[LargeFormat] RE: IR filters

[Marc Falcone]

Hi, Clive,
The RG-9 is a Schott-glass filter, it has no a 3 digits designation because 
it is not a long pass filter, but a band pass filter, so the designation 
"RG-9" is  probably because the central wavelenght is 900 nm. But the band 
is very large and don't affects IR films a lot. It can be compared to a 
"RG-730" which transmission percentage begins to drop progressivly from 
about 850nm and above, but the loss is not significative for normal IR film, 
unless it is a special long wave IR film (1200 nm) or digital backs. This is 
the very best filter for direct visualisation of short IR, you can see 
through it and see very brightly the near IR. It is available in 1mm, 2mm or 
3mm thickness. They are available at www.schottglasstech.com  .I have 
especially ordered a piece of RG-9 in diameter 82mm, 2mm thick that I have 
mounted in a 86mm filter ring. For direct IR viewing, ready made pieces of 
2" x 2" are available in 1, 2 or 3mm thick. The original glasses are 6 1/2 
by 6 1/2 square and they can cut them to every shapes and size you want. I 
paid US$ 250 for my 82mm circular piece, but ready made 2"x2" are about US$ 
50 per piece.

Marc


>From: Clive Warren <cocam@blueyonder.co.uk>
>Reply-To: largeformat@f32.net
>To: largeformat@f32.net
>Subject: Re: [LargeFormat] RE: IR filters
>Date: Sun, 16 Jun 2002 01:34:42 +0100
>
>At 12:06 am +0000 16/6/02, Marc Falcone wrote:
>>Hi, Diane,
>>
>>I used the R72 and RG-9 with Konica IR 750 in a 6x12 panoramic back
>>mounted behind my Sinar F2 4x5 and had good results with ISO between
>>5 and 8.
>>Marc
>
>big snip
>
>Marc,
>
>Am assuming that the RG-9 is a Schott-Glass filter as they use the RG
>designation. Usually there are three numbers after the RG. What is
>the RG-9? The RG-695 is the R72/89B equivalent.
>
>Your ISO ratings are similar to mine for Konica IR750.
>
>More info in the InfraredFAQ at http://www.infraredfaq.org
>
>Cheers,
>        Clive
>
>_______________________________________________
>LargeFormat mailing list
>LargeFormat@f32.net
>http://www.pairlist.net/mailman/listinfo/largeformat


_________________________________________________________________
MSN Photos is the easiest way to share and print your photos: 
http://photos.msn.com/support/worldwide.aspx