Digital microscopes...

Alyson was asking about Digital USB Microscopes, and would you believe, I actually have one.

One of those terribly embarrassing things where someone kind asks what what you'd like, you say "Ooh, ooh, a DUM please," they buy you one, you use it for five minutes, then put it in a drawer...

I've just dug it out again, and taken photos of a couple of leaves, both with the DUM and with my hand-lens-and-cheap-mobile-phone trick.

Item one: Common Lime leaf with nail galls.

Taken with DUM, which has its own built-in light.

2: same leaf, using hand-lens x20 and the light from the DUM.

Ah, I'm not actually in the same place on the leaf, so that's not a very good comparison, sorry, but it was so beautifully in focus that I felt I had to include it.

Focusing is a bit of an issue in both cases - more below.

 Right, same as top picture, the fork in the veins, one big one, one liddle one, not quite at the same angle.

Again, hand-lens, this time using its own in-built light.

 .

 This is a pear leaf with damage and browning, taken with the x20 hand lens.

This is the same leaf, with the DUM. Much better definition on the small veining.

Regarding focusing, each method has problems.

As mentioned in the Amazon review for the DUM, the stand it comes with is not particularly good. It would be a worthwhile investment to get a better one.

I found that you have to hold the body of the DUM in order to twist the focusing ring, then when you release it, of course it's not quite in focus any more. It takes a bit of practice to get it right, and it's a shame they don't have a mouse-operated digital focus for it.

The hand-lens is simpler, but again it's sometimes difficult to get the focus just right.

In both cases, I imagine that practice would make, well, if not perfect, then a lot better.

The DUM is advertised as being 10x -200x, but I did not find a way to select the magnification - it was more a case of twisting the zoom until the object became sharp. But I haven't used it for aaaaages and there might be more instructions on the CD that came with it.

Hope this helps!