lense question

[Saintsix]

your best bet is sigma 150-500mm runs for about $1200. that will work for you. when the big guys come out at dusk/dawn your going to need a tripod so you can use a high iso and slow shutter speed to be able to gather enough light for those long low light photos, second option is getting like a 300mm F4 and using a 2x tele converter. both options will need Slowwww shutter. to take fast pics you wont like the price range its a hell of a jump.

zooming in and using a manual focus might be your best bet for getting the focus you need.

 

[SCraig]

your best bet is sigma 150-500mm runs for about $1200. that will work for you. when the big guys come out at dusk/dawn your going to need a tripod so you can use a high iso and slow shutter speed to be able to gather enough light for those long low light photos, second option is getting like a 300mm F4 and using a 2x tele converter. both options will need Slowwww shutter. to take fast pics you wont like the price range its a hell of a jump.

zooming in and using a manual focus might be your best bet for getting the focus you need.

I have a Sigma 150-500 and there's no way I could tell how many points a Whitetail Deer has at 300-500 yards using it. 500mm is only about 14x, and a crummy pair of binoculars is at least 20x.

 

[jhodges10]

This is a (horrible) shot of a White Tail shot at about 100 meters with a 300mm lens. Quadruple that distance and it's going to be a spec. I seriously doubt that even a 600mm would allow you to count the points at 400 yards.

35mm on a D5100 is considered "Standard" so a 350mm lens would be 10x magnification. Even a 600mm lens would only be 17x.

There was a deer in that pic?

Besides if he's going to drop $10k on a lens surely the extra $500 for a 2X TC is chump change. If you really want to shoot deer get a 70-300 VR, a comfortable deer stand and a salt lick to bring your range down to 30-50 yards. If that doesn't work for you then you're not giving us all the info as to what you're trying to do. For taking photos there's no reason you can't get closer to a whitetail or draw them closer to you.

 

[gryffinwings]

What do you consider a reasonable price?

You can get a 75-300mm lens, very inexpensively. The cheap ones aren't great quality though.
nikon 70-300mm | B&H Photo Video

That probably won't be long enough for 300-500 yards away. For that, you'll want something more in the 400-600mm range, and there are few options that won't break the bank.
There are a few 500mm "mirror" lenses that are around $100. The quality is pretty much terrible, but it gives you a lot of reach for little money.

If you are wanting to shoot images like you see in wildlife magazines / sites etc., then expect to spend many thousands of dollars.
SLR Lenses | B&H Photo Video

While for the most part your correct that most mirror lens are crap, more correctly call a catadioptric lens, there are a couple that are actually quite good, but I've heard they can be a little finicky because they can be sensitive to vibrations. I've read that the Nikkor Reflex 500mm f/8 is pretty decent as well as the Sigma 600mm, which I've only heard about.

Here's some light reading on them http://taishimizu.com/151/Reflex-Nikkor-C-500mm-f-8-Mirror-Catadioptric-Lens-Review

However in the case of use here, I would not get a Nikkor Reflex lens here, a cheaper lens to work with would be the 55-300mm or 70-300mm lens, those are the longest cheaper nikon lens, not sure if they will work here. I'm not sure what else there is, Sigma makes the 150-500mm lens, not sure on quality and might be out of your price range.