I have been reviewing and researching for months what sort of lens I should get for extremely low light situations (just after dawn or at sundown) for wildlife for the most part.
I missed some great opportunities some time back with an 80-200 F/2.8 on a mono-pod (now replaced with a 70-200 VRII). I almost always have a mono-pod with me but our eyes are miraculous light gatherers when the sun has gone down or has yet to rise while most lenses will not achieve similar results.
I don't like the graininess of high ISO. I have a D700 body. I was taking pictures of Waved Albatross on Española Island (Galapagos). I did try ISO 3200 which was not so hot. Changing EV and bracketing did give some marginally better images. The problem is that you hive between 1 and 2 hours walking on fixed paths and you are not allowed to stop for long amounts of time. There are tons of constraints when visiting Galapagos.
Post processing did improve things but not enough. I do plan to go again and I'd like to be ready this time.
The 135 DC F/2.0 is said to possess fairly fast focusing. On a DX body (I also have a D300S) the reach - through cropping - would approximate 200mm. I don't think that the various 85 mm's have enough reach. I'd rather have a prime lens rather than a zoom lens under those conditions.
Carrying heavy equipment in rocky places like Española is something you will regret fairly quickly (unless you can afford to have a porter with you). It's best to carry a light camera bag, 1 camera and just 2 lenses (3 with a 50mm). The 18-200 (which I have) is too dark once dusk is approaching.
Has anybody ever used a 135 DC F/2.0 for wildlife?