Pentax K-5 AF accuracy

cbope · 01-29-2012, 08:29 PM

Originally posted by philbaum

Gimbal is absolutely correct, V1.12 does not correct this (i forgot the release on the shutter button step)

I hope everyone tries this - its an eye opener. The SR icon goes out for 2 seconds - which is a long time for ordinary shooting. Maybe this is the smoking gun behind "random OOF"?

If a photographer is relying on SR, and its 3 or 4 step speed reduction, and he tracks the action with the camera or recomposes after focusing, he's left with a blurry image for 2 seconds while the SR becomes effective again. If you rely only on shutter speed, i.e. 1/1.5*FL, then the movement of the camera will not generally cause OOF.

Gimbal, Thank you for reminding me, again

I confirmed this yesterday, initially I thought the hand icon was going off and staying off when I lifted my finger from the shutter while moving the camera. It does go out for a second or so, and then it comes back on indicating stabilization. It seems to be very repeatable, focus on something, lift finger off shutter, pan the camera a bit and then the hand comes back after a short delay.

I'm going to try shooting for a week with SR off and see if it improves the number of keepers. I've not really had a big problem, but I have had some shots come out softer than I expected and I'm wondering if SR could be causing it. To be honest, when I got my K-5 I just left SR on and have been shooting, not paying too much attention to the hand icon in the OVF.

philbaum · 01-30-2012, 01:07 AM

I shot about 600 pictures tonight during 3 One Act play rehearsals with the SR turned off. I've only checked about 100 out of the 600 but they all seemed to be sharp except for some occasional blurred hand motion or dof that was inadequate for the spacing of the actors. In all cases, there were areas of sharpness within those pics. I've got some deadlines to meet in processing pics in the next 2 days so won't be able to do any sort of immediate count, besides its a bit tedious with this many images.

When i shoot actors on a stage, there is no time to check the VF for an active hand icon, its strictly watch the action, choose and snap pictures that look promising. If you're doing landscapes, still life, etc. i can see using SR. but not if one doesn't have time to watch the hand icon.

Glad to hear that others are doing so well with the SR off.

Gimbal · 01-30-2012, 01:43 AM

In THEORY it shouldn't be worse if you shoot before SR is ready as in those cases the SR should act as if it was off. That's because there are no movement of the sensor until you fully depress the shutter button anyway, so it should never be caught half ready. It's either ready, or it's not. And if it's not ready it will act as if it's shut off.

But then I did some simple tests about panning with SR, and the early tests (I need to do some more tests to be sure) suggests that panning doesn't work at all well, quite the contrary, it introduced blur. (This did not happen with the K10d)
So that could be a source of blur in certain situations.

But again, more tests needs to be done.

philbaum · 01-30-2012, 10:20 AM

Originally posted by bossa

I have to agree and say that I have had more reliable results with SR OFF in the past. I just did a few test shots where I deliberately shot when the SR hand indicator was OUT in the VF. Even though the camera was NOT MOVING there is motion blur in the shot but when I waited for the HAND to light up there was none..

bossa's test is elegantly simple!

Just wait after moving the camera and shoot in the 2 sec. interval until the hand comes back on. If one did 10 of those tests, then thats a pretty reliable indication that its a weakness, vulnerability of the SR system and probably other such systems. I assumed when i first bought my K10, that SR was going to take care of me, all automatically - no such luck. Its just another tool in the chest, and sometimes it works, and sometimes it doesn't.

One interesting test would be this:

Perform bossa's test but with an 1/(1.5xFL) or greater shutter speed. This would answer the question of whether the SR in its 2 second coming up to speed period, is actually detrimental to normal sharpness, or simply passively ineffective in producing any more sharpness than the shutter speed normally provides..

Christine Tham · 01-31-2012, 11:44 PM

Just an update everyone.

I finally got my K-5 back today - it was a warranty repair so no cost to me.

I haven't really done extensive testing, but I did shoot several test pictures in situations when I noticed the inconsistent focus problem, in roughly the same conditions (it was the same set of objects, indoor lighting).

I can confirm that the AF accuracy and consistency is now good - at least as good as when I first bought the camera.

So basically I concur with creampuff's experience - sending it for repair seems to improve the AF accuracy and consistency.

RGold · 01-31-2012, 11:49 PM

Do you know what was fixed?

JohnTaylor · 02-02-2012, 01:28 AM

I notice that focusing is slower and less accurate with FA limiteds than with newer design lenses, luch as Sigma 85mm f1.4 and 18-135mm WR.

Perhaps some of the problems with AF depend on the lens you use?

bossa · 02-02-2012, 01:41 AM

Originally posted by RGold

Do you know what was fixed?

CR Kennedy have my 50-135 and told me they never list what was done to the lenses at least. My K-5 came back 3 weeks ago and they did tell me they put a new Focus mode lever module in there (the one on the back).

My 50-135 had a zoom collar getting sloppy and it is only several months old. God knows what happened to it because it has never been bumped etc. It is possible they dropped it though because they insisted on me handing it over without any protection at all and they just stood it up on the counter behind the front reception. I don't think they'd own up to that though.

MartinEA · 02-02-2012, 02:04 AM

In support I bought a Pentax K5 a few months before Xmas. I was looking to use these cameras for wedding photography for the dynamic range. I too have noticed mine is not so great on the auto focus as I hoped when compared to my Canon gear. I like the camera but I wish it did it auto focus thing better.

westmill · 02-02-2012, 11:56 AM

Originally posted by MartinEA

In support I bought a Pentax K5 a few months before Xmas. I was looking to use these cameras for wedding photography for the dynamic range. I too have noticed mine is not so great on the auto focus as I hoped when compared to my Canon gear. I like the camera but I wish it did it auto focus thing better.

Well now you know to turn off the SR and only use SR with caution ! It might not sort it 100% but it
really does seem to be a hindrance. Think back to all those out of focus shots... is it poss you had the SR switched on ? Try it

MartinEA · 02-02-2012, 01:15 PM

Why would I take SR off whentaking shots?

**TER-OR** · 02-02-2012, 01:18 PM

It's recommended to turn off SR when taking panning shots - following moving objects. I haven't found a problem, myself, but outdoors taking panning shots I'm shooting pretty high shutter speeds anyway.

westmill · 02-02-2012, 01:19 PM

Originally posted by MartinEA

Why would I take SR off whentaking shots?

I should read the posts

Top of this page and previous page etc !

westmill · 02-02-2012, 01:22 PM

Originally posted by TER-OR

It's recommended to turn off SR when taking panning shots - following moving objects. I haven't found a problem, myself, but outdoors taking panning shots I'm shooting pretty high shutter speeds anyway.

Its not just panning and even high shutter speed shots can be affected it seems.
Its worth reading the last couple of pages on this matter. It was a bit of an eye opener.

MartinEA · 02-02-2012, 01:40 PM

I see, well no panning shots but thanks anyway.

02-02-2012, 01:41 AM	#158
bossa Veteran Member Join Date: Jul 2011 Location: Adelaide Posts: 4,546	Originally posted by RGold Do you know what was fixed? CR Kennedy have my 50-135 and told me they never list what was done to the lenses at least. My K-5 came back 3 weeks ago and they did tell me they put a new Focus mode lever module in there (the one on the back). My 50-135 had a zoom collar getting sloppy and it is only several months old. God knows what happened to it because it has never been bumped etc. It is possible they dropped it though because they insisted on me handing it over without any protection at all and they just stood it up on the counter behind the front reception. I don't think they'd own up to that though. Last edited by bossa; 02-02-2012 at 01:58 AM.

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01-29-2012, 08:29 PM	#151
cbope Veteran Member Join Date: Dec 2011 Location: Helsinki Posts: 664	Originally posted by philbaum Gimbal is absolutely correct, V1.12 does not correct this (i forgot the release on the shutter button step) I hope everyone tries this - its an eye opener. The SR icon goes out for 2 seconds - which is a long time for ordinary shooting. Maybe this is the smoking gun behind "random OOF"? If a photographer is relying on SR, and its 3 or 4 step speed reduction, and he tracks the action with the camera or recomposes after focusing, he's left with a blurry image for 2 seconds while the SR becomes effective again. If you rely only on shutter speed, i.e. 1/1.5*FL, then the movement of the camera will not generally cause OOF. Gimbal, Thank you for reminding me, again I confirmed this yesterday, initially I thought the hand icon was going off and staying off when I lifted my finger from the shutter while moving the camera. It does go out for a second or so, and then it comes back on indicating stabilization. It seems to be very repeatable, focus on something, lift finger off shutter, pan the camera a bit and then the hand comes back after a short delay. I'm going to try shooting for a week with SR off and see if it improves the number of keepers. I've not really had a big problem, but I have had some shots come out softer than I expected and I'm wondering if SR could be causing it. To be honest, when I got my K-5 I just left SR on and have been shooting, not paying too much attention to the hand icon in the OVF.

01-30-2012, 01:07 AM	#152
philbaum Veteran Member Join Date: Oct 2007 Location: Port Townsend, Washington State, USA Posts: 3,659	I shot about 600 pictures tonight during 3 One Act play rehearsals with the SR turned off. I've only checked about 100 out of the 600 but they all seemed to be sharp except for some occasional blurred hand motion or dof that was inadequate for the spacing of the actors. In all cases, there were areas of sharpness within those pics. I've got some deadlines to meet in processing pics in the next 2 days so won't be able to do any sort of immediate count, besides its a bit tedious with this many images. When i shoot actors on a stage, there is no time to check the VF for an active hand icon, its strictly watch the action, choose and snap pictures that look promising. If you're doing landscapes, still life, etc. i can see using SR. but not if one doesn't have time to watch the hand icon. Glad to hear that others are doing so well with the SR off.

01-30-2012, 01:43 AM	#153
Gimbal Pentaxian Join Date: Apr 2007 Location: Sweden Posts: 2,106	In THEORY it shouldn't be worse if you shoot before SR is ready as in those cases the SR should act as if it was off. That's because there are no movement of the sensor until you fully depress the shutter button anyway, so it should never be caught half ready. It's either ready, or it's not. And if it's not ready it will act as if it's shut off. But then I did some simple tests about panning with SR, and the early tests (I need to do some more tests to be sure) suggests that panning doesn't work at all well, quite the contrary, it introduced blur. (This did not happen with the K10d) So that could be a source of blur in certain situations. But again, more tests needs to be done.

01-30-2012, 10:20 AM	#154
philbaum Veteran Member Join Date: Oct 2007 Location: Port Townsend, Washington State, USA Posts: 3,659	Originally posted by bossa I have to agree and say that I have had more reliable results with SR OFF in the past. I just did a few test shots where I deliberately shot when the SR hand indicator was OUT in the VF. Even though the camera was NOT MOVING there is motion blur in the shot but when I waited for the HAND to light up there was none.. bossa's test is elegantly simple! Just wait after moving the camera and shoot in the 2 sec. interval until the hand comes back on. If one did 10 of those tests, then thats a pretty reliable indication that its a weakness, vulnerability of the SR system and probably other such systems. I assumed when i first bought my K10, that SR was going to take care of me, all automatically - no such luck. Its just another tool in the chest, and sometimes it works, and sometimes it doesn't. One interesting test would be this: Perform bossa's test but with an 1/(1.5xFL) or greater shutter speed. This would answer the question of whether the SR in its 2 second coming up to speed period, is actually detrimental to normal sharpness, or simply passively ineffective in producing any more sharpness than the shutter speed normally provides..

01-31-2012, 11:44 PM	#155
Christine Tham Veteran Member Join Date: Nov 2008 Location: Sydney, Australia Photos: Gallery Posts: 2,269 Original Poster	Just an update everyone. I finally got my K-5 back today - it was a warranty repair so no cost to me. I haven't really done extensive testing, but I did shoot several test pictures in situations when I noticed the inconsistent focus problem, in roughly the same conditions (it was the same set of objects, indoor lighting). I can confirm that the AF accuracy and consistency is now good - at least as good as when I first bought the camera. So basically I concur with creampuff's experience - sending it for repair seems to improve the AF accuracy and consistency.

01-31-2012, 11:49 PM	#156
RGold Junior Member Join Date: Jan 2012 Location: Portland, Oregon Posts: 26	Do you know what was fixed?

02-02-2012, 01:28 AM	#157
JohnTaylor New Member Join Date: Jan 2012 Photos: Albums Posts: 20	I notice that focusing is slower and less accurate with FA limiteds than with newer design lenses, luch as Sigma 85mm f1.4 and 18-135mm WR. Perhaps some of the problems with AF depend on the lens you use?

02-02-2012, 02:04 AM	#159
MartinEA New Member Join Date: Oct 2011 Posts: 14	In support I bought a Pentax K5 a few months before Xmas. I was looking to use these cameras for wedding photography for the dynamic range. I too have noticed mine is not so great on the auto focus as I hoped when compared to my Canon gear. I like the camera but I wish it did it auto focus thing better.

02-02-2012, 11:56 AM	#160
westmill Veteran Member Join Date: Jan 2012 Location: Stoke on Trent Photos: Gallery \| Albums Posts: 1,146	Originally posted by MartinEA In support I bought a Pentax K5 a few months before Xmas. I was looking to use these cameras for wedding photography for the dynamic range. I too have noticed mine is not so great on the auto focus as I hoped when compared to my Canon gear. I like the camera but I wish it did it auto focus thing better. Well now you know to turn off the SR and only use SR with caution ! It might not sort it 100% but it really does seem to be a hindrance. Think back to all those out of focus shots... is it poss you had the SR switched on ? Try it

02-02-2012, 01:15 PM	#161
MartinEA New Member Join Date: Oct 2011 Posts: 14	Why would I take SR off whentaking shots?

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02-02-2012, 01:18 PM	#162
TER-OR Site Supporter Join Date: Apr 2009 Location: Dundee, IL Photos: Gallery \| Albums Posts: 6,699	It's recommended to turn off SR when taking panning shots - following moving objects. I haven't found a problem, myself, but outdoors taking panning shots I'm shooting pretty high shutter speeds anyway.

02-02-2012, 01:19 PM	#163
westmill Veteran Member Join Date: Jan 2012 Location: Stoke on Trent Photos: Gallery \| Albums Posts: 1,146	Originally posted by MartinEA Why would I take SR off whentaking shots? I should read the posts Top of this page and previous page etc !

02-02-2012, 01:22 PM	#164
westmill Veteran Member Join Date: Jan 2012 Location: Stoke on Trent Photos: Gallery \| Albums Posts: 1,146	Originally posted by TER-OR It's recommended to turn off SR when taking panning shots - following moving objects. I haven't found a problem, myself, but outdoors taking panning shots I'm shooting pretty high shutter speeds anyway. Its not just panning and even high shutter speed shots can be affected it seems. Its worth reading the last couple of pages on this matter. It was a bit of an eye opener.

02-02-2012, 01:40 PM	#165
MartinEA New Member Join Date: Oct 2011 Posts: 14	I see, well no panning shots but thanks anyway.