Rollei IR 400 in mixed light with IR flash
I'm shooting an extended project that will include some concert photography. The venue forbids flash photography during the show, which presents something of a problem. Light levels will be low and I don't want to have to switch to digital for this section of the project.
So, I thought about shooting Rollei IR 400 with an IR flash. I am not looking for the IR look, so I will not use an IR filter on the camera lens.
Instead I am aiming for the IR filtered flash to act as an invisible IR fill light that will be picked up by the extra IR sensitivity of the film.
So, essentially I will shoot:
- Mixed light
- No IR filter on lens
- Heavy duty IR emitting flash (on camera)
- Rate Rollei IR 400 @ 400
Also does anyone have any experience pushing Rollei IR 400 to 800 or 1250?
I'm going to run a few tests in advance, but would like to hear from anyone who has experience with this.
Thanks in advance.
Last edited by Harry Lime; 03-29-2012 at 08:51 PM. Click to view previous post history.
Would tge focus shift present a problem when mixed with the visible light to expose the image?
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My guess is it might offer some help, but perhaps not much. I doubt focus shift would be much of a problem, as the Rollei material doesn't extend very far into the IR range. That same limited IR range could mean you won't get much fill, as in daylight the film requires about six stops additional exposure with a 720 nm IR filter which passes the near IR range barely outside the visible wavelength (but I guess there's one way to find out. )
Could be fun to try. What will you use for an IR flash?
It's an interesting idea. I am a bit doubtful that you'll get much boost for the IR flash, though. What's it output spectrum? if you put an rm72 over the light source, I doubt you'll get much extra exposure of the film. It'll just have to be tried.
This film has rather limited IR sensitivity. A very deep red flash should be much more effective and not too intrusive. But bear in mind that you probably lose 3 stops of flash power when you gel it.
The reason why the IR flash strategy works well with digital is that the digital sensors are very IR sensitive, so much so that it is a problem. Alas the Rollei film and superpan and the Efke and Ilford films aren't nearly as IR sensitive.
Weegee did a similar technique with black painted flash bulbs and IR film. Might try using flashbulbs?
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Just remember that Weegee was "in your face" most of the time. For most concerts, that isn't the case.
On further thought, back in the Bronze Age, ca. 1958 or so, a friend of mine attempted to rig up an IR flash using a kit built electronic flash that was a bit of a monster and the IR filter from some WWII/Korea night vision gear. The filter was about the size of the filters for Kodak bullet style safelights. Even though you couldn't see through it, there was a quite visible deep red glow when the flash fired. It was orders of magnitude less disturbing than an open 120 ws flash, but it wasn't exactly 'stealth." Not sure he ever did anything with it but the experiment itself.
(And I dunno, IR works with the dig!t@l stuff if it's designed for it, or has had the IR cutoff filter removed. But with a 760 nm filter, my EOS40D needed many seconds of exposure in bright daylight to catch anything. I don't follow it closely, but AFAIK, the fundamental sensor elements pick up IR readily, but the package includes filtration to seriously attenuate the IR.)
Originally Posted by keithwms
I'll match the IR filer on the flash to the spectral sensitivity of the film.
Unfortunately ROLLEI IR seesm to only go as far as 820nm. KODAK HIE went well over 900nm...
Looks like this fellow is shooting with an IR flash and mixed light. Notice the black shark eyes...seems to work though.
Going to run some tests.
Originally Posted by Harry Lime
Yes, the Rollei (and similar) film only pokes a bit past the visible red. To get "true" IR effects I find that deep filters and rather large exposure compensations are needed with this film.
Let me suggest superpan and a deep red gel over the flash.