Is this IDAS PS1 similar to the one used with cameras like the 300D
Sorry Dave, just saw your question.
I believe it's the exact same filter, just an earlier version (P1 rather than P2 - don't know the difference). For the Canon it's the filter that goes between the bayonet and the lens in some kind of custom holder.
It's frequency curve is here:
sciencecenter.net/hutech/idas/filtdata.htm
Trev
  