Search results for 'back focus' - page 1218
DA* 50-135 focus issue
Hi, folks. I'm in a bit of a quandary over my DA* 50-135. It started failing to lock focus at 135mm or slightly below, although it was fine at other FLs. This seems to relate to an SDM issue and I was getting ready to post it to Pentax repair in France (where I live) when the problem disappeared. I'...
Posted by Aero on 13/03/2021 - 15:24
DA* 50-135 focus issue
I never owned that lens but did have a DA* 16-50 which had lazy AF. I used to start up by manually focussing to the extremes a few times, then turn on the AF and make the thing focus from both extremes to a point in the middle ground a few times. Once done it worked fine for the photo session. Next ...
Posted by pschlute on 13/03/2021 - 15:34
DA* 50-135 focus issue
Thanks, Peter. I'll try your system for a while and keep my fingers crossed.
Posted by Aero on 13/03/2021 - 17:43
DA* 50-135 focus issue
Sounds like you have something with AI installed... always when threatened with mechanic the symptoms miraculously disappear...our old Golf was a pig until it got onto the road the VW garage was, then it ran perfectly. Is the problem with AF at low light? It's been a problem with my lenses and ...
Posted by Pwynnej on 13/03/2021 - 19:49
DA* 50-135 focus issue
Is the problem with AF at low light? It's been a problem with my lenses and the lens hunts (not limited to DA* glass either). If SDM works on other occasions it doesn't sound like the SDM motor but maybe the sensitivity of the AF sensor... Battery maybe? Light level made no difference. What I c...
Posted by Aero on 13/03/2021 - 21:22
DA* 50-135 focus issue
Knock it back a few millimetres and it would work normally. The 17-70mm is well known for developing the same fault. That problem is the SDM motor.
Posted by Mike-P on 19/03/2021 - 07:38
DA* 50-135 focus issue
The repair people will know very well what the problem is, having seen it probably thousands of times before. They will be able to replace the faulty parts even if the problem isn't manifesting itself at the time the lens gets to them.
Posted by Jonathan-Mac on 19/03/2021 - 08:42
DA* 50-135 focus issue
Many thanks, chaps. Off to the repair shop it goes.
Posted by Aero on 20/03/2021 - 21:04
DA* 50-135 focus issue
Quick update: the French repair people, PM2S, are fixing it for the equivalent of £180. I think that's money reasonably well spent if the repair holds up for a while. Thanks again for your advice.
Posted by Aero on 28/04/2021 - 15:40
Advice on lens fog... balsam separation or oil condensation? Cost?
My guess would be that it can't be repaired without replacing an entire element group, in which case you may as well replace the whole lens if you can find one. Might be worth dis-assembling the lens, I've taken quite a lot of lenses apart successfully and have been able to restore them to 'good ...
Posted by davidstorm on 18/03/2021 - 19:35
Advice on lens fog... balsam separation or oil condensation? Cost?
SMC PENTAX 1:4/20 the early K mount 20mm with 12 elements in 10 groups http://kmp.pentaxians.eu/lenses/ultra-wide/k20f4/ Just bought, arrived today. I'm looking if its fixable before sending it back. (Seller told it was perfect, fluid, clean, bla bla bla.. )
Posted by mark88 on 18/03/2021 - 20:45
Advice on lens fog... balsam separation or oil condensation? Cost?
Hi Mark Just re-read your post, i.e. that you received it today. Send it back immediately, it's not your risk, the seller should have disclosed it and would have been aware of this. Regards David
Posted by davidstorm on 18/03/2021 - 20:52
Advice on lens fog... balsam separation or oil condensation? Cost?
Watch the seller on ebay, it might go back up for spares. If you buy it cheap then you don't mind taking the punt. Old Pentax lenses, especially primes are dead easy to take apart, just be methodical with what came out, in what order and what way around! I use 99.9% isopropyl alcohol and use that...
Posted by cardiffgareth on 18/03/2021 - 21:52
Advice on lens fog... balsam separation or oil condensation? Cost?
Nope, heard a technician and the response is its a very risky operation. So I sent it back for refund.
Posted by mark88 on 21/03/2021 - 12:03
16-50mm f2.8 with a AF focus issue
I've been quoted £180, assuming it involves replacing the SDM motor but thought I'd ask y'all about selling it as is. The AF doesn't work until I manually focus a little whilst half pressing the shutter to AF. Then it kicks in and is fine. Don't know if it stays functioning, like the chap descri...
Posted by davidxgreen on 02/06/2021 - 19:41
16-50mm f2.8 with a AF focus issue
Sounds too much to me. I ended up manually focussing my DA 16-50 most of the time.....with better results.
Posted by pschlute on 02/06/2021 - 20:23
16-50mm f2.8 with a AF focus issue
Both my 16-50mm and 50-135mm do exactly the same thing and I had the motor on the 50-135mm replaced about 14 months before it started doing it again. I don't find it a real problem waking the lenses up before use (they awake much faster if you use liveview for some reason) but if you want then conve...
Posted by Mike-P on 02/06/2021 - 20:37
16-50mm f2.8 with a AF focus issue
Thanks Mike-P - I'll drop Harris a note now. and pschlute - that's an option too, but I do think I need AF, especially at the widest angles -
Posted by davidxgreen on 03/06/2021 - 07:41
16-50mm f2.8 with a AF focus issue
Follow-up for Mike-P - I did indeed get in touch with Haris What a nice chap, only asked for postage and converted my non-working lens to screw drive. I just got it back from him and it's like a new lens. Faster AF than it's ever been. I didn't realise it was just a software thing, thought it in...
Posted by davidxgreen on 12/06/2021 - 20:24
16-50mm f2.8 with a AF focus issue
Glad you got it sorted David - and Yes, Haris is indeed a helpful and nice guy, he's offered me help and advice on several occasions 8) I did mine a few months back and it's so nice to have it back to good working order - this lens gets quite a lot of stick and some quite unfavourable reviews,...
Posted by LennyBloke on 12/06/2021 - 20:39
