Diffraction Limit

Started Aug 28, 2013 | Discussions thread
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Anders W Forum Pro • Posts: 21,465
Re: In other words...

Great Bustard wrote:

Anders W wrote:

Great Bustard wrote:

Anders W wrote:

Great Bustard wrote:

Steen Bay wrote:

Took a look at FZ200 in IR's 'comparometer' to see what kind of resolution we're talking about here. The resolution test chart is shot at f/4 (DoF/diffraction equivalent to f/22 on FF and f/11 on mFT), and I'd say that the resolution is about 2200 lw/pH. Not that bad for a sensor with 3000 vertical pixels.

The question is how that resolution would fare against a camera with a FF system at f/22 sharpened to the same degree.

You know me -- I'm quite the fan of the FZ200 and quite the fan of putting anything I say to the test.

So, if you can sport me links to a photo from the FZ200 at f/4 (or any other superzoom) and a RAW (DSLR jpg engines don't sharpen like compact jpg engines) photo of the same scene from FF at f/22, I'll be happy to process the FF photo and post a comparison.

Here's the link you need for the FZ200. Take your pick among the RAWs available on that page and find the corresponding one for the the FF camera you want to compare with.


In general, just find the IR review of the camera you are interested in, then click on "Samples" in the top menu and then on "Thumbnails" in the menu that appears below the topmost one.

Those are all at f/4, which is fine, but where do I find f/22 pics on FF? I found this, for example:


but nothing at f/22.

Hmm. Didn't think of that minor complication.

Odd, as it's my most used setting.

For some strange reason, it seems like the test sites prefer to shoot cameras in the aperture range where they do best. Wonder why they do that.

You're asking the wrong person.

I am afraid you might have to ask for some diligent forum member with a FZ200 as well as an FF camera to help you out here.

Steen posted above that they have an f/22 pic shot in RAW with the 6D, but I couldn't find it.

Yeah, I saw that. So my idea was less crappy than I thought for a while. And from your own cam and all. Ain't that nice?

Where the file is? Look here, last one in the initial series of the building:


Anyway, on a more serious note, I know it's subjective, and dependent on the type of photography that one does, but it's very rare that I come across a scene where f/8 on FF (f/4 on mFT) wouldn't give enough DOF.

I suspect that's true in my case too.

For sure, in the case of macro, or near macro, many need deeper DOFs, and TSE lenses can be used for to excellent effect for ultra deep DOFs without the adverse affects of diffraction by tilting the focal plane (when is mFT going to get TSE lenses?).


On the other hand, most seem nonplussed by the resolution loss due to heavy diffraction softening, and this coincides well with a rash of threads in 1022 where people were claiming that even at 17x22 inches, they could see no difference in resolution, whatsoever, between a 5 MP E1 and a 10 MP E30, without the aid of a magnifying loupe (and the person making this claim claims he has 20/10 vision).

So, when we put these together, what I'm thinking is that all modern systems, including compacts, have resolution to spare, and that most people have no use for the amount of resolution their equipment actually gives them.

Of course, it's curious, then, that these same people will ooh and ahh over how sharp this or that lens is.

Don't know about prints. Haven't had much opportunity to do such exercises with those lately. But I remember seeing them quite clearly in the darkroom with the enlarger when I did lens tests way back when. Does that count?

As to the present, I don't have much difficulty seeing differences in lens performance on the monitor even at ordinary display size, at least if the difference is clear enough. So here's a test for you (and others) based on test shots from SLRGear with the Oly 17/2.8 and the Pany 20/1.7, both wide open on the same camera (E-P1, 12 MP). Put those side by side at full ordinary display size, so that each covers the monitor (but not larger, don't peep). Then tell me if you see any difference with regard to "sharpness" (resolution, microcontrast, including color contrast), and if so what more specifically you see.



Myself, as I've said many a time, I think that IQ, at best, is simply a component of a quality photo, and that, at best, detail is simply a component of IQ. Indeed, given how often I'm shooting wide open on FF, where the resolution is clearly far from its max, resolution takes a back seat to other considerations. That said, I would always welcome more resolution, and not shoot at a setting that gave me less resolution unless that setting had advantages that outweighed the loss in resolution.

That's pretty much my position too. But one thing that I'd like to add is that I often enjoy looking at (and show) images in higher than ordinary display size (i.e., zooming in here or there on the final jpeg) for reasons other than technical inspection (why shouldn't we do such zooming now that we have that option easily available). Another is that I do hope to see the day when I have something better than a 2 MP screen in front of me. In fact, I hope to do so pretty soon. And it'd be nice if there was some sharpness in my shots to spare when that time comes.

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