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Author Topic: I don't know how to read an mtf-graph  (Read 6333 times)

hasselbladfan

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I don't know how to read an mtf-graph
« on: April 11, 2012, 12:39:47 PM »


I am already longtime in photography, but I have to admit I don't know how to read such a graph.

Can anybody give me a crashcourse? Point me to what I need to look for (bad or good).

Much appreciated.
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Slobodan Blagojevic

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Re: I don't know how to read an mtf-graph
« Reply #1 on: April 11, 2012, 01:00:23 PM »

BartvanderWolf

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Re: I don't know how to read an mtf-graph
« Reply #2 on: April 12, 2012, 06:03:05 AM »

I am already longtime in photography, but I have to admit I don't know how to read such a graph.

Can anybody give me a crashcourse? Point me to what I need to look for (bad or good).

Hi,

There's a lot of information in an MTF curve, but it requires interpretation as well (which takes a bit of experience). It's more useful when comparing several options.

In general it shows you how much contrast is reduced as a function of spatial frequency (high frequency is fine detail, low frequency is overall contrast).

Some more background in addition to the Zeiss references:
http://www.normankoren.com/Tutorials/MTF.html

Cheers,
Bart
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JGU1956

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Re: I don't know how to read an mtf-graph
« Reply #3 on: April 14, 2012, 02:13:51 AM »

Here's another article which for a highly technical subject seems quite readable:  https://www.lensrentals.com/blog/2009/06/have-you-seen-my-acutance
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Christoph C. Feldhaim

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Re: I don't know how to read an mtf-graph
« Reply #4 on: April 14, 2012, 05:25:51 AM »

The link Slobodan posted above is the first of a series of 2 very well written papers by Mr.Nasse from Zeiss.
The blog of them is here:
http://blogs.zeiss.com/photo/en/?page_id=18

The second paper, which goes deeper into the matter can be found in issue 31 and there are also a bunch of example images to download, which are referred in the article.
The second PDF is here:
http://www.zeiss.com/C12578620052CA69/0/A6DCEB1C6ACCE37DC12578D200390F82/$file/cln_31_mtf_kurven_2_en.pdf
The images are in the zip file here:
http://lenses.zeiss.com/content/dam/Photography/Camera%20Lenses/international/zip/cln_blog/MTF_images.zip

I found the second article extremely useful, especially to understand what MTF curves do NOT tell, and why self testing is so important.
Both articles together are a long read, but IMO its definitely worth it.

Have fun reading!
Cheers
Chris

hasselbladfan

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Re: I don't know how to read an mtf-graph
« Reply #5 on: April 17, 2012, 12:59:30 PM »

Thanks, Guys. It will keep me busy for a while. :)
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