Focus test

admirable

admirable

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Jim
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What do you think,

Front/Back focusing or OK

Taken from about 10-12 ft

70-200 2.8Is

I was aiming for the green line


focustestwe8.jpg
 
I would repeat the test but focus on something that's perpendicular to the lens. Still have the ruler in the shot at 45deg to check the results. The reason being is that aiming AF at an angled surface won't give predictable results and probably lean towards front focusing anyway - the AF will lock onto the part that is closest to the camera with the highest contrast.
 
Should be on a tripod, one shot mode and manual focus.. thats what they say anyways :)
 
Aaaahhh, you got it then :D
 
Canon Bob said:
Manual focus......surely this is simply a test of whether the AF is accurate?

Bob
Click to expand...

when i asked sigma for help they gave me a list of things to do to test and they said it should be in one shot mode and manual focus to test if the lens needs calibrating.. this is a while ago but pretty sure thats the instructions:)
 
KIPAX said:
when i asked sigma for help they gave me a list of things to do to test and they said it should be in one shot mode and manual focus to test if the lens needs calibrating.. this is a while ago but pretty sure thats the instructions:)
Click to expand...

I suspect that test would be for a de-centered element....Sigma's unfortunate speciality. The test they asked you to perform would have been to look for a situation where one side was OOF when the other side was sharp.
The test above states that the focus was in the centre.....

All assuming that my interpretation of what the OP is looking for is correct.

Bob
 
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