Search results for 'back focus' - page 2051
Panning Advice
Hi, I suggest shake reduction off and a monopod. Several years of F1 at Silverstone (not been with my Pentax though) proved the slow bends up to Luffield best as you had right to left pan to start, slow nends towards you and then accelerating away all from same viewpoint. Good light of cour...
Posted by wvbarnes on 08/07/2011 - 19:35
Panning Advice
Hi Tim. I used to shoot bike races when I was younger using a Pentax MX manual focus, https://www.pentaxuser.com/photo/the-late-bob-smith--british-champion--17409/large ..... It's easier these days with the modern stuff. The best advice I can give is to pick a landmark where you intend to take...
Posted by johnwhit on 08/07/2011 - 19:57
Kx Auto focus not functioning
Hello there, I'm a newbie to this forum and I have a problem. My K-x will not autofocus with the DA16-50 lens. Press the shutter release half-way down and nothing happens. However, all the other Pentax lenses focus fine on the K-x? If I put the DA16-50 on a K-5 it works fine and there is no prob...
Posted by GordonR on 09/07/2011 - 14:30
Kx Auto focus not functioning
Are the other lenses that focus fine on the K-x SDM lenses or screw-drive AF ones? Just wondering if that could be the key to the problem.
Posted by johnriley on 09/07/2011 - 14:42
Kx Auto focus not functioning
The lenses have an autofocus coupler (screw drive). For an example, I have tried the DA 50-135, DAL 55-300 and DA 12-24 and they work fine. The DA 16-50 worked at first, and to my recollection has not suffered any abuse. When I examine the contacts on the K-x I can see no difference compared to t...
Posted by GordonR on 09/07/2011 - 14:56
Kx Auto focus not functioning
It looks as if the SDM in the 16-50 is not working. Unfortunately if SDM fails it does not revert to screw drive. You coud try cleaning the SDM contacts both on the lens and in the camera mount (two brass contacts). Otherwise you will have to send it in for repairs. I hope it is still under warra...
Posted by helios on 09/07/2011 - 15:05
Kx Auto focus not functioning
The lens with the problem is the only one with SDM. The K-x would use SDM if available. It can't 'fall back' to screw drive. The fact that the lens works on a K-5 would point to the problem being with the K-x. Clean the contacts on the K-x camera body; try again.
Posted by JohnX on 09/07/2011 - 15:07
Kx Auto focus not functioning
I did not read your original question properly. JohX is quite right. I agree that if the lens works on a K-5 the problem must lie with the K-x. It would still be worth cleaning the SDM contacts but it looks as if the camera might require servicing. Incidentaly if the camera is out of warranty yo...
Posted by helios on 09/07/2011 - 15:21
Kx Auto focus not functioning
Thank you for your response Archie. I do not understand how the 16-50 would work on the K-5 if it were faulty? I will clean all the contacts, as you say.
Posted by GordonR on 09/07/2011 - 15:23
Kx Auto focus not functioning
The DA 50-135 is SDM and works well on the K-x. I do not understand why the 16-50 will not? I have re-cleaned the contacts and suffer with the same results. Thanks JohnX your ideas are appreciated - have you any further suggestions?
Posted by GordonR on 09/07/2011 - 15:34
Kx Auto focus not functioning
Best of luck with the contact cleaning. The relevant contacts are the pair made of brass just inside the camera mount. They were originally the PZ (power zoom) contacts in the days when Pentax made Power Zoom lenses but are now used to power the SDM motor.
Posted by helios on 09/07/2011 - 15:37
Kx Auto focus not functioning
The DA 50-135 is SDM and works well on the K-x. I do not understand why the 16-50 will not? I have re-cleaned the contacts and suffer with the same results. Thanks JohnX your ideas are appreciated - have you any further suggestions? That is very odd. The other possibility is that if the battery i...
Posted by helios on 09/07/2011 - 15:48
Kx Auto focus not functioning
Interesting point - what sort of batteries are you using in the K-x?
Posted by johnriley on 09/07/2011 - 16:01
Kx Auto focus not functioning
Apologies. Missed the 50-135, and that it works ok. The suggestion about enough power is a good one to follow, but I note also that the 16-50 '...worked at first...', which suggests something has changed. Different batteries perhaps? Don't miss what Archie said about cleaning the contacts jus...
Posted by JohnX on 09/07/2011 - 16:43
Kx Auto focus not functioning
I had to replace the K-x batteries last week, Helios, no change. The battery indicator indicates that they are good, but I will install a new set just in case. John Riley - I have been usinf Energizer Lithium batteries, as they normally get me through 2,000 or more shots. You are right on JohnX, ...
Posted by GordonR on 09/07/2011 - 17:33
Kx Auto focus not functioning
I believe the focus motor on the K-5 is a bit stronger than previous Pentax cameras. When SDM fails it tends to go slowly over time, maybe that extra power is enough to keep the 50-135mm focusing on the K-5.
Posted by Mike-P on 09/07/2011 - 17:59
Kx Auto focus not functioning
I have cleaned and recleaned camera & lens contacts, installed two different sets of new batteries and checked the lense fit to the K-x, which is relatively snug and certainly just as tight as the K-5. While the 50-135 does auto focus on both the K-x & K-5, the 16-50 will auto focus on the K-5 but ...
Posted by GordonR on 12/07/2011 - 01:41
Kx Auto focus not functioning
Through your process of elimination, it does sound like the lens. Reading through various threads here, it appears that on occasion, some people have 'loosened up' a lens by turning the focus ring gently from lock to lock a few times (off camera). But you say this particular lens cycles itself...
Posted by i-Berg on 12/07/2011 - 03:33
Kx Auto focus not functioning
Thank you i-Berg (I don't know what a "Pentax Pro Master" is, but it certainly conveys an importance). I will have the lens looked into.
Posted by GordonR on 12/07/2011 - 20:11
Kx Auto focus not functioning
But you say this particular lens cycles itself when you engage the auto-focus function, but does not lock on at all? I'd be taking the lens in for a look. But locking on seems to be a fault of the AF-module in the camera though. The only thing the lens has to do is moving the focus around and it d...
Posted by Anvh on 12/07/2011 - 20:24
