jcolwell Offline Upload & Sell: On
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maholyoak wrote:
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(1) Do you do it on every AF lens and body combination you own? Or just telephotos?
(2) Do you use any aids other than a focus chart and if so what? (Dot Tune, other software)
(3) Have you found much variation from lens to lens?
(4) The canon manual suggests ideally doing it under the same conditions that you are shooting. Is it really that inconsistent?
(5) Is there a need to repeat it assuming the same body-lens combination? E.g., annually.
1. Yes, thirteen lenses on three cameras, with 1.4x and 2x Extenders on seven lenses (only with f-stops the camera can AF).
2. Yes, sort of. I use LensAlign II with real time LiveView through EOS Utility, on my notebook.
3. Some variation, not a lot. Of the 62 combinations I tested (with current cameras and lenses), 40 were zero and 22 were non-zero. Most were +/- 1 or 2. The three largest absolute values were -5, 5, and 10.
4. I don't know what you mean by "inconsistent". If you have a most-often used distance, why not use that? I generally use the 50x(focal length) recommended by Canon, but shorter for long lenses that I test indoors (my max indoor range is about 12 m). I check the long lens results with longer outdoor targets, and they're all OK.
5. There was some talk about re-testing after the 1DX service recall and firmware update. I checked a few, and they were the same, or +/-1 step, which is probably within the error when I test them. Otherwise, I only retest for new gear or if somethimg has been repaired.
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