Pulling focus on lenses that the barrel moves

L

Lor

Well-known member
I have seen many post regarding type of lenses, including a couple of my own, but I have not seen any clear solution to pulling focus on lenses that the barrel of the lens move up and down or gets shorter and longer when focusing. Besides using the friction wheel, I don't see anyone providing a lens gear or a clear solution to compensate for the barrel of the lens that gets longer and shorter as the lens is being focused. I'm guessing that those who uses the Nikkor 80-200mm f2.8 or the Nikkor 50mm f1.4 macro must encounter the same problem I have.
 
Most follow focus systems for SLR lenses have a wide lens gear so the gear can slide up and down and the teeth will mesh as it slides.

If your talking about the trombone zoom lenses, I usualy stick a ring on it then zoom it and move the follow focus. Since you should never (or very rarely) zoom in the middle of a shot, its not usualy a problem to slide the follow focus up the rods...
 
I had the same question before buying my FF. 4 out of 5 of my lenses are AI and have barrel movement, but my gears have never slipped.
 
I have the Nikon 50mm f1.4 macro, 135mm f2.8 and 180mm f2.8 and they all moves. Once the barrel moves, the gear ring slipped and no longer able to control the lens focus ring. Any suggestion on what type of gear ring to use for lens barrel that moves about an inch? I was thinking that perhaps someone might sell gear rings that are wider than the normal onces so it it won't slip.
 
While most lenses nowadays have all internal mechanics, there are still plenty of lenses out there that have considerable external movement in them. This is not an uncommon problem, and is one that I've encountered once or twice in the past. I have the Bartech Wireless system with the M-One motor, and even with the widest gear on my motor I've encountered a lens or two that has breathed a bit too much.

What I'll do first is set the lens at one of its extreme stops (either infinity or minimal focus). I'll then mount the motor so the gears are just barely engaged, and when the lens moves throughout the length of its throw, it engages more and more...and then less and less as it reaches the opposite end of its travel. This will usually be enough for most lenses.

If the extreme circumstance does come up where the entire length of the lens throw is STILL too much for my gears, I'll simply disregard a certain section of the lens. It is unlikely that in one single shot, the focus will travel from minimal all the way to infinity. So, I'll simply set up the gears to be engaged throughout the distances I know will pertain to the upcoming shots, obviously providing some generous padding on either side.
 
Any idea where I can find some of the widest gear rings for my Nikon lenses? I don't have a wireless remote system.
 
I think I misunderstood the term "widest" gear ring. I am not referring to the diameter of the gear ring. I'm referring to the width of the gear and not the ring diameter. Imagine that if the width is small/normal like those I've found, when the lens barrel shortens/lengthens, the gear is going to slipped because the gear ring on the lens barrel moves up or down and becomes disengaged.
 
The SGpro ones are quite wide, (bout 10mm) and having had them next to redrock rings, they are much nicer. The quick and easy clickon design from the redrock rings is great, but the SG rings are much stronger and sturdier.

You could always put two next to each other...
 
I think I have a couple of the SGPro lens look alike. However, the problem is it's quite cumbersome or tedious to have to screw all those screws in and out when putting it back into the case.

Here's a picture that shows what I'm looking for.

lens-gear-ring.jpg
 
I have a 60mm macro that extends about 2" it seems. I tested with my RR follow focus and found that placing the ring (SG pro used) in the middle of the lens focus barrel and connecting the FF to the absolute front edge of the lens ring (edge farthest from camera) allowed a full rotation of the lens from minimum to infinity.
 
Thanks for responding. So you're using a Red Rock gear ring, correct? Any particular ring size?
 
I typically use SG pro rings since they are 360* design and the barrel on extending macros will need a lot of rotation.

Redrock rings will work too but you might bump the bolt at full rotation.
 
RafCamera said:
We make different gears. You may either specify inner (and external, probably) diameter and width of the required ring, or send us your lens(es) with that issue, and we'll make corresponding ring(s).
http://rafcamera.com/installation-of-geared-rings-p-661.html
Thanks
Click to expand...

I think that may be the solution to the problems I'm having. I'm not sure what diameters I have but I need the gear ring width to be 1" to 2" wide. The lenses I owned that have this problem are Nikkor 50mm f1.4 macro, Nikkor 135mm f2.8, and Nikkor 180mm f2.8. Please let me know how much will it cost per gear ring.

Many thanks for the response.
 
Price will be $80/$100 depending on the width (1" or 2"). I don't have any of these lenses, but I have a question. Are you sure that you need a wide ring for Niccor 50mm. I found description at http://khoking.photomalaysia.com/myphotography/mynikon/50mm14ais/index.htm, and it seems to me that focusing ring doesn't move. Or maybe macro lens is different?
I didn't checked other lenses from your list yet. Will ask you about some pictures and measurements, most probably...
 
The 50mm macro is different. I have both the standard and macro. The macro does move a lot. If you have time, you may try to find out the diameter of those lenses. I'll also check on it tonight.

Thanks!
 
Basically, I need two side pictures of each lens (at mininum focus and at infinity), and diameter of the focusing ring. If you can supply this, please email to me at sales @ rafcamera dot com
Thanks
 
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