Mounting infra-red filter behind curtain.

[TheVDM]

Hi, I like to shoot with Rollie IR400 film as it allows usable shutter speeds for hand held using an R72 filter but there is the inconvenience of having to compose the shot, then slide in the Cokin IR filter before pressing the shutter.

Has anybody experimented with using R72 or similar gel filters cut out and mounted behind the curtain just in-front of the film, allowing you to compose, meter and focus (with a slight adjustment for the IR wavelength) with ease while out without a tripod.

Cheers
Jim

 

[anikin]

Rollei film handheld? Are you sure? After accounting for the IR filter I always end up down to about ISO 6 plus or minus.
I tend to use IR film with a rangefinder or TLR camera. This way no issues with composing. That's a neat idea with gels though! Worth a try.

 

[TheVDM]

That's right, with bracketing I usually end up around ISO 3, 6 & 12. Maybe not so hand held this time of year although in the height of summer I can get a 40th of a second plus (with steady hands), I'm just lazy with the tripod, even the carbon fibre one is too heavy to get out of the boot

I might try getting a spare SFX filter to cut apart for experimenting as the SFX filter gives good results with Rollei IR 400 and if I remember rightly it allows an extra stop of light over the R72.

 

[Truzi]

I have read somewhere, perhaps on APUG, that unexposed and developed slide film may provide an adequate IR filter. I've no idea if this is true, or what it's cutoff would be. Just a thought.

 

[TheVDM]

I forgot about that, it could be a good starting point for a test, I have experimented with exposed and developed film before (i.e. the tongue of the film that has been fully exposed to light and developed). I think it let's in a little more than 720nm with a little 'visible' light too.

I think that could be the start of my experiments to convert my EOS1 to a simple IR camera (strangely enough I have just pulled a film down from drying to scan with a nice bit of exposed film on the end)

Thank you.

 

[MattKing]

IR films are the best argument for a TLR or rangefinder there is.

 

[Tom1956]

Kodak HIE was the would-be greatest. But why oh why they failed to put an AH backing on it, because it bloomed horribly. But TERRIFIC sensitivity.

 

[spatz]

Just out of interest i read on a cinematography forum that a film once was shot with cameras that had mirror film backing plates. In addition to the idea of using a filter near the shutter, perhaps using a mirror in place of the backing plate will increase the light hitting the film giving you greater shutter speeds and a bit of that aura effect that HIE and ir820 had. Just a thought of course...

Sent from my GT-I9000 using Tapatalk 2

 

[TheVDM]

That's another idea to try out in hopefully getting a faster shutter speed, I've decided to leave the EOS 1 alone and dig out the EOS 10 that I bought a while back as a dedicated IR camera (only had an EOS 300 at the time with IR lights to count the sprockets). I will have a look and see if I can get a spare backing plate to re-design, perhaps the other half has a make-up box with a small mirror in the lid (might be in trouble but it will be worth it).

Some good ideas going around here, just a shame that British weather wont allow some good IR shots for another 6 months!