Thanks for the replies
Of course I understood I had to buy some close up filters, but as Vincent I was also wondering how focussing will work.
I am the proud owner of the technilogical marvel that is the Holga, and recently I bought their close up filters. They are wonderfully simpel to use, set focus to infinity and hold the camera at the distance indicated at the filter. Seems to deliver sharp focus at the desired point (sharp for a Holga of course!).
Since I never was really good at math, I don't understand Stuart's advice completely. How do I know how much a certain filter affects the focussing distance? Does a +1 half the distance?
Hopefully someone can offer some further insight