Originally Posted by
Geoff F
I would go bigger than 105mm for insects. That is a good size lens for flowers, or other inanimate objects where you can get really close to the subject but for most insects you are lucky to get within 1 ft.
The 150mm is a popular general purpose lens and the Sigma version is well liked and possibly a bit cheaper. Personally, I use the Sigma 180 which gives a bit more working distance. But this comes at an increased price and is a rather heavy tripod use lens. I wouldn't worry about going down to anything like F2.8 for insect work