Infra red photography

[Overread]

Just a few quick thoughts/questions on this :

1) If you have a DSLR modified to take IR photos do you have to also use an IR filter on the lens or is this included in part of the camera's internal sensor modification

2) If you don't have to use an IR filter on the lens will using one cause any possible problems/degradation (beyond that expected by adding a good quality filter)?

3) If you have a DSLR with live view capabilities modified to do IR photography I assume that the LCD on the back, in live view mode, would display the IR light as normal.

 

[mikehaugen]

Sorry I don't have any answers for you, but I am interested in seeing someone that has done this post some pictures. I always have wondered about this because when I think infrared camera, I think of one that only sees heat signatures, really nothing that your eyes will see and most of these cameras are about $40,000. I assume that the dslr conversion is something completely different? Didn't mean to highjack your thread, I was just hoping to see some pictures.

 

[photocist]

This isnt mine, but an example for infrared film.

http://flic.kr/p/89xBVS

Its not like an infrared scope in black ops lol. There is also infrared color film. Click on this link for an example: Tree and Swan - Kodak EIR smaller | Flickr - Photo Sharing!

 

[Garbz]

1) If you have a DSLR modified to take IR photos do you have to also use an IR filter on the lens or is this included in part of the camera's internal sensor modification

Depends on the modification. Many places give you the option of putting an IR filter over the CCD and compensating the focusing system slightly. The other option is putting a sheet of glass over the CCD. This will mean you need an IR filter on the lens, or an IR cut filter on the lens. Without one or the other you'll end up with a red haze on your photos. But the focus doesn't need to be compensated.

Each has its advantages. Putting the filter on the sensor means you can compose your shot. Putting it on the lens means you can't see through the viewfinder, but it also means with an IR cut filter on the lens your camera is returned to normal.

2) If you don't have to use an IR filter on the lens will using one cause any possible problems/degradation (beyond that expected by adding a good quality filter)?

Flare. An additional ghost of a bright light source is not avoidable even with top quality multicoated filters. That's all. The problem is that you lose your ability to quickly compose and take the photo, instead now you need to either use a tripod compose and place the filter on before taking a picture, use liveview, or guess your composition.

3) If you have a DSLR with live view capabilities modified to do IR photography I assume that the LCD on the back, in live view mode, would display the IR light as normal.

True.

Sorry I don't have any answers for you, but I am interested in seeing someone that has done this post some pictures.

This is a modified digital camera. Take note that the sky does not produce much infrared. Leaves do, the ground is sand so it does too. This is typical of the contrasts you get in the 720-980nm range.

This is an unmodified digital camera. Since there's a filter on the camera sensor blocking IR light the effect isn't anywhere near as dramatic. This picture already has boosted contrast too. It kind of sucks, compare it to the one below. Take note of the clouds. This picture has a 8-10second exposure on a tripod. All the other pictures I posted are shot handheld. This is what happens with unmodified IR cameras.

In this picture I used infrared film Efke IR 820 so this covers the 720-820nm range. It's in similar conditions to the one above.

 

[Overread]

Thanks Garbz!
It just clicked in my head that with an IR filter on the lens I'd only be able to see black through the lens because the human eye+brain setup can't see IR light!

Sounds like if I want to make an IR capable camera for night-time shooting I'll have to accept that my 400D is not going to work save for a precomposed photo. I'd need a camera with liveview output and then make the choice on how to setup the filter system on the camera. Use liveview to compose and take the shot (going for a sheet of glass over the CCD and then an IR filter on the lens itself thus to allow for AF to at least have some chance of helping).

Combine that with an IR bulb (to light the scene) and then IR flash units to help with exposure of the scene itself (that or more bulbs over the area depending on the setup and distances involved and power of the bulbs).

EDIT - just a thought is is possible to tint an IR shot into natural colours? I seem to recall reading somewhere that someone had managed to do it (or it was a UV shot or some other colour spectrum that we don't normally see).