Rollei 400 IR Film without a filter

[tony_duda]

<p>Does anyone know if this film, used without a red or IR filter, is still able to capture in the near infrared range, or will visible light "wash out" anything caught in the near infrared range? In other words, I want to be able to capture the visible and near infrared spectrum in the same exposure. I'm not interested in an infrared-type look in the shots (white trees, dark sky, etc.), only being able to capture an extended range in the same shot (400-740 nm or so). As I need to use the camera hand-held and can't use a tripod, a filter would slow down my shutter speeds too much. Thanks in advance for any replies.</p>

[nigeljohnwade]

<p>You probably want Ilford SFX then which only goes to about 750nm and doesn't have as much classic infrared look about it, even with a filter, and you can shoot at 200ISO. The rollei film goes to 820nm but the datasheet states that rated at 400ISO without a filter it behaves as normal film. It might be worth trying the rollei with a deep red filter and shooting at 50ISO.</p>

[tony_duda]

<p>Thanks, Nigel. I mentioned 740nm as the cutoff only because I didn't know the Rollei film went to the 820nm range. Actually, that would be a bonus, even better. I wonder when Rollei states that the film acts as a normal panchromatic film without a filter, they mean that no near IR information is recorded on the film without a filter?</p>

[tony_duda]

Also, one more question, and then I'll stop asking so many questions :-)

 

For infrared flash photography with these films (Rollei 400 IR and Ilford SFX 200), is it better to use an IR pass filter over the lens, or to use an IR pass filter over the flash? Which would give better results in the IR range?

[peter_fitzsimons]

<p>"I wonder when Rollei states that the film acts as a normal panchromatic film without a filter, they mean that no near IR information is recorded on the film without a filter?"<br /><br />Correct, it will just work like a normal B&W film. Rollei Superpan 200 or Retro 400S with a filter that cuts off around 665nm might achieve the effects you want.</p>

[john_shriver]

<p>The IR films are sensitized over the whole visible light range, and then have an extra sensitizing dye that provides sensitivity some distance into the infrared range. However, the sensitivity in the IR range may be lower than in the visible range. So it could easily be swamped without a filter.<br>

At any rate, you really won't get a noticeable IR affect without a filter to eliminate most or all visible light. Just be sure to use a filter that doesn't cut off all wavelengths your film is sensitive to.<br>

You don't need an IR filter with IR flashbulbs. (Unless there's a lot of ambient light you want to exclude.) You do need film that is sensitive to the wavelengths the IR flashbulb emits.</p>

[tony_duda]

<p>Thanks everyone for your advice.</p>

[cm_mcmullen]

Hi Tony

Two quick thoughts: first you might try some test shots with/without a yellow filter. It will cut down on the visible wavelength without too much of a hit on your exposures.

Second, I'd go with normal flash. I don't recall using flash with IR film but with IR digital regular flash is great: I get much more range out of my Canon flash that way. Which may meanyou should do some tests to adjust yoiur flash exposure.