The Holga HPL-P is simply a pinhole mounted in a Pentax K-Mount lens barrel instead of an actual lens. The whole thing is plastic (like all things Holga) and looks very much like the Holga HL-P which is simply a plastic Holga lens mounted in a plastic K-Mount lens barrel.
As you can see from the image above there is a pronounced vignette effect in all four corners. This is the result of being designed for an APS-C crop frame digital sensor rather than the full frame negative of a 35mm SLR which is what I used to shoot this picture. Still, the image is not too shabby and does display the usual “look.” All I did in the way of post processing was brighten the colors of the scan up a little in Picasa.
The greatest challenge to using this gadget (I really can’t call it a lens now can I?) was trying to see anything in the viewfinder of the SLR. It was mostly dark as a result of the tiny aperture. In spite of extensive research (even reading the instructions that came with the HPL-P) I was unable to find any definitive information on the thing except that it has a .25mm diameter pinhole. Based on that and some empirical data from the exposure values of the pictures taken I have estimated the aperture to be about f133.
The image above was taken using my Pentax ZX-L loaded with a roll of CVS 400 color film at a ½ second shutter speed.
Frankly, I am a little disappointed with this “pinhole lens.” I had hoped it could be used with a 35mm camera and that the image would be as good at least as my Home-made cardboard pinhole camera but I believe the pictures from the latter are much better than the former.
Next I will try it on a DSLR with a crop frame sensor and see what happens.