sigma 70-300 apo

hi all
would you use this lens for motorsport?and whats a good price second hand

I guess it also depends on what body you'll be using - could you get away with using a high ISO without impacting too much on IQ?

I've got one - I've not yet used it for motorsport but I would think it would be OK. Can be a little soft and lacking contrast but you can fix some of this in PP. Depends also what kind of motorsport and how far away / where you'll be standing.
F1 will need very fast autofocus, you'd probably need a longer lens 'cos you'd be further away, and a high continuous shooting rate. Saloon car racing will be less demanding and banger racing you should be fine.
Paul

Let's take my general approach for shooting at the 300mm end on my Tamron 70-300. Stepping down to F8 achieves very good sharpness; and I would risk a high ISO in order to maintain F8. It's far easier to reduce noise than sharpen an image - and the results look much better too.

Though most reviews do say the Tamron is sharper than the Sigma version - however that being said I do not believe the Sigma suffers from the extreme purple fringing which the Tamron does.

It's for you to decide what matters most - but I'd certainly try the technique I use. Unless it's a really miserable day!

I'm certainly no expert on motorsport photography but recently went along to Oulton park with my DA55-300. It produced some very good results but like the Sigma it's not the fastest lens and needs good light. I was there on a very bright,sunny day & still needed Iso 400/800 for the longer focal length shots.

I previously owned the Sigma (& Tamron) but found it a little soft passed 240mm, the Pentax is definitely quite a bit sharper, as is the Tamron. I guess it has the potential to produce good results with the above caveats (good lighting, relatively close action)

Simon

In terms of AF speed; the Tamron does has quite the advantage over the Pentax, so for motorsport I can see that's being quite useful (not that I've ever photographed motorsport mind).

All I seem to be talking about is my Tamron in a couple of threads - I must have Tamron Tourette's!