Spotted this lens :
Specs :
http://www.dirtcheapcameras.com.au/s...idProduct=1385
A review of it :
http://photosig.pcphotoreview.com/ca...5_3128crx.aspx
Looks like a good general purpose zoom telephoto that also has enough apeture to be useful for astrophotography.
I like it's 82mm diam and relatively fast speed (I know it's not f2.8 which would be wonderful to have in a zoom with same fl but you'd have to rob a bank , or win Lotto , or find a friendly bank manager , to buy ), and the fact it is an APO design and made in Japan are pluses. The price looks reasonable too.
Canon's EF 90-300mm f/4.5-5.6 USM and EF 100-300mm f/4.5-5.6 USM only have an apeture (filter size) of 58mm.
Canon's EF 70-200 f/2.8L USM has an apeture (filter size) of 77mm and looks like a nice bit of kit , it's considerably more expensive than the Sigma and with selectable sensor speeds up to 3200 is probably overkill.
The Sigma APO 100-300mm f/4 looks like it might be a good match for the EF 17-85mm f4-5.6 IS USM that comes in 40D enthusiast kit.
What do you guys think of it ?