70-200... whats this switch for?

[Harpo]

Just received a rental 70-200mm 2.8 IS L II USM from LensRentals.com for my alaska trip next week... WOW! it really kicks up the quality and the image pops compared to my kit lens! My niece was over last night for a get together, and Im really impressed with the portraiture quality of this lens. Im really looking forward to Alaska now!

Anyways, one question... there is a switch above the AF/MF switch on the lens that says 1.2-(infinity symbol), and 2.5-(infinity symbol). What does that do?

Thanks!

[Donald]

Mike

That's to switch between what you want the closest focus point to be. The normal setting would be at 2.5; i.e. 2.5metres is the closest that the auto focus will focus. In exceptional cases (well for me it's exceptional) when you want to autofocus more closely (down to 1.2m), switch it. Uses more battery power.

[arith]

Can leave you confused though when trying to focus and you can't lock on. I thought maybe there wasn't enough light so put a speedlight on, it was ages before I realised the switch was in the wrong position. I leave mine on 1.2.

[rpcrowe]

Focusing on distant subjects is noticeably quicker when the focus limiter is set on 2.5 to infinity. If you are focusing on a subject between 1.2 and 2.5 meters; selecting that option will allow the lens focus closer than 2.5m.

As Steve mentioned, it is sometimes confusing when you are thinking of a lot of other parameters to realize that the lens is not focusing because you have the 2.5-inf option selected.

However, I have gotten used to this and will almost automatically switch over to 1.2-inf whenever I am shooting relatively close subjects. They don't have to be just between 1.2 and 2.5m away - I switch to the closer option whenever I am shooting subjects within say, 4-5m; like shooting portraits.

[Donald]

Focusing on distant subjects is noticeably quicker when the focus limiter is set on 2.5 to infinity.

That is a very, very good point. I forgot to say that. If you're working with moving subjects, you want the auto-focus to be fast (and it is blindingly fast when set at the higher figure).

[rpcrowe]

Get some type of rain cover for your camera/lens. A cheap alternative would be the OPTECH Rainsleeve which is dirt cheap. One thing about the weather in Alaska, expect anything and if you don't like the weather, wait an hour and it will change (often for the worse). I spent ten days at the end of July - beginning of August on Alaska's Kenai Peninsula and it rained every day! They called it the "Year Summer Forgot To Arrive!"
Here is a picture of my buddy taken on August 2, 2008 at Soldatna, Alaska.

A tacky but workable alternative is a plastic trash bag...

[Harpo]

Thanks all for the explanation! It makes sense. Yup, got a rain cover for this trip! Weather forecast now has rain in it... Also rented the 2x TC III to go with it.

[Val Mansfield]

As Steve mentioned, it is sometimes confusing when you are thinking of a lot of other parameters to realize that the lens is not focusing because you have the 2.5-inf option selected.

Yes! I got caught out last weekend!