Thinking about a Sigma lens...any thoughts?

[Todd_ID]

I'm pretty seriously considering a Sigma 50-500mm f/4-6.3 for mainly wildlife.  For the zoom range and speed it seems to be a decent value, plus it comes with a 1.4x teleconvetor free through Amazon.  What do you guys think about the price:features ratio?  It'll be on my Nikon D40x.  The reviews sound promising, but $1000 is a bunch of money to toss out there if the performance is going to be lacking in any way.

Here it is:
http://www.amazon.com/Sigma-50-500mm-4-6-3-Telephoto-Cameras/dp/B0009F3MPQ/ref=sr_1_1?ie=UTF8&s=electronics&qid=1261885152&sr=8-1

I've also been thinking hard about the Nikon 70-300 VR f/4.5-5.6 at $515 also sitting in my Amazon cart now.  What are your comparisons between those two lenses?  Having never shot at either 300mm or 500mm, how much of a difference do you see in composing your shots between these two lenses; i.e., what is the usable yardage for the two zoom ranges for full body shots; is there enough of an advantage in going from 300-500, or should I spend the $500 price difference on other hunting gear?  How about the low-light ability between the two?

[jackelope]

look at the reviews on fredmiranda.com too.

nikon shooters are pretty few and far between on here but the photog guys know lenses.  i think ricochet on here is a nikon guy.

[boneaddict]

It will not be nearly as good as a Nikon or a Canon lens, but can still take great pics.  My first main lens was a 400 5.6 Sigma on my Canon.  Its what took the picture on the front of the regs.   

[bow4elk]

Don't own one but was seriously shopping when all my gear was stolen out of my truck  .  All the research I had done convinced me it was a good way to go considering quality and cost.  I was looking at a f/2.8 120-300mm APO.

[Wazukie]

I shoot a Nikon D80.  The Sigma 50-500 is a much better lens than the Nikon 70-300, even the VR.  The Sigma gets one of the best reviews from serious shooter for a lens that has that kind of range.  If I ever can raise the money for one, thats my next lens.  Im a missionary/Pastor and dont make much $$$$$.  Most would prefer a Prime lens but who can afford one.

Just my    Just cause its a Nikon lens doesnt mean its a good one.

[norsepeak]

I have a sigma camera that is in new condition with a big lens on it that I have hardly used that I'd be willing to sell cheap if you can use the lens.  I don't know the particulars right off hand, but if someone is interested, I can grab the camera tomorrow and fill ya in on the details.  

[jackelope]

you might also check out lensrentals.com and see maybe you can rent one to try before you buy it...test drive maybe...

http://www.lensrentals.com/category/telephoto/for-nikon

[Clipboard guy]

Definitely test the lens before buying.  I bought a Nikon D90 and have a Sigma 70-300.  I asked Sigma directly if the two were compatible and they assured me that it would work perfectly.  Famous last words....  The auto focus is nowhere near close to being in correct.  If you can test the two together in as many light levels as you can you may save yourself a headache in the end.

[kenbell27]

I have used the sigma 170-500mm with my Minolta 9xi then switched it over to my Sony A-700.  I like the the pictures that the lens takes.

[huntnphool]

6.3 at 500mm is pretty slow, you will need a tripod and or pretty good light to be able to use it on anything beside stationary critters. Add that 1.4 and you will gain length but lose another stop. I would look a different direction myself, maybe the 70-200mm 2.8 coupled with the 1.4. You will have to get a little closer but I think you will be much happier in the long run.