SDM Problem with DA* 50-135mm


malfis

Link Posted 14/09/2021 - 19:19
Could I please ask for some advice?
Whenever I try to use the above lens for the first time on any particular day it takes me ages to Ďwake upí the SDM by constantly switching the camera on and off and trying to activate the autofocus.
Is it easily solvable or does it mean itís a terminal problem with the lens, and if so approximately how much does a replacement SDM cost?
Iím loathe to ditch the lens as itís a super copy.
Thank you.
Lots of gear - but not a lot of idea!

Mike-P

Link Posted 14/09/2021 - 20:49
It's not terminal as both my 50-135mm and 16-50mm have done the same thing for years.

I have found (on the K-1 at least) that they wake up a lot quicker if you use liveview first. Alternative is to change them over to screw drive with a hack available on Pentaxforums.
. My Flickr

pschlute

Link Posted 14/09/2021 - 20:56
Yes, my old 16-50 was notorious for this. My method was to have AF on, half press the shutter and manually turn the focus ring (quick-shift) to and from the extremes a few times. Lens would eventually wake up.

It went on for years like this and never failed entirely.
Peter



My Flickr page

HarisF1

Link Posted 14/09/2021 - 23:20
Yes, as above, rotate the focus ring through the whole range with the AF button pressed and the lens cap on.

Option 2 is to convert to screwdrive.

Option 3 is to remove the mount and rotate the motor manually with a screwdriver. This might have the effect of loosening the grease in the unit (theory)

Chrism8

Link Posted 15/09/2021 - 07:08
Mike-P wrote:
I have found (on the K-1 at least) that they wake up a lot quicker

Option 4 is you've a good reason according to Mike-P to purchase a K1 LOL
Chris

www.chrismillsphotography.co.uk

" A Hangover is something that occupies the Head you neglected to use the night before".

-------------------------------------------------------------
K1 - Sigma 85mm F1.4, Pentax DFA 150 -450 F4.5 / 5.6, Pentax DFA* 24 - 70 F2.8

Sigma 100-300 F4, Samyang 14mm F2.8, Pentax DFA* 70-200 F2.8

K3iii + K3ii + K5iis converted to IR, Sigma 17 - 70 F2.8, Pentax 55 - 300 F4.5 / F5.6 PLM

Mike-P

Link Posted 15/09/2021 - 09:20
So if ever there was a reason to buy a K1 there it is ... To use as a wake up tool for a lens you will never use it with.
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Pwynnej

Link Posted 15/09/2021 - 09:29
Both my 16-50 and 60-250 went from working well to not working at all, there was never a grey phase. My recently departed DA300 was no problem.

I have heard from multiple sources that a seemingly failing lens can be given a burst of life through intense use and correct storage. Alas, I went from fully working lens to dead lens and another cheque for £150-180.
Z-1p, K-1, P50
F50 1.7. FAs 24, 35, 50 1.4, 85, 135. DFA15-30, DFA24-70, D-FA*70-200. D-FA 100. The SMC-FA Limited Trinity.
Metz 45 CL-4, AF500FTZ. AF540FGZ.
Some Mamiya and some Nikon

Helpful

Mike-P

Link Posted 15/09/2021 - 09:33
Yet strangely Pentax always maintained there was no problems with the SDM motor in those lenses .

I have always thought the 50-135mm is one of the best performing lenses ever made by Pentax.
. My Flickr
Last Edited by Mike-P on 15/09/2021 - 09:39

Pwynnej

Link Posted 15/09/2021 - 11:36
The 17-70 was another lens that was supposed to be immune to SDM failure but the one I tested at Jessops in Richmond failed out of the box - I was looking at it when my 16-50 was at Johnson's... the 17-70 IIRC was only SDM and had no screw-drive option.

I did try the 50-135, but as I had the Sigma twins at the time thought the 60-250 would be the better replacement for those. It was nice, the guy who owned the 50-135 was inquisitive about my 85*. so we had a sway for a day.
Z-1p, K-1, P50
F50 1.7. FAs 24, 35, 50 1.4, 85, 135. DFA15-30, DFA24-70, D-FA*70-200. D-FA 100. The SMC-FA Limited Trinity.
Metz 45 CL-4, AF500FTZ. AF540FGZ.
Some Mamiya and some Nikon

malfis

Link Posted 15/09/2021 - 17:17
Mike-P wrote:
It's not terminal as both my 50-135mm and 16-50mm have done the same thing for years.

I have found (on the K-1 at least) that they wake up a lot quicker if you use liveview first. Alternative is to change them over to screw drive with a hack available on Pentaxforums.

pschlute wrote:
Yes, my old 16-50 was notorious for this. My method was to have AF on, half press the shutter and manually turn the focus ring (quick-shift) to and from the extremes a few times. Lens would eventually wake up.

It went on for years like this and never failed entirely.

HarisF1 wrote:
Yes, as above, rotate the focus ring through the whole range with the AF button pressed and the lens cap on.

Option 2 is to convert to screwdrive.

Option 3 is to remove the mount and rotate the motor manually with a screwdriver. This might have the effect of loosening the grease in the unit (theory)

Thanks for your suggestions - I'll try them all before I consider reverting to screwdriver!
Lots of gear - but not a lot of idea!

Mike-P

Link Posted 15/09/2021 - 19:25
malfis wrote:
Mike-P wrote:
It's not terminal as both my 50-135mm and 16-50mm have done the same thing for years.

I have found (on the K-1 at least) that they wake up a lot quicker if you use liveview first. Alternative is to change them over to screw drive with a hack available on Pentaxforums.

pschlute wrote:
Yes, my old 16-50 was notorious for this. My method was to have AF on, half press the shutter and manually turn the focus ring (quick-shift) to and from the extremes a few times. Lens would eventually wake up.

It went on for years like this and never failed entirely.

HarisF1 wrote:
Yes, as above, rotate the focus ring through the whole range with the AF button pressed and the lens cap on.

Option 2 is to convert to screwdrive.

Option 3 is to remove the mount and rotate the motor manually with a screwdriver. This might have the effect of loosening the grease in the unit (theory)

Thanks for your suggestions - I'll try them all before I consider reverting to screwdriver!

I think buying a K-1 is a bit overkill tbh.
. My Flickr

womble

Link Posted 15/09/2021 - 19:44
Sounds like an excellent excuse to me...
Kris Lockyear
It is an illusion that photos are made with the cameraÖ they are made with the eye, heart and head. Henri Cartier-Bresson
Lots of film bodies, a couple of digital ones, too many lenses (mainly older glass) and a Horseman LE 5x4.

My website

pschlute

Link Posted 15/09/2021 - 19:56
Mike-P wrote:


I think buying a K-1 is a bit overkill tbh.

Only a very little bit
Peter



My Flickr page
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