Nikon D800/E Diffraction Limits

Started Apr 28, 2012 | Discussions thread
Forum ProPosts: 26,139
Re: Nikon D800/E Diffraction Limits
In reply to SNRatio, May 5, 2012

SNRatio wrote:

bobn2 wrote:

And the D3 has less resolution at f/11 than it has at f/5.6. The D3X has more resolution at every f-number. DOF comes at the cost of resolution, that is inevitable. Throwing pixels at an imaging problem improves resolution.

I see, you have an extremely wide definition of "meaningful".

Not at all, I'm just not going along with your meaningless line of reason.

If you can't see the meaning yourself, you might perhaps want to be a little bit more careful in branding others' concerns as "meaningless"?

I wish people would make up their minds. First I'm accused of having too wide a definition of 'meaningful', now it appears you think its too narrow.

At least if you want to be taken seriously.

I'm not worried about not being taken seriously by people who can't be taken seriously.

That is not at all the point. DOF comes at the cost of resolution. Oh I see that I said that before. Sure, if your 'much used f-stops' are f/16 equivalent and so-on, then there really isn't much point using any FX camera, or DX for that matter. You might as well save money and inconvenience and use a compact. These cameras, whatever the pixel count, only come into their own for shallower DOF's. Though, even at deep ones a 36MP camera will be marginally better than, say, a 12MP one.

This also applies to f/11, which may also be a no-go land in your book, the way you argue..

Not so much. f/11 gives the same DOF and diffraction blur as f/2.7 on a 1.7" compact, so it's on the limits of compact territory. It's not 'no go land' at all, it's just if you do all your photography there, then you get hardly any benefit from a DSLR.

Go communicate your insight to the macro shooters, and some landscapers plus, plus.... You really have a job to educate them.

That's not my problem. If they wish to waste their money and muscle power on enormous heavy cameras and lenses when a smaller cheaper camera would do the same job, it's them who loses, not me.

And your "DOF comes at the cost of resolution" mantra easily overlooks one of the real advantages of increasing resolution.

It may be a mantra, but it is true. It's hard to argue with physics (my mistake, it's quite easy to argue, hard to achieve 'meaningfulness' in its face).

For instance, with the D3X, with several lenses, you can stop down one additional stop and have about the same MTF as the D3 - and this may be even much more pronounced with the D800.

It depends from which stop you are stopping down. When the system is truly diffraction limited, you gain little to nothing.

- but hey, I'm a megapixel fan, sure the benefits extend way above where most people talk about the camera being 'diffraction limited', and you cant get a 36MP compact (though you can get a 41MP phone).

You are far from the resolution limits of the sensors then, but that may not be the most relevant issue for many applications - like macro and some types of landscape.


The interesting, and practically relevant, phenomenon here is not the trivial truth that all sensors lose resolution to diffraction on stopping down, but the amount of degradation. While the D3 typically loses 20-25% linear resolution upon stepping down from f/5.6 to f/16, the D7000 may lose 40-45%. And the D3200 possibly a good bit more, when an adequate lens is used.

That's a silly 'glass half empty' argument. Who is interested in how much you've lost ? What matters is how much you have .

I've really lost track of which side of the argument you're on. You've just berated me for overstating the large DOF diffraction loss, now you're berating me for saying that obsessing about losing a higher percentage of the original resolution is silly.

You are clearly not very interested in why such considerations may be very important to quite a few shooters, so I just urge you to keep your silliness characterizations to yourself. It's best for you, I think.

Now you're being silly.

First one you will be shown to be wrong, the 50/1.8G is a pretty good lens. Second two, sure, but still an improvement.
What's certainly true is that there is no fixed 'limit'.

Preliminary data don't seem to support your prophethic abilities, however much you trust them yourself. At lensrentals, they tested the 50/1.8G to 1045 centrally, well below the 70-200 II (1080) and the ZF.2 50/1.4 (1137).

I don't trust lens rentals tests at all. Their resolution curves are very strange and don't seem to correlate with anyone else's. There are many pratfalls in lens testing, and I guess that they are falling into some of them.

And I think I give up on trying to bring up/point to the phenomenon of "asymptotic".

asymptotic is a good word, but again, wanting to talk about the phenomenon leaves me a bit bemused about which side of the argument you are on.

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