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01-29-2011, 05:28 AM   #1
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Got my K-r back from service

So I just got my K-r back from service. The repair notes are not very descriptive, it only says "AF sensor adjusted". But the AF is in fact much better now. I still have some front focus in artificial light, but it is only noticable at very wide apertures (>2.8), and it is small enough to be fixable by the microadjust. To me, this is acceptable and in line with what I've seen on other DSLRs.

Anyways, I'm done shooting test charts for now

FA 50mm, f/1.4, ISO 800, 1/80s

01-29-2011, 07:41 AM   #2
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I'm still waiting on mine.... I'm happy to hear positive things about your camera. So in natural light, front focus is gone?
01-29-2011, 08:01 AM   #3
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one check for me

Hi Eric, can you please do one thing for me; in <2.8 A can you compare a live-view shot with a thru the view-finder focus shot? I'm interest to see what the difference is? I find no matter what light condition the view-live performance is perfect.
01-29-2011, 08:26 AM   #4
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Cute Baby

QuoteOriginally posted by EricT Quote
So I just got my K-r back from service. The repair notes are not very descriptive, it only says "AF sensor adjusted". But the AF is in fact much better now. I still have some front focus in artificial light, but it is only noticable at very wide apertures (>2.8), and it is small enough to be fixable by the microadjust. To me, this is acceptable and in line with what I've seen on other DSLRs.

Anyways, I'm done shooting test charts for now
Hi,

Cute baby there. They grow up too fast.

Cuteness aside, I assume that you can see that nothing in the baby's face is even close to being in focus?

Maybe you missed a bit on the focus point alignment with your intended focus point, which could be, but the only thing in sharp focus in that shot is the bit of cloth just past the front shoulder just in front of the right ear (left in the image).

If the focus point was missed a bit or is mis-aligned with the red indicator (which does happen) this could happen, but otherwise, your camera front-focused badly in this shot.

No offense or attack intended, but I am interested to discuss with people why they think this is acceptable for a new camera just back from service for this very issue?

To me, the missed focus area is glaringly obvious and given the OOF face area, very distracting. It would be different if the OOF was part of some sort of foreground with a sharp object purposely juxtaposed in the background, or an overall soft effect or something like that, but I somehow doubt that you intended to have the shoulder area in focus and the face OOF.

Lastly, maybe this was an improvement from the before-service condition, but if the camera is still front focusing as this image would indicate, service did not correct the problem, which might mean that Pentax still needs to address the root cause if the issue.

Ray

01-29-2011, 08:38 AM   #5
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Ray, at 800 ISO and so poor lightning conditions, the sharpness is not so evident. But you're right, seems like that little nose and little mouth are in focus and not the eye(s). And I agree with you: not acceptable for a new camera to have issues, no matter what.
01-29-2011, 12:18 PM   #6
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QuoteOriginally posted by jcespite Quote
Hi Eric, can you please do one thing for me; in <2.8 A can you compare a live-view shot with a thru the view-finder focus shot? I'm interest to see what the difference is? I find no matter what light condition the view-live performance is perfect.
Live-view focusing is always perfect, and is not affected by light temperatures. This is due to the way contrast detect autofocus works. In my opinion, this is one of the huge advantages of mirrorless cameras, no more worrying about front/back focus issues. Unfortunately, this comes at the expense of autofocus speed, especially for tracking.
01-29-2011, 12:34 PM   #7
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@Ray and ursamajor. I guess I should have anticipated such comments. This was not intended to show AF performance, simply to show that I have more important things to worry about than focus charts The hilarious part is, this shot was made using live-view focusing! Note that this was handheld, at relatively low shutter speed and very shallow depth of field. I, or the baby, have probably moved slightly after aquiring focus. So let this be a lesson:
  • Proper focus testing is hard
  • You should not draw unsubstantiated conclusions

Here are two more test shots, the first using live view, the second with normal AF. Both are 100% crops, and the shots were made with a tripod. I had to put in somewhere around -5 in MA, don't remember the exact figure. I'm perfectly happy with this performance. As I said, already at f/2.8, the front focus is not noticable with MA turned off. For applications where critical focus at wide aperture is necessary, you should use manual focus anyway due to the size of the focus points.

01-29-2011, 01:01 PM   #8
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Looks pretty soft.

QuoteOriginally posted by EricT Quote
@Ray and ursamajor. I guess I should have anticipated such comments. This was not intended to show AF performance, simply to show that I have more important things to worry about than focus charts The hilarious part is, this shot was made using live-view focusing! Note that this was handheld, at relatively low shutter speed and very shallow depth of field. I, or the baby, have probably moved slightly after aquiring focus. So let this be a lesson:
  • Proper focus testing is hard
  • You should not draw unsubstantiated conclusions

Here are two more test shots, the first using live view, the second with normal AF. Both are 100% crops, and the shots were made with a tripod. I had to put in somewhere around -5 in MA, don't remember the exact figure. I'm perfectly happy with this performance. As I said, already at f/2.8, the front focus is not noticable with MA turned off. For applications where critical focus at wide aperture is necessary, you should use manual focus anyway due to the size of the focus points.
Your test shots look soft to me, so I am not sure what this is supposed to prove...

BTW, your thread topic was about your serviced camera and your comments posted with a sample image indicate that things are much better now. Maybe so, but color me not convinced based upon your posts in this thread.

If you are happy with this level of performance, I suppose that is all that matters.

Ray

01-29-2011, 03:36 PM   #9
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Chill down, Ray. I'm not trying to prove anything here, I'm just reporting my experience before and after service, as requested by several members here. Do you own the FA 50mm lens? This is representative of its performance wide open. Remember, this is a 100% crop, with no sharpening applied. Even if these pictures are soft, they prove that contrast AF and phase-detect AF give similar results.

Oh, here is another picture. The K-r actually works at narrow apertures as well. Amazing!

FA 50mm, f/8, ISO 200, 1/125s. Lit by a Metz AF-48 flash in a 24" softbox.
01-29-2011, 04:09 PM   #10
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QuoteOriginally posted by EricT Quote
Chill down, Ray. I'm not trying to prove anything here, I'm just reporting my experience before and after service, as requested by several members here. Do you own the FA 50mm lens? This is representative of its performance wide open. Remember, this is a 100% crop, with no sharpening applied. Even if these pictures are soft, they prove that contrast AF and phase-detect AF give similar results.

Oh, here is another picture. The K-r actually works at narrow apertures as well. Amazing!

FA 50mm, f/8, ISO 200, 1/125s. Lit by a Metz AF-48 flash in a 24" softbox.
Ray chilling down is really not needed in my opinion.

Your posts and examples are certainly not convincing me the front focus issue is fixed on your camera or that it is close to perfect and is therefore good.

Last edited by betaPhoto; 01-29-2011 at 07:44 PM.
01-29-2011, 07:31 PM   #11
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Eric - No Worries

QuoteOriginally posted by EricT Quote
Chill down, Ray. I'm not trying to prove anything here, I'm just reporting my experience before and after service, as requested by several members here. Do you own the FA 50mm lens? This is representative of its performance wide open. Remember, this is a 100% crop, with no sharpening applied. Even if these pictures are soft, they prove that contrast AF and phase-detect AF give similar results.

Oh, here is another picture. The K-r actually works at narrow apertures as well. Amazing!

FA 50mm, f/8, ISO 200, 1/125s. Lit by a Metz AF-48 flash in a 24" softbox.
Eric,

No need to worry about chilling. Just posting my observations.

FYI, I own the following 12 lenses right now (LBA is not a new thing for me as I have been shooting Pentax since 1978 ):

DA 16-45
DA* 16-50
DA 40
DA* 50-135
FA 31
FA 43
FA 77
FA 50
Tamron 28-75 f2.8
Tamron 90mm macro f2.5
Sigma 18-50 f2.8
Sigma 70-210 f2.8

The FA50 is known to be low contrast wide open.

I gave away two DA 50-200's, 2 18-55s, 2 F 50 f1.7s, 1 FA 24-90, and some other stuff I cannot remember (relatives get the hand-me-downs).

I sold the FA 28 f2.8 and more recently the DA 14 f2.8.

Since the dawn of the digital era I have owned and extensively shot with:

2 istds bodies
2 K100 bodies
2 K10 bodies
2 K20 bodies (I still have one)
and 3 K5s that I returned for FF at EV 3-4.

Note that every one of the K5 bodies had FF shift in reduced light. I returned one K10 for focusing issues and it was exchanged.

However, I have shot quite extensively indoors with all of the bodies, and while all FF in lower light, I am able to keep the subject within the DOF so that they look acceptably sharp with every one of them but the K5.

My indoor settings are ISO 400 f 5.6 with bounce flash, and with every K5 I tried, I could not keep the subject within the DOF at f5.6 unless I dialed in all of the AF adjust. Of course, if a lens starts out more FF than another, it may be that it cannot be dialed in at all in lower light (my 43 is like this).

The Kr seems to have a very similar problem that is more than well documented.

I guess that it would be good news(?) if Pentax simply needs to repair thousands of cameras for some mechanical fault, but it is just not clear that the repair route works, hence the interest in seeing results for "repaired" cameras.

Have fun with the little one (mine are long grown, but I am a grandfather several times over).

Ray

Last edited by Ray Pulley; 01-29-2011 at 07:33 PM. Reason: Added a lens!
01-29-2011, 10:10 PM   #12
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The FA 50/1.4 is well-known for its softness wide open. That first shot is exactly what I would get from any of my cameras using this lens under any circumstances. And none of my cameras front focus, or back focus. Stop it down a little and it is razor sharp. It's a characteristic of this lens, and very useful for portraits.
01-30-2011, 03:38 AM   #13
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Thanks, Ray. That sure is an impressive lens collection! Sorry about the previous comment, I guess I just misinterpreted your wording, easy to do on the internet.

For me, the level of front focus right now is on par with what I've seen from my other DSLRs (including Nikon bodies). Your indoor settings are exactly what I use as well for most indoor shots, ISO 2-400, f/5.6 and bounce flash. No microadjust is needed for sharp pictures with these settings.

Pity about your K5 bodies. It seems like Pentax is working very hard on a firmware fix for this. I'm confident that it will be fixed for the K5, less sure about the K-r since it doesn't have the extra AF sensor (it must be there for a reason, right?).
01-30-2011, 06:34 PM   #14
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Beautiful shot.

QuoteOriginally posted by EricT Quote
Oh, here is another picture. The K-r actually works at narrow apertures as well. Amazing!

FA 50mm, f/8, ISO 200, 1/125s. Lit by a Metz AF-48 flash in a 24" softbox.
02-01-2011, 06:05 PM   #15
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Less complaining, more photography

QuoteOriginally posted by krebsy97 Quote
Beautiful shot.
I agree. How many special moments of time and place like this image were not captured because we're all trying too hard to win an argument and not out using the camera? I've never seen a focus test I'd hang on my wall. So ends my participation, I've got photos to take,

Brian
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