Optical Gate remote shutter release

fjcvisual · January 25, 2012

Hi everyone, Looking for insights into this area from you all. I think this approach is mostly taken from high speed photography, but this is not a 'high speed' scenario, but it is in motion.

Essentially, I am looking for an optical gate (not sure if this is what they are really called) that will remotely release my shutter. The gate needs to be about 15 feet wide. From there I plan to have pocket wizards remotely trigger the strobes.

Wireless would be nice, but not mandatory. All speedlights, gate and camera will be withing a 30 foot radius. The specific piece I am looking for is the optical gate it self assuming it also includes the wired or wireless communications back to the camera.

any insight would be greatly appreciated.

thanks Jim

ziggy53 · January 25, 2012

I suspect that you are looking for a "light curtain" or a simple light beam to test for either a subject to break or for a subject to complete (by leaving).

Any sensible answer would depend upon much more than you have been willing to share. For instance:

Do you need a beam type or a curtain type of field to test?
Visible light or invisible light (IR or UV)?
Continuous or pulsing?
Mains powered or battery powered?
Single event test or continuous testing with reset and re-activation?
Environmental considerations? (Mostly moisture and temperature considerations.)
Safety or security considerations? (What happens if the system fails and are humans at risk?)
Redundancy considerations?
Durability considerations?
Does this system need to "awaken" the camera as well as trigger the camera?
Specific consumer/commercial camera or custom camera?
Cost considerations and budget?

Lots more questions. It would be helpful if you could give a very detailed description of the situation and problem that needs this system.

fjcvisual · January 26, 2012

Thanks Ziggy, I have answered the questions below as best as I can inline. I will describe my project in a bit more detail:

Essentially, think of a 15'x15' vertical plane that when broken will trigger the camera, which in turn will trigger the remote flashes (via pocket wizards). The object will be large like the size of a small car and moving at about 5-8 miles per hour. I want the image to be low key so the background will be blacked out. Only the subject and a frame around the subject will be lit. I will want to freeze the subject.

ziggy53 wrote: »

I suspect that you are looking for a "light curtain" or a simple light beam to test for either a subject to break or for a subject to complete (by leaving).

Any sensible answer would depend upon much more than you have been willing to share. For instance:
Do you need a beam type or a curtain type of field to test? >>>>> Well, since the plane to be broken is 15x15, I suspect a curtain will be best, however, I am sure i could position a beam that would allow me to produce predictable results.

Visible light or invisible light (IR or UV)? >>>>> Invisible

Continuous or pulsing?>>>>> Not sure if I know the pro's and con's enough to answer. But i suspect if the pulse was fast enough (given the speed of the subject) either would be fine. Unless of course there was a significant cost implication.

Mains powered or battery powered? >>>>> Battery

Single event test or continuous testing with reset and re-activation? >>>>> I imagine that I will take one photo with about 30 seconds before the next one. Possibly longer. But either way, I would be in control of when it happens. So it could either manually reset, or automatically.

Environmental considerations? (Mostly moisture and temperature considerations.) >>>>> i would be setting up outside around the golden hour

Safety or security considerations? (What happens if the system fails and are humans at risk?) >>>>> No, its just a photo.

Redundancy considerations? Not likely. >>>>> think of a portrait session. Other than additional units. If the parts failed the shoot would come to an end if not fixable.

Durability considerations?>>>>> Consumer grade

Does this system need to "awaken" the camera as well as trigger the camera?>>>>> I would be at the camera so i could awaken it, but it would be nice if it did it on it's own.

Specific consumer/commercial camera or custom camera?>>>>> Nikon D300s

Cost considerations and budget?>>>>> Unlimited Yea right. I would want to take a conservative approach to the cost until I felt comfortable. Then possibly upgrade where necessary.

Lots more questions. It would be helpful if you could give a very detailed description of the situation and problem that needs this system.

puzzledpaul · January 26, 2012

fjcvisual wrote: »

Essentially, think of a 15'x15' vertical plane that when broken will trigger the camera, which in turn will trigger the remote flashes (via pocket wizards). The object will be large like the size of a small car and moving at about 5-8 miles per hour. I want the image to be low key so the background will be blacked out. Only the subject and a frame around the subject will be lit. I will want to freeze the subject.

Am wondering how 'deep' the object is and whether some sort of (adjustable) delay is needed / required?

ie at what stage of the object moving thro' the 'gate' will the photo actually be taken ... or are you considering taking a series of shots, so's you can select the most suitable?

Will the object be aware it's having its pic taken?

pp

fjcvisual · January 26, 2012

puzzledpaul wrote: »

Am wondering how 'deep' the object is and whether some sort of (adjustable) delay is needed / required?

ie at what stage of the object moving thro' the 'gate' will the photo actually be taken ... or are you considering taking a series of shots, so's you can select the most suitable?

Will the object be aware it's having its pic taken?

pp

i am not expecting to need a delay, although that flexibility may be nice. I would want to have the photo taken just as the subject broke the plane. The subject would be about 8-10 feet deep, but I would only want the front 3-4 feet lit.

Yes, the subject will know the picture is being taken.

ThatCanonGuy · January 26, 2012

I know that on the Canon 1D Mark II, there's a Personal Function that trips the shutter whenever a subject enters the plane of focus. You set manual focus, and once the camera receives focus confirmation, the shutter clicks. Maybe your camera has something like this?

puzzledpaul · January 27, 2012

Do you have any idea of the spacial accuracy / resolution required?
ie what's the cross-sectional area / shape of the most likely first (front?) bit of the object to pass thro' the gate and where abouts within the 15ft square area this might occur?

This info would be less relevant if you were considering a scanning or multiple reflection array type of system, but if - for instance, you knew that the first part (3ft dia) thro' the beam was likely to be 5ft off the ground, +/- a couple of feet ...then a couple of beams would cover all possibilities, likely to be cheaper and almost certainly easier to setup (imo).

I've never used gear like this for photographic purposes, but I have for other (simpler) counting / object present ones, using IR devices.
Of the 2 types I had available, I found that those that incorporated both transmit and receive heads - in the same unit - were easier to set up, since power was only needed at one end of the beam - a reflector being at the other.

If, however you're talking about an object, 6in in dia (say) that can cross thro' the 225 sqft frame at any point, that's a somewhat different proposition.

Do you have any idea of what total delay between object sensing and pic actually being taken is ... ie shutter + other lags, related to speed and dof considerations.

eg if it was 100ms, then 9 > 12in (approx) of object would have passed thro' the frame before pic was taken.

Any idea about lens focal length, distance of cam from frame ... and will gear be safe

As ziggy says - lots of ???

pp

ziggy53 · January 27, 2012

PocketWizard has done projects similar to this (event based camera remote trigger), although I haven't read of a light curtain application specifically. I suggest contacting them directly and giving them your details and specifications. They are generally very helpful.

http://www.pocketwizard.com/

I suggest that you should expect this project to run in the small thousands USD for the size portal (15ft square) that you have indicated and considering your total need as presented.

Here is one source for the light curtains themselves. Feel free to contact them for pricing and suitability.

http://www.bannerengineering.com/en-US/products/6/Machine-Safety/45/Safety-Light-Screens-Type-4
http://www.bannerengineering.com/en-US/about/contact-us

You may also wish to consider other "field" type sensors, such as ferro-magnetic if appropriate.

For the absolute cheapest trigger circuits (circuits which would interface with a detector to create an electrical pulse compatible with a PocketWizard transmitter), look at:

http://hiviz.com/tools/triggers/triggers3.htm

These folks are about as reasonable as it gets, since they are marketing towards hobbyist photographers. They probably don't have anything perfectly suited to your application, but I suspect that information you collect from PocketWizard plus these folks could guide you towards a solution.

fjcvisual · January 31, 2012

I wonder if I am making this more difficult than it should be. Nick Nichols (NatGeo) did a project where he triggered his camera once a tiger entered this water hold area. I will try to find something on it and post.

ziggy53 · January 31, 2012

fjcvisual wrote: »

I wonder if I am making this more difficult than it should be. Nick Nichols (NatGeo) did a project where he triggered his camera once a tiger entered this water hold area. I will try to find something on it and post.

http://michaelnicknichols.com/nickstake/How-do-camera-traps-work.html

http://www.nationalgeographic.com/explorers/projects/bioblitz/bioblitz-capturing-tigers/

fjcvisual · February 1, 2012

Thx ziggy. Yes that is it. I was able to find some brand names to begin the product search. Looking promising.

Jim

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Optical Gate remote shutter release

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