Infrared filters

[SAShruby]

I'm looking for 95mm 720nm IR filter. I see some on Ebay, i.e. here (http://cgi.ebay.com/95mm-95-mm-Infrared-Infra-Red-IR-Filter-720nm-720_W0QQitemZ180369447584QQcmdZViewItemQQptZCamera_Filters?hash=item29fedb5aa0&_trksid=p3286.c0.m14) or here (http://cgi.ebay.com/95mm-95-mm-IR72-720-720nm-IR72-INFRARED-FILTER-for-HOYA_W0QQitemZ350206878247QQcmdZViewItemQQptZCamera_Filters?hash=item5189f4e227&_trksid=p3286.c0.m14).

Anyone has experience with those? Is there any other, not $400 Hoya filters they're reasonably good?

Thanks.

[vinny]

For that size, I'd go the Lee gel route. There's really no such thing as a high quality cheap glass ir filter, unfortunately. For $99 I'd be tempted though.

[BetterSense]

Has anyone ever seriously tried using unexposed, processed slide film as an IR filter? It should work, but I've never heard of anyone using it seriously.

[Bob Salomon]

Heliopan makes excellent ones from Schott glass. In 95mm the closest they have is 715nm and those are about $418.00 retail (605.00 list).

[SAShruby]

If I win 1st prize in 649 lottery, I will pay $418 for one.

[Gary Beasley]

Has anyone ever seriously tried using unexposed, processed slide film as an IR filter? It should work, but I've never heard of anyone using it seriously.

You need two layers of unexposed processed E-6 film or three layers of fully exposed processed C41 to get an approximation of an R72. If your film in in good shape physically you can get good results

[SAShruby]

I might go ask this on APUG.

[Chauncey Walden]

For (I believe) $119.95, the various 95mm Harrison & Harrison IR filters give you more choice in a quality filter.

[amoebahyda]

I got these IR sharp cut filters made by Fujiflm from Japan; each of these cost 1932 Yens which equivalent to around USD 21.25 each. They are 100mm square Tri-Acetyl-cellulose sheets to be use with 100mm gelatine filter holder; I use them with the Hasselblad professional lenshade which has a 100mm filter compartment to hold the gel sheet.

The cutoff frequencies of these filters are 760, 820, 860, 920, and 960nm.

http://i294.photobucket.com/albums/mm100/amoebahydra/Photo%20Equipment/IRfilters.jpg

[tgtaylor]

If a 100mm square filter will work, the Cokin 007 Z filter is great and cost ~$80 or less. I understand that it's pretty much the same as the Hoya R72 and requires 6 stops of compensation.

[amoebahyda]

I got these IR sharp cut filters made by Fujiflm from Japan; each of these cost 1932 Yens which equivalent to around USD 21.25 each. They are 100mm square Tri-Acetyl-cellulose sheets to be use with 100mm gelatine filter holder; I use them with the Hasselblad professional lenshade which has a 100mm filter compartment to hold the gel sheet.

The cutoff frequencies of these filters are 760, 820, 860, 920, and 960nm.



Response curve of these filters

http://i294.photobucket.com/albums/mm100/amoebahydra/Photo%20Equipment/IRfiltersresponsecurve.jpg