Smart Photography 201707

Screengrab 12: There was no issue with AF accuracy at

infinity. Hence no adjustment was made. The curser is at

‘zero’.

Screengrab

13: After all the

adjustments

are done, you

need to click on

the Rewriting

button. This

will ensure

that all the new

adjustments

will be applied.

Screengrab

14: Before

the software

applies the

adjustments, it

takes a sort of guarantee from you that you definitely want

to go ahead with the new settings. Click on Agree and the

new settings take place.

Screengrab 15: Rewriting firmware is complete and now

you can close the program.

You should now take some test shots again and satisfy

yourself that the lens is autofocussing very accurately. If

not, repeat the procedure.

You might ask, how is the Sigma USB Dock system

different from the camera manufacturer’s in-built AF fine

tuning system?

Here are the differences:

1. The in-built AF fine-tuning system found in some
   D-SLRs are basically for Prime lenses only and AF can be
   adjusted for one distance only.
   2. With zoom lenses, you can fine-tune
   only for one marked focal length. This
   means that after the adjustment, AF
   may not be as accurate at other focal
   lengths.
   3. With the Sigma USB Dock, you can
   fine-tune AF for Primes as well as
   Zooms. With Primes, the software
   allows you to fine-tune AF for four
   distances. With zooms, AF fine-tuning
   is permitted for four focal lengths and
   for four distances per focal length. This
   means a total of 16 adjustments are
   possible, resulting in a much superior
   AF fine-tuning.|SP

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Smart PhotographyJuly 2017

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