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Blogger 301 Redirect Plugin DSLR Filmmaking Blog: October 2013

Tuesday, October 22, 2013

Choosing follow focus gear rings

Canon 5D Mark II w/Fotga DP500 II follow focus and generic 60-70mm fixed diameter ring
The cinemazation of DSLR cameras have created a need to add 0.8 pitch follow focus gears to standard photography lenses. Many such gears exist on the market; however, not all are created equal - a fact that is not immediately apparent until you've already experimented with a few.

The prevalent types of follow focus gears available to the prosumer cinematrographer today come in three different variants:

  • Left: Plastic, adjustable diameter gear ring with friction lock and lever
  • Center: Rubberized, adjustable diameter gear ring with tooth lock
  • Right: Fixed outside-diameter ring w/10mm variable inner gear ring diameter (various sizes available), made by Cinematics and others
I've used all three in the field - following are my thoughts on each:

Semi-hard plastic, adjustable gear ring with lever

The adjustable plastic gear ring is my least favorite in that the toothed reverse of the plastic isn't that grippy. I've yet to have it slip, but it does not inspire confidence. Likewise, the lever locking mechanism of the lever is cheap, damages the gear teeth, and the lever gets in the way of follow focus units unless oriented to the opposite side of the rig.

On the other hand, the plastic gear teeth engage well with follow focus units, and it is especially handy when using an older, manual telephoto prime for focus control.

 
Rubberized adjustable gear ring
The rubberized gear rings can are soft enough to grip a lens - and grip well - but this also causes the teeth to flex while meshing. The toothed receiver also works well to keep the ring tight.

Unfortunately, coupled with small-diameter lenses and a follow focus mounted in certain places, these rings will jump teeth - and visibly so on screen. Nevertheless, they are effective on larger-diameter lens barrels.


Cinematics 80-90mm at left, generic 60-70mm at left
These fixed-diameter rings are my personal favorites, having the ability to reach a follow focus unit with ease, regardless of lens barrel diameter. This style of gear ring is presently available as a generic (only one at present, it seems) and by Cinematics with slight differences between each. Both companies produce inner diameters ranging from 60-70mm up to 108-116mm. In my experience, the generics have enough adjustment to fit barrels down to 57mm comfortably; possibly smaller.

The generic's plastic-knob bolt is durable, despite its cheap appearance.

Cinematics' units have a smoother finish than the generics and have an allen head bolt with a proper steel nut, but otherwise show no superiority over the generics in operation or durability. Unlike the generics, they are available in red and blue (I've also seen purple) as well, which is fine if you're a hipster who must color-coordinate your camera rig to your fixed-gear bicycle and Macbook. Personally, I see no point to it - why call more attention to an L-series lens by putting red gear rings on it?

Additionally, a pair of these rings can provide both focus control and a precise zoom control for lenses with fixed zoom rings - such as Canon's L-series. Given the lack of perfect video-quality fluidity in even the L-series lenses - not to mention the fact that most photography lenses are varifocal - controlling zoom through a second gear ring and follow focus unit can be a stress-free method of ensuring a perfect take on the first try.

-Kurt "Man with the 5D"

No monetary compensation was provided for the mention of the any of the products mentioned or shown in this article.

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