[wildherre]

Have been looking at TAMRON SP 300 mm 1:2.8 LD (IF) lenses for my 10D. I cant decide if I want a manual or AF version. I am interested in shooting nature & wildlife as well as motorsports & other fast paced sporting events in natural light. I would like to know if the auto focus would be fast enough & accurate enough for motorsports or would I end up using manual focus to get good results anyway?
Does the autofocus do a better job than I can do manually on fast paced shots? wildherre

[Adam]

If you're planning to take sports photos, AF is probably more convenient, yet you can still use MF regardless.

MS guarantees that your DOF and focus is as you want it, but it requires a bit more time setting up. It's fine for wildlife, but not close-up sports.

[roentarre]

For sports, it is almost impossible to bring 300mm f2.8 into a sports ground as you will be kicked out of the games very quickly. It is either for the sake of terrortism prevention or preserving the rights for those who paid high prices to photograph the games...

Unless this is used to photograph a basketball or netball game, this focal length is too short. A decent A rear 2X S or L teleconverter would make up the better reach without much compromise of glass quality. However, it would be manual focus anyway.

Tamron 1.4X teleconverter is pathetic used on all my telelphoto lenses - an image killer: soft and washed out colour for everything

Pentax F 1.7X teleconverter is out of production and it is though AF but very slow. It seems to reduce the glass quality of original telephoto lens to a large extent on my book ...

Tamron 300mm 1:2.8 LD (IF) has 2 versions. The newer version has better bokeh quality than the former one with clearer image. AF has been slow but dead on accurate. This lens does not have internal motor so it will eat into the k10d battery a lot.

Even for wildlife, it was recommended for elk or some large wild animals shoot out rather than some agile finches or small creatures.

When I used the canon counterpart, the autofocus is instant as soon as the shutter is half pressed and IS of the lens gives you some sort of Thai massage pushing your torso backwards...

I am not too sure I wanted to have Tamron 300/2.8 either. I prefer things pentax and a pentax 300 f2.8 like what Ron and Marc will be lovely. They are not of fast AF either but it is pentax ! Fanboy club thing.

Regards