However, my journey into the world of macro photography has barely begun and I'm confident there are much better pictures ahead, waiting to be taken once I've learned more.
Today I thought I'd post links to some reviews of the Sigma 50mm macro lens. It was originally announced in 2004, as seen from this article on the Digital Photography Review site. However, they don't appear to have a subsequent review of the lens when released.
The first review is from the ePhotoZine website, and is dated January 2006. The one difference I've spotted is that the lens reviewed had a switch to move between auto-focus and manual focus. This is absent from my lens, probably because the same switch is built into my Sony A350 camera.
In general the review of the lens is positive, although it does pick out a couple of minor issues with slow auto-focus and the lack of a soft case. The former I've already encountered when trying to take pictures of bees on clover. The bees spend a few seconds on the clover head - plenty of time of a picture - but they're constantly moving as they forage for nectar. This seems to prevent the lens from achieving focus for long enough to shoot.
As for a soft case - I've long accepted that camera and lens manufacturers no longer supply any sort of cases with their products. Irritating, but it's a commercial reality that accessories push up produce prices.
The internet give a voice to ordinary people, particularly when it comes to product reviews. Amazon is a great source for these, and reviews for the Sigma lens are extremely positive. I've linked to the reviews for the Canon mount lens as there are more of these than for Sony.