Generic Lenses??

[Poider]

I am looking for a lens to share between my wife and I for bird watching, I have considered sigma or tamron 150 to 500mm, I was warned away from the generic lenses because the maximum aperture at the long end is f/6.3, which is not real good fro low light, but couldn't we just compensate with a slightly longer shutter speed, after all for shots that far away we are going to be using a tripod any way and the difference between the 6.3 and 5.6 is not that great anyway is it, or am I being ignorant?
Peter

[Aegea]

It's quite possible to compensate for aperture by using a slower shutter. You may find problems with slower shutter speeds for birds because they're twitchy little creatures, many of them, particularly the smaller birds. So you tend to end up with motion blur from the subject moving. Not so much of a problem with larger birds such as geese or hawks, or if you are willing to accept a lower keeper rate.

Also in-flight photos need 1/1000 second or faster to be sharp.

[mbrobich]

Big question here is what is your budget ? The Sigma 150-500mm on a D7000 will give you around 225mm-750mm equivalent at $1199 plus taxes. Nikons in that range will probably at least double that.

I just sold my 150-500mm and loved it, just didn't use it enough. As for low light, luckily you have a very good sensor in the D7000 to compensate for the higher F stop.

Here's one of a seagull in flight as an example with the Sigma: