[barondla]

If the SDM fails completely can the lens still be focused manually? None of the K mount lenses use focus by wire do they?
Thanks,
barondla

[FozzFoster]

Yes, I believe SDM should still focus manually if the af fails...
The newest PLM af motor is focus-by-wire, I believe.

[c.a.m]

If the SDM fails completely can the lens still be focused manually?

I have a DA* 50-135 SDM. It was repaired several times, including replacement motors twice and the general focusing mechanism once. In one of the failures, the lens would not autofocus and it would focus manually only in one direction; it seemed to be jammed. In the other SDM failure instances, it would focus manually with no issue.

I converted the lens to screwdrive in 2016 and it has worked flawlessly since then.


- Craig

[Bertrand3000]

As far as I know, only the following lenses are using focus by wire :

- HD DA 18-50 RE

- SMC DA-L 18-50 RE

- HD DA 55-300 RE PLM

They do not use SDM motors, though, only DC (for the two 18-50) and PLM (for the latest). They are not known to fail, unlike some SDM lenses.

[aslyfox]

yes, the PLM is focus by wire

and you can focus it manually

Manual Focus
Like most other DA lenses, the 55-300mm PLM features Quick Shift focusing, for immediate manual override. It's not particularly handy for action shooting of the type described above, but if you're shooting slow-moving or static subjects and not getting the results you want from the AF system, you can simply turn the focusing ring to DIY it.

You can also put your body in manual focusing mode and use the ring, full-stop. However, like other AF lenses, the DA 55-300mm PLM's focusing ring doesn't provide very good accuracy or much tactile feedback. It's loose and imprecise compared to a film-era manual lens. The ring's placement near the lens mount is also slightly less convenient than the front-placement on other lenses, though personal taste may vary.

Remember that regardless of which method you choose, since the 55-300mm PLM focuses by wire, your camera has to be on for any kind of focusing to work. . . .

Read more at: HD Pentax-DA 55-300mm F4.5-6.3 PLM WR RE Review - Focusing | PentaxForums.com Reviews

[TedH42]

yes, the PLM is focus by wire

and you can focus it manually

Read more at: HD Pentax-DA 55-300mm F4.5-6.3 PLM WR RE Review - Focusing | PentaxForums.com Reviews

However, the camera must be turned ON to focus the PLM at all. The trick of leaving your camera off while you wander, seeing a possible shot, and just bringing the camera up to your eye to check composition and framing, does NOT work. While bringing the camera up to your eye, the additional action of turning it on must be done. Just something additional to learn, but once learnt, works quite well.

It's a personal preference as to when to turn the camera off again.

[Coljon]

When i had an SDM failure on my 16-50 I couldn't focus manually. The focus ring would turn but the lens was stuck at infinity. It woke up eventually by continually pressing the AF button for about 15 minutes and then slowly came back to life - including manual focus.