Most electronics are sensitive to IR like silver halide is sensitive to UV/blue intrinsically. Often the peak of their sensitivity is in IR. Youd have to know the particular detector being used in your camera.Are you sure that the 645N's meter is within its sensitivity range when you stich an R72 filter on the front of the lens?
That filter is substantially opaque to a lot of visible light.
Youd have to take your meter and put an R72 in front of the meter and check how many stops it drops by in metering the scene. CdS are common for meters, and silicon photodiodes also common and are the second type with more sensitivity in IR than anywhere else, that type may employ an IR-cut filter over the sensor, like digital cameras doMost hand meters have little or no IR sensitivity. Are in camera meters different?
How did you get such a strong effect with just a normal filter?I bought some expired Konica IR from someone on this forum, really great film. This is with a red filter.
Bishop Hall by Bryan Chernick, on Flickr
Kinkaku-ji by Bryan Chernick, on Flickr
I wonder how we find out what the P65N or even I suspect the older P645 in-camera meter is in terms of the graphs. Do the graphs indicate that any of the three sets of spectral sensitivities will do the job of giving the four stops required for extended red sensitivity films?
You would also think that such in-camera meters would not be confined to Pentax and thus you'd expect other camera users to report that R72 give them the right the exposure as well. Maybe they just have bothered to report this. The problem is that we get almost no threads which report good news in an exchange of information. By this I mean most users who find that that there is no problem with their in-camera meters for IR photography are unlikely to share this information. We tend to be a "problem" forum only and any exchange of information stems for a problem not a desire to exchange information for its own sake
Anyway there are probably too few of us here on Photrio who have P645n or P645s and a R72 filter to test and report on this but it would certainly be helpful if those who can report do so
Unfortunately as I reported i do not have a R72 to test.
pentaxuser
Athiril so if most camera makers of say relatively modern build cameras such as the P645N use CDS will these meters actually meter correctly for near IR film? Assuming that is the case then you'd expect a range of cameras such as Canon and Nikon to do an equally good job of metering for near IR film. This being the case then isn't it likely that if these meters are OK for near IR then is it likely that the same makers would not want to sacrifice the metering abilities for non IR films and non IR filters so it sounds as if each maker would fit an IR cut filter as well
So we are no nearer working out why the P645N is so accurate at metering near IR films, are we, unless there is something deliberately built in to P645N meters that other cameras do not have ?
pentaxuser
Athiril so if most camera makers of say relatively modern build cameras such as the P645N use CDS will these meters actually meter correctly for near IR film? Assuming that is the case then you'd expect a range of cameras such as Canon and Nikon to do an equally good job of metering for near IR film. This being the case then isn't it likely that if these meters are OK for near IR then is it likely that the same makers would not want to sacrifice the metering abilities for non IR films and non IR filters so it sounds as if each maker would fit an IR cut filter as well
So we are no nearer working out why the P645N is so accurate at metering near IR films, are we, unless there is something deliberately built in to P645N meters that other cameras do not have ?
Just the red filter. The camera was a Ricoh Diacord L.How did you get such a strong effect with just a normal filter?
In my experience the difference between regular film and IR with a standard 25A red filter is negligible.
Did you use a polarizer on top?
Zomei IR filters are inexpensive, I have a 680nm one.What are filter options?
Real IR filters are expensive and one trick ponies, even old Wratten gels.
But they might be the only sensible thing in the end?
What are the options for DIY?
You forgot Rollei Superpan 200. But keep in mind that Agfa doesn't produce Avophot Pan 400 for some time now and Rollei IR, 400S and Superpan 200 are likely the same film. The only difference is who does the conversion.[/QUOTE]What we lack in this thread is a clear concise list of all of the IR films currently available and the characteristics, pros and cons.
Let me try a first wee step.
SFX 200
View attachment 256180
Rollei Infrared 400
View attachment 256181
Rollei Retro S400
View attachment 256182
Rollei Retro S80
View attachment 256183
Is this all of the NIR/IR films currently fresh and on sale?
All we know is that in a particular set of circumstances the meter reading from that camera did the job.It would look as if we may never get to the bottom of why the P45N in-camera meter works correctly for at least Rollei 80S but I assume this might be the case for all near IR films on which an IR filter has been used.
Back when I used this stuff (mid 1990s) I didn't yet own a real IR filter and I got very nice results with a regular old R25, and, yes, I shot handheld. I suspect an R72 would have been better, though, and that probably would have required a tripod.View attachment 256129
Wow! Can we have something like this back?
You really don’t need anything but a 25 or 29 filter.
It even says so in the data sheet.
Of course a real IR filter will “improve” things (depends on what you’re after) but only slightly.
You could shoot this handheld no problem.
Well, you might get the hang of it eventually........But hey I have had only sixty years of experience doing this.
Fixed.You forgot Rollei Superpan 200. But keep in mind that Agfa doesn't produce Avophot Pan 400 for some time now and Rollei IR, 400S and Superpan 200 are likely the same film. The only difference is who does the conversion.
Here are a few from 1978-1980, Kodak HIE. Was really fun stuff. (Zeiss Icarex 35S TM Pro; CZ 50mm f1.8 Ultron)
curve by Mark Wyatt, on Flickr
mystical man by Mark Wyatt, on Flickr
Mariah by Mark Wyatt, on Flickr
There appears to be some good eBay package deals with a stack for the same price as one IR.Zomei IR filters are inexpensive, I have a 680nm one.
You can use 2 layers of developed unexposed slide film. Thats why I used when I had a 12-24mm lens that took rear gel slot filters.
Aviphot Pan 200 seems to be a current product according to Agfa's website. Over the years, Rollei's repurposed films from Agfa's stocks may have changed. Aviphot Pan 400 might have been used in the past, but it's no longer available, so Rollei IR could have been the 400 variant, whereas today it's converted from the 200. Generally speaking, Maco aren't very upfront about the source of their films, but nevertheless, I'm glad that they make the effort to make some interesting aerial films available to us. And yes, all repurposed Agfa film stocks with the clear polyester base make spectacular slides. They also dry dead flat, which is another bonus.Fixed.
Not sure about the datasheet since it appears the A/G stock it was derived from (Aviphot Pan 200) is not produced anymore.
I understand that Superpan 200 is especially good with the Scala reversal process, because of it’s clear base.
Is that something that’s true for the other “Rollei” films?
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