Sigma70-300mm f/4-5.6 DG Macro Telephoto Zoom Lens for Pentax SLR Cameras

I have been using DSLR's for about 5 years. I started with the Canon t3i and when I wore it out I decided to move to Pentax with the K-5IIs. I chose this lens for it because it was both in my price range and had good reviews. That was the best choice I could have made! This is a top-notch lens, especially for the price. I had the long zoom kit lens for my Canon and it was loose and not near the build quality of this lens, nor was it as crystal clear. This lens allows the camera sensor to get the best information possible. I simply cannot say enough good things about it! The only annoyance, as others had noted, was that to zoom past 200mm you have to flip a switch, but its not the end of the world and you get used to it. I literally cried with joy at the images I could get with this. It is quick to focus, stays in the position I put it, is crystal clear, and oh the bokah! Depth of field is amazing, and I am convinced to get a shorter range Sigma for close-up work. You won't regret purchasing this lens. All the photos I am including were taken in low light on a cloudy day late in the afternoon or inside a building with no lights on. No flash was used, just the camera, lens and I.

I ordered this to go along with the Pentax K30 with 18-55 included lens. The 18-55 is weather sealed and takes a great regular shot but nothing compared to this self powered monster. We are newbies but when your photos come out looking like the magazine you know you have great technology in your hand.The lens has a motor which is important if your new because manual focus is a bit harder. I found it locks on easily enough and produces some of the best photos I have ever taken. As you lens shop you will be impressed at how decent the price is for what you are getting from this add-on.

I've had this lens for about 18 months, and it is a great value for the money. I needed a longer lens than my 50-135mm for outdoor dog shows. I bought it primarily for use at 200-300mm in mainly sunny conditions, where it is adequate but soft at f/5.6, good by f/8. The autofocus is marginal for fast-moving objects, though not surprising for a relatively slow f/5.6 lens.(I later purchased the highly-rated Pentax 55-300mm, with broadly similar specs, at about twice the price, expecting a significant upgrade. Compared with the Signma, the Pentax is mechanically superior in all respects, optically superior in contrast and chromatic aberration, and about the same in terms of autofocus. Surprisingly, however, it is slightly worse in terms of sharpness, notably edge sharpness.)Pros:- Good sharpness. A bit soft at 300mm, but significantly improved by stopping down to even just f/6.3 or f/7.1.- 1:2 macro at about 3 feet is a fun feature, and gives you some distance from skittish creatures.- Very usable telephoto zoom range.- Light enough for hand-held shots, even at 300mm in good daylight.Cons:- Suffers from color fringing in high contrast situations (APO version should be much better; and should also improve contrast).- Zoom, and to a lesser extent manual focus, can be "sticky" (not smooth).- Has a plastic feel, although it has been durable in use.With a little attention to good photographic technique, this lens can produce high-quality pictures. The best quality photos are achieved at f/8 to f/11, always using the lens hood, and with a monopod or tripod at longer focal lengths --- or if handheld, using shutter speeds at least the inverse of the focal length (i.e., on a 1.5x crop sensor camera, 1/450 second or faster when shooting at 300mm).If I had the same needs, I would gladly purchase again, although I think the extra $50 for the APO model is definitely worth it.

Honestly, you get what you pay for. I'm not going to pretend this is the end-all of lenses or that it blew me out of the water. It's a very acceptable zoom lens for a very very decent price. I've been very impressed with the quality of Sigma's optics, and this is no exception. The lens is very clean, very crisp, and takes very nice photos. That said, the zoom is slow and noisy, and autofocus tends to just derp hardcore sometimes. When focusing on a very close or very far object, it will often zoom all the way in and out a few times attempting to focus on the object. These are all things I'm willing to accept for the price I paid. Pictures in the 80-150mm range come out very crisp and the lens is decently fast. 150-300mm definitely will require a tripod or other sturdy object unless it's very bright and you're shooting at 800-1600 ISO. It's good introductory lens and a great add-on to any Pentax K-5 K-7 or K-30 kit. All the negatives aside, I've taken some fantastic photos with this. It's done very well for daytime shoots of wildlife and I've gotten many "national geographic" type photos with it.The bottom line: If you wan't to be blown away with ultra-crisp photos at low ISO at 300mm, this lens is not for you. If you want a decent zoom lens that you will use with a tripod and mostly for daytime-use at a low low price, get this lens!

I haven't used this lens very much yet, but preliminary results are excellent. It was much cheaper then the "Pentax" comparable lens and seems to be as good as or better quality. The mount is metal where my Kx mount is plastic. Some reviewers mention noise level being high. I personally don't think there is any difference from my Pentax lens that came with my Kx. The zoom is smooth and focus responds quite well. The macro function allows you to zoom in very close to small objects. Very satisfied with the product and Amazon shipped it free within the 5-8 day estimate.

THis is a great lens but the auto focus only lasted a couple of years. I still have it but if I want to use it I need to use manual focus.