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10-22-2009, 07:26 AM   #31
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QuoteOriginally posted by ogl Quote
dear friend, give us, please, the formula.
I have a formula indeed. But is is sort of complicated and not really required.

Once you know that figures can be interpreted for higher resolving sensors as well, you develop a kind of natural feeling for the figures.

Esp. lenses which resolve better at f/5.6 than at f/4 are less suitable for high resolution sensors. If they are about equal, 15MP are still ok.

10-22-2009, 03:57 PM   #32
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falconeye, first off, don't be ahead of yourself by assuming that I didn't read the article from Zeiss or my supposed inability to read figures.

If you need reminding, MTF curves do not always tell the whole story of a len's performance. The MTF curve here are derived from digital image files. The MTF curves for a lens shot with the K10D and K20D or K-7 will be different simply because the number and size of the sensor pixels, design of the low-pass filter, sensitivity of a CCD to CMOS sensor, the algorithms used for image processing including degree of sharpening. All have an impact on the MTF.

So please don't say it doesn't matter that the camera used was a K10D and that one can extrapolate how it will perform on higher resolutions. The fact is the MTF curves will vary with different cameras models and brands. No need to make excuses for photozone. Their test results are relevant only for the discontinued K10D.


K20D DA 15mm

Last edited by creampuff; 10-22-2009 at 05:08 PM. Reason: link
10-22-2009, 04:23 PM   #33
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This lens really suits me for ease to carry with relative flare resistance performance. Besides, it looks very cute with a metallic hood: sleek, simple and classic.

While the talk about sharpness being way out of proportion, I love the corner to corner sharpness being relatively even that allows simpler sharpening to create the clinical sharp look desired.

As many interesting photographers I have encountered and learnt from over the years, this type of lab report provides some clues about the lens but not its full application.

BTW the sample galleries always look sooooooo boring. Yet, they are called field testing. A lot of crap.
10-23-2009, 02:22 AM   #34
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QuoteOriginally posted by creampuff Quote
falconeye, first off, don't be ahead of yourself by assuming that I didn't read the article from Zeiss or my supposed inability to read figures.
creampuff, you are right. Please, accept my apology.
QuoteOriginally posted by creampuff Quote
The MTF curve here are derived from digital image files. The MTF curves for a lens shot with the K10D and K20D or K-7 will be different simply because the number and size of the sensor pixels, design of the low-pass filter, sensitivity of a CCD to CMOS sensor, the algorithms used for image processing including degree of sharpening. All have an impact on the MTF.
This is correct and I said exactly the same. Additionally, I said that you can derive the MTF curve on one camera from the MTF curve on another. So, may I propose to read the article from Zeiss again?
QuoteOriginally posted by creampuff Quote
So please don't say it doesn't matter that the camera used was a K10D
I didn't say that it doesn't matter.
QuoteOriginally posted by creampuff Quote
Their test results are relevant only for the discontinued K10D.
I only said that it is relevant for higher resolving cameras too. Like learning from the aperture of best resolution which won't depend on camera resolution.

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