Sigma 170 - 500 - Is it any good?

I know my wife would be starting to place me on a Kebab with my new K5 in my mouth and roast me over a slow fire if she would read this one BUT I have set my heart on a Long Range Telephoto Lens to go with my new K-5 .
I stumbled up on this lens when I was 'just looking through some lenses' when I noticed this and the Sigma 150-500mm and I believe that this would make my set-up nearly complete (noticed the 'nearly? That's when my wife will really go nuts and not even the big man in the sky will know what she will do then to me!:blush.
Anyone got any experience with this one? Are there major differences between this one and the 150-500mm? Which one would be the better one? I noticed the price difference is about £200 or so.
I would not get it for a few month but I like to know what I put my money to the side for and I look at about 3 to 4 month time when she, who has to be obeyed, has calmed back down to a normal level as this would at the moment shoot her past the moon (may would make some interesting pictures with the 8" Telescope. Astronomical wife watching
At the moment I am still alive, but I wonder for how long if she finds this one out!

Scott (an ex member on here) used to use the 170-500mm on his Pentax and get some great results but I think, given the choice I would take the 150-500mm in this instance. You get HSM which should mean faster quieter AF plus digital coating and I think Sigma are doing an extended 3 year warranty at the moment.

... and optical stabilisation which may be better than the in body shake reduction. A lot of lens for £750.

well I got my new toy now so I may as well get some decent lenses as well and I am sure make much more use of a 500mm then of a 10mm.
I am not set on the make or anything yet other than that it has to cover the 150 to170 - 500mm range and I do expect that I have to pay £££ for it (maybe someone sells his here or on feeBay as it does not has to be new.) but like I say it is another 3 to 4 month down the line anyway and looking cost nothing I just like to do my homework early so I know wht to get and to look out for and I definitely have to keep this one from the wife for the time being!

I would have been divorced long ago.

I love her really and she is as good as gold but I just have to treat her now for a while so I get back in the good books and I know she will help me again then but at the moment....... She even told me that the K5 is looking like a dump blond so I know that I have to take a step back, but then again Astro Wife Watching and maybe taking pictures of the 'lift off' would sell good enough to finance one of those lenses.

I have one, had it for a few years and it is addictive the 500mm length.

You really have to work with it though, you can hand hold it, but pin sharp images are hit and miss. Tripod is really suggested every time to get results.

Also, I always use mine in TAv mode, expecially for birds and where there is tree cover. Flip it to F8-F11 and 100 sec and you are away.
beyond 450mm it does get a bit soft, but some unsharp mask brings the images back.
Bokeh is okay, not fantastic, but okay.
Lastly, the AF is VERY noisy, and I mean chainsaw noisy but unless you are going to shoot a sleeping dormouse you will be fine.

Hope this helps.

May I suggest a new ironing board?

Or flowers. Homepride is good........

If you want to hide it the DA 40 LTD would be much better.

The big Sigmas are not good hiding lenses.

[IMG]http://i217.photobucket.com/albums/cc222/Oggy3323/Image1.jpg[/IMG]

the 170-500mm is cheaper and can be had for about 300/400, the af is noiser and the lens is alot lighter, but i found it sharper at 500mm wide open, the 150-500mm is nice and quit but needs stopping down to f8 to get decent sharpness, and cost alot more, as for os in the lens you dont really need it as the body has it, i find in body the same as in the lenses.

Ok a couple of things. I mainly want it for wildlife and whitewater canoe. I would use it with a tripod only in any case as anything longer then 200mm may become unstable anyway unless you get good speed.
AF is a must in this price range and about the noise, well I would get a neoprene sleeve anyway and I guess that would take care of that one,
I tried the ironing board and she is telling me to take it as a surf board with the camera strapped to the front and have fun, As for flower, she gets the and other bits regular.
She knows I got a Wii on order with everything she wants.
I could pay the lens with that!
OGGY: What lens is that and how much are we looking at? That looks like a bit better than the Sigma. Is that an original Pentax?
Not even SRS has anything like it in the shop.
I am jealous now.

its a siggy 150-500mm fully extended with lens hood on.

It just loos so different then in the pictures that I have seen so far, but then again they where only small and not mounted.
I guess I could put that to good use for what I want it for.

You should have got this.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=300497480307&ssPageName=STR...