AF Adjustment

*skid2964* · 10-21-2009, 06:48 PM

I have ordered a K-x, but I still have my K20D. I have been reading about why folks are upgrading to K-x and why they are not. One reason was AF adjustment, the K-x doesnt offer this like the K20D and K-7.

How often is it actually utilized? Those of you with a camera that allows this adjustment, how often have you actually had to make an adjustment?

I ordered the K-x and I was going to sell the K20D until I read about this. I might want to keep it now.

schmik · 10-21-2009, 07:45 PM

My only advice is:

take the camera, mount your mosted used lens
open the aperture
shoot away (shorter distances will highlight the issue)
review

If you happy with the result then leave it alone. If there are lots of OOF shots then start messing with it.

If you hardly ever shoot close and wide open then don't bother. If you don't own any 'fast' glass then it also may not be worth it.

mike

*Wheatfield* · 10-21-2009, 09:47 PM

On my K-20, all of my AF lenses benefited from adjustment. My K-7 seems better.

jsherman999 · 10-21-2009, 09:53 PM

Originally Posted by schmik

My only advice is:

take the camera, mount your mosted used lens
open the aperture
shoot away (shorter distances will highlight the issue)
review

If you happy with the result then leave it alone. If there are lots of OOF shots then start messing with it.

If you hardly ever shoot close and wide open then don't bother. If you don't own any 'fast' glass then it also may not be worth it.

mike

.

Good advice, and you may want to take a look at the discussion on this in this thread.

Personally, I highly value AF adjust on my K20D. I sold my K-M partly because it didn't have it, and I really wish my D90 had it.

I haven't decided if the lack of AF adjust has disqualified the K-x for me, though. It's a compelling camera.

.

Class A · 10-22-2009, 03:14 AM

You don't need an AF adjustment feature if you either

are in luck and your camera works fine with all your AF lenses, or
you don't shoot with critical apertures where AF precision is called for.

I guess the K-x will also have a hidden debug menu which can be activated one way or the other. This typically only allows to change one setting for all lenses but for those critical applications it is worth going into the debug menu to set the optimum value for a particular lens.

*skid2964* · 10-22-2009, 07:45 AM

I really have only one fast AF lens right now (FA50mm f1.4). I will test with it and see. I plan on getting a 50-135mm f2.8 sometime soon.

Originally Posted by Class A

You don't need an AF adjustment feature if you either
are in luck and your camera works fine with all your AF lenses, or

you don't shoot with critical apertures where AF precision is called for.

I guess the K-x will also have a hidden debug menu which can be activated one way or the other. This typically only allows to change one setting for all lenses but for those critical applications it is worth going into the debug menu to set the optimum value for a particular lens.

Parallax · 10-22-2009, 10:19 AM

All but one of my lenses requires some degree of adjustment on both of my K20D bodies. One of the lenses just happens to FF by the exact amount that one of the bodies BF, so it doesn't need a correction on that body.

r0ckstarr · 10-22-2009, 10:50 AM

What is the proper way to test the AF to see if you need an adjustment.

*skid2964* · 10-22-2009, 11:14 AM

Originally Posted by r0ckstarr

What is the proper way to test the AF to see if you need an adjustment.

This site has some good info and a downloadable/printable test sheet in PDF format.

Focus Chart

p0opstlnksal0t · 10-22-2009, 11:23 AM

question on this issue...

If I notice that my K-X is BF or FF on a certain lense or all lenses, and they are quick shift, couldnt i just grab the focus and adjust myself to focus how i want it?

jsherman999 · 10-22-2009, 02:32 PM

Originally Posted by p0opstlnksal0t

question on this issue...

If I notice that my K-X is BF or FF on a certain lense or all lenses, and they are quick shift, couldnt i just grab the focus and adjust myself to focus how i want it?

Yep, welcome to the wonders of quickshift!

And once you get good at it, it's very fast and accurate to use that method. You'll also feel like a Leica shooter, they claim that their MF rangefinders are faster than AF once you practice.

p0opstlnksal0t · 10-22-2009, 03:23 PM

so is this what all the focus is about?

or does it actually look focused in and zeroed in on the viewfinder or live view, yet records the picture out of focus?

Class A · 10-22-2009, 04:28 PM

Originally Posted by r0ckstarr

What is the proper way to test the AF to see if you need an adjustment.

Have a look at these AF adjustment hints.

Originally Posted by p0opstlnksal0t

... couldnt i just grab the focus and adjust myself to focus how i want it?

If you are that good with MF, you certainly can. Most stock screens, however, make precise focusing below f/2.8 very hard, since they do not allow you to see the real DOF below this ratio anymore.

Originally Posted by p0opstlnksal0t

or does it actually look focused in and zeroed in on the viewfinder or live view, yet records the picture out of focus?

Unless there is an additional problem (sensor or focusing screen out of alignment), an FF/BF issue will manifest itself in the viewfinder, during LV, and in the recorded image.

p0opstlnksal0t · 10-22-2009, 04:43 PM

well ima noob to dslr so i guess i just need to try it out... i never had any problems manual focusing on my old canon ae-1 film camera

r0ckstarr · 10-22-2009, 04:51 PM

Thanks for the links. I really think my 18-250 may need some adjustment. After 50mm, it seems to autofocus just a little before the subject, and puts the subject out of focus.

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Edit: I went to do the chart test. I got everything set up, tripod, focus chart, and all. When I went to choose Option 37, AF adjustment, it was already set to #2 - ON. I can't say that I have ever messed with this one. I turned it off so that it uses the manufacturers specs and will do some more testing with it.

Again, thanks for the links and info.