K-5 Focus Questions


davidstorm

Link Posted 31/03/2013 - 23:10
I would welcome some advice from the knowledgeable members regarding some AF questions on the K-5.

Today, I've done a Wedding Shoot with Shaun Wilson and to ensure everything was ship-shape prior to this, I systematically calibrated the AF on all my lenses yesterday, both on the K-5 and the K-5IIs. Whilst carrying out this task I was a bit perturbed to discover that the K-5 Mk1 was way off in terms of the AF and needed a minimum of +8, with +10 required on most of my lenses. Some probably need more than +10, but this is as far as the AF Fine Adjustment goes. In contrast, the IIs needed very little adjustment and was consistently excellent in its AF performance on all my AF lenses. My questions are:

1. Can the K-5 be calibrated correctly, either by myself or a repairer so that it does not require +10 Fine AF Adjustment?

2. Once calibrated, would the AF stay at the calibrated level or can it drift off again?

3. Would such calibration be covered under the 2 year warranty (camera bought from SRS 1 year ago), if +10 adjustment is not sufficient to correctly calibrate my lenses?

My observations from the calibration seem to be borne out in 'real world' use, where I always turn to my IIs first, not necessarily because of the improved sensor sharpness, but because of the more accurate focussing. The IIs consistently produces excellent results. Also, I find the IIs much easier to focus accurately with manual focus lenses; is this the same reason that the AF is not accurate perhaps?

BTW, my questions don't relate to the improvements in AF on the K-5II, they are about a problem with my K-5 which consistently requires a fine AF adjustment of +10; similar issues exist with all my AF lenses, so this is an issue with my particular K-5 body.

Many thanks in anticipation of some good advice.

Regards
David
Flickr

Some cameras, some lenses, some bits 'n' bobs
Last Edited by davidstorm on 31/03/2013 - 23:11

johnriley

Link Posted 31/03/2013 - 23:24
If everything needs adjusting, then clearly time to attend to the K-5. I would imagine that calibration could drift, but I think I would expect it to be more wear and tear than anything else.

For example, the lens is spinning along and has to stop accurately. If it was a car then we'd adjust the brakes from time to time, and eventually replace the pads. Maybe not an exact comparison, but the area of mechanical wear is what I am thinking of.

Likewise lenses might wear as well over long periods of usage. To be fair, the instructions tell us to have an overhaul of the camera every one or two years to maintain performance. I know we never do, I certainly don't, but with the number of frames we shoot compared to film cameras, maybe we should think about it?
Best regards, John

Algernon

Link Posted 01/04/2013 - 08:07
If they are all on the + side you could enter Debug Mode
and change the setting to +100 which is the same as +10.
Your lenses should then be around +/- 0

The +/- 10 in the normal menu isn't enough it should be
+/- 20, but I've never seen anyone asking for that in any
threads asking Pentax for improvements.

'
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi

Helpful

dpm

Link Posted 01/04/2013 - 09:53
try "apply all" of 8 and then do individual calibrations again.

Algernon

Link Posted 01/04/2013 - 09:56
dpm wrote:
try "apply all" of 8 and then do individual calibrations again.

That just applies 8 (+ or -) to any old lenses that don't
have ID's to go into the 20 lens dB

-
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi

pgweber

Link Posted 01/04/2013 - 10:06
When we discussed AF adjustment before, someone agreed with my supposition that the adjustment was like adding a shim (or even an imaginary negative shim) between the lens and body to adjust the focus (lens focal point) to sensor distance.

If there is the possibility of something working loose around the mount on the body, isn't it possible that the focus to sensor distance will change and won't this be progressive with increasing number of lens changes??

Such a change to the body would affect all lenses as David has described.

One could try tightening all the screws around the mount but only if you are prepared to recalibrate all your lenses.
Peter

Pentax K5
Pentax DA 18-55 Mk1, 50-200 (Samsung), 16-45, 55-300 Mk1, 35 f/2.4
Pentax MZ6 + FA28-90, FA50 f/1.4, M 50 f/1.7
Tamron 80-210mm & 28mm
Last Edited by pgweber on 01/04/2013 - 10:21

johnriley

Link Posted 01/04/2013 - 10:25
These sort of calibrations are best done by those who have the equipment and actually know what the procedure is. I wouldn't try adjusting a lens mount by guesswork.

Cameras are precision instruments and really should be calibrated by the repair houses that are properly equipped.
Best regards, John

davidstorm

Link Posted 01/04/2013 - 11:37
Algernon wrote:
If they are all on the + side you could enter Debug Mode

Hi Algi, thanks for this suggestion, very helpful. I know how to enter Debug Mode on the K-x, but how is it done on the K-5? Is the same modset file that is used for all cameras?

Regards
David
Flickr

Some cameras, some lenses, some bits 'n' bobs

SkilakDeZoo

Link Posted 01/04/2013 - 11:39
dpm wrote:
try "apply all" of 8 and then do individual calibrations again.

Hi, I have the same issue with my K-5 almost all of my lenses have to be +10. Recently I bought 21mm ltd and had to return it as it needed more than +10 units. So sad it is limited only to +/-10, up to 20 should be ideal. I have tried as you recommended, first "apply all" of +10 and then +10 for "this one" and I cannot see any difference. I think you can use either all or one, not a combination of both. In the manual, there is written that using "all" and saved overrides "one".

SkilakDeZoo

Link Posted 01/04/2013 - 11:41
Algernon wrote:
If they are all on the + side you could enter Debug Mode
and change the setting to +100 which is the same as +10.
Your lenses should then be around +/- 0

The +/- 10 in the normal menu isn't enough it should be
+/- 20, but I've never seen anyone asking for that in any
threads asking Pentax for improvements.

'

Hi, how can I enter the debug mode? I cannot find it in the menu. Thanks for any help in advance.

JohnX

Link Posted 01/04/2013 - 11:41
I'd send off the K5 and a +10 lens for calibration. There's a mechanical adjustment available via the base plate. I have details of 'how-to' for a K20D but not the K5.

Once one lens is accurate I'd guess most/all of the others will be adjustable via AF adjust if required.

Doubt it'll be covered under warranty (but worth a try).

JohnX

Link Posted 01/04/2013 - 11:46
SkilakDeZoo wrote:
dpm wrote:
try "apply all" of 8 and then do individual calibrations again.

Hi, I have the same issue with my K-5 almost all of my lenses have to be +10. Recently I bought 21mm ltd and had to return it as it needed more than +10 units. So sad it is limited only to +/-10, up to 20 should be ideal. I have tried as you recommended, first "apply all" of +10 and then +10 for "this one" and I cannot see any difference. I think you can use either all or one, not a combination of both. In the manual, there is written that using "all" and saved overrides "one".

'Adjust All' and 'Adjust One' are not cumulative, and I don't think the Debug hack is available for the K5, so it'll need mechanical re-calibration.

davidstorm

Link Posted 01/04/2013 - 11:51
I've found a link to PK_Tether which includes an option to enable Debug Mode. It seems that the route available via a Modset file on older bodies doesn't work on the K-5 as they have made the software more secure against 'hacking' (not that the debug menu is hacking because it's designed into the software).

link

Regards
David
Flickr

Some cameras, some lenses, some bits 'n' bobs
Last Edited by davidstorm on 01/04/2013 - 11:51

SkilakDeZoo

Link Posted 01/04/2013 - 11:58
JohnX wrote:
SkilakDeZoo wrote:
Quote:
try "apply all" of 8 and then do individual calibrations again.

Hi, I have the same issue with my K-5 almost all of my lenses have to be +10. Recently I bought 21mm ltd and had to return it as it needed more than +10 units. So sad it is limited only to +/-10, up to 20 should be ideal. I have tried as you recommended, first "apply all" of +10 and then +10 for "this one" and I cannot see any difference. I think you can use either all or one, not a combination of both. In the manual, there is written that using "all" and saved overrides "one".

'Adjust All' and 'Adjust One' are not cumulative, and I don't think the Debug hack is available for the K5, so it'll need mechanical re-calibration.

I have found something about the debug mode - http://www.dpreview.com/forums/thread/3218086

Algernon

Link Posted 01/04/2013 - 12:01
davidstorm wrote:
Algernon wrote:
If they are all on the + side you could enter Debug Mode

Hi Algi, thanks for this suggestion, very helpful. I know how to enter Debug Mode on the K-x, but how is it done on the K-5? Is the same modset file that is used for all cameras?

Regards
David

Ricehigh should have covered it all. link

The K-5 is similar, but you need to install PKTether
to turn it on via the USB lead link

Turn it off from the camera menu when done.

Don't adjust anything other than the correction amount under
debug..... See the K-x screenshots (similar to K-5).

-
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Last Edited by Algernon on 01/04/2013 - 12:02

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