Hi I'm Will and I'd like to make a camera Obscura tent

#1

Hi, I’m currently putting together a camera Obscura tent of sorts and I need some help with one particular part. I’ve bought a 2mx2m gazebo sown black out lining to cover it. I’ve tried making a hole in the side and putting a lens in it to project on to the opposite ‘wall’ but the effect isn’t wow enough. It’s a bit dim and the lens in the side of the tent is constantly being blown back and forward. I think a turret on top that reflects light down through a lens might be better (see image

20170808_201004.jpg2988×5312 3.33 MB

. The difficult part is the turret. Any suggestions on this? I was thinking of laser cutting a 400x400 box for the mirror and a larger circular disk to go under it and attach to the tent poles, like in the picture.
Cheers
Will

1 Like
#2

Interesting!

Won’t the lens, erm, un-obscura the obscura part of the camera?

What’s the bigger problem? The amount of light or the movement of your aperture hole?

Turret is not a bad idea, but maybe it would be easier, in terms of both the build and deployment, to build a rigid stand on one of the sides of the tent, and making sure the distance between it and your light sensitive surface remains constant, despite the wind moving other parts of the the tent?

1 Like
#3

Hi Luke, thanks for your reply.
Obviously the original camera obscuras (latin for dark room) didn’t have lenses, just a hole and a slightly blurry image, but all high quality modern demonstrations use a large lens to increase the aperture and therefore brightness.

You are right, definitely easier to make, store and transport without a turret! But you get the cool effect of being able to rotate the turret if I do go for that, so I’m not 100% sure yet.

The movement and brightness are issues that occur at different times. If I use a 2m lens to focus it on the opposite side movement is minor but the brightness is an issue, though I have ordered a slightly larger lens with anti-reflection coating. Maybe there would be some way to make the inner side more reflective as well?
In another situation, when using a 20cm or 50cm lens with a piece of paper in front of it, the brightness is good enough to show through the paper, but movement is a big problem. I’ve got a cheap tripod that might stablise the side with the lens in. What would be good is to have a large curved translucent screen at the focal distance to view the image through. I’m not sure how to go about that though.

#4

I see what you mean about the rotating turret - could be a unique feature (adding to the complexity and set up, but shouldn’t be prohibitively difficult to actually make and test out). Maybe a basic, but stable (wooden?) tower-like structure inside, and then rotating cap-like top part sitting on it? I guess initially it wouldn’t even need any ball bearings, because it wouldn’t matter that much if the pan was smooth or not. To make it all precise and robust you’d have to have some metal parts where the tower and the cap would meet, but in terms of cost and difficulty maybe just build either a prototype or even a scale model first out of wood.

Alright, that’s my two cents, most of which you probably already considered, but I hope someone else can offer more detailed advice - maybe even made something in the space that could be a reference.

#5

You might consider projector paint to get a nice bright image, but it ain’t cheap. £100 for 2-3m² coverage

1 Like
#6

Thank’s for your help Luke :smiley:

#7

Great idea! Although if I use it on the gazebo covering I’d worry about it splitting when I fold it away. I’ll contact a seller to see what they say. But since you suggested projector screens, I had a look and found this super cheap offering on ebay