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02-15-2009, 10:09 PM   #1
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"Focus by wire"?

Are Pentax DSLR lenses "Focus by wire", or mechanically focused when in MF mode?



[kurt]

02-15-2009, 10:24 PM   #2
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QuoteOriginally posted by shuttervox Quote
Are Pentax DSLR lenses "Focus by wire", or mechanically focused when in MF mode?
Like virtually all SLR lenses, Pentax lenses are manually focused mechanically.
02-15-2009, 10:30 PM   #3
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QuoteOriginally posted by shuttervox Quote
Are Pentax DSLR lenses "Focus by wire", or mechanically focused when in MF mode?



[kurt]
I don't quite follow you regarding
QuoteQuote:
mechanically focused when in MF mode?
Manually focusing is mechanical regardless of brand. Regardless of the autofocus mechanism and design, manual focusing requires physical turning to focus.
02-16-2009, 05:52 AM   #4
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QuoteOriginally posted by Blue Quote
I don't quite follow you regarding Manually focusing is mechanical regardless of brand. Regardless of the autofocus mechanism and design, manual focusing requires physical turning to focus.
Not quite... Most current Olympus lenses are focus by wire. The focus is not mechanical when you turn the focus ring. Even in manual focus mode, turning the focus ring on most Olympus lenses engages a motor that will focus the lens. Consider the focus ring more of a button you can turn like a jog-shuttle on an old VCR or video editing deck. There is no mechanical link at all.

02-16-2009, 06:36 AM   #5
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I believe Pentax SDM (only) lenses are also "focused by wire". There is no mechanical link between focus ring and focus mechanics. But I may be wrong.

Anyone care to test a DA17-70, off camera (no power), and turn the focus ring to check this?
02-16-2009, 07:23 AM   #6
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Aren't those technically the same thing? When a pilot "flies by wire", he's got a direct mechanical/wire link to the controls and the parts of the plane he's moving.

I'll check out my 50-135 for the same thing though.

QuoteOriginally posted by shuttervox Quote
Are Pentax DSLR lenses "Focus by wire", or mechanically focused when in MF mode?



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02-16-2009, 07:31 AM   #7
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No, fly by wire has no mechanical link whatsoever. It's strictly electronic signals passed to the flight computers which then control what the plane actually does. Pretty much just like in a video game.
02-16-2009, 07:41 AM   #8
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My two DA* lenses (16-50 & 50-135) focus with no power and not mounted to the camera. The focus rings have a mechanical link to the focusing elements. They just have a clutch to disengage from the SDM motor when you turn the ring.

02-16-2009, 07:41 AM - 1 Like   #9
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QuoteOriginally posted by legacyb4 Quote
Aren't those technically the same thing? When a pilot "flies by wire", he's got a direct mechanical/wire link to the controls and the parts of the plane he's moving.

I'll check out my 50-135 for the same thing though.
Having a wire connecting you isn't the same as a mechanical connection. Turning/pushing/pulling a switch that directs electrical flow to a distant motor/controller/actuator isn't the same as moving the part yourself. Fly by wire could be taken a step further and be remotely controlled via wireless. It's more like using the remote control on you camera versus actually pushing the shutter button.
02-16-2009, 07:44 AM - 1 Like   #10
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QuoteOriginally posted by JavaJoe Quote
Having a wire connecting you isn't the same as a mechanical connection. Turning/pushing/pulling a switch that directs electrical flow to a distant motor/controller/actuator isn't the same as moving the part yourself. Fly by wire could be taken a step further and be remotely controlled via wireless. It's more like using the remote control on you camera versus actually pushing the shutter button.
Regardless, with Pentax AF lenses the mf focusing is done manually. So are Nikon, Canon and Minolta.
02-16-2009, 11:54 AM - 1 Like   #11
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QuoteOriginally posted by JavaJoe Quote
Fly by wire could be taken a step further and be remotely controlled via wireless.
It then would have to be called
"Fly by wireless" though
02-16-2009, 01:13 PM - 1 Like   #12
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QuoteOriginally posted by Presto Quote
My two DA* lenses (16-50 & 50-135) focus with no power and not mounted to the camera. The focus rings have a mechanical link to the focusing elements. They just have a clutch to disengage from the SDM motor when you turn the ring.
I have no doubt about this two lenses having a mechanical link between focus ring and focus mechanism, since both can AF with any Pentax AF body, including film era bodies. What I am wondering is about the SDM ONLY lenses like the DA 17-70.
02-16-2009, 01:18 PM   #13
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Olympus are focus by wire and I don't care for it on either model I own. Here are some reasons
1. Can't even manual focus without camera being on. Thought it was broke when I was playing with new camera first day. Batt was charging.
2. No close focus/infinity stops on lens. They just keep turning and turning.
3. Kit lenses are unsmooth feeling when focusing.
4. Kit lenses have no distance scales.
Sure there are more reasons.
thanks
barondla

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02-16-2009, 02:47 PM   #14
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QuoteOriginally posted by barondla Quote
Olympus are focus by wire and I don't care for it on either model I own. Here are some reasons
1. Can't even manual focus without camera being on. Thought it was broke when I was playing with new camera first day. Batt was charging.
2. No close focus/infinity stops on lens. They just keep turning and turning.
3. Kit lenses are unsmooth feeling when focusing.
4. Kit lenses have no distance scales.
Sure there are more reasons.
5. Makes camera feel like electronic toy rather than profession photographic equipment.
6. Focusing wears down the battery for no reason whatsoever.
02-16-2009, 03:01 PM   #15
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Whoops, mixed that one up.

I defer to the comments on that!

QuoteOriginally posted by Jodokast96 Quote
No, fly by wire has no mechanical link whatsoever. It's strictly electronic signals passed to the flight computers which then control what the plane actually does. Pretty much just like in a video game.
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