Maco/Efke IR 820c, any experience?

[xtolsniffer]

The 89B (I think it's an R72 equivalent) should have a cut-off point from 680nm, and the film response curve goes up to 825, so there should be a little leeway there. The film datasheet lists the 89B as being +4 stops, rating it at ISO 6, which I think is a little optimistic!

[Robert Hall]

Your filter is too dark. The filters you should use are either Wrattan 29 (deep red), or B+W 092/Hoya RM72 (even deeper red, almost opaque, but still red). Don't bother with a 25A, as it's too light.

The 89B (Hoya RM90) is opaque, and the light it filters is beyond the film's designed response curve. It's fine for Kodak HIE/HIR, which was the best IR film.

Brian,

If you use a lighter filter, such as the wratten 29, you will get very little IR look from efke if any at all, but the others are ok.

I rate mine at an asa of about 1/2 to get some shadow details and use a 750nm cut off filter.

[Brian C. Miller]

wildbill, Schneider Optics has changed their available literature, and the charts showing their filter responses isn't published any longer. The 092 is listed as "IR Dark Red," and the 093 is listed as "IR Black." Cokin filters equates their 007 to 89b, which B+H Photo Kodak 89b is listed as "Opaque Infrared."

[Neal]

Dear xtolsniffer,

I have used Efke IR820 in my Contax RTS and Mamiya 645E using a B+W 92 filter at EI 100 (Xtol 1+2, 13 minutes in Jobo) and it works very well. If there is a lot of foliage I will reduce the exposure by a stop but that is about it. I don't even bother to bracket anymore.

Neal Wydra

[DWThomas]

A couple of years back I came up with data that put the 89B filter at 695 nm cutoff which I would expect to be OK. I used the Efke IR820 with both 720 and 760 nm filters successfully. The 760 only took about one additional stop over the 720. The Rollei IR400 cuts off at shorter wavelength and is pretty tedious with the 760 filter. I used HC110 -- dilution E for the IR -- so I can't relate the results to XTOL.

[RolleiflexLife]

Hello,
the transmission curves of 92 and 93 filter are now on the "Industrial Filters" section of Schneider Optics website.

http://www.schneiderkreuznach.com/in...r%20Filter.pdf