Lens rental M43 lens test

Started May 10, 2012 | Discussions thread
RCicala
Regular MemberPosts: 124
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Re: Confused.
In reply to Kuppenbender, Oct 3, 2012

Kuppenbender wrote:

Photozone also tested both lenses with the same software (imatest) but came up with dramatically different results.
http://www.photozone.de/olympus--four-thirds-lens-tests/740-pana25?start=1

Could this be due to a different definition of 'centre', different cameras (GX1 Photozone/OMD Lensrentals) or user error?

All of the above are possible. If you're into geeky testing stuff, this goes into some detail about it:

http://www.lensrentals.com/blog/2012/09/why-arent-the-damn-numbers-the-same

In summary, though, very common causes of Imatest variation are:

1) Camera used (both resolution and microlenses can make a difference)

2) Test target areas chosen for analysis (Absolute corners can't be measured, but different targets are measure slightly different distances from the corners. This is especially pertinent in m4/3 work since targets are basically 2:3 ratio designs.)
3) Use of jpgs vs raw images for calculations, and which raw converter is used.
4) Camera - chart testing distance (this can vary by 100% with different labs)
5) And, of course, copy variation, both for lens and test camera.

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