"Play" in focusing - Nikon 50mm F1.4

Hello,

I purchased a 50mm F1.4 AF lens for use with a D200. I notice that
there seems to be a fraction of an inch (maybe 1/16th) play in the
focusing ring after the autofocus has done it work. Is this normal?
I have just moved to autofocus and digital.

Regards.

Nobody wrote:

I purchased a 50mm F1.4 AF lens for use with a D200. I notice that
there seems to be a fraction of an inch (maybe 1/16th) play in the
focusing ring after the autofocus has done it work. Is this normal?

Mine does it too. It's slight and inconsequential, and it's normal,
but I just did a side-by-side comparison and my 50/1.4 seems to do it
more than other (non-AFS) lenses. I'd never noticed the difference
before. I don't think it's anything to worry about, though.

--
Jeremy |

Nobody wrote:
Hello,

I purchased a 50mm F1.4 AF lens for use with a D200. I notice that
there seems to be a fraction of an inch (maybe 1/16th) play in the
focusing ring after the autofocus has done it work. Is this normal?
I have just moved to autofocus and digital.

Regards.

My Canon lenses have the same looseness. I gather it's to minimize the
drag on the focusing motor, specially with lenses where the front
element rotates. Perceptible stiffness would raise the current drain
from the battery while focusing, and may prevent the focus from being
precise, maybe even stalling the motor before focus is reached.

Colin D.

--
Posted via a free Usenet account from http://www.teranews.com

Colin_D wrote:

My Canon lenses have the same looseness. I gather it's to minimize the
drag on the focusing motor, specially with lenses where the front
element rotates. Perceptible stiffness would raise the current drain
from the battery while focusing, and may prevent the focus from being
precise, maybe even stalling the motor before focus is reached.

It may cause slow focussing. It may cause a lot more power use.
But then the motor is matched to the very lens it sits within.
(Are your lenses FTM-capable, btw?)

It won't degrade focus accuracy: Canons AF checks the lens' focus
setting and corrects it until it's within the stated tolerances.

On the other hand, there is no measure-check-redo loop for the
AF one-shot setting.

-Wolfgang

Wolfgang Weisselberg wrote:
Colin_D wrote:

My Canon lenses have the same looseness. I gather it's to minimize the
drag on the focusing motor, specially with lenses where the front
element rotates. Perceptible stiffness would raise the current drain
from the battery while focusing, and may prevent the focus from being
precise, maybe even stalling the motor before focus is reached.

It may cause slow focussing. It may cause a lot more power use.
But then the motor is matched to the very lens it sits within.
(Are your lenses FTM-capable, btw?)

Yes, ring-motor ftm. And the motor is matched to the lens for the
amount of friction built-in to the particular lens design, and may well
not have enough grunt to drive a stiffer lens, if one attempts to reduce
the looseness.

It won't degrade focus accuracy: Canons AF checks the lens' focus
setting and corrects it until it's within the stated tolerances.

If the setting is not correct because of stiffness, the camera won't fire.

On the other hand, there is no measure-check-redo loop for the
AF one-shot setting.

-Wolfgang

Colin D.

--
Posted via a free Usenet account from http://www.teranews.com

"Nobody" wrote in message
...
Hello,

I purchased a 50mm F1.4 AF lens for use with a D200. I notice that
there seems to be a fraction of an inch (maybe 1/16th) play in the
focusing ring after the autofocus has done it work. Is this normal?
I have just moved to autofocus and digital.

Regards.

My understanding is that the play is there because the manufacturers use
little if any lubrication to free up and speed up the autofocus. Most AF
lenses not only feel loose but rattle if you shake them.

Colin_D wrote:
Wolfgang Weisselberg wrote:

It won't degrade focus accuracy: Canons AF checks the lens' focus
setting and corrects it until it's within the stated tolerances.

If the setting is not correct because of stiffness, the camera won't fire.

If the camera is still trying to focus the lens, it will not fire
_in one-shot AF modus_. It _will_ fire in Servo AF mode. Important
difference.

-Wolfgang