Sigma 50-500mm f/4.5-6.3 APO DG OS HSM SLD Ultra Telephoto Zoom Lens for Pentax Digital DSLR Camera

The Sigma Bigma is a great lens. The price is not trivial, but well without reason and cheaper than any comparable considering the level of performance.I shoot almost every day, just for the joy of doing it. My primary interest being photography, I'm also a camera collector. Mostly of things I would have liked to have owned in their day. Leica screw mounts are my favorites from early to late. I have an extraordinary IIIg, in the first 25 ever made that from all we can tell was never actually used, i.e. a showroom piece. It needed a CLA.To stipulate, I was a working pro for 11 years, doing news, advertising illustration and anything else I could sell. I've owned and worked with sub 35mm to 8x10. I loved the work, the reasons I left were complex.Before that I worked as an apprentice for four years in an old school portrait house. But I've worked with and own all manner of lenses. In my earliest days we still worked with Big Berthas, 5x7 Graflex SLRS with VERY Long lenses or the Baby Berthas which were 4x5 Graflex SLRs with much the same lenses mounted. i.e. there was no specific lens. But imagine a Graflex, hood and all, with 2,000 or 3,000 mm lens. My preferred cameras of the period were Nikon Fs and compatible lenses. For the most part I was Nikon-Nikon. Then it was Olympus OMs - I was no longer in the trade, but they suited me.Now it's Canon, no dig on Nikon or Olympus, which won me over after my working Nikons were stolen.The Bigma is a great lens. There is no directly comparable L lens and just as well, It would be a very tough call if faced with that call. I might have scraped around to buy one. But price is a factor in any even. But quality matters to me. I've owned a first rate Canon D0 70-300, a great lens, which costs a fair chunk. It was out of action for a few weeks and I bought a Sigma 70-300 substitute until the damage could be repaired. The Sigma costs a fraction of the L and it's performance was pretty damned good and it had some nice features, e.g. Macro focusing, that the Canon didn't have.Now they come with this monster. My primary camera now is a Canon 5D Mark II and the full frame is brutal on lenses. I sometimes see reviews from users who cite vignetting on cropped sensor cameras from a lens that in my experience doesn't vignette much on the full frame at full frame wide open, but most primes vignette a bit wide open. This Sigma is a significantly different lens than the previous Sigma lens of the same zoom range, i.e. 50-500.For one thing the filter size has increased substantially which seems to reflect not random desire, but n overall improvement of the optics. It might seem that going 50-500 is a real stretch given the weight of this monster, 4.5 pounds, which should be double strapped or bagged for carry with the 5D2. It's not. There's nothing more frustrating than have a prime 500mm mounted and suddenly you need a quick shot of something close, not wide, but normal; the Bigma covers it.This is not a lens you want to wear routinely for 10x zoom, as we sometimes do with the consumer-prosumer cameras. That weight will wear on you. I'm now pushing 70, severely arthritic and easily fatigued. I have to balance not just how I carry, but what I carry. Yet, I so love full frame. I finally stopped carrying film cameras on travel, both from added weight and the vastly improved quality of digital. For me in most circumstances it's superior.Some have mentioned monopods as a minimum requirement. There are alternatives, i.e. similar to movie mounts. I don't disagree with the monopod and use mine carbon fiber lightweight when I can. This is where the f 6.3 maximum aperture comes into play at longer focal lengths. At nominal 500 mm, Bob Atkins says it's very close to an honest 500mm and while that changes as you move to shorter focusing distances so the focal length is less.The combination of very long focal length, weight, etc., make controlling shake or camera movement critical. This is one of my highest areas of praise. Working from a sitting position or similar, using my chest to brace elbows, I've managed crisp pictures at 1/5th or less wide open. Not what I'd recommend trying for a money shot, but it wasn't a fluke. I've done a lot of sharp images at speeds of under 1/30th of a second. I was always good at long hand=helds, but age doesn't help as a rule, so I'm reasonably convinced that it's a good system.I have not done exhaustive tests of the lengths at different focal lens and f/stops. I will say this. Canon specs call for a lens that is faster than f/5.6 to make its autofocusing work. been surprised the auto-focus works as well as it does, which is 90 percent of the time which surprises me given that it works even at f 6.3 most of the time including times when i have trouble seeing what it's focusing on.I was born and raised a manual focus man who appreciates the auto-focus systems. But I try not to pretend it answers for everything. People who claim one camera system or another is superior on focusing miss something. The further up the ladder you move on pro or semi-pro cameras, the more you're supposed to know. As the "Digital Journalist" said, Auto-Focus is a wonderful crutch, but every user needs to know how to focus the thing.The manual focus override works well on this lens. I can b difficult in low light/low contest if there's not enough contrast for the focusing system. I can only that no one should plan a money shot in a place they haven't checked out and considered why interrupts focusing sensors. With this lens, when you need selective focus, you really want to ride heard on focus.One other note, because there are some very good posts on this lens. Having working with a top quality 500mm prime, I don't think this lens will produced the same quality image as an equivalent prime. FWIW, None of my expensive Canon L's really ensure up to the primes at the same focal length. Don't mistake me. The 24-70 and 24-105 and the rest are great lenses. Just that s a rule, a prime is different to the discerning eye.Butto finish this off, I'm very impressed by the low light contrast of the lens. I've shot images of Dandelions and flowers of ornamental grass, wide open,where this lens makes a higher contrast image (int he right way) that allows you to see just how finely focused and high definition this lens is capable of.At thispoint, for this focal length soon, there's not a better one on the market with this much verstatility. If the relatively slow F/Stop bothers you, remember this, for from 4.5 to F/2.8 would probably cos at least twice this weight.If you're a birder, especially if you're using a high MP 1.6 crop of real quality, e.g. the 7D, this is a really important lens. Especially if you can sit on your deck or porch or whatever. You shouldn't plan on using this lens with a non-Sigma extender. That's not unusual. I have some lens that work fine with non-oem extenders. But there are canon lenses that really don't do well with non-OEM brands. Also, if you're lucky and have enough light, it will probably auto-focus with the 1.4x, but almost certainly not the 2.0x.Lastly, there are two Sigma 50-500mm lenses. The old one doesn't measure up to the new lens. It tends to have less contrast and crispness. It's not a bad lens. But the difference between the old discontinued lens and this one is huge. I've used the old one and wouldn't buy it. This one, I bought and I own. I could have sent it back. I did send back a prime lens of another make in this area of focal length.

I've had this lens for a few days and am very pleased with it. Given the fact that it's covering such a wide range, I didn't expect it to have very high IQ, yet I am pleasantly surprised. I measured it against my super sharp Nikon 70-200mm f/2.8 VRII with TC-17, both @ 340mm f/6.3 and f/8, and the IQ is about the same on a D300s, even though on a full frame D3s, the 70-200mm + TC-17 is slightly sharper. This is quite remarkable, because 70-200 f/2.8 VRII is one of the best lenses Nikon has ever made, and it can produce better pictures at 100mm than the highly regarded Tokina 100mm macro lens I own, and even when shooting macros, the 70-200 + TC-17 + Canon 500D combo is comparable to the Tokina 100mm.Image color is great, with vivid contrast. I had a few bird shots at fully extended 500mm and they turned out to be great pictures. CA is minimum too, only slightly visible when fully zoomed in, and no worse than my 70-200+1.7 combo. Focus is fast, even though it has always been a challenge for me when shooting sports and moving animals. Build is very solid. It's about the same length as the Nikon 70-200mm VRII without the hood, and about 20% wider. Maybe I am already used to the 70-200mm, this lens is not as heavy as I expected, maybe just a little heavier, and certainly handheldable. The OS certainly helps, and I can shoot handheld 500mm at 1/30sec with good image quality. The OS can be turned to 'off', '1', or '2'. When not shooting at high shutter speed, I used '1' only and I suppose '2' is for shooting from moving car on a bumpy road. I haven't tried manual focus yet. Zoom in and out is a little tight, and that might be the only negative I can find with this lens so far. It's not hard to get used to it, so not a big deal, and you can be sure that lens creeping will never be a problem, even though it still comes with a zoom lock.Overall, I am extremely happy with this purchase. With an unmatched covering range of 50 to 500mm, it is a great lens for shooting kids sports, which is the main reason I bought this lens. With the high IQ, it's also a great lens for shooting birds. I think it's well worth the money.

I purchased this lens and had high hopes, the construction was good and the weight wasn't a problem. The problem was that right out of the box the autofocus didn't work right,constantly hunting to lock. I suggest that if u purchase this lens and have a problem out of the box don't wait just return for new one. I returned and purchased the 150-500mm and was perfect right out of the box. Sigma makes a great product and I will definitely purchase their products again