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Author Topic: Canon 50D review out  (Read 38151 times)

jani

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Canon 50D review out
« Reply #100 on: November 05, 2008, 09:07:01 am »

Quote from: Slough
Why don't you just accept that your statement that all lenses - with a few old exceptions - show negligible change in resolution down to and including F16 is, errr, not completely founded in reality?
I think it may have something to do with you not showing that this is the case.
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Ray

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« Reply #101 on: November 05, 2008, 10:20:42 am »

Quote from: Slough
Why don't you just accept that your statement that all lenses - with a few old exceptions - show negligible change in resolution down to and including F16 is, errr, not completely founded in reality?


If you have to ask such a question, I can't help you. I'm rather amazed that you should expect anyone to disregard the results of their own testing and accept someone else's word, without evidence, that their results are wrong. We all know that good lenses are not as sharp at F16 as at F11. However, resolution in the recorded image is a combination of both lens resolution and sensor resolution. The additional resolving power of the 50D, combined with a little extra sharpening, produces a result at F16 which is as detailed as the 40D at F11, with my equipment. I have demonstrated this to my own satisfaction. It matters not one whit to me if you choose to believe I've misrepresented the results of my tests. You're not the one taking my photos.

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« Last Edit: November 05, 2008, 10:22:54 am by Ray »
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Slough

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« Reply #102 on: November 05, 2008, 12:06:42 pm »

Quote from: Ray
If you have to ask such a question, I can't help you. I'm rather amazed that you should expect anyone to disregard the results of their own testing and accept someone else's word, without evidence, that their results are wrong. We all know that good lenses are not as sharp at F16 as at F11. However, resolution in the recorded image is a combination of both lens resolution and sensor resolution. The additional resolving power of the 50D, combined with a little extra sharpening, produces a result at F16 which is as detailed as the 40D at F11, with my equipment. I have demonstrated this to my own satisfaction. It matters not one whit to me if you choose to believe I've misrepresented the results of my tests. You're not the one taking my photos.

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Sorry?

"We all know that good lenses are not as sharp at F16 as at F11. "

Well, going by your earlier posts you don't.

As regards the statement that "The additional resolving power of the 50D, combined with a little extra sharpening, produces a result at F16 which is as detailed as the 40D at F11, with my equipment. " well that is a new point not made by you before. You have a habit of saying one thing and meaning another.

Whatever. You make a good Humpty Dumpty.
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Slough

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Canon 50D review out
« Reply #103 on: November 05, 2008, 12:08:18 pm »

Quote from: jani
I think it may have something to do with you not showing that this is the case.

I suggest you read about diffraction.
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jani

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« Reply #104 on: November 05, 2008, 06:02:21 pm »

Quote from: Slough
I suggest you read about diffraction.
Eerily enough, that was what I was about to suggest to you, but I considered it too rude to do so to a fellow photographer.

Considering that you brought it up that way, however, I don't, anymore.

Since you don't appear to know much about diffraction and why it isn't a significant effect of a particular lens design, as much as it as to do with the aperture, I not-so-humbly suggest that you re-read the theory, and reconsider that you might be confusing "diffraction" with another technical term related to lens performance.
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Slough

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« Reply #105 on: November 05, 2008, 06:55:51 pm »

Quote from: jani
Eerily enough, that was what I was about to suggest to you, but I considered it too rude to do so to a fellow photographer.

Considering that you brought it up that way, however, I don't, anymore.

Since you don't appear to know much about diffraction and why it isn't a significant effect of a particular lens design, as much as it as to do with the aperture, I not-so-humbly suggest that you re-read the theory, and reconsider that you might be confusing "diffraction" with another technical term related to lens performance.

 
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Slough

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« Reply #106 on: November 05, 2008, 09:06:21 pm »

Quote from: jani
Eerily enough, that was what I was about to suggest to you, but I considered it too rude to do so to a fellow photographer.

Considering that you brought it up that way, however, I don't, anymore.

Since you don't appear to know much about diffraction and why it isn't a significant effect of a particular lens design, as much as it as to do with the aperture, I not-so-humbly suggest that you re-read the theory, and reconsider that you might be confusing "diffraction" with another technical term related to lens performance.

You pretend to be polite whilst being rude. I have no idea what point you are trying to make if any.

Ray stated that lens resolution is pretty much constant throughout the aperture range for most lenses apart from old designs. I disagree with that statement. He has now changed his mind.

"Since you don't appear to know much about diffraction and why it isn't a significant effect of a particular lens design, as much as it as to do with the aperture, I not-so-humbly "

Quite why you make such an obvious statement is beyond me. It is the very reason why I disagree with Ray's original statement.  

In most camera lenses the resolution is nowhere near the diffraction limit except when stopped well down other aberrations being dominant at wider apertures. Some Schmidt cameras are fast - e.g. F1.0 - and much closer to being diffraction limited. I am sure you can find information on this from Google. Some of it might be accurate.

You might wish to read up on concepts such as the Dawes Limit and Rayleigh limit, which are measures of the theoretical maximum resolution of a telescope, but have relevance to camera lenses when stopped well down.
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jani

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« Reply #107 on: November 06, 2008, 10:50:03 am »

Quote from: Slough
You pretend to be polite whilst being rude. I have no idea what point you are trying to make if any.
I didn't pretend to be polite, I was admitting that I was being rude, quid pro quo.

Quote
You might wish to read up on concepts such as the Dawes Limit and Rayleigh limit, which are measures of the theoretical maximum resolution of a telescope, but have relevance to camera lenses when stopped well down.
Here's one for you.

I'm not the one claiming that diffraction has something to do with other effects than the aperture.
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Slough

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« Reply #108 on: November 06, 2008, 11:53:04 am »

Quote from: jani
I'm not the one claiming that diffraction has something to do with other effects than the aperture.

I don't understand what you mean by that sentence. And your point is?
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