Sigma 150-600mm 5-6.3 Sports DG OS HSM Lens for Nikon

I recently purchased this lens for a trip to Costa Rica. I had a hard time convincing myself not to purchase the Canon 100-400mm II due to the Canon reputation for quality and the lighter weight of that lens. The main reason I went with the Sigma was because I would be shooting a full frame 6D and wanted the extra focal length. I was planning on shooting many birds on the trip and knew that this focal length could make all the difference. So I made the purchase and have been very pleased with the results.As most people have pointed out this lens is quite heavy. Not so much a big deal if you are used to holding most of Canon's big white lenses, but if you are new to how heavy an ultra-telephoto lens can be it may be a shock. My setup weighed 9.4 lbs including camera, lens, and wimberly plate. Hand holding can be tiring quickly, so if you have to wait for your subject for a long time to get the shot, you will definitely want to look for support options. I picked up a Wimberly sidekick and attached it to my tripod which works beautifully when I need it. Typically though I am hand holding this lens and I can tolerate it for short periods. The weight does make it feel like it is going to be a tough lens for years to come.Overall sharpness is very good. You will not get prime lens results as no zoom can really do this. Best results that I have seen so far is from f/7.1 to f/8. Make sure you adjust micro focus settings if you camera allows before judging sharpness as this can significantly impact your results.One struggle I found with this lens is keeping ISO from getting so high as not to get a lot of noise from your camera. I was in the jungle for most of our trip, and I had to go as high as ISO6400 in some cases and still did not get a good shot. As long as you are ok cleaning up a little noise, you can get usable shots at ISO 3200 and below (at least from a 6D). However in bright light I was able to be ISO800 and below and the results at this level are awesome. Just be aware that this lens requires a lot of light or high ISO settings.Construction quality seems to be very good for the lens as well. If you shake the lens - you get minimal wobble from the lens barrel and nothing from inside. It looks beautiful with the black finish and white lettering and the rubber pieces on the end of the hood an lens are a nice touch. Sigma says the lens is weather sealed (see Sigma website for marketing videos) and the lens has a mount gasket that makes this apparent. I can say after being in a Costa Rican jungle rainstorm that I had no problems with this claim. I do question just how water resistant a zoom lens can be, so I will still take precautions.The lens also has a zoom lock feature which I use constantly (mostly at 150mm and 600mm). The 150mm lock is nice for storage.Focus is fast and accurate in my opinion. Is it as fast and as accurate as other Canon white lenses? No, but it is quite close from my experience. Taking bird photos with the 6d while hand holding is a little tough to measure though, because the auto focus sensor array on the camera is not that dense and holding the lens steady on a small subject is difficult. I think that any major focusing fault was more user error and camera limitations then anything I can attribute to the lens.I would highly recommend picking up the Sigma USB dock with this lens. Default firmware of this lens has IS only work as the photo is being taken. I find this very annoying and thought that my lens was actually broken when I got it. If you purchase the dock, you can change this to start stabilization when the focus button is pressed - like all canon lenses are setup. I much prefer this even if it eats more battery. It makes it much easy to hand hold and aim at the subject. Using the dock, you can also change the focus speed to faster than default, which I think is better. The dock will also allow you to adjust the focus at particular focal lengths, which is nice. I actually only used the camera micro-adjustments and got good results so I didn't bother using the dock adjustments, which can be tedious.Overall I'm really happy with this lens. I wish I could shoot at lower ISO's and the lens was lighter, but that is the tradeoff to not pay $10K+ to get to 600mm. If you are shooting when light easily available, I think you will be very happy with the results.

I'm replacing the CAnon 100-400 IS USM (original version) with this lens. The things that attracted me to the Sigma are the focal length, the all black body (I kind of hate the white body of L glass), and the updated technology (better OS, for example).Upon getting this lens, I noticed the box was huge. I was hoping the lens wouldn't be as big as the box made it seem. I was wrong. This lens is enormous. It's something so big that my large camera backpack may not fit it. It will be hard to take this out on casual hikes like I did my 100-400 (see the photo comparison of the size). And it will be really hard to handhold for long. I better hit the gym.On the styling front, the all black style is very sleek. The only thing I don't like about the design is the lens cap and hood. The lens "cap" is actually fabric, and it slides over the front of the lens. This is not quick to put on and off, so I will likely be leaving it off more than on.And the lens hood, besides also being enormous, is all metal. While that is nice from a protection point of view, it does make the lens heavier. And the last thing this lens needs is to be heavy.But enough about the size and design of the lens, how does it perform. I have taken the lens out a number of times, mostly in morning light, but also a bit indoors in the evening. The results have been about what I expected for image quality, and better than I expected for image stabilization.The Image quality can be seen in the included photos. Even wide open this is producing nice results. Stopping down to f/8 improves image quality a bit. Going to f/11 keeps the quality on par. Anything beyond that shouldn't really ever be used.But the image stabilization, wow! I have shot 1/40s at 600mm, and had sharp images. That is a solid 4 stops slower than the 1/600s handheld guideline for the focal length. I haven't yet played around with adjusting (using the Sigma dock) the IS, but I have heard that using Dynamic IS makes it even better.I have also found image focus to be good, although I plan on testing that and making adjustments if needed with the Dock. So far, things seem sharp, but it feels like they could be ever so sharper. It feels like the lens is backfocusing just a little bit when at 600mm. Luckily, the Sigma dock allows for a ton of adjustment here. You can not only set micro focus adjustments at the long end and short end of the zoom range, but also a couple stops in between. And you can also set the micro adjustments for different object lengths, in case you need a different adjustment for close objects vs far away objects. This process is likely going to take me an hour or two, but it should make the lens perform even better than it does out of the box.Focus has been pretty fast for me, even in a few tough situations. There are adjustments for this too in the dock. You can set it to fast, but less accurate. Slower but more accurate, or a balance. I have so far shot at the balanced setting, but I plan on trying out the slower but more accurate setting as well (I pref accuracy over quick focus 99% of the time).Finally, a couple of things to note. Back to the size/weight, I have found the tripod collar cannot be removed. If I were doing only handheld shooting (which is actually most of the time) I would like to remove that to save on weight. If I get out an allen wrench, I could remove the bottom portion, but then I have to keep track of the screws. Also, the front element is very heavy, so there is a lens lock, but my version only locks at the marked focal lengths. I hear the new version of the lens locks at any length, which would be nice in some situations.Overall, I'm pleased with this purchase.

Well built (metal exterior), sharp lens at 600mm. Some reviews said auto-focus is noisy. mine is not. This is a heavy lens, more than 6 lbs. Do not put it on a weak tripod. Hand holding possible but difficult. Found out the manual focus ring works even when in auto-focus, which is a good thing, I think. Comes with a cuboid carry cased with strap, but It fits better (with Nikon D7500 attached) in my Victorinox backpack in 150mm mode. Of course not much else fits in backpack after that.