Go Back   Physics Help Forum > High School and Pre-University Physics Help > Light and Optics

Light and Optics Light and Optics Physics Help Forum

Reply
 
LinkBack Thread Tools Display Modes
Old Jun 6th 2014, 06:33 AM   #1
Junior Member
 
Join Date: Jun 2014
Posts: 2
Lightbulb How to build a short throw projector for a photography studio

Hi!

It’s been a while since I last studied how light travels using formulas so I think it is fair to say that I need some “professional help”
I am a photographer and I want to build a projector
Now, that might sound easy but I need a projector extremely powerful – all in order to project an image on a background behind the people I am photographing - because in the studio I am working with strobes brighter than 500w and the normal projectors do not output enough light to register on the camera.
The solution I have in mind is simple: replace the bulb in a LCD type projector with a strobe and problem solved!
I think this is going to work … but by doing this I now need to have a computer attached to the projector.

What about using some transparency slides and just the lens from a projector (like this lens assembly), all inside a snoot like this one
Where should I put the slide – I mean what will be the best way of putting these together – would I need another lens before the slide in order to concentrate the light … and probably other many questions I still need to find and then find an answer for them!

What about building one from scratch? Buy lenses according to a diagram and assemble everything on my own?
2 requirements: the projector should be a short throw one (I need maximum image size from a short distance (1m let’s say) and the slides should be as big as possible (to avoid printing issues!)

So … anyone willing to help!
Thank you very much!
xseven is offline   Reply With Quote
Old Jun 6th 2014, 10:37 AM   #2
Physics Team
 
ChipB's Avatar
 
Join Date: Jun 2010
Location: Morristown, NJ USA
Posts: 2,272
Can't you use a slower shutter speed so that the projected image in the background has more time to register on the camera CCD chip? The strobe fires for what - about a millisecond or so, right? So slowing the shutter speed should allow the rear projected image to register better without over-exposing your subjects. Also have you tried shielding the rear screen from the light of the strobe so that it doesn't get washed out? As for making a projector with a strobe light source - can't help you there, but given the short duration that a strobe fires for I suspect it won't solve your problem - the intensity of light would be brighter than you get from a standard projector but for a much shorter duration of time.
ChipB is offline   Reply With Quote
Old Jun 6th 2014, 10:48 AM   #3
Junior Member
 
Join Date: Jun 2014
Posts: 2
A slower shutter speed is not an option as the people are not very good at standing still ... especially kids!
The strobes are going to be in sync, fired with the same remote trigger so that's not going to be a problem!
xseven is offline   Reply With Quote
Old Jun 6th 2014, 12:52 PM   #4
Physics Team
 
ChipB's Avatar
 
Join Date: Jun 2010
Location: Morristown, NJ USA
Posts: 2,272
The point I was trying to make is that you have one strobe (or set of strobes) lighting your subjects, and one strobe acting as a projector, whose light is filtered and dimmed by the intervening slide. Consequently the scene projected on the rear screen will be much darker than the subjects. You may have to filter or dim the strobe on the subjects so that the rear-projected scene is of similar brightness.
ChipB is offline   Reply With Quote
Reply

  Physics Help Forum > High School and Pre-University Physics Help > Light and Optics

Tags
build, photography, projector, short, studio, throw



Search tags for this page
Click on a term to search for related topics.
Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
i need just a small push to this one( verical throw) Marko Kinematics and Dynamics 23 Jun 25th 2015 04:23 PM
Why we can't build a QFT of gravity? ndung Quantum Physics 20 Jan 20th 2015 05:52 AM
Shooting with a cannon (angle horizontal throw) Nforce Kinematics and Dynamics 6 Oct 7th 2010 05:15 AM
If you were to build a ftl drive what would it look like roland of gilead General Physics 0 Jan 25th 2010 01:15 PM
hammer throw deformation nejikun Kinematics and Dynamics 2 May 3rd 2009 10:52 AM


Facebook Twitter Google+ RSS Feed