Micro-adjust question

[David Pugsley]

I'm testing a new lens and have found that going to the negative extreme (-20) has very little affect from 0 while the other extreme (+20) has a great impact. Is this common? I should note that the lens seems just about perfect at 0 so it's not a problem. I just found it odd that one end of the scale shows next to no change from neutral.

Cheers

[James Shadle]

Check this out: http://www.birdphotographers.net/for...ustment-tricks

[Jeff Cashdollar]

David,

Let me know what you think of this thread, send me a PM if you wish. It has very detailed narrative and would be interested in your perspective - thanks.

[David Pugsley]

Thanks James, much appreciated!
This is a new technique to me. Sadly it took me until post 74 to realize it can't be used with my MkIII. :) Back to old-school efforts.

I was more interested in why one adjustment extreme had next to no affect while the other end of the spectrum did. I suppose it may be DOF phenomenon.

[arash_hazeghi]

yes the MA method in that thread will not work for older cameras, is this only one lens that is behaving so or is it the same with all lenses?

[David Pugsley]

yes the MA method in that thread will not work for older cameras, is this only one lens that is behaving so or is it the same with all lenses?

I can't say with certainty as I have not done thorough enough testing. The lens in question is a 500 f/4. I do know the previous owner sent it to Canon with his MkIII for calibration so this could be a cause. I do need to say again that focus seems to be just fine with the lens. I just found it odd that the negative MA adjustments had little or no effect while the positive adjustments did.

[arash_hazeghi]

I can't say with certainty as I have not done thorough enough testing. The lens in question is a 500 f/4. I do know the previous owner sent it to Canon with his MkIII for calibration so this could be a cause. I do need to say again that focus seems to be just fine with the lens. I just found it odd that the negative MA adjustments had little or no effect while the positive adjustments did.

it isn't normal for the sharpest focus plain to be at the edge of DOF, it could also be that shift register unit in AF chip has been accidentally or intentionally disabled by Canon, but if you are getting sharp results that you like then who cares...