Originally posted by photolady Is it? I found one and thinking about buying but want to know if f4 is too slow and wouldn't be good in low light situations.
The da300mm f4 is pretty good at f4 and works really good with the 1.7x afa, if there is plenty of light. The da300 is not real fast to focus though. The 1 stop you get with a 300mm f2.8 will cost a lot. I had the tamron 300mm f2.8 and it had to be stopped down because of fringing, so the f4 was better as it had AF. I wanted a f2.8 also and even sold my motorcycle and bought a FA*300mm f2.8, beautiful lens, too bad it was not sharp and pentax refused to fix it. (when they did their own service) I found the best option for good telephotos was with canon, I wasn't sure about the sigma's and the teleconverters being useable with the SDM focus. Back then the price of the canon 300mm f2.8 was $4K, but the new one is a lot more.You can get a used canon lens from fred miranda or keh and use it a while, and sell it later for what you paid for it, so it kind of makes sense if you can swing it. They do have good service too, which is important to me. I would like a K5 with a EF lens mount.
If we hit the powerball, a 400mm f2.8IS vii will be mine.
Here's one that needed f2.8