Flutterby™! : Infrared Film 2005-04-05 12:32:41.045921+00

Infrared Film

2005-04-05 12:32:41.045921+00 by ebradway 16 comments

Since I managed to get the weight of my aerial photography rig down so low, I'm now looking to add a second "sensor" to the gondola. It would be great to get simultaneous infrared photos with my digital true-color imagery. Does anyone have any experience with infrared film? I want to use it with a fairly inexpensive point-and-shoot with IR remote control like the Olympus Stylus 400.

The reason I can think of to stay with film for that is lower capital costs. I don't know about point-n-shoots with remotes though.

For digital: It might take mechanical modification of a camera, but I think some of the Sony

digital cameras have IR modes. The problem as I've heard it is that they only let you use the IR mode in low light (because of the whole "sees through clothes" scare), so to take daylight IR shots you have to open up the camera and modify it so the IR filter gets locked out of the way.

Oh yeah: One of the things I remember from reading the Photo.net archives was that some modern cameras use an IR based system to count sprocket holes for frame advance, so you should do a search on your camera model and "IR" to see if someone else has used it for the same.

Calibrated digital IR is very expensive. The cameras are very heavy and the CCDs are low-resolution. I get this question alot along with "why not use some kind of military surplus night vision goggle". Most IR systems like that are designed to help you detect motion at night. All they really show is differences in IR emmisions. What they don't show with any real accuracy is the wavelength of the emissions. I need to be able to develop IR signatures for what I am photographing.

I saw some of the mention of IR blurring of some cameras. Generally it's not as bad as it seems. The center of the image should be fine.

#Comment Re: made: 2005-04-05 17:14:54.509147+00 by: jeff [edit history]

If cost/weight weren't such important factors, I'd recommend these folks for digital IR imaging:

I did some more research. Evidently the older Sony 2.11mpix CCD used in some of the older Sony's have very good near-IR sensitivity. Newer CCDs have sacrificed IR sensitivity for visible resolution and all of the Sony's block IR capture during the day. You can buy a Sony camera already prepped for IR use. Other cameras have IR filters in the lenses that have to be removed manually.

The Olympus C-2020Z had the best IR sensitivity. The popularity of this camera for non-standard uses shows in its $288/refurb price. The camera is only 2.11mpix but it features a threaded lens for filters and an IR remote. It's old enough that it only has a serial port for data transfer.

#Comment Re: made: 2005-04-05 18:13:25.609678+00 by: mvandewettering

Without hardware modifications, the exposure times are quite lengthy and the autofocus basically doesn't work at all, so I'm not sure how successful this would be with this camera on a moving platform.

Looks like the Minolta Freedom is a 35mm point-n-shoot with an IR remote, the remote looks to be $20, looks like you can get a refurb for $120 + shipping. Unfortunately it's a cheap point-n-shoot with a lens to match, lots of vignetting on the short end. Is there an IR module you could scarf to disassemble something like a Yashita T4 to give it a remote?

I've done some investigation into this issue myself. Key points: 1) IR film is very difficult to meter properly for. The film itself is expensive, as is the processing. 2) To do digital IR, you need a camera that accepts a threaded filter. This rules out the cheaper cameras unless you want to go guerrilla, which seems likely in this instance (been reading your blog for while, Dan!). 3) Many digital cameras do include an ir-blocking 'hot mirror' before both the CCD and maybe the exposure sensor. The Sony's you mention (the DSC F505, F707, F717, and F828 family) do have a night mode where it pulls those filters out of the way of both sensor and CCD. It does have a limit on how fast you can shoot in that mode. I've used my Canon digital rebel to shoot some IR. You don't get much signal. Long exposures and then take the image into digital processing and adjust your white,black and grey levels to bring up the image. A cheap way to see if a digital camera blocks IR (and to what degree), just point a TV/VCR/DVD remote at your camera and look at the LCD or shoot a photo while pressing buttons. If you can see a (usually green) light, you're getting IR. Doing Aerial photography will be tough as you need to shoot quick to get an unblurred shot and IR is going to provide many fewer lumens than visible light (not sure lumens is the right unit, but you know what I mean).

#Comment Re: made: 2005-04-05 20:55:16.435142+00 by: ebradway [edit history]

I can get Kodak B&W IR film for about $11/36exp and Color at $20/36exp. Locally, I can get it developed to strip positives which can then be scanned for $6/roll BW and $8/roll color. If had the extra money, I'd buy an Olympus C-2020-Z and try it. It's lower-resolution than the C-60 I'm current using for true-color, but would work well as a backup.

An advantage of the BW infrared is that it is higher speed. If the near-IR is mapped to shades of grey, I can use it as a fourth layer with the image captured by the CCD in the digital camera. At this point, the best bet is to get an Olympus point-and-shoot and try some IR film in it.

On threaded filters, Ruby found a little device that screwed into the tripod holes and held a standard filter out in front of the lens on a point-n-shoot. I've done something similar with styrene to build a slide digitizer with my D60. You just have to worry about light creeping in from behind, but that's what black felt covered matte board is for.

Radix, I think Eric's platform is a balloon, which makes the "aerial photography" bit not in the extreme shutter speeds you want from, say, a helicopter, but still not the seconds you get with a standard IR filter and an unmodified digital camera.

It's ironic, but on a helicopter, I'd use vibration dampeners to eliminate the jitter. On a ballon, I'm dealing with possible wide swings of the camera platform. I've been trying to come up with ways to reduce the swing effect. In still wind, I can handle maybe as much as 1/10th of a second of shutter speed. Anything more than that is dubious.

A bit more research found that using Kodak Ectachrome EIR color film, I can expect to use an shutter speed of 1/250 sec. That's plenty fast enough. But I still have the problem of what kind of camera to use. James Aber in his KAP rig, uses a Canon EOS RebelX with plastic lens because of weight.

#Comment Re: made: 2005-04-07 20:39:02.392621+00 by: ebradway [edit history]

I just found Jen's Site with a great comparison of digital camera IR sensitivity. Her pictures with the Olympus 2020 are at 1/60 shutter speed. Even better, her mod'd Minolta D7 has even greater IR sensitivity and functions at 1/250 sec shutter speed.