Bobby Middleton wrote:
> Can someone give me a source for a 48mm size 23a filter? I can get a 25a
> from B&H but I would prefer the 23a. Are there other options to the 23a and
> 25a for tri-color work? I've got a 49mm 23a but it won't fit into my set-up.
> Bobby Middleton
>
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Hello Bobby:
I have both the 25A and 23A filters. You should use the 25A for tricolor.
The 23A is a light red (more like a dark orange to my eye) filter and should not
be used. If you did use it, then how would your represent the 23A color in
Photoshop when you construct your tricolor image? Also if you are using special
narrow band filters for tricolor, how do you represent these colors in Photoshop
when constructing the tricolor image? These are questions that have always
puzzled me. When I was doing tricolor about 5 years ago I used the standard
Kodak Wratten filters recommended by Bill Fletcher.
If you are using a Lumicon off axis guider you can use a 48 to 49 mm
step-up ring that will allow you to use the easier to get 49 mm filters with
your system. I am not sure where I got mine, but you might try Lumicon or B&H
Photo in New York.
Michael Stecker
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