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04-30-2011, 12:43 AM   #1
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Pentax AF really need fixing

When i started using pentax (K10D) I had only one lens, 18-200 sigma, was very happy with it but only because it would not show there is problem with pentax AF.
next up K20D and I was still happy but i got my first fast lens, FA50f1.4 so the trouble were to come soon but I was happy because I would only use my new lens indoors for parties and never took it outside.
all other lenses were F4 and higher so they would not show the problem other then odd OOF shot which is normal thing to happen.
K7, I haven't use it much but once again it was always slow lenses outdoors so issue never came up.
then I got K5, wow what a nice camera, pentax really done it well, right?, not at all as it turns out, I don't care how good the sensor is if i can't trust my camera AF, read on....
with K5 being so great I was only fair to get some new lenses, sigma 17-50 f2.8, this lens was so sharp even at f2.8 I was really happy with my purchase, then i took it outside and oh dear, absolute mess, getting shot in focus was just not possible on sunny day UNLESS i used liveview focus. it didn't click in yet that pentax might be the problem here so i blaimed sigma and sent it off for refund, then i got pentax DA* 16-50 f2.8, better but still serious issue outdoors on sunny day when wide open two copies same issue, both decentered on top of that and one just shocking, so of it went back to shop for refund.
then i got sigma 70-200 f2.8, really nice copy BUT only indoors.
clearly my K5 is broken, well i got another one but made sure i can return it if i'm not happy with it and sure enough it is doing same thing.
could be my lenses doing so? hard to believe so many lenses act same way but just to be sure i got K20D from my neighbour with another FA50 f1.4 he had it set to F3.5 on camera when asked why, he said he can't get sharp picture outdoors if he open lenses wider so i took his K20D and tested with my fast lenses and what do you know, they ALL act same way, outdoors if wide open they really badly out of focus, his lens does same thing.
setting to +7 on focus auto adjustment works but you can't trust the camera and unless you monitor exposure every time you have no hope and just have to cross fingers and expect some luck
so what i notice is that it doesn't changes with white balance but it changes with exposure, and it isn't gradual as far i seen but simple drops to 0 (on AF adjustment) or outdoors when sunny you need +7, with no artificial lights turn on indoors it goes back to 0 for adjustment so it is something affected by exposure.
as much K20D was acting same way it wasn't as bad, with f2.8 lenses you could almost be happy at all times or with mid way point on AF adjustment but K5 is just USLESS and considering how many lenses I tried and bunch of cameras there is sersious issue there and pentax needs to fix this.
if i didn't just buy few new lenses pentax would be history for me and I was loyal customer for quite a few years and i just hate the idea of moving away from pentax but to have modern dSLR that have sure poor focus performance just makes no sense, I take my mate old canon 400d with 1.4 lens and it is sharp no matter what time of the day it is and this really makes me mad and sad

04-30-2011, 01:14 AM   #2
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Oh, boy. Just when I began to think that the AF problems are mostly history and finally ordered one...
04-30-2011, 01:45 AM   #3
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you can work around the problem but considering how long pentax been making cameras this is quite sad that user can't trust AF when fast lenses are used outdoors.
also it isn't K5 alone as with fast lenses you can reproduce same issue to some degree with k20D as well (i'm guessing same could apply for k10D or K7 but I can't put my hands on one right now and in past when i owned them i never used fast lenses in daylight).
04-30-2011, 02:07 AM   #4
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I dont mean to critisize your exeprience, and this is really unfortunate to happen to you

Anyways, there are alot of people here with K-5 and fast glass. Havent heard anything about this sort of faults here on this forum. Doesnt have to mean that there isnt any fault, because it clearly is in your case.

Hope you will get to the bottom with this and that you will be able to enjoy your gear!

04-30-2011, 02:17 AM   #5
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Our friend dgais has many fast lenses, why don't we ask him to take a few indoor/outdoor test to see if he can't replicate some of these issues?

However, I've not uncovered any outdoor issue on our K-5's with faster lenses(50/1.4)
04-30-2011, 02:18 AM   #6
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The more I am reading the experience with K-5 the less I am happy about Pentax success. Curently I use K200D and it's quite old now, still working well, however there will be one day when I need it to change. Which model? K-5? I guess no, it's a bit expensive and not really well made. Just read some storeis when weathersealing just doesn't work in the rain, read some cases with AF problems, read some cases with weird Live-view work. K-7? Well, looks like older and a bit worse camera is more trustive. K20D? This has a lot less functions, is slower, louder however there are no so many problems as with new models. So, i guess i have to buy K20D next or k-7, but no k-5 which is sad.
I believe TIPA could give an award to K-5 not to D7000, however stains in the sensor and other problems just doesn't fit otherwise well made camera. So, old pentax still rules,still works as hard as you need. It's K20D time babe.
04-30-2011, 02:53 AM   #7
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QuoteOriginally posted by the swede Quote
I dont mean to critisize your exeprience, and this is really unfortunate to happen to you

Anyways, there are alot of people here with K-5 and fast glass. Havent heard anything about this sort of faults here on this forum. Doesnt have to mean that there isnt any fault, because it clearly is in your case.

Hope you will get to the bottom with this and that you will be able to enjoy your gear!
I already got to the bottom of this, question is can pentax do as well?, clearly they tune everything in laboratory (no shock) in conditions that K5 works REALLY WELL.
i can go to party with almost no light and take perfectly focused pictures but let me go outside and i can reproduce same problem with MULITPLE pentax cameras and quite a handful of lenses, problem isn't isolated to my one bad item, i know better than that before i start pointing fingers.

QuoteOriginally posted by JohnBee Quote
Our friend dgais has many fast lenses, why don't we ask him to take a few indoor/outdoor test to see if he can't replicate some of these issues?

However, I've not uncovered any outdoor issue on our K-5's with faster lenses(50/1.4)
if dgais would like to have a go then best is to take some photos with fa50 f1.4 at f1.4 where subject is further than 3-6 meters away from camera and in direct sunlight or almost direct sunlight, iso set to 80 or shutter speed will hit limit, you do NOT need full on direct sunlight to have this problem show but to make it easy for testing lets stick to that
SR off
can't think of other conditions needed to reproduce this
being closer to to subject makes issue go away as well
i done it with so many lenses and cameras i go as far as saying give me the gear and i will reproduce it 100% of time.
04-30-2011, 03:29 AM   #8
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QuoteOriginally posted by Croc Quote
i can go to party with almost no light and take perfectly focused pictures but let me go outside and i can reproduce same problem with MULITPLE pentax cameras and quite a handful of lenses, problem isn't isolated to my one bad item, i know better than that before i start pointing fingers.
I wonder if this really is the same well documented front focusing problem? Perhaps yours is calibrated/accurate in the low light tungsten environment and in better light in effect back focuses? Have you tried fine tuning the AF outside to see if that brings you the tungsten FF problem?

04-30-2011, 03:37 AM   #9
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they always say pictures tells better story so here it is couple of examples
first k20D, no AF adjustment (tested with two different copies of FA50 f1.4)

indoor shot (books) is spot on AF, outdoor with not that much more light seriously out of focus (you can see xmas tree holder is sharp), center point used high constrast subject
https://picasaweb.google.com/crocau/K20DFA50F14?authkey=Gv1sRgCIjjjty65bPCaA#

now K5, basket ball post, AF adjustment on 0 and we get out of focus text (yet again high contrast subject) change AF adjustment to +7 i think it was and picture is fine
cd box is indoors with AF adjustment on 0 again yet it is sharp....

https://picasaweb.google.com/crocau/K5FA50F14?authkey=Gv1sRgCMvjn6GBrfHj3gE&feat=directlink
04-30-2011, 03:43 AM   #10
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QuoteOriginally posted by Raffwal Quote
I wonder if this really is the same well documented front focusing problem? Perhaps yours is calibrated/accurate in the low light tungsten environment and in better light in effect back focuses? Have you tried fine tuning the AF outside to see if that brings you the tungsten FF problem?
i though about this but we talking here of same problem on multiple cameras showing same issue, even k20d demonstrates same problem just not as much.

and yes adjustment to +6/+7 does great job but then indoors i'm starting to see problems, not as much but there is still a problem and with modern dslr like k5 that is just NOT GOOD ENOUGH and when i have party that is half/half inside and outside like i had 2 weeks ago it is nightmare because unless you rememeber to switch it around every time you move around the place you looking at lots of shots that are good for nothing, not to mention forget about doing quick snaps when something special happens, what do i do than? scream out "please pause the action while i adjust my camera!!!" ? once again NOT GOOD ENOUGH

being loyal to pentax is starting to get on my nerves now
lets see if i remember well
k10d tilted viewfinder
k20d cracking lines followed by chip at base of the camera
k7 green lines joys
k5 stains, AF issues (this one you can add to other models too) (also sticky shutter button, fixed and now doing it again)

but i'm most mad at k5 because it is such fine device, focus when adjusted and under not changing conditions is fast and spot on, iso performance, dr rang, all is just outstanding but if i can't trust it it really turns in to nothing more but frustration orginally i was sure k5 will be model i might keep for couple of years before i jump to next model but now i can't wait for the next model having fingers crossed that it will finally give us good AF system.

Last edited by Croc; 04-30-2011 at 03:53 AM.
04-30-2011, 03:43 AM   #11
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AF is fine once it is properly calibrated. You just need to bring all the equipment to authorised service to get all the AF points alligned correctly, if there is such a problem.
Refunding the lens for another lens and changing camera for another camera isn't likely to help. Neither is complaining on the internet - you are crying on a wrong grave. Those who could help you do not read these forums.
Expecting a lens in 1x-5x/2.8 category to focus properly with any camera out of the box is very naive, no matter what brand.
04-30-2011, 03:55 AM   #12
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QuoteOriginally posted by elho_cid Quote
AF is fine once it is properly calibrated. You just need to bring all the equipment to authorised service to get all the AF points alligned correctly, if there is such a problem.
Refunding the lens for another lens and changing camera for another camera isn't likely to help. Neither is complaining on the internet - you are crying on a wrong grave. Those who could help you do not read these forums.
Expecting a lens in 1x-5x/2.8 category to focus properly with any camera out of the box is very naive, no matter what brand.
why dont you read whole thread before you post reply next time?
04-30-2011, 04:46 AM   #13
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Croc, sorry to hear of your experience, however not all K-5 owners share your issues.
And be clear in your own mind that there is no need for you to have any brand loyalty - if you're not happy you know what to do. There are many of us here that are, and have been for generations of Pentax cameras, including myself, and have the results to show for it, e.g. see No more tests! just pictures - PentaxForums.com and The death of The Soft K5 urban legend - PentaxForums.com.

I have also been shooting with fast glass, including the FA 50/1.4 and FA Limiteds and do not experience any discrepancies between indoor and outdoor focusing - this is with all of my Pentax dSLRs, past and present (6 different ones).

Now, your complaints are nothing new here on the forum here either; see K5 - disappointly soft AF - PentaxForums.com, Send it back or is it normal. - PentaxForums.com and More about low light AF - PentaxForums.com. But each person's problems are unique even if slightly, so if you are certain you have issues with your own camera, then your two choices are either to get yourself a good copy, or to switch.

Last edited by Ash; 04-30-2011 at 05:02 AM.
04-30-2011, 05:17 AM   #14
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Since Croc's K-5 experience does not remotely mirror mine, (s)he wins today's "Ignore" award.

Cheers...
04-30-2011, 05:52 AM   #15
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QuoteOriginally posted by Ash Quote
Croc, sorry to hear of your experience, however not all K-5 owners share your issues.
And be clear in your own mind that there is no need for you to have any brand loyalty - if you're not happy you know what to do. There are many of us here that are, and have been for generations of Pentax cameras, including myself, and have the results to show for it, e.g. see and The death of The Soft K5 urban legend - PentaxForums.com.
i went over every picture in that thread and NON of them demonstrates death of urban legend about K5 being soft, I don't think i seen even one picture that is sharp in that whole thread and was shot at f1.4, NOT ONE and the only one shot at f1.4 (old clock) was in fact OUT OF FOCUS by a country mile, so nobody there got results to show for it, how can anyone use that thread as example of pentax good AF is just crazy to me, seriously if you going to set aperture so high where DOF is so massive that you can close my eyes spin the ring at random and still get focus spot on in manual focus on top of that but tell me how on earth does that shows that k5 doesn't have focus issue?
I got 100000+ pictures that are keepers done with pentax with many that freakish sharp but that does NOT change the fact that there is problem with autofocus i just figured out how to deal with it for most the time and in past where i used slower lenses and would just not see the problem BUT there is a problem and your links if anything confirmed what i been saying.
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