Focusing Distance??

[gravity0]

Ok, I just purchased the 70-200mm L lens, great lens. Freaken chrystal clear images. It burn holes in my kit lens. Wow, this lens is amazing. My question is what is the distance range switch. My thought is it's just for fast focusing on images at a set distance. My camera is a Canon BTW. But it has 1.4mm and 2.5m switch. What's it for? Is it just used to focus quickly on a subject?

Thanks again,

Grav.

 

[Overread]

If your shooting at far off subjects (those that are 2.5m or more away from you) then you can use the switch so that the lens won't bother with the 1.4-2.5m section of its focusing - so its quicker and reduces the hunting time of the lens as well. Of course if you then have to go closer you have to set it to the other setting first - though remember the lens has an HSM focusing system so you can always grab the focusing ring and adjust the focus manualy without turning AF off -- but this only works in single shot AF mode, if your in AI servo the focus willl keep on working then your fighting the motors which is bad (and you will lose anyway)

 

[Big Mike]

That's correct. It's a 'limiting' mode. It limits the focus to the farther range (2.5m+) so that you don't accidentally focus on something closer.
For example, if you were shooting sports and were having to shoot through a fence. You could flick the switch and the lens would not try to focus on the fence, allowing you to focus on the players faster.
Or maybe you are shooting a bird in a tree, while walking through the woods. With this mode, you might be able to avoid focusing on branches that are in your line of sight, and concentrate on your subject.

Just don't forget to flick the switch back...or you may get plenty frustrated when you can't focus on something close.