R72 (89B) vs 093 (87C) on Maco 820c Infrared

Through a comedy of errors (about $0.1K) I wound up with a B+W 093 (87C)
that has 50% transmission at 850nm and only 18% at 820nm where the Maco drops off.
The Maco datasheet states that the 87C is NOT recommended.

That kind of thing doesn't stop me!
Went out and shot a roll of bracket exposures with both filters.
That felt real good.
Souped it in XTOL 1+2 for 16 minutes.
That felt real good too.

Conclusion: You can use an 87C on Maco IR820c!
It works like an R72 with a 6 stop neutral density!

On your left is the R72 - half second at f/16
On your right is the 093 - 30 seconds at f/16

I just love it when someone ignores the manufacturers carefully researched instructions, and gets results. Well done.

Yup, the 87 filter is a terrific filter for IR...been using it for years. Just switched to the 89b to get a little more speed (yes, I've been listening, Robert Hall!!!). The other beauty is that the 87 is generally a little less expensive, too.

Have fun with it!

Cool, good to see it worked!