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Focus test thread

democrates · 2009-11-18 02:31:14

After the f1.4 thread discussing focus issues I thought some people might be interested in testing and optionally sharing results here. Having searched for focus test sheets I decided to cobble up my own in inkscape based on what I'd seen. Click image below to find the 'original' full size for print if you like (my old…

18-11-2009 2:31am

#1
democrates

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After the f1.4 thread discussing focus issues I thought some people might be interested in testing and optionally sharing results here.

Having searched for focus test sheets I decided to cobble up my own in inkscape based on what I'd seen. Click image below to find the 'original' full size for print if you like (my old frikken printer is banjo'd and the new one isn't set up yet so I can't test it just yet apart from a shot of it on the screen...).

Info/thinking:
For front/back focus testing the sheet should be tilted back, say 30deg off horizontal.

The black bar is to ensure the point of focus beyond doubt, the light area around this should help and while that sacrifices sharpness information around the centre of the test shot the rest of the sheet should be enough, plus the centre area is usually sharp anyway.

The scale is in cm when printed at 300dpi (don't use 'fit to page') and if the sheet is at a known angle you can calculate precise distances

There's more scale marks to the top/back since focus apparently degrades over a shorter distance in the front than beyond the point of focus

That's the theory anyway, all feedback welcome or just enjoy

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