Canon lenses calibration

Started 5 months ago | Discussions thread
Zeee Forum Pro • Posts: 21,949
Re: Canon lenses calibration

CESA wrote:

Ken60 wrote:

Forgive me if I repeat things, ( did not have time to read all back posts)

If you look at the Focal target it has a line of a very specific length at the top. It is important that whomever prints this target does it to the size as specified, and the target is the correct length.

If you have a mate with a good quality inkjet, that understands printing, buy them a beer ..... a good target is important, as is keeping it flat and true to the camera. Next thing to do is remember that nothing beats good diffused daylight, no shadows or bright bits. Keep the light levels up, fluorescent flicker, led lighting and levels that require mid length shutter speeds are a problem. Read all the instructions and follow to the letter. Focal checks for your distance to target and warns you . I use the Pro version , has a few extra bits and will calibrate longer lenses.

This program diagnosed a fault in a lens I owned, it noted the change in the specifics of several tests and warned me to get it serviced ! Great bit of kit if you follow every instruction, waste of time if you are sloppy.

Thanks for you input.

I was doing basically everything that focal requires with the exception using their target so I printed out the target on the supermarket close by and did some experiments.

3.7m, 3.5m, 2m and 1.5m.

The length of the line has been introduced on the software.

The lighting they say it really doesn't matter if it is daylight or artificia l light. I have used a room with very good lighting overall although have added an additional lamp close to the target not making it even across the target but don't thing this would cause any problem.

As long as it isn't fluorescent or LED. Not sure about LED. It is in the manual.

The shutter speed was around 1/250m. The target distance of 2m and 1.5m were done on top of a carpet floor but have used a 2kg weight on the tripod to make it more sturdy.

Conclusion that I have reached after the second attempt.

The software couldn't reach any conclusion at 1.5m.

at 2m came up with AFMA of +9.

at 3.5m +6 and at 3.7m +5. So, at the recommended distance the AFMA setting can be said to be around that +5/+6.

I left this setting and shot another photo at 2m and 1.5m they were out of focus.

At 3.5m and 3.7m the test shots I did were good.

Switched back the AFMA to +9 and did some test shots at the above mentioned distances 3.7m, 3.5m, 2m and 1.5m and all of them were very nice.

Didn't do any AF consistency where the quality of the focus is assessed (the best one was close to QoF=2050 can't remember with which setting) at all those distances with the AFMA setting at +9.

When the FoCal targets arrive I will perform again all these tests with a more even light around the target besides the ones on the ceiling (there are two) and will test the QoF at the given AFMA setting that the software comes up with and see what do I get. Probably will do it before any AFMA calibration just to check and have a baseline although based in previous tests.

The AFMA of +9 seems to fit all distances but need to do some real life outdoor shoots to assess this.

At that setting the QoF on some quick shots inside the house to a person at 1.2m, 1.5m and 2m seemed ok. Will have to try it at 3.7m as well.

In the past I was using +18 because I did it on the fly at the working distance and the QoF was excellent at 1.2m, 1.5m and 2m. Will make a comparison as well on this +9 vs +18. Don't know if it is a false perception or what. Need to check the eyelashes and eye.

Will probably use the software to make this comparison with the target +9 vs +18 and 1.5m.

I think that's it. Feel free to comment please.

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I feel even more confident that soon things will have a wonderful conclusion

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