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jvmorris
I Am The Man Who Was Not There.
Premium,MVM
join:2001-04-03
Reston, VA

[Lens] Using an autofocus lens with a follow focus setup

Okay, this is a question about using a standard (and older) Nikkor 24-120 zoom lens with a follow focus system to manually set focus for video. And yes, I've set both the lens and the camera to manual focus, and turned off VR on the lens (since I'm shooting from a tripod).

Changing focus (even manually) seems very stiff; the strap-on gear strap slips sometimes regardless of how tightly I try to put it on the lens.

First question (for anyone who knows the answer), is this stiffness in manually changing focus typical for the 24-120? My older Tokina F/2.8 lenses turn quite easily in manual mode.

Second question, if it's NOT normal what do I need to do to rectify the problem.

The lens seems to work just fine for still photography in autofocus mode, so I'm wondering if there might be a problem with manually changing focus that I need to rectify.

TIA.
--
Regards,
Joseph V. Morris



mk1_416

@start.ca

Haven't used any of the lenses, the only thing I can suggest is have the lens inspected, make sure the AF/MF switch is fully disengaging AF when MF is selected.

Does the focus get any more/less stiff when you get the lens cold/hot? If so it could be that there is gunk built up in the gears.



jvmorris
I Am The Man Who Was Not There.
Premium,MVM
join:2001-04-03
Reston, VA

There is a difference between having the lens set to A/M versus M, but it's not very significant (now). I've switched back and forth between the two settings and, when set to manual, have rotated the ring back and forth several times. That may have bought me a bit more play. It's probably been years since I used that lens in Manual mode.

I don't think it's temp-related. It's about 70F inside and I had it outside yesterday and it feels about the same in both situations.

Think I'll ask on Nikonians forum before taking it in for inspection. It's been years since I had a local camera technician that I felt comfortable with and that shop is even gone now.
--
Regards,
Joseph V. Morris



rcroning
D700 Rocks
Premium
join:2005-05-21
Winnipeg, MB

1 edit
reply to jvmorris

A few things to check and do:
-Take the lens off the camera and try the focus ring. If it turns smoothly and easily, then there is some electronic glitch that needs to be addressed.
-If it is still stiff and this is an older lens, the lubricant may have dried out. In this case it needs to be sent in for a cleaning and re-lube.
-When on camera, does the AF work smoothly?
-Is it possible that the strap is on too tight and is distorting the focus ring and causing the issue?
-Maybe the M/A - M switch is not functioning on the lens. There should be a S/C/M switch on the camera body that also does this for you. Try turning that to M as well.



jvmorris
I Am The Man Who Was Not There.
Premium,MVM
join:2001-04-03
Reston, VA

Okay, let's take this by the numbers,

said by rcroning:

A few things to check and do:
-Take the lens off the camera and try the focus ring. If it turns smoothly and easily, then there is some electronic glitch that needs to be addressed.

With the lens off the camera and the gear belt removed, and the switch on the lens set to M, the action seems to be getting less tight and smoother as I 'exercise' the manual focus. Of course, this may be purely subjective but I don't think so. But it's still not as easily twisted as the focus ring on the Tokina 12-24. (Of course, that's got a physical clutch rather than a switch to disengage autofocus.) But what did you mean about some "electronic glitch"?

-If it is still stiff and this is an older lens, the lubricant may have dried out. In this case it needs to be sent in for a cleaning and re-lube.

Well, I'm sort of betwixt and between on that one; maybe this week I'll take it up to Ace Photo and see if they've got a resident tech on hand.

-When on camera, does the AF work smoothly?

Yes, as far as I can tell, there's no obvious tightness or roughness when using the autofocus.

-Is it possible that the strap is on too tight and is distorting the focus ring and causing the issue?

No. If anything, I'd say the gear strap is a bit more stretchy than I'd like. It's also very smooth on the inside and, if anything, tends to slip on the rubber focus ring embedded in the lens casing. The ribbed focus ring grip on the Nikon is also much less pronounced than that on the Tokina.

-Maybe the M/A - M switch is not functioning on the lens. There should be a S/C/M switch on the camera body that also does this for you. Try turning that to M as well.

Not QUITE sure what you're referring to here. Both the D70 and the D7000 have a little rotary switch on the camera body directly behind the lens mount, but that's only marked as "AF" or "M". However, on the D7000 directly under the mode selector dial on the upper left of the camera body, there's a second control dial that's marked with "S", "CL", "CH" and four other symbols, which I guess I really should look up.
--
Regards,
Joseph V. Morris


rcroning
D700 Rocks
Premium
join:2005-05-21
Winnipeg, MB

said by jvmorris:

Not QUITE sure what you're referring to here. Both the D70 and the D7000 have a little rotary switch on the camera body directly behind the lens mount, but that's only marked as "AF" or "M". However, on the D7000 directly under the mode selector dial on the upper left of the camera body, there's a second control dial that's marked with "S", "CL", "CH" and four other symbols, which I guess I really should look up.

There is a switch on the body, next to the mount that allows the user to turn focus from AF to manual. The one on the lens is generally more accessible. Some lenses may not have a switch, therefore the one on the body.

The S, CL and CH are your shooting modes; single shot, continuous low and continuous high. The others may include self timer, mirror lock-up and Live View.