Old filters?........>

[Arch]

I bought a load of filters today for a cracking price...... this guy wanted to sell his old nikon film camera with case etc..... and it had loads of extras..... so i got 15 filters of him for 1 pound each :mrgreen: ....... and there was some good ones in there too......

Anywho.... I came across one which only says "Hoya 52mm UV [0]"..... on the rim...... but looks infared to me..... then inside the box i found a hand written note saying 'Wratten N0 87 for B/W..... Rate at 25 ASA'

So this is indicating that it is indeed infared...... and i'v found a bit of info saying that the wratten number is to do with how much light gets through..... but my question is....

What does the rate at 25 ASA mean?....... and more importantly, i'v JUST ordered the Hoya R72 filter to do IR photography..... should i cancel my order?..... will this do the same job on my Nikon D50?...... i noticed that it said 'for black and white film'.... but not sure if it will still do the same thing, but maybe need a longer exposure?

Any help would be appreciated

 

[markc]

This should help with the difference in filters: http://www.burren.cx/photo/ir_cameras.html

R72 passes 720nm and up. The Wratten 87 passes 800nm and up. The 87 is deeper into the IR, which might result in extraordinarily long exposure times, since the Nikon internal cutoff is something like 750nm max. The 87's curve does start just as the D70's curve ends, so you can at least get something. I don't know about the D50.

 

[Arch]

ah good stuff, thanks mark :thumbup: