SDM lens & camera's focusing switch


unhappysnapper

Link Posted 15/11/2016 - 15:26
This might seem like a daft question to some, but can anyone advise me, with regard to using a SDM lens……..

When the focus selector switch on the lens is switched to AF, what position should be selected on the camera’s focus selection switch?

I have a Pentax K30 with AF.S/C/MF settings, I don’t yet own a SDM lens, but I am considering one.

JAK

Link Posted 15/11/2016 - 15:41
For auto focus both switches need to be on AF. If either or both are on MF that's what you'll get.
If you use back button focussing rather than the shutter release focussing you get the best of both worlds. The lens will focus when you press the rear AF button, but will not try again when you press the shutter release so you don't have to wait while it tries to focus yet again. Might not be ideal for every subject but often works the best, though might need a bit of getting used to.
I've been trying to think of any instances where back button focussing may not be ideal. I'm still thinking... nothing's come to mind so far!
John K
Last Edited by JAK on 15/11/2016 - 15:47

redbusa99

Link Posted 15/11/2016 - 16:14
just note when you disable shutter release focus it disables CIF as well, should you wish to use it shutter release focus has to be enabled. found that out after thinking it had gone wrong when i switched to back button focus
K3 II and the odd lens or 2

Flickr

unhappysnapper

Link Posted 15/11/2016 - 17:15
JAK wrote:
For auto focus both switches need to be on AF. If either or both are on MF that's what you'll get.
If you use back button focussing rather than the shutter release focussing you get the best of both worlds. The lens will focus when you press the rear AF button, but will not try again when you press the shutter release so you don't have to wait while it tries to focus yet again. Might not be ideal for every subject but often works the best, though might need a bit of getting used to.
I've been trying to think of any instances where back button focussing may not be ideal. I'm still thinking... nothing's come to mind so far!

Thanks for the advice....much appreciated.

unhappysnapper

Link Posted 15/11/2016 - 17:22
redbusa99 wrote:
just note when you disable shutter release focus it disables CIF as well, should you wish to use it shutter release focus has to be enabled. found that out after thinking it had gone wrong when i switched to back button focus

Thanks for the info...much appreciated

JAK

Link Posted 15/11/2016 - 17:24
Pleasure. Note your user name, why are you an unhappy snapper? Or has that changed since getting a Pentax?
John K
Last Edited by JAK on 15/11/2016 - 17:24

unhappysnapper

Link Posted 15/11/2016 - 17:39
JAK wrote:
Pleasure. Note your user name, why are you an unhappy snapper? Or has that changed since getting a Pentax?

I joined the forum as I had the dreaded aperture motor failure on my K30 (now resolved).
At the time I was very unhappy, but now I'm a bit happier !!
It was a play on the term "happy snaps"

JAK

Link Posted 15/11/2016 - 18:01
Pleased your K30 is sorted and happier now!
John K

unhappysnapper

Link Posted 15/11/2016 - 18:21
JAK wrote:
Pleased your K30 is sorted and happier now!

Seems OK now, fingers crossed

gfurm

Link Posted 16/11/2016 - 08:23
redbusa99 wrote:
just note when you disable shutter release focus it disables CIF as well, should you wish to use it shutter release focus has to be enabled. found that out after thinking it had gone wrong when i switched to back button focus

In fact that's not true. Put camera or lens in MF, press and hold back af button, press shutter release. CIF works, at least on my K3 II.

Greg
Pentax K-3 II, DA 50/1.8, Sigma 18-35/1.8, DA* 300/4, 1.4x HD DA Converter
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