# Anyone testing lens contrast?



## rfdesigner (Apr 9, 2017)

I'm shooting with mid range lenses and generally pretty happy with the results, I'm also caring less and less about resolution as a differentiator between images.. light, composition, subject all trump the technical side, so I've become more concerned about effects you can see in small prints or web size images. If an image I take doesn't work at web size then I'll cull it. So I've changed to caring about technical aspects that show in small shots.

The biggies are :

Boke and OOF effects.
Contrast & Colour.
AF accuracy/consistancy.

Boke and AF are well covered across the net, but Contrast and Colour?

I understand that coatings do a lot to improve lenses Colour and contrast. A good coating will not produce reflections that could otherwise produce diffuse and highly out of focus washes of light across the sensor, thus reducing contrast and muddying colours, especially if those washes have any colour to them due to variaitions in performance of coatings with wavelength.

So.. if coatings can improve colours then they are good, and there must be a quatifiable test for this, and so I dug around and found this:

http://www.imatest.com/docs/veilingglare/

They have tested a very small handful of lenses.. but try as I might no one else seems to be doing this test or anything else that is useful in any real way.

DPreview : no
DXOmark : no
TDP : well they do a test but the result is highly subjective, I certainly can't compare lenses using it.
Dustin : a comment here and there on "strong contrast", difficult to compare lens to lens.
photozone.de : no

and just for fun this is what you get without coatings: http://nofilmschool.com/2012/12/whats-special-about-uncoated-lenses

So anyone come across a site that measures lens contrast?


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## Zeidora (Apr 9, 2017)

That's what a MTF does. Contrast also as a function of angle, frequency of pattern and distance from center. MTF is provided by some manufacturers, is cited in a number of lens reviews.


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## rfdesigner (Apr 9, 2017)

Zeidora said:


> That's what a MTF does. Contrast also as a function of angle, frequency of pattern and distance from center. MTF is provided by some manufacturers, is cited in a number of lens reviews.



no it's not, or at least not the way the data is measured or presented.

MTF looks at maybe 90% contrast or 50% contrast

This isn't that measurement. it's looking at just how much is possible at very low frequncies.

is it 99%, 99.5%, 99.8%, 99.9%

which will produce noticablely different results


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