Originally posted by timbo13 thanks, Douglas, for your explanation. I think I sort of knew all this in the back of my brain somewhere but now it is much clearer! I would love a nice macro lens, it's probably my next addition but the money isn't there right now. I posted my picture mostly for fun and to play with the idea of measuring small things.
I used to do a lot of imaging small things professionally ( I worked in R&D for a computer storage device company ) and I miss the access to the neat toys I used to use! The world of the very small is really wonderful. I enjoy seeing the macro images in this thread and elsewhere in the forum.
Well, if you read threads here and elsewhere it is quite common to see that people believe that a 1:1 capable macro lens becomes capable of 1.5:1 when they put it on a digital camera. I can see how they think, but it's not how it is defined.
As for macro lens, there is many other cheaper ways. One very handy is to get a vivitar macro 2x converter (also sold as Kenko, soligor, Ricoh and others, I think Kenko made all of them) which can turn a 50 mm f1.8 lens into a 100 mm f3.6 1:1 macro lens, a 100 mm lens into a 200 mm 1:2 macro lens etc. Suddenly all your lenses become macro lenses. And if you start with a good fast lens, you get a rather decent substitute for a real macro. With KA bayonet they go for 50-100 euros and with just K for much less. Panagor had a similar device that was a 3x converter, but I don't think it is worth to lose that much more light, and I don't think they can be found with KA.
Interesting job you had. Care to guess how large the hard drives will be able to be in the future? Will they keep up with the pixel-race?