Sooner reaching diffraction limit with higher megapixel cameras

[David_Winston]

I am trying to grasp my head around certain things. One of them is diffraction, according to Cambridge in colour it is dependent of pixel pitch of the sensor,the aperture of the lens and of course the final size and viewing distance of the print. Neglecting the print size and the viewing distance and just focusing on aperture and pixel pitch. Will increased megapixels lead to sooner hitting the diffraction limit?

So if you were to jam 60 or 70 megapixels in a full frame sensor wouldn't you at one point reach diffraction very soon? I think it was some manager from Fujifilm that said, that FF's limit would be around 60mp to 100mp. Was it that that he was referring to?

I did some testing with an A7iii and an A7R iii with the same lens of a lens testing chart at various apertures (5.6 to 11). 5.6 where diffraction starts to kick in. When I downsampled the A7R iii image down (both no sharpening) I still found the A7R iii to be sharper at all apertures.

Why is that so? Is that gain in resolution outweighing the diffraction? Or is the jump from 24mp to 42mp just not that big?

Or should I have tested at smaller apertures (maybe then I would have seen the difference (I rarely use f16 so I didn't feel I should test it)?

What do you think? Will 70mp FF cameras even be useful?

 

[J A C S]

Also factor in the lens aperture. With some primes, lenses with very large apertures like f/1.2 and f/1.4, diffraction can start at f/9 and f/11.

I have never heard of this. Can you supply a source for this information? If true possibly it's due to the number of elements and type of glass used which can be different in fast lenses than slow lenses. Another possibility is at small apertures a smaller % of the glass elements is used compared to slower lenses.

It is very simple. At f/9 or f/11, physics changes and light becomes a wave. Above that, it is particles. The magic aperture is f/9.1919191..

That doesn't address the statement, that diffraction starts at different apertures with fast lenses than slow lenses. I was speculating that if true, and I doubt it is, what could cause it.

I suspect it was a joke.

It didn't seem at all like a joke and I don't think it was. There wasn't even a hint of sarcasm.

I thought that this was so absurd that it was obvious that it was sarcasm. Especially in the context of the other posts of mine here.

 

[tbcass]

I suspect it was a joke.

It didn't seem at all like a joke and I don't think it was. There wasn't even a hint of sarcasm.

I thought that this was so absurd that it was obvious that it was sarcasm. Especially in the context of the other posts of mine here.

Actually I have seen far more absurd statements made here that were not jokes. I have also had some of my sarcastic comments taken seriously. Not everybody is equally knowledgeable and many rely on incorrect information supplied elsewhere on the web. This is where a smiley emoji can save a lot of confusion and is what I now do to make my intent clear.

--
Tom

 

[bobn2]

Also factor in the lens aperture. With some primes, lenses with very large apertures like f/1.2 and f/1.4, diffraction can start at f/9 and f/11.

I have never heard of this. Can you supply a source for this information? If true possibly it's due to the number of elements and type of glass used which can be different in fast lenses than slow lenses. Another possibility is at small apertures a smaller % of the glass elements is used compared to slower lenses.

It is very simple. At f/9 or f/11, physics changes and light becomes a wave. Above that, it is particles. The magic aperture is f/9.1919191..

That doesn't address the statement, that diffraction starts at different apertures with fast lenses than slow lenses. I was speculating that if true, and I doubt it is, what could cause it.

I suspect it was a joke.

It didn't seem at all like a joke and I don't think it was. There wasn't even a hint of sarcasm.

I detected the sarcasm. It was neatly done.

 

[Tony Beach]

I am trying to grasp my head around certain things. One of them is diffraction, according to Cambridge in colour it is dependent of pixel pitch of the sensor,the aperture of the lens and of course the final size and viewing distance of the print. Neglecting the print size and the viewing distance and just focusing on aperture and pixel pitch. Will increased megapixels lead to sooner hitting the diffraction limit?

It's not a "limit;" it has an impact though. The analogy would be when you hit a brick wall head on you are limited in going any further, but if you graze it as you drive by it then it impacts how fast you are going.

So if you were to jam 60 or 70 megapixels in a full frame sensor wouldn't you at one point reach diffraction very soon? I think it was some manager from Fujifilm that said, that FF's limit would be around 60mp to 100mp. Was it that that he was referring to?

Lens capabilities and diminishing returns as you stop down the aperture on them.

I did some testing with an A7iii and an A7R iii with the same lens of a lens testing chart at various apertures (5.6 to 11). 5.6 where diffraction starts to kick in. When I downsampled the A7R iii image down (both no sharpening) I still found the A7R iii to be sharper at all apertures.

Not surprising.

Why is that so? Is that gain in resolution outweighing the diffraction?

Yes.

Or is the jump from 24mp to 42mp just not that big?

It's big enough to notice an improvement in sharpness.

Or should I have tested at smaller apertures (maybe then I would have seen the difference (I rarely use f16 so I didn't feel I should test it)?

A long time ago I did this test and have found it useful ever since then. The bottom line is the diffraction impact is not as great as the resolution limit.

What do you think? Will 70mp FF cameras even be useful?

Yes, and the biggest reason I would offer is that it will help eliminate moire.