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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Auto focus pulling with laser distance finder?

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Lee M

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Is there something on the market that will turn a wireless focus based on a laser distance finder that detects the distance between the sensor and the subject and automatically turns it? One would think this should exist. If not, what is a good laser distance finder used by the Red community to assist in focusing?
 
Preston's Light Ranger 2 works in tandem with their FIZ 3 system. Since a complete FIZ 3 system is around $30K USD, I would guess that a complete LR2 system is in a similar price range? You really should just call them and ask though.

The Andra demos that I've seen at NAB the last few years were pretty amazing, but I haven't heard of the system being tested on any high profile projects yet. Maybe they are being used now. I would guess that it will be priced in the same ballpark as Preston if and when it is finally released.

The RedRock Micro system would likely be a fraction of the cost of the other two systems, but I can't tell from the link if it is a shipping product or still just a concept. Not really in the same ballpark, but could be good enough for small jobs.
 
Wow you would think there would be a consumer friendly kits available by 2017. Laser range finders are a couple hundred, a dji wireless focus system is $2k, all one would have to do is program a microcontroller to tell the the wireless focus how far to turn based on the distance read of the range finder. I am thinking of something less complicated that doesn't have to constantly track a moving subject, just a subject that is in one spot instead of having to bring out the measuring tape
 
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I can't see how a laser device could ever be better than an experienced assistant camera operator. You need somebody who not only knows how to focus, but also how to swap out lenses, how to zoom, how to check the camera settings, and otherwise assist the camera operator and/or DP. None of this stuff is automatic and none of it is easy.
 
Lee M said:
Wow you would think there would be a consumer friendly kits available by 2017. Laser range finders are a couple hundred, a dji wireless focus system is $2k, all one would have to do is program a microcontroller to tell the the wireless focus how far to turn based on the distance read of the range finder. I am thinking of something less complicated that doesn't have to constantly track a moving subject, just a subject that is in one spot instead of having to bring out the measuring tape
Click to expand...

That's just not practical, if they are still just focus the lens! Really?
 
Lee M said:
Wow you would think there would be a consumer friendly kits available by 2017. Laser range finders are a couple hundred, a dji wireless focus system is $2k, all one would have to do is program a microcontroller to tell the the wireless focus how far to turn based on the distance read of the range finder. I am thinking of something less complicated that doesn't have to constantly track a moving subject, just a subject that is in one spot instead of having to bring out the measuring tape
Click to expand...

Well, the problem is that a laser is visible to the eye and also to the camera (not to mention potentially dangerous to the actor's eyes, where you typically want to measure to), so you would need to have a system that was synchronized to the camera shutter and turned the laser on and off during the unused half of the shutter cycle. I believe this was the design of Preston's original Light Ranger, as used in the film 'Without Limits' (hence, Light Ranger 2 in the current iteration). Most camera assistants will use a handheld laser rangefinding tool like a Leica Disto or Hilti PD series to get marks before a take, but never during a shot when the laser dot might be seen on camera.

This is why most distance rangefinders for film like the Cinetape use ultrasound. Unfortunately, this is not very precise or accurate beyond about 20'. If the actor sticks out their arm in front of their body, the Cinetape may read that instead of the face or torso, and the shot would be out of focus. So this is a tool for approximating focus, in conjunction with real-time human judgement. For the longest time, there was nothing else that worked as well at the level of precision required. The Light Ranger 2 and especially the Andra really are cutting edge, which is why they cost what the cost. If this really were that easy to do, dozens of Chinese companies would have made it already...
 
Satsuki Murashige said:
Well, the problem is that a laser is visible to the eye and also to the camera (not to mention potentially dangerous to the actor's eyes, where you typically want to measure to), so you would need to have a system that was synchronized to the camera shutter and turned the laser on and off during the unused half of the shutter cycle. I believe this was the design of Preston's original Light Ranger, as used in the film 'Without Limits' (hence, Light Ranger 2 in the current iteration). Most camera assistants will use a handheld laser rangefinding tool like a Leica Disto or Hilti PD series to get marks before a take, but never during a shot when the laser dot might be seen on camera.

This is why most distance rangefinders for film like the Cinetape use ultrasound. Unfortunately, this is not very precise or accurate beyond about 20'. If the actor sticks out their arm in front of their body, the Cinetape may read that instead of the face or torso, and the shot would be out of focus. So this is a tool for approximating focus, in conjunction with real-time human judgement. For the longest time, there was nothing else that worked as well at the level of precision required. The Light Ranger 2 and especially the Andra really are cutting edge, which is why they cost what the cost. If this really were that easy to do, dozens of Chinese companies would have made it already...
Click to expand...
depends on power and wavelength whether it is in any way potentially harmful or visible on camera.
There is at least one 3D scanner for digitizing volumes that has OSH certified eye safe laser using infrared (I believe) wavelength.
Issue would be more power required for any long distance (maybe then would be unsafe if someone walked closer) and cost / utility. For two shot - you have what two laser systems? LOL
 
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