please help troubleshoot a unique projection situation

[poprobot]

Initially, please let me introduce myself - this is my first post here... I am a musician with some video experience, but not an expert in the A/V field by any stretch. Hopefully I will find some solutions here to a unique problem.

 

I play drums in an American rock quintet.

For performances, I plan to project stills/animations and other graphics on to a 60cm bass drum resonant head, using an inexpensive pocket LED projector mounted inside the drum.

 

Here is the projector I currently have:

http://www.amazon.co...rds=optoma+pico

Here is an example of the bass drum (for visual reference)

http://www.drumcente...ine-pearl-2.jpg

Here is a video from another drummer who seemed to have successfully accomplished this (although I cannot get in contact with them to discuss)

https://vimeo.com/26703867

 

The depth of the drum is about 35cm, the projector is about 5cm, which gives less than 30cm throw distance for the projected image. I need that image to fill the 60cm head.

 

My first question is, what kind of macro lens or other adapter/gadget is necessary to enlarge the image for such a short depth of field (essentially a 2:1, correct?) And will it be something I can mount on this tiny projector?

 

Secondly, if I were to mask my images/animations within the software before creating the digital files, will that suffice in creating a circular projection? Or, is it necessary to "pinhole" the projection lens in order to create this effect?

 

Thank you in advance for your assistance!

[Tom Baldwin]

The Vimeo clip appears to be projected from outside the drum (look at the reflections on the chromed port).

 

I wonder if you're going to be able to find a suitable material for rear projection which doesn't adversely affect the tone of the drum - not being a drummer, I don't know what effect changing that parameter alone will have (and good R.P. material is essential for rear projection, so your choices are limited)

[Mystic]

remembering my optics courses, you should be able to do that with one or two lenses (at worst you can always invert what you're projecting if it's displayed upside down). The biggest challenge I guess is to put the optical source in the axis of the bass drum and not too close to the beating side. In these kind of setups the wires can also be a burden. but I'm scientifically interested into the solution you will use :)

[Stuart91]

Would a projector be able to sit steady enough inside the kick drum whilst it is being played? I imagine some vibration in time with the beat could be a neat effect but I suspect, given the average lead-footed drummer, that there could be significant movements that could make the image unwatchable.

[Jivemaster]

There is a possibility that you could find an afocal wide angle adaptor (intended for a camera) that would become suitable for your projector with some vibration resistant adhesive. There is a chance (slim) that you could find a small enough +1 dioptre lens to fix on the front of the projector lens which might enable it to focus that close (but will not be wide angle).

 

FAR BETTER you could find a place on stage to hide the projector to simply front project onto the drum skin. You will need to keep the projector in a fixed place relative to drum or the image will wander in place and focus.

 

IMO a projector inside the drum will vibrate with the beat and make a very shaky image.

 

Afocal adaptors were common for twin lens reflex (film) cameras and if available may be cheap junk in camera shops

http://www.ebay.co.uk/itm/Official-Canon-wide-converter-WC-DC52A-0-7x-Lense-With-Adaptor-For-Powershot-S1-/221766429793?

 

Any attempt at mirrors inside the drum will likely lead to much image vibration due to the projector and the mirror moving to the beat.

[ninjadingle]

Have you thought about projecting through the batter head? Or do you use oil filled heads? (Though that could produce quite a funky effect too....)

 

Or you could mount the projector on one of the stands they use to hold internal mics permanently in place? At least then the projector will resonate in time with the head?

 

Or just FP it - much easier!