Re: Filters

[Clive Warren <cocam@xxxxxxxxxxxxxxx>]

>Date: Mon, 21 Feb 2000 14:36:58 -0500
>From: Dan Vint <dvint@xxxxxxxx>
>Subject: Re: Filters
>
>Actually the answer isn't there, that was why I was asking. At least I
>didn't find a mapping from Wratten to anything.
>
>I did find that an 87c is a 093 in B+W and an 89B is an 092 in B+W and
>Wratten 12 is a 099 B+W.
>
>It doesn't appear that Tiffen has any IR filters and I found the Hoya (2
>filters) but they aren't rated to the Wratten system.  Hoya has an R72 that
>passes IR above 720nm and an RM90 that passes above 900nm - which I guess
>makes the
>R72 an 89B and the RM90 somewhere between an 87c and 87b.
>
>..dan
>
>
>At 02:15 PM 2/21/00 -0500, you wrote:
>><<Can someone provide the filter numbers (or the closest match) for the
>>following manufacturers
>>Wratten B+W Hoya    Tiffen
>>#87
>>#87c>>
>>
>>I don't know them off hand but it is all in the FAQ
>>at  http://www.cocam.co.uk/CoCamWS/Infrared/INFRARED.HTM
>>
>>There is a chart for that  ;-)
>>
>>~Holly~

Holly,

Thank you for having faith in the FAQ - sorry to disappoint you on this
occasion....

Dan - you have earned yourself a place in the FAQ as a contributor in the
next version :-)

Have been very busy with various things web over the last few weeks and
will be updating the FAQ with Dan's contribution and the links section.
Have also added a few smaller snippets of information. Surprisingly I have
only had a few more URL submissions since the request for peops on the list
to submit their URLs - will leave it a few more days before the
reorganisation.

If you do want to submit your URL then please use the link in the FAQ as it
pops up a handy form and makes life easier for me. It's also more likely
that the URL will be included :-) You can also change currently listed site
descriptions using the form.

Nipped out a couple of days ago with an old 2x3 Speed Graphic loaded with
Konica and used an 89B handheld in front of the lens, it was very relaxing
until it started to rain.....

Now that the weather is improving ie less snow and ice, hope to shift the
balance of work to allow more time for photography. Beats sitting here
tapping on the keyboard.

I used to use one of the Hoya R72 filters but found that the surface
coating on the glass was a little suspectas the thickness was uneven. The
cost of the filters is also rather high.

The glass screw-in opaque filters are fine for use with rangefinder cameras
but irritating if you need to compose the photograph through the lens on an
SLR or ground glass with a large format camera and have to remove the
filter to see through the viewfinder.










All the best,

             Clive   http://www.cocam.co.uk
                     Photographic Services, Filters and Equipment, Infrared FAQ
                            http://clive.bel-epa.com
                            Adventures in Cyberspace - Digital Art and Photos


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