Testing IR film with electronic flash

[xkaes]

Not that I'll ever find the time, but if I do I'd like to try some B&W IR film with an electronic flash. I'd be using an IR filter on the lens, but the flash may or may not have an IR filter. I'll also be using a flash in NON-TTL, auto-exposure mode.

I'll run some tests first, of course, starting with one flash model, the film's ISO, and varying the exposure.

Anyone have any tips to consider?

 

[AnselMortensen]

Basic stuff:
Just remember that flash exposure is aperture-dependent, not shutter speed dependent...so test, and bracket with aperture.
Don't forget to use your appropriate flash-sync shutter speed.
Test with a test subject at the same expected flash-to-subject distance as you will be shooting. (Inverse square law, yada yada)
Take GOOD notes.

 

[xkaes]

I'll start out with a gray card as a subject and vary the aperture from one end to the other guesstimating what the flash distance MIGHT be -- with the help of my flash meter. That's only going to be about eight exposures. If I'm lucky, one might come out OK, and I can fine tune it -- for that flash at least. I hoping that electronic flashes don't vary very much regarding IR spectrum output.

 

[Sirius Glass]

I'll start out with a gray card as a subject and vary the aperture from one end to the other guesstimating what the flash distance MIGHT be -- with the help of my flash meter. That's only going to be about eight exposures. If I'm lucky, one might come out OK, and I can fine tune it -- for that flash at least. I hoping that electronic flashes don't vary very much regarding IR spectrum output.

Which filter or filters will you use for your tests?

 

[Kino]

Interesting topic.

Have you seen this?

KV-FL1 Multispectral Flash with IR and UV Flash Filters – Kolari Vision

kolarivision.com

 

[neilt3]

With infrared photography where the light source is a flash , you would normally put a filter on the flash , not the lens .
Assuming the flash doesn't have an infrared blocking coating on it otherwise you'll get nothing regardless .
Use something such as this ; ebay link

You also say that by just using an IR pass filter on the lens you'll use the flash in NON-TTL, auto-exposure mode.
I've used the Rollei IR film quite a bit in 135 , 120 and 5x4 , metering off a weathered grey ( lump of rock etc ) I take a meter reading as ISO 6 .
If your not using a filter on the flash , does it have an ISO 6 setting ?
Otherwise the exposure will be off .

Putting a filter on the flash will reduce the flashes output and you can shoot as if it's regular film and rely on the flashes sensor .
For correct exposure like this , I treat it as ISO 320 film .

It also depends on what the reason is for flash photography in infrared is .
If it's nature photography or whatever else goes on in the dark , using a flash that can be seen scares wildlife away .
A flash that doesn't produce visible light , doesn't .

If it's static subjects your photographing in the dark , you could get some cheap infrared LED lamps , and illuminate with them .
A longer shutter time would be required .