Nikon 55-200mm Compact Telephoto Zoom Lens With Vibration Reduction (AF-S DX VR)
Would this lens be alright for wildlife photography, i have a limited budget.
Will be used on Nikon d40.
Anything slower than f/2.8 is going to be a challenge shooting when wildlife is most active (early morning, early evening) and after f/4 it becomes significantly more difficult- most consumer and the 80-400VR prosumer zooms are f/5.6 to f/6.3 at the long end. Going from f/2.8 to f/4 requires twice the light, going to f/5.6 requires twice the light again.
Anything under 300mm is going to be a challenge for wildlife that's wary of people and/or small. If you can sit in a blind or have excellent stalking skills it'll be ok, otherwise you have to have places available where the wildlife is pretty tame and used to people. Some folks will tell you that anything under 600mm is going to suck- I've had good luck at 500mm and 400mm, and I'd hate to be stuck at 300mm.
You could use this lens at the zoo and get ok pictures, though you're going to have to deal with distracting backgrounds a lot of the time if you can't find great shooting angles. Good wildlife shots require shallow depth of field to isolate the subject most of the time (there's an occasional "behavior in situ" sort of shot that works, but it's rare.)
In the "too slow for the morning but lots of reach" category are the Sigma 50-500 (f/6.3, but not too bad at 500mm and around $1000, the 80-400VR (sloooow, won't AF on the D40 around $1100.) Hands-down the Sigma is the better lens (I own both.)
In the "Not enough reach, but fast enough) category is the Sigma 70-200/2.8 (around $720) That might allow large/close approach stuff and you're at 280mm at f/4 with a 1.4x TC- if that lens goes well with a TC, that may be the best lowball option, but you'd have to add the cost of a Tamron/Kenko 1.4x TC.
In the "Enough reach, and almost fast enough" category is the 70-300mm Nikkor ($450) - Thom Hogan doesn't like this lens at 300mm though, so I'd try it in a store to see if it'll produce acceptable results to you.
Finally, there's the 300/4 AF-S which is about $1100. The 300/4 is a great lens and the sensor on the D40 may let you go high enough ISO to get good shots with it.
The only thing worse than wildlife is the subset "birding" in terms of equipment cost, size and performance. If your budget is small, you can bait if your ethics allow, or you can deal with the subset of creatures that'll allow a close approach (generally a vehicle is the best platform for that in the places that works,) or sit in a hide waiting for good light.
