I don't doubt your word but I don't understand why. Is there a human
vision component that is helping piece the image together? I think
something like that is hypothesized for digital due to the lack of grain.
Chuck Norcutt
C.H.Ling wrote:
> No one would argue there is degrade in image quality at F22 but I will not
> put all my trust to calculation figures. I didn't see any 4MP (even 8MP)
> digital camera can produce the image I got here at F22, I'm happy to see if
> there is one.
>
> BTW, besides slight lost in resolution there is greater drop in fine
> contrast at F22, use suitable unsharp mask can bring the F22 image very
> close to the F4 one. For instant, I tried 10% R20 + 80% R0.8, it gives great
> improvement without visable artifacts.
>
> C.H.Ling
>
> ----- Original Message -----
> From: "Chuck Norcutt"
>
>> Well, the fact is that 4MP can still make a passable 8x10. But why have
>> a 21MP camera if your happy with 4? You have to look carefully but
>> there are most certainly big differences in the two photos. For
>> example, near the center and at the top of the building is a large
>> square red logo with "H", "K" and a stylized "S" shape in the center. A
>> little over twice its width and to the right of that logo is what looks
>> like a fan in a gray metal housing. In the f/4 image the louvers in the
>> fan housing are quite sharp and distinct. But in the f/22 image they've
>> been nearly blurred out of existence. And these are straight lines
>> which are the easiest things for the eye to see. In fact the eye
>> sometimes sees straight lines where they don't exist by trying to
>> connect fragments of detail. In other words, the detail here has been
>> obliterated. Can I prove it's now a 4MP image? Nope. Can you prove
>> that it's not? All I can say is that it has lost fine detail that the
>> camera and lens are capable of resolving and did resolve at a wider
>> aperture.
>>
>> Chuck Norcutt
>>
>>
>> Ken Norton wrote:
>>>> So at F22 the image only have 4MP resolution, right? But this 4MP image
>>>> looks pretty good to me.
>>>>
>>>
>>> Wow, that F22 image is just horrid. I can plainly see that the lens is
>>> diffraction limited at F4.
>>>
>>> NOT!
>>>
>>> Good example of how diffraction limits seem to have a different bearing
>>> in
>>> the digital world than in the dark ages of film. Now, can anybody show me
>>> hard evidence that we really are running into diffraction limits with our
>>> new fangled digital cameras?
>>>
>>> AG
>
--
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