Thursday, November 26, 2009

A Few Words On The New Lens Gears

I thought I would take a few minutes to share some of the thought and design process that went into the new Pro Lens Gears.

Since March of this year I have been experimenting with many designs for lens gears and searching for an "off-the-shelf" solution. There are a lot of large diameter gears available, but they are all usually quite expensive and have a very thin gear face width, 1/16".

My favorite lens gears were the ones made by Redrock micro and I frequently would refer customers there, instead of purchasing the DIYish solution I was using. RRM's gears are quick and easy to install, no worries about alignment like some other designs. They are also large in diameter which means less torque is required from the follow focuses gearbox to turn the lens (helpful for some "stiffer" lenses like Zeiss.) Unfortunately they are not cheap at $64 each and you would need a few sizes if you have a variety of lenses.

So the challenge with designing the new Pro Lens Gears was how to incorporate the large diameter and quick on-off feature of Redrock's lens gears, while also making them adjustable and cheap.


An early rendering

I am fortunate enough to have several connections in the local machining community and one day a couple of months ago Tommy from Redline Mold was at the shop. He sort of half-jokingly asked me if I was ready to build a mold (we had discussed this a while ago, but I was no where near ready for such a big commitment.) The answer was yes. The D|Focus really needed a more professional lens gearing system. So we set to work to come up with a design. Tommy suggested a few thing and we went back and forth a bit. Then it hit me, why not have one gear, with some kind of interchangeable "leg" system to adjust for the various size lenses? This has been done before, with screws, but the problem is that it takes a long time to get them setup and adjusted correctly. But having fixed length "Legs" with a pinching style of gear tensioning onto the lens, the length of the legs wouldn't have to be exact.

I set to work on a prototype, using an existing lens gear that I had left over from experiments, I super-glued some nylon screws to the inside and used a Dremel to cut them to length. I was not sure it was going to work but to my surprise, even with the hack-job dremeling the legs to length, the gear held remarkable secure to the camera lens!


First CAD drawing of the New Pro Lens Gear

I struck a deal with the JAG35 crew to help pay for the mold. They have been selling the D|Focus for several months now and have been in need of a lens gearing system to go with it. Then it was just a matter of getting the CAD drawing to Tommy and letting him go at it.


One side of the Mold. The T shaped inserts are what form the retaining slots for the legs.


The other side of the mold with the Mold Cavity.

Tommy is a freaking pro and had this thing together much faster than we were expecting.



Injection molding is not cheap. There is a large initial investment and a relatively large minimum number of parts the molder will make. But the benefit is that the cost per part is very cheap. So once the mold is paid for the whole process becomes a good investment (assuming one can manage to keep selling the parts!) Also, when its done by a pro like Tommy, your parts come out looking top notch!



I couldn't be more pleased with the final result! The lens gears work exactly as I imagined and look as professional as they can. Unfortunately they are more expensive than the cheap DIYish solution I was offering. Sorry about that, but I think they are still within most people's price range. Definitely not as hard to justify as Redrock's $64 solution.

2 comments:

  1. Great article Dave, you should put a link to your sales page!

    ReplyDelete