Sigma's Optical Stabiliser promises to give up to four stops worth of camera shake compensation. I found that at 150mm, it was possible to take sharp shots most of the time at 1/20sec, which is about three stops slower than the recommended shutter speed for that focal length. At 500mm I found 1/60sec about the limit where I could comfortably hand-hold and get sharp results most of the time, which is also about three stops slower than the recommended shutter speed. At 200mm image quality is very similar to that at 150mm with very good sharpness and negligible chromatic aberration. As with any lens with this range, you can only use MF with a TC, but that's a minor issue. Though no lightweight, it's not as heavy as you might expect, weighing 62.8 oz, much less than Sigma's 120-300 2.8 lens, which weighs 104 oz. At 500mm wide open (f6.3) the image is slightly softer and lower in contrast than at 500mm. I'd guess what I'm seeing is probably a small amount of uncorrected spherical aberration, but whatever the cause, stooping down by 2/3 stop to f8 bring up the sharpness and contrast. The edges of the frame aren't as sharp as the center and show a small amount of chromatic aberration. At 500mm I'd probably try to shoot at f8 with this lens if I wanted maximum image quality, however I wouldn't do so if I needed the extra shutter speed that f6.3 would allow. Vignetting is observed with the Sigma 150-500mm f/5-6.3 APO DG OS HSM, especially when the lens is used with a full frame DSLR, wide open or at 500mm. The images below show the extent of corner darkening when shooting with a full frame camera

Sigma 150-500mm OS Bird Photography with Sigma 150-500mm OS

It all comes down to your specific shooting requirements. Some folks who focus mainly on sports photography may find that a camera like the D500 is a better choice for their needs. For example, the AF-C frame rate on a D750 is 6.5 frames per second, while the D500 shoots at 10 frames per second. The buffer on a D750 is 48 images compared to 200 with the D500. So, if you plan on shooting in AF-C mode the D500 would outperform the D750 on that particular dimension. If you shoot in low light much of the time then a full frame camera is likely better for your needs. Shooting with a cropped sensor camera also would give you a 1.5X crop factor. These are only a few of the many considerations that could enter into your decision.

Quality

At 150mm vignetting is negligible if the lens is stopped down to f11, but at 500mm the corners are darker even with the lens stopped down to f11. This Sigma 150-500 OS was a big oportunity for me and I buy it. I'm very happy with, from about one year. This lens gave me my money's worth and does what I wanted it to do. I use it on my last two trips - Montana and Colorado. Was a good lens for wildlife - on trails and in the car. I left this lens on a second body - and grabbed it off the rear seat when needed. Can't do THAT with the 200-400 or larger prime lens. At 400mm center sharpness remains high the edges are slightly less sharp with the lens wide open. There's a small improvement stopping down to f8, but not so much that I'd feel that I had to do so to get a sharp shot. Chromatic aberration is low, but visible at the edges of the frame. While sharpness certainly isn't bad, I think you can see it's not quite as good as it was at 400mm and f8.

Sigma 150-500mm F5-6.3 APO DG OS HSM Lens for Pentax Digital Sigma 150-500mm F5-6.3 APO DG OS HSM Lens for Pentax Digital

Wildlife photographers will also appreciate the useful minimum focus distance of 86.6” (2.2m) at all focal lengths including 500mm and the lens’ maximum magnification of 1:5.2. With a 86mm accessory thread and measuring 9.9 x 3.6” (252 x 94.7mm) it’s a comparatively compact model but it’s no lightweight at 62.8 oz (1,780g).Having had a Sigma 150-600mm some years before getting a Sigma 150-600mm C, I can tell you that there was what I would call a good deal of difference in the copies I had. My Nikon 80-400mm G that replaced the Sigma 150-500 was a good bit sharper at the longer end than the Sigma 150-500. So I sold the Sigma not long after getting the Nikon. Reason I bring up the 80-400G is because every review I've seen where they compared the 150-600 lenses to the 80-400G has all the newer lenses sharper than the 80-400G at 400mm. As for focusing, sorry never used the old Sigma for BIF or sports. But the Sigma C is definitely usable for sports in the daylight. Is it worth it for you? Don't know you well enough to say.

Sigma 150-500mm F5-6.3 DG OS HSM Overview: Digital

I must confess that given the price differential and performance of this lens that I do not understand why anyone would go the 50-500 route. The Sigma 150-500mm f/5-6.3 DG OS HSM is a stabilized super-telephoto zoom lens; indeed it’s one of only two stabilized telephoto zoom lenses reaching 500mm focal length, the other being Sigma’s own 50-500mm 4.5-6.3 DG OS HSM. Sigma AF 120-400mm f/4.5-5.6 DG OS HSM, 20% shorter and over 100 EUR cheaper but otherwise the same. At 150mm, this lens performs impressively. Sharpness across the frame is very good at all apertures. Peak performance at the focal length is at f/11, although the difference between here and the sharpness at maximum aperture is only very slight. Even after post-processing, I liked the Tamron produced files better than those from the Sigma 150-500mm OS. They just seemed sharper, had richer colors, and just ‘popped’ more. That’s not to say that you can’t get some decent images using the Sigma. You certainly can. It just takes more time in post to get them to where they need to be. NIKON D800 @ 500mm, ISO 1600, 1/1600, f/6.3I've had very good results with the basic D3300 and the Sigma 150-600 Sports, but, as always, VR/OS is an issue as usual. Certain shutter speeds, on tripod, works better with with VR/OS off, while handheld is no problem with it on. In bright sunlight, the Sigma performed better and the jpegs looked cleaner, although the shadows areas on some images still had a bit of muddiness to them. In good lighting focusing with the Sigma was very fast and accurate. If any Photography Life readers have ever tried to capture a swallow in flight over water…you know exactly how challenging that can be. I've also used it with a Sigma 1.4X teleconverter, and although focussing becomes super critical, with perseverance it provides stunning images.