Re: Filters with Konica... need suggestions!

[Clive Warren <Clive.Warren@xxxxxxxxxxxxx>]

>
>> Holly,
>>
>>  Think we have discussed this previously.
>>
>>  The Wratten 89B (R72) filter is probably the best filter to use with Konica
>>  750 film.
>>
>>  Have another look at the examples on the CoCam web site in the Gallery
>>  section for Konica with an R72 filter.  There is no haze.
>>
>>  There is also recently updated information on the use of filters with films
>>  in the IRFAQ on the same site.
>
>
>So all of those IR pictures are Konica with the R72?   It does look like
>foliage is much whiter!!  I hear that there isn't enough light nm coming
>through the 89B for Konica film...  is that true?  Let me know  ;-)  And you
>said that R72 is the same as 89B....  so is that a Kodak brand wratten
>filter.. the 89B??
>
>Thanks!
>~Holly~


Holly,

Well as we say here, the proof of the pudding is in the eating......

All the IR pictures in the gallery were taken using Konica 750 and a CoCam
R72 filter.  The R72 filter conforms exactly to the Wratten 89B spectral
specification.  I called the filter an R72 as the 50% absorption cutoff is
at 720nm.

Regarding enough infrared light for the Konica film, you are probably
thinking about the 87 or 87C filters which require excessive exposure times
for Konica 750mm film.  Konica 750 film does not have the same range into
the infrared spectrum as Kodak High Speed Infrared film.

A quote from the IRFAQ should clear up the Wratten issue:

"Frederick Charles Luther Wratten was a famous English manufacturer of
photographic filters in the 1870s. Photographers and filter manufacturers
now  use the Wratten ratings as a very accurate way of specifying the
spectral characteristics of filters regardless of manufacturer."



All the best,

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


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