction limited" at f/8, then System A is the higher resolving system, all else equal.

I'm sorry, but I don't understand why that seems odd.

Sorry -- I meant "sounds odd", not "seems odd". Just sounds like if one system is "diffraction limited" at f/4 then it would not resolve as well as another system that is "diffraction limited" at f/8, 'cause, for me, it's as though it were saying the f/8 "diffraction limited" system keeps getting better and better 'till f/8, whereas the f/4 "diffraction limited" system stops at f/4.

Anyway, that's why it sounds off to me.

Hmm. I would have thought the opposite. For example, we usually think that it's a good thing for a lens to be diffraction limited at maximum aperture (as some mFT lenses very nearly are). Since the term "diffraction limited" simply means that aberrations other than diffraction aren't limiting resolution, you want the system to be "diffraction limited" at the widest aperture possible. Or am I missing something?

I see what you're saying, and, to be honest, I can't disagree.  So, the earlier a lens is "diffraction limited", the better it is, since that means the optical aberrations are small compared to diffraction.  I guess my objection was that "diffraction limited" sounded like "resolution limited".

OK, you've convinced me. 

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