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10-05-2013, 11:38 AM   #1
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sigma 17-70mm F2.8-4 Contemporary full time manual override?

Bought one, can't do full manual override,
bh description says it can
Sigma 17-70mm f/2.8-4 DC Macro HSM Lens for Pentax 884109 B&H
sigma website doesn't say
pentaxforum review says it can

So what is it? I am sure I can turn it if I force it. It seems to happen to other mount as well

10-05-2013, 11:45 AM   #2
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Don't force it! If it engages the AF motor on the camera, it can ruin it, be careful. I dont know about that lens, but I remember reading quite a few threads where people used various lenses and tried to force the focus ring while the camera was in AF mode, which broke the AF gears on the camera. Even quickshift lenses need to be used correctly, like waiting for the AF action to complete and sliding the focus ring correctly. Maybe there is a youtube video about it? Also, Sigma is known to make different variations of lenses in the same focal length, but with different features. Make sure you are looking at the right manual.
10-05-2013, 11:54 AM   #3
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QuoteOriginally posted by pentax user Quote
Bought one, can't do full manual override,
bh description says it can
Sigma 17-70mm f/2.8-4 DC Macro HSM Lens for Pentax 884109 B&H
sigma website doesn't say
pentaxforum review says it can

So what is it? I am sure I can turn it if I force it. It seems to happen to other mount as well
The lens should have full time manual focusing, so maybe your copy is a dud?

Adam
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10-05-2013, 03:39 PM   #4
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It should have full time override if I understood it correctly, atleast all HSM ones I've tried have it. Maybe a broken clutch?

10-05-2013, 03:43 PM   #5
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QuoteQuote:
"● Hyper Sonic Motor
The HSM (Hyper Sonic Motor) ensures high speed and quiet AF as well as full-time manual focus
override by rotation of the focus ring. With the enhanced AF algorithm, smoother AF is achieved. "
http://www.sigmaphoto.com/sites/default/files/pr_en_17-70_28-4_dc_macro_os_hsm_1212_2.pdf
10-05-2013, 03:59 PM   #6
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A while ago, I dropped my Sigma 50 F1.4. Subsequent to that, the focusing would have a very high-pitched whine, and the manual override/quick-shift would not work. The focus ring would not turn easily, and I could force it - but it was very difficult and scary. So Sigma fixed that, and now it's fine.

Not saying that you dropped your Sigma lens, but my similar experience with a stuck focus ring says impact might be the cause.
10-05-2013, 05:52 PM   #7
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QuoteOriginally posted by pentax user Quote
Bought one, can't do full manual override,
bh description says it can
Sigma 17-70mm f/2.8-4 DC Macro HSM Lens for Pentax 884109 B&H
sigma website doesn't say
pentaxforum review says it can

So what is it? I am sure I can turn it if I force it. It seems to happen to other mount as well
The new Sigma does not have quickshift/full manual override. If you try to manually shift the focus while the AF is engaged you'll break it. Use the AF/MF switch.
10-05-2013, 05:53 PM   #8
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I got this one second hand, the guy sold me this said no full time manual override
In manual mode, body mf, lens mf, it's not as freely rotate as pentax 17-70
but a bit more like manual focus old lens with a bit friction . Is this the case in your copies?

10-05-2013, 05:57 PM   #9
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QuoteOriginally posted by VisualDarkness Quote
It should have full time override if I understood it correctly, atleast all HSM ones I've tried have it. Maybe a broken clutch?
That's what I thought, but not what people say on various occasion
Maybe not all mounts are created equal
10-05-2013, 06:04 PM   #10
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QuoteOriginally posted by pentax user Quote
I got this one second hand, the guy sold me this said no full time manual override
In manual mode, body mf, lens mf, it's not as freely rotate as pentax 17-70
but a bit more like manual focus old lens with a bit friction . Is this the case in your copies?
Yes, the focus is dampened nicely (like on old MF lenses) when in MF, not loose at all.

I think the PF review and B&H are just parroting the Sigma press release, which obviously is wrong (at least for Nikon and Pentax mounts).

From the Photozone review of the 17-70 "C" Nikon mount

...the lens still features a simplified version of Sigma's HSM (hypersonic AF motor), which is fast and nearly silent, but does not allow full-time manual (FTM) override in single-shot AF mode. To focus manually, the lens needs to be set to the corresponding mode with the usual A/M switch on the lens barrel.
10-05-2013, 06:13 PM   #11
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so pentax forum's review just parroting the Sigma press release or the review guy force the focus ring hard

problem solved
thanks guy
04-16-2014, 11:09 PM   #12
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I am reviving this thread due to my recent purchase of the Sigma 17-70/2.8-4 Contemporary. The lens does indeed lack any kind of quick-shift feature. In fact the instruction manual specifically cautions against attempting manual focus with the AF feature turned on. The review on this site is not accurate when applied to the current Sigma product.


Steve
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