Which Zoom Telephoto Lens

Help please, I wish to buy either the Sigma 150-500mm f/5-6.3 DG OS HSM, or, Sigma 120-400mm F4.5-5.6 APO DG OS HSM Lens, both on good offers from SRS. I just cannot decide. Either will be used for nature/general shots. Any advice will be MUCH APPRECIATED. Sensible answers please (regarding the additional 100mm). The lens will be used on K5.

Hmmm I can see your predicament. I havnt used the 120-400 so cant offer an opinion there. But what I will add is that last year. I purchased the 150-500 and have been very pleased with the results I have gained with it. Though often, when I was trying nature shots it sometimes wasnt long enough. It can be a little soft at 500mm but great at 470mm, Its a big heavy lens on a days shoot. So the 400 will at least be lighter to carry. Or indeed used in hand held mode. When I got mine the 120-400 was more more expensive. So the choice was an easy one. Some other will also say a smaller lens and a converter is as good if not a better option. I think there is mileage this argument. I certainly dont regret my purchase.

Thanks Stuart. To add to the mix, SRS price for 400 is £499.00 for the 500 £599.00. I really am undecided. I have a DA 55-300, SRS are telling me that the Kenko converter will really struggle for focus with it.

there is a rebate of £50 off the 500 link below.
http://www.sigma-imaging-uk.com/quicklinks/737/index.htm
Upto the 28th of feb..2013..

Thanks to col55555ine I have resolved my own problem. I was aware of the £50.00 cashback on the 150-500 but pessimistic as ever thought I would have to pay £50.00 on top of SRS price and then claim it back from Pentax, bringing the price down to £599.00. Quick call to SRS, no, I pay £599.00 and then claim the cashback, bit of a no brainer really, £549.00 for the lens with free delivery. Job done and I will sleep tonight. Thank you all.

Senior moment, the cash back of course is from Sigma, and the delivery wasn't free. But what a cracking price.

Delivery should be free. If you ordered it from SRS. As you are a forum member.

Thanks for that Stuart I will give them a call tomorrow. Thanks John

Cliff P has one of these for sale in the classifieds

Thanks Stuey. Deed already done. Bought 150-500 from SRS. Regards John

just ordered one for myself - £549 - can't go wrong...

A follow-up to my original post. Received my 150-500 from SRS today, (prompt delivery and well packaged by the way). Of course with any new lens, quickly shredded the packaging and attached the lens to camera. Observations after about a dozen shots. Bear in mind I am not in the first flush of youth but the results are very satisfying. All were hand held with lens OS on, K5 SR off. At 500, 1/50, f8, 1600 ISO. All were taken by me standing in my dining room, shooting through the conservatory (double glazed)from about 30ft and as I say, hand held. I am having trouble believing that I could actually hand hold a 500 at 1/50. How lucky we are to have this amazing equipment available to us, Very happy chappy.