New lens Adapter Concept/Prototype

So here’s a little something I have been working on. This was born out of necessity and the reality of shooting 4K ENG style with a large sensor camera. Like many I needed a zoom lens with a good zoom range. 10x zoom was my minimum. While you can get some very nice PL zoom lenses, for example the Fujinon Cabrio 19-90mm this is only a 4.7x zoom. There are higher ratio zooms like the beautiful Angenieux 24 to 290, but this is a massive lens requiring a massive tripod and not at all suitable for ENG or handheld shooting. Sony F3 and F5/F55 users do have the option of the Sony SCL-Z18X140 which is an 18mm to 240mm servo zoom. It’s a good lens, not fast (f3.5 – f6.3) but useful, but quite a lot of money for such slow lens that is clearly based on DSLR optics. So, what about a DSLR lens? Well that’s what I started to look at, there’s plenty of choice, including the Tamron 18-270 a nice and useful 15x zoom range (just be aware that the Tamron’s focus back to front compared to most broadcast and film lenses). There are also the Canon and Sigma 18-250mm lenses.

Anyway… I’m trying to standardise on one DSLR mount and that’s Canon, so that means I need electronic aperture control for many of my lenses. Why Canon and not Nikon with it’s manual iris? Well almost all Nikon lenses focus back to front which is a real PITA. I purchased an MTF Effect Canon mount and control box, this gives me a Canon mount and now I have electronic iris control plus optical image stabilisation if the lens has it. But the electronics engineer in me started to wonder if it was also possible to add a servo to the lens to create a power zoom. After several abortive attempts, lots of swearing and not an insignificant spend on motors and gearboxes I finally got it working, a servo motor to drive an off-the-shelf DSLR zoom lens, or a PL mount zoom lens. Then I wondered about combining the zoom rocker with an iris control. This is where things got really interesting as I was delving into new territory for me and that’s micro controllers. In addition Canon don’t publish details of the language and signals needed to control their lenses. Almost no-one has completely cracked all the codes needed to drive the lens, so I had to reveres engineer the protocol. After a few weeks of tinkering late into the evenings (sorry to my wife and daughter!) I finally had the major codes and could program a controller to drive the lens.

Now it’s all combined into a single box. A zoom rocker and servo motor to drive the zoom ring. A thumb wheel on the hand grip that operates the iris and a second small box with a knob to control focus, plus image stabilisation control. This means you can fit handles to the ring and have the focus control wherever you want. I have also developed a miniaturised lens control box without the zoom servo and rocker. This is the size of a match box and includes a thumbwheel/knob for iris and a port where you can plug in the remote focus control.

The next phase is to add Bluetooth control. This should be relatively straight forward now I know the lens protocols. I can already add bluetooth to the micro controller, so I just need an App to talk to it. Anyone out there good at writing iPhone Apps? I’d really like to get full remote control of zoom, iris and focus on an iPhone.

When will this become a product? Well I am working with a well known manufacturer in the UK at the moment to see if we can make this an affordable product. If that deal doesn’t work out then I’ll go the Kick-Starter route and do it myself. It will probably end up as two different products. An all-in-one box with zoom rocker and Canon lens controls and a second unit that just has the zoom rocker and servo for use on PL or Nikon lenses.

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13 Responses to New lens Adapter Concept/Prototype

  1. Pingback: New lens Adapter Concept/Prototype | Roberto Cimatti

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