R72 Filter With Normal Film?

retina_restoration

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That's a nice photo, Matt. But it's nothing like what HIE would have rendered.
 

xkaes

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F4U said:
Since these non Kokak IR films are't really the real deal, do you still have to refocus to the IR mark on the lens?
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Just set the distance in between and stop down enough.
 

Sirius Glass

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F4U said:
Since these non Kodak IR films aren't really the real deal, do you still have to refocus to the IR mark on the lens?
Click to expand...

I have not needed to refocus Rollei IR 400 film, but then I tend to use larger f/stop numbers.
 

Ivo Stunga

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750nm is the very edge of visible light - meaning you don't need to refocus all the way to the red dot/stripe/curve.

I've tried the refocusing thing on many films and some little bump towards the red can be helpful for close-ups, but one can just use smaller aperture to have greater depth of field, as @Sirius Glass stated. You tend to do this with landscapes anyways, and landscapes is what mostly people use NIR films for.
Although close-ups are very much possible, even near macro.
 
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OP
OP

F4U

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I remember HIE with fondness to a degree, and consternation. In 35mm with D76 it was grainy to a terrible degree. And I hated the image blooming. Putting the matter into context, it was offered to us creative-minded photographers, but not meant for us. It was a military film that found it way into scientific and medical use also. Once again, putting it into context, my personal complaint was the blooming, caused by the clear base that allowed light piping, and no anti-halation backing. This may have been intentional, for it's primary intended use.. In war, the bad guys would hide under foliage and tree growth, stringing up man-made camouflage netting to cover their tanks and cannons. To the naked eye or to ordinary film in a recon plane, that netting looked just like everything else. But to infrared film, the chlorophyll in the plants and trees provided contrast, as they rendered much lighter. And the blooming made the netted areas show up better. It was areas of dark and light they wanted to see. That's where to aim the artillery fire. Perhaps this latter day "infrared film" isn't so bad. It has anti-halo backing and a dyed film base. The blooming is gone. That's a good thing. For those who still want the "dreamy" effect, a Softar filter can add that.
 

Ivo Stunga

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F4U said:
In 35mm with D76 it was grainy to a terrible degree.
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I wonder how it might look like reversed, because BW Reversal produces very little grain. Delta 3200 comes out about as one might expect a ~400 film to look like.
 

ags2mikon

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I just ordered some Rollei 400 infrared to see for myself. Now I just have to wait for the red white and blue truck of joy and happiness to show up.
 

Petrochemist

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F4U said:
Excellent! Is my Hoya R72 filter the most extreme infrared filter there is (for consumer use)?
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It's about the most extreme you can use with IR film, but there are plenty of stronger types for digital. It does vary considerable by film but from what I've read I don't think any available IR film actually sees wavelengths above about 800nm.
One of my old IR books shows the spectral response of Kodak high speed infra red film reached as far as 900nm & gave some response throughout the visible, while Konica Infrared 750 shows two bumps of sensitivity one @390 to 500nm and another from 670 to 800nm with nothing in between)

R72 has a transition point (50% max transmission) near 720nm
When I first tried IR with an unmodified K100d (fairly sensitive for a stock camera) I got a cheap chinese set of IR filters than included 720nm, 760nm, 860nm & 960nm filters.
The 960nm turned out to have a very gradual transition from blocking to transmitting well over 150nm while all the others are nearer 20nm transitions - So the 960nm transmits more at 820nm than the 860nm one does. I know I could see something through the 960nm filter, though not quite as much as through the 720nm/R72.

FWIW silicone as used in digital sensors becomes transparent to IR somewhere between 1000nm & 1100nm, so converted digital cameras can't see beyond that (nor could the lab spectrometer I used for checking the transmission of my filters).
True thermal cameras have to use other materials for the sensor, IIRC Gallium Arsenide is the most common option for those.
 
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Sirius Glass

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Andrew O'Neill said:
Here's the video, in case you are interested...

Click to expand...

Why not start with Rollei IR 400 and the 720 filter? You would not have to take three days to get the exposure in range for more serious printing.
 

Ivo Stunga

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Or even better - why not Adox HR-50 or the cheaper IR options from Rollei Analog - like Superpan 200, Retro 400S and RPX25?
 

Andrew O'Neill

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Sirius Glass said:
Why not start with Rollei IR 400 and the 720 filter? You would not have to take three days to get the exposure in range for more serious printing.
Click to expand...

It was an experiment.
 

Ivo Stunga

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ags2mikon

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And thank you for the experiment! If you look at the data sheets it will give you some idea as to what to expect as proved by Andrew. I do find it a bit annoying that Rollei packages the the same film as multiple flavors and different pricing. I haven't noticed that with Ilford.
 
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