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12-25-2011, 12:14 AM   #31
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QuoteOriginally posted by D4rknezz Quote
Did you try what jolepp said?
Sheesh, don't people read???

From post #7:

QuoteOriginally posted by Christine Tham Quote
the annoying imprecision in the AF is STILL THERE, even in relatively good light.
And before you ask, yes I do understand the importance of using a tripod, ensuring that the camera has a good unambiguous target, doing the test from multiple conditions (lens pre-focused, front focused, back focused etc.). I have been using cameras for over 30 years and and started out with a Yashica rangefinder. I currently have 5 Pentax bodies starting from the Spotmatic. 6, counting the *ist D which my brother still uses. [Edit: oops, 7 - forgot about the broken Super A - okay, I am not good at getting rid of old camera bodies.]

12-25-2011, 12:14 AM - 1 Like   #32
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I was one of the earliest to get a K-5 when it was first launched and recently I decided to send my K-5 together with my new DA* 55mm f/1.4 to Pentax Japan to get focus calibrated as I felt even the AF adjustment available on the camera couldn't get me tack sharp images. Prior to that my Sigma 70-200mm f/2.8 HSM didn't seem very sharp, especially wide open.

Well when I got back my K-5 from Pentax Japan, I was blown away by how sharp the camera focuses. No focus issues both indoors in incandescent lighting or outdoors at all. My DA* 55mm and my Sigma are like completely new lenses, just so uber sharp even wide open. So in conclusion I have to say it wasn't the lenses but the camera body that needed a tweak. I have to thank Pentax Japan for a stellar job and quick turnaround.
12-25-2011, 12:25 AM   #33
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QuoteOriginally posted by creampuff Quote
Well when I got back my K-5 from Pentax Japan, I was blown away by how sharp the camera focuses. No focus issues both indoors in incandescent lighting or outdoors at all. My DA* 55mm and my Sigma are like completely new lenses, just so uber sharp even wide open. So in conclusion I have to say it wasn't the lenses but the camera body that needed a tweak. I have to thank Pentax Japan for a stellar job and quick turnaround.
Okay, thanks very much for this info. I think you have given me hope that I can get my camera back to the accuracy it had when it was new. I will ask for a repair quote in the new year.
12-25-2011, 02:02 AM   #34
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You have of course tried different lenses before you came to the conclusion that it is the camera and not the FA43 that owns the problem?

12-25-2011, 06:04 AM   #35
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QuoteOriginally posted by Gimbal Quote
You have of course tried different lenses before you came to the conclusion that it is the camera and not the FA43 that owns the problem?
I was just about to ask the same question. Try another lens to rule out the body before you send it in.
12-25-2011, 10:04 AM   #36
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QuoteOriginally posted by Christine Tham Quote
I have suffered permanent damage to my right eye as a result of high cholesterol, and it can no longer focus properly.
Sorry about that. Retinal artery occlusion? Yikes.
12-25-2011, 10:18 AM   #37
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I read that just fine

Which is why I asked whether you did what jolepp asked. I barely used dslr camera for more than a year, and only have an intermediate/semipro camera less than 8 months, and my camera has less than 4k shots on it (i'd be surprised if it has 3k), so I wont argue that you are a more experienced camera owner .

Though I do programming on the side, and when there is a problem with multiple variables in my code, what I need to do is assign each variables but one variable to a static value, and see what that last one is doing. Repeat each process with a different variable till you find the problem.

So - again, static variable 1: tripod, static variable 2: stationary target, static variable 3: good light, preferably artificial, static variable 4: wireless remote trigger.
The only variable being tested? autofocusing motor , when the focus ring is slightly tweaked between each shot. A worn and torn body will then go all over the place, and a working body should nail it everytime. Good luck!




QuoteOriginally posted by Christine Tham Quote
Sheesh, don't people read???

From post #7:



And before you ask, yes I do understand the importance of using a tripod, ensuring that the camera has a good unambiguous target, doing the test from multiple conditions (lens pre-focused, front focused, back focused etc.). I have been using cameras for over 30 years and and started out with a Yashica rangefinder. I currently have 5 Pentax bodies starting from the Spotmatic. 6, counting the *ist D which my brother still uses. [Edit: oops, 7 - forgot about the broken Super A - okay, I am not good at getting rid of old camera bodies.]
12-25-2011, 11:13 AM   #38
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QuoteOriginally posted by D4rknezz Quote

Though I do programming on the side, and when there is a problem with multiple variables in my code, what I need to do is assign each variables but one variable to a static value, and see what that last one is doing. Repeat each process with a different variable till you find the problem.
Since you have done some programming, you may appreciate one variable I discovered that made a difference.

I even tested whether the camera behaved differed under different settings of the AF Fine adjustment parameter. I have discovered that the camera focus accuracy improved (but still not perfectly consistent) if I turned off AF Fine adjustment completely, compared to AF Fine adjustment enabled, but both global and lens specific settings set to 0.

I've posted about this back when I first bought the camera and discovered it has the infamous "front focus in dim yellowish light" problem, which was supposedly "fixed" in firmware 1.03. I discovered my camera slightly front focuses when the AF Fine adjustment setting was enabled (even when the values were all set to 0) but the problem is greatly reduced if I turned off AF Fine adjustment. Firmware 1.03 did not fix the front focus issue for me (the camera still misfocuses in dim lighting, but it was something I was willing to tolerate, because it only happened in very dim conditions - the same conditions under which my K10D also misfocuses and the Canon 1D Mk III refuses to focus),

12-25-2011, 12:28 PM   #39
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QuoteOriginally posted by Christine Tham Quote
Okay, thanks very much for this info. I think you have given me hope that I can get my camera back to the accuracy it had when it was new. I will ask for a repair quote in the new year.
You're welcome. Just for your info, Pentax Japan replaced a new sensor and they made adjustment to the AF module. Even on my non-SDM/HSM lenses, the focus accuracy for my adjusted K-5 has been spot on, as can be seen by this shot taken with the Sigma 30mm f/1.4 wide open under fluorescent lighting.

http://farm8.staticflickr.com/7174/6559641397_c57873849e_o.jpg
12-25-2011, 12:32 PM   #40
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QuoteOriginally posted by Christine Tham Quote
I discovered my camera slightly front focuses when the AF Fine adjustment setting was enabled (even when the values were all set to 0) but the problem is greatly reduced if I turned off AF Fine adjustment.

Ya thats interesting. Im gonna check what i set mine to now!
12-25-2011, 01:30 PM   #41
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I have taken over 20,000 photos with my K5 and it hasn't changed focus. It is quite a bit better than my K7. K5 and Sigma 30 (my only f1.4 lenses), both require quite a bit more focus adjustment on the K7 than the K5. Unless you dropped it, or something happened to the auto focus module, not sure why it would change.

Good luck!
12-25-2011, 03:52 PM   #42
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QuoteOriginally posted by creampuff Quote
You're welcome. Just for your info, Pentax Japan replaced a new sensor and they made adjustment to the AF module. Even on my non-SDM/HSM lenses, the focus accuracy for my adjusted K-5 has been spot on, as can be seen by this shot taken with the Sigma 30mm f/1.4 wide open under fluorescent lighting.

http://farm8.staticflickr.com/7174/6559641397_c57873849e_o.jpg
Thanks once again. You have confirmed my suspicion, which is that the misfocus is actually caused by a badly calibrated colorimetric sensor in the AF module, which is why the misfocus happens with both SDM and non SDM lenses (on mine, I first noticed the misfocus on my DA* 50-135, but I did the testing on my FA43 to eliminate the possibility of SDM malfunction).

For some reason, Pentax applies different focus offsets depending on whether AF fine adjustment is enabled or disabled. I suspect the camera is more accurate when AF fine adjustment is turned off because the camera relies on a more extensive set of lookup tables.
12-25-2011, 08:35 PM   #43
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QuoteOriginally posted by Christine Tham Quote
... I suspect the camera is more accurate when AF fine adjustment is turned off because the camera relies on a more extensive set of lookup tables.
^^ ??? ("lookup tables"?)

I think this whole thing is most likely attributed to a naive initial assessment of the K-5.

More accurately, you are now comparing CDAF accuracy to PDAF accuracy, where the PDAF camera has rather large AF sensors and a semi-old base AF module. Your relative opinion of the PDAF camera has simply changed - not it's performance after 20K clicks.


.
12-26-2011, 03:53 AM   #44
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Oh oh. A new, and not very pleasant discovery.

For a brief period, the camera refused to AF at all on non SDM lenses (FA43 and DA70), and all I could hear was the whine of the AF motor. Fortunately, after turning the camera off and on a few times, and mounting and unmounting the lens, it's started focusing again.

Also, I discovered after turning off the AF fine adjustment, the DA* 50-135 now focuses perfectly.

So I guess the problem may not be the colorimetric sensor after all. I hope it's not the motor, because that could end up being an expensive fix.
12-26-2011, 08:43 AM   #45
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QuoteOriginally posted by garyk Quote
Ridiculousness post by a woman.. Wow.
Classy.
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