[madison_wi_gal]

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This was with a 850nm filter (had a hard time finding a cheap 830 in 49mm) with a DA 21mm Limited:

Ooh NICE! 850 filter on my list now.

[abruzzi]

well the 850 and the 830 will be very close--take what you can find. There is clearly enough sensitivity beyond 850 that I could handhold that shot at ƒ8 and 1/50 and ISO 100--thats only 3 stops down from what regular camera would do.

[madison_wi_gal]

Hoya does not make a 27mm (for the 40XS) in any IR wavelength. Who makes a decent one?

[kypfer]

Hoya does not make a 27mm (for the 40XS) in any IR wavelength. Who makes a decent one?

My 40XS arrived fitted with a 27-37mm stepping ring (and a lenshood to fit that), so I'd guess stepping rings to 49mm would be an answer, then an easy-to-find 49mm filter and hood to finish the job
Alternatively, Hama and B.D.B have produced 'dis-assemble-able' UV filters in 27mm, one of those could be re-fitted with a piece of suitable filter material … assuming one can still purchase sheets of i/r filter material
I've used Ilford SFX, Kodak Wratten 89B and Lee 87 filter sheets in the past … cut a circle of material to a suitable size with a pair of scissors and job done

[abruzzi]

I've been using Zomei 760 and 850 filters bought off of eBay. they're good enough for my purposes (I'm not hyper-anal-retentive about resolution, so I don't need a B&W or Heliopan filter.)


760: ZOMEI 25-82mm IR Filter 760nm X-Ray Infrared Filter For Camera Canon Nikon Sony | eBay

850: ZOMEI 25-82mm IR Filter 850nm X-Ray Infrared Filter For Camera Canon Sony Nikon | eBay