At F/1.8 I observed extreme vignette (often not desirable, depends on your style) and softness all the way to the centre. But hey, no harm trying it out before buying, I might have just gotten a bad copy.
But if you are doing landscape, or need ultra-wide, or want great bokeh, then FF has the advantage. The 20mm lenses for Canon are not particularly good. You should be looking at 24mm f1.4II or 35 f1.4 or Carl Zeiss 21mm if you are going FF. Otherwise a 17-55 or 11-16 should be able to give you almost all you need on crop. Crop also has a great telephoto advantage if you are doing wildlife or birds.
Last edited by An drew; 13th May 2010 at 11:33 AM.
Considering the fact that you have change from 500D to 7D, I guess to are already into photography or into investing on photographic equipment. This is just my opinion, if you are interested in a hobby or a sport buy the best that you can afford without robbing the bank. As this can save you money in the long run and stop you from further upgrading. Example: I used to admire watches when I was young and bought many cheap ones then decided to buy one very expensive ones and I stopped buying more watches. Funnily all the cheap watches add together is more expensive than my one expensive one. In my early golfing days, I bought a cheap set of golf clubs and upgraded a few times, so decided to buy the best I can afford and I have been using the same set of clubs for the last 10 years. Save money. Just my thoughts.
5D2 / 5D3 / 16-35 2.8L II USM / 24-70 2.8L / 100 2.8L IS Macro/ 70-200 2.8L IS
Actually price was one of the reason i bought a 7D ( GOt it very cheap ) and is also the reason i looking at a 5DmkII too...but have better use of the money instead of keeeping 3 cameras which the 500D cant be sold ( Kenna warn by CO already )
Not into watches but i dont think i have a need to buy the best golf club ( Maruman pheonix) but just one that suits me but one thing for sure is i spend alot of money on titleist Pro V and send them into the ponds