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how to present lens test results
  
 
perselio
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p.1 #1 · p.1 #1 · how to present lens test results


Hello,

New member here. Sorry if this question has been asked before but a basic search hasn't yielded any useful results. I'm trying to learn how to present lens test comparison results. Most people show a sample photo with red rectangles over sections of the image, then use some kind of template to show 100% crops of those areas at various apertures. Could anyone please point me to a online tutorial/guide on how to do this?



Apr 26, 2017 at 02:22 PM
jcolwell
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p.1 #2 · p.1 #2 · how to present lens test results


Hi perselio,

Welcome to FM.

I do that sort of thing. Here's a few examples.

EF 16-35/4L IS test images http://www.fredmiranda.com/forum/topic/1313373/0&year=2014#12531288

Comparison of Zeiss 25/2 ZE and Canon L lenses http://www.fredmiranda.com/forum/topic/1403832

For Landscape (f8-11) is 24-70 II really better than f4 IS? http://www.fredmiranda.com/forum/topic/1436334/2#13611971

I use a manual process. I usually shoot at least three images with the same everything (camera, lens, shutter speed, f-stop, ISO, subject, ...), and then repeat it with the same everything, except for using a different lens. Later, I open the first file for 'lens x' in PS CS6, put it in a relatively small, square-ish window in the PS CS6 workspace, and then do the same for the other two, same-images. Then, I put each window at 100% (one pixel from sensor for each dot in the display, keystroke ^0 [control-zero] in PS CS6), and arrange them in a row of small, square-ish windows. I use the Navigator window to centre each window at the same location in the test scene (which is usually covers a very small part of the entire image), and compare them to identify the best of these three. Of couse, the "best" sometimes depends on what is being examined, but it's usually sharpness (= resolution + contrast). Other aspects could be vignetting, flare, distortion, colour, ..., but these are often evaluated from the full image, or large parts of it.

Anyway, I save a .pdf of the "best" one, and delete the others (from PS CS6, not from the computer), and repeat the whole process for each test condition. If there's five lenses, I end up with five small, square-ish windows, each showing the same part of the test scene, at 100%. When I save each .pdf file, I use a descriptive file name, which usually includes at least the lens name, and that automatically becomes the name of the PS CS6 window (in title bar at top left). Then, when I have the windows arranged as I want, I take a screen snapshot, dump it into IrfanView (freeware), crop it, and save it with another descriptive filename (e.g. far-left edge). I do this for typically four to seven locations in the test scene (centre, left and right edges, a couple of corners (if they contain image matter), and maybe some 'midfield' locations), and so I have four to seven composite images that I post on FM. The links above show examples of what I've discussed.

Cheers,
Jim

P.S. The red rectangle you can see in the Navigator window (when it's included) is automatically provided by PS CS6, to show where you're currently located in 'the bigger picture'.



Apr 27, 2017 at 08:25 PM
perselio
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p.1 #3 · p.1 #3 · how to present lens test results


Hi Jim, thank you so much for your detailed reply, this is extremely helpful! My comfort level with PS is rather low at the moment but I'm working on it... I'll have a go at your method and get back to you with any questions if I get stuck. I spent ages looking for an explanation like this on the internet but with no luck.


Apr 28, 2017 at 09:42 AM







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