Pentax 17-70 Quick-Shift Manual Focus?


salixarbour

Link Posted 12/03/2009 - 11:47
Hello, all.

I've just taken delivery of the SMC Pentax DA 17-70 f4 AL[IF] SDM lens.
(I need a tea-break after writing that).

I read a review stating:
"Thanks to a Quick-Shift system, manual focus override is instantly possible in Single-Shot AF mode".

My lens doesn't appear to have any quick-shift switch.

Please tell me, am I being silly or was the review report inaccurate?



Regards.

Alan Lowe-Jones.
Camera: K20D.
Lenses: Pentax DA* 55mm f1.4 SDM, Pentax DA* 16-50 SDM, Pentax 18-250 SMC DA, Pentax-M 50mm f1.7, Sigma 70-300 F4-5.6 DG macro.
Flash: Pentax AF360.

bforbes

Link Posted 12/03/2009 - 11:52
it does not have a switch i think it means you can manual focus without switching the camera to manual. that's what happens on my k10
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/

MattMatic

Link Posted 12/03/2009 - 12:12
It means you can turn the focus ring manually even when the lens and body are in "AF" mode.

So, you can half-press and get the camera to focus, then hold while you adjust the focus ring manually

Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)

salixarbour

Link Posted 12/03/2009 - 12:33
Many thanks, Matt/Barrie.

Thanks for that info. I does seem an odd thing to perhaps want to do, then again, maybe that's my inexperience showing.

I read that the turn/travel in the manual focus ring is so short/sensitive that it makes manual focusing difficult anyway.
Having read the reviews, I was aware of that, so not really a problem.

Matt, thanks for pointing me in the 17-70 direction in the first place...a couple of weeks ago in another thread. just one question though:

My manual focus ring is quite light to the touch/easy to turn/more so than my 18-250. Does that seem about right?

Regards.

Alan.
Camera: K20D.
Lenses: Pentax DA* 55mm f1.4 SDM, Pentax DA* 16-50 SDM, Pentax 18-250 SMC DA, Pentax-M 50mm f1.7, Sigma 70-300 F4-5.6 DG macro.
Flash: Pentax AF360.

johnriley

Link Posted 12/03/2009 - 12:36
It sounds right, so I wouldn't worry.

The Quick Shift system is actually very useful when fine tuning macro shots. I used to use manual focus only for close up shots, but now use AF and adjust as required manually. It is more efficient for still life subjects.
Best regards, John

Clarky

Link Posted 12/03/2009 - 12:49
johnriley wrote:
It sounds right, so I wouldn't worry.

The Quick Shift system is actually very useful when fine tuning macro shots. I used to use manual focus only for close up shots, but now use AF and adjust as required manually. It is more efficient for still life subjects.

Could'nt agree more John
Camera:|K-7|
Pentax Lenses:|DA12-24/f4 ED AL|DA35Ltd Macro|FA31Ltd|FA77Ltd|FA50/1.4|F70-210|FA20-35 f4/AL|A*200/f4 Macro ED|A50/1.7|A50 Macro f2.8|1.7xAF adapter|
Voigtlander|125/f2.5SL Macro APO Lanthar|
Sigma Lenses:|EX DG 100-300 f4|2X & 1.4X TC|
Flashes:|AF540FGZx2|RingFlash AF160FC|

bforbes

Link Posted 12/03/2009 - 13:41
salixarbour wrote:

My manual focus ring is quite light to the touch/easy to turn/more so than my 18-250. Does that seem about right?

Yeah it's OK. mine feels as if it's not moving anything it's so light
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/

salixarbour

Link Posted 12/03/2009 - 13:58
Thanks to all.

That makes me feel better.

I did so want a little MF/AF switch though!

Regards.

Alan.
Camera: K20D.
Lenses: Pentax DA* 55mm f1.4 SDM, Pentax DA* 16-50 SDM, Pentax 18-250 SMC DA, Pentax-M 50mm f1.7, Sigma 70-300 F4-5.6 DG macro.
Flash: Pentax AF360.

MattMatic

Link Posted 12/03/2009 - 15:02
Quote:
I did so want a little MF/AF switch though!

Two options:
1) Switch to MF on the body
2) Use the custom menu to turn off "Focus on half-press" and just use the dedicated "AF" button on the back.

I use option 2 - kind of "Auto focus on demand". Much prefer it to anything else

Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)

beakynet

Link Posted 12/03/2009 - 15:45
salixarbour wrote:

I did so want a little MF/AF switch though!

You need the DA* 16-50 for that!
Bodies: K5IIs, K7, MZ5n, LX, MV
Lenses: DA*16-50, DA18-55WR, DA18-135, DAL35, M50 F2, A50 f1.4, FA50 f1.4, DA*50-135, DA55-300, Tamron 70-300, DFA 100 WR Macro, M135 f3.5, Sigma 120-400 APO DG HSM, Tokina 500 f8.0
Flash: Metz 58, Metz 48
Accessories: BG4, Pentax right angle finder, Pentax mirror adaptor lens, O-ME53 Viewfinder Loupe
Auto 110 System: Auto 110, Winder, 18mm, 24mm, 50mm, 70mm, 20-40mm, AF100P, 1.7x telecon

RichardDay

Link Posted 16/03/2009 - 10:23
salixarbour wrote:
Many thanks, Matt/Barrie.

Thanks for that info. I does seem an odd thing to perhaps want to do, then again, maybe that's my inexperience showing.

I read that the turn/travel in the manual focus ring is so short/sensitive that it makes manual focusing difficult anyway.
Having read the reviews, I was aware of that, so not really a problem.

Matt, thanks for pointing me in the 17-70 direction in the first place...a couple of weeks ago in another thread. just one question though:

My manual focus ring is quite light to the touch/easy to turn/more so than my 18-250. Does that seem about right?

Regards.

Alan.

The 18-250 being a Tamron design, doen't have quick shift.

Having quick shift is a great feature, as it enables you to "tweak" the focus point after AF or (especially if you use the rear AF button only), you can manually focus without forcing the AF motor gear chain, and then use AF to "trim" to the final position, this is a very quick way to achieve focus lock very quickly. It's much more noticeable on lenses with a large focus rotation angle.

Having recently acquired a Tamron 70-200 f2.8 (no quick shift), I do miss that particular ability, as sometimes the AF isn't quick enough or "misses" and has to complete a full cycle before re-capturing the AF lock, especially with a TC fitted as they slow down the AF speed.

The 17-70, being SDM only and having a small focus rotation angle, is a very quick focussing lens, unlike some other SDM lenses which are fairly slow, noticeably the new DA*55 and the DA*50-135 which is no speed demon, again due to a large focus rotation angle.

Many of the screw drive AF lenses have large focus rotation angles, I'm specifically thinking of the D-FA macros and the DA 55-300, those lenses benefit considerably from quick shift + AF trim operation.
Best regards
Richard Day

Profile - link - (click on About for equipment profile) - My Flickr site - link
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