AF Adjustment

Ever since I first got my DA* 16-50mm I have been less than impressed with it's performance, especially wide open. So much so it basically got put in it's box and left unloved for most of it's life. I bought it used off Ebay and couldn't return it as the seller went unregistered almost immediately after I bought it.

Anyway, the other day I decided to get it out again and this time I did some AF microadjustment ... this is the results with +5

Without adjustment

[IMG]http://img.photobucket.com/albums/v188/Sockpuppetuk/IMGP0142_zps6aab7768.jpg[/IMG]

With adjustment

[IMG]http://img.photobucket.com/albums/v188/Sockpuppetuk/IMGP0144_zps276f6e44.jpg[/IMG]

Now 100% crops

[IMG]http://img.photobucket.com/albums/v188/Sockpuppetuk/IMGP0142_cr_zpsdabeeada.jpg[/IMG]

[IMG]http://img.photobucket.com/albums/v188/Sockpuppetuk/IMGP0144_cr_zpse7ff46b3.jpg[/IMG]

I suppose the point of this post is just to say anyone who has not done any adjustment of your lenses then try it, you may be surprised by the results.

MikeP I too have not been over the moon with my DA* 16-50mm, time for some adjustment trials I think.

Fletcher8

Any reason why the exposure seems brighter on the corrected picture?

Nope, I noticed that as well.

TAv mode - Same shutter speed/aperture/focal length .. did notice the auto ISO jumped from 800 to 1100 though so that's probably the reason.

Edit: These weren't processed in any way, just straight Raw to Jpeg conversion.

I wasn't overawed by mine either. One SDM failure, a trip to JPS and it's now awesome.

Now let down by operator incompetence

This is exactly the sort of post that makes the mind boggle that AF adjustment on a per-lens basis was not included as a matter of course on all camera models since the inception of DSLR photography.

This coming from a K200D owner, with AF adjustment only as a global setting and having to hack the camera just to get to that...

I hope you enjoy your newly-discovered lens, Mike.

And it would be so simple to make this self-calibrating - focus in contrast detect, switch to phase detect without changing focus, read and store the phase detect offset ...

As an aside, was there any form of focus adjustment on the K-100d?

I'm using this again whilst my K-30 is being looked at and it back focuses horribly

Edit: just googled this on the bus to work. Seems a special service menu is the only way and it's a global setting for all lenses. Might try this later on...

Sounds like the K200D. Be careful,you could damage the camera if you fool with any other settings.

interesting idea. I'm trying to think of a reason why this couldn't work, but can't

Agreed, me too!

Patent that one!

Agreed, me too!
Patent that one![/quote]The problem I have found is that a lens can front focus at one end of its range and back focus at the other. I have experienced this with DA* 16-50, DA*50-135 and DA 16-45. It is a lesser problem on the K5 compared with the K10, but it still exists and as a result the adjustments I make are always a compromise.
So to expand on this idea I would like the option to save at least three AF adjustments per lens.

Regards - Steve

On the Canon 5DMKIII and 1DX I believe you can save setting for the min and maximum zoom lengths.

I think Sony or Olympus have multiple focus points per lens as well. And of course the Sigma dock allows you to do it, except they don't make the dock for pentax fit lenses.

yes I'd go along with that.

Currently I adjust mine with a bias to the near field as that's where the biggest inaccuracies occur in my experience. but yes it is a compromise.



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