IR Help

Howdy folks!

Alright so here's the deal. I recieved today a bag of old film. 3 rolls of Agfapan Vario-XL and a roll of Kodak Ektachrome Infrared Film. I will be using a Pentax K1000 with a Pentax-M SMC 50mm f/1.7 lens. Primarily being used outdoors.

So my questions are:
Do I need any sort of filters. The sheet inside says a Kodak Wratten No. 12 for outdoor with an ISO rating of 100 set on the camera.

Where is the focus shift marker on the lens. The gentleman who gave this film to me said a red diamond, but it seems stuff focuses to it already, slightly to the left is a red line.

The focus shift isn't much of an issue to, I'll keep it to a solid f/8 for aperture, I really need to know about the filter.

The filter is NOT an infrared filter. NO 12. is a yellow filter used for black and white film photography to enhance things such as foliage. What you need is a proper infrared filter. The SMC 50mm's use 49mm filters. The wratten filter you have is a gel filter. If your lens has a filter holder you can use a gel infrared filter but trust me don't ever bother with this unless you have a wide angle camera or are going to make some savagely large enlargement where the optical quality gains of gel filters will be noticable. Instead use a glass infrared filter. Don't skimp here. Use something from B+W preferrably or Tiffen (not as good but still top notch). You want something like this: http://www.schneideroptics.com/ecomm...D=592&IID=3509.
That filter will run you about $100-140 which at first might seem like a turn off, but trust me these things are built with such precision that it's not too big a price to pay. The focus shift IS noticable. There's a red diamond on some lenses but if not just use f/8 to f/12 (not lower than this because then diffraction kills image quality) and eyeball the metering and you should get some stunning pics.