The Sigma 150-600mm Contemporary Lens for Nikon

The Dilema

Prior to my recent trip to Costa Rica, I spent some time debating whether or not I should bring the Sigma 150-600mm Contemporary lens to pair with the Nikon D850. The choice to bring a super telephoto lens to one of the most beautiful and biodiverse places in the world would generally be a "no brainer", but this lens in particular had me second-guessing. It's heavy, and it requires a lot of space in the camera bag. With the widest aperture being f/6.3 at 600mm, it's not a "fast" lens; It might not be able to handle rainforest lighting conditions, and a teleconverter is out of the question because of the further reduction in light reaching the sensor. It's also not weather-sealed, which could be a problem in the pronounced moisture conditions presented by the rainy season. Would I be able to capture images with a level of quality that justifies the inconvenience, discomfort and risk associated with this lens?

Moisture

I was heading to the rainforest....during rainy season. It rained quite a bit during this trip. Not constantly, but frequently enough that it was a constant concern for which I had to be prepared in terms of both prevention and recovery. My chief concern was protecting the (not weather-sealed) lens during actual rain, for which I acquired some plastic sleeves that could be quickly deployed to keep the camera and lens dry. I did have to use them during some real downpours, and they were effective. Another concern was general environmental moisture, for which I picked up some re-usable silica gel packets to absorb this moisture and keep the gear in my bag dry. The ones I got change color as they absorb moisture, at which point they can be placed in a microwave or conventional oven to be dried out for use again. I used several packets in my camera bag, and had to dry them out twice during a two-week trip, and again once I arrived home. I always had a small quick-drying towel handy to wipe moisture that did make it to the lens body or to wipe condensation from the glass. Condensation was another significant challenge, but not specific to this lens. Would it be worth risking damage to the lens?

Physics

This lens weighs 4.25 pounds (1930 grams). Many of the activities during this trip involved hiking...in high humidity. Adding 4.25 pounds to a backpack, or hanging it around my neck by way of a camera strap, requires some justification. I'm not opposed to sweating, but it had better be worth it. Aside from actual use, I would have to carry this thing in my backpack during travel. An extra 4.25 pounds doesn't sound like a lot, but it ended up being a significant percentage of the total weight of my camera bag. The space it consumed in my camera bag also meant that other items could not come along because they simply would not fit along with this lens. So, it also became a question of what opportunities I might miss (e.g., video) versus what I could possibly capture if I chose to bring this lens. Would missing those other opportunities be worth it?

Lighting

The rainforest is notoriously dark, and even more so during the rainy season thanks to the increased cloud cover. While there are moments approaching ideal lighting conditions, these are unpredictable, and especially so when they need to align with similarly unpredictable encounters with wildlife.

Were there subjects I missed completely because of this lens? Absolutely. One notable miss was an encounter with a resplendent quetzal. We only saw one the entire trip, and it was as cooperative as a wildlife subject could be, but it's perch in the shadows at some distance made it impossible for me to capture it adequately. The only thing I didn't try was the tripod because the sizable crowd attempting to catch a glimpse of this creature precluded the possibility of dropping three legs on the ground; The fully-extended 600mm lens was challenging enough in this situation. In other instances, finding the balance between ISO and shutter speed to achieve acceptable sharpness hand-holding a lens of this size with usable noise levels and adequate exposure was impossible.

Would I be able to successfully capture enough good photos in these condition to justify the inconvenience of the weight or the risk of water damaging the lens?

Results

I did choose to bring it. So, was I able to capture any good images? Yes! And, I had much more success than I expected given the limitations of this lens (and my skill).

These are a small sample of the photos for which I'm glad to have brought this lens along.

ISO 640, f/6.3, 1/500s, 600mm

ISO 6400, f/6.3, 1/1000s, 600mm

ISO 12800, f/6.3, 1/400s, 600mm

ISO 3600, f/6.3, 1/1600s, 600mm

ISO 8000, f/6.0, 1/800s, 420mm

ISO 12800, f/5.3, 1/800s, 240mm

ISO 3200, f/6.3, 1/640s, 600mm

Things I've Learned

In the process of using this lens in these conditions, I've learned a few ways to maximize the possibility of successfully capturing satisfying images with it.

The D850's 45.7mp sensor's resolution allows for some pretty aggressive cropping, which can make up for lack of reach in some cases. For instance, it allowed me in some cases to shoot at a shorter focal length to access a wider aperture to get a better exposure.

I've never really used the Auto ISO feature of any camera, but I have been experimenting with it recently in preparation for this trip. I believe I came away with some shots I would not have otherwise because I might not have been so bold with pushing the ISO if I had managed it manually. 8000? 12800? I had not been comfortable with ISOs in that range because of the associated noise. I did limit it to 12800 though.

That leads me to the topic of noise reduction software. Those higher ISO ranges do in fact result in noisier images. However, the noise reduction technology available today is pretty incredible. Adobe Lightroom, DxO PureRaw, Topaz Denoise and other software like these are very capable of removing noise artifacts from high-ISO RAW images.

I've also been practicing a technique whereby I shoot (hand-held) bursts of photos at atypically low shutter speeds, and finding that I can achieve a higher success rate if I increase the size of the burst as I decrease the shutter speed. For example, at a 600mm focal length, I would typically not choose a shutter speed less than 1/640s, even with the image stabilization in the Sigma, because the chances of me getting a sharp result are reduced due to camera shake. However, I've found that I can get an acceptably sharp result with a shutter speed as slow as 1/400s at this focal length if I shoot a burst of 8-12 images. This means that I can lower the ISO to mitigate the introduction of noise, and still get at least one acceptably sharp image.

I found the autofocus unreliable for shooting wildlife at the longer end of the focal length range in these low-light conditions. I had much greater success using manual focus, which limited me to still or slow-moving subjects. Thankfully, there were plenty such subjects.

Surprises

While my primary target with respect to this lens was wildlife, I was surprised to discover that it performs well for other types of subjects, namely landscapes. I didn't go crazy shooting landscapes with it since I had a 16-35mm with me for that purpose, but I did grab a few when I was either too lazy or too concerned about moisture to execute a lens change.

ISO 500, f/11, 1/200s, 150mm

10-image panorama, ISO 320, f/11, 1/800s, 150mm

Conclusion

The Sigma 150-600mm lens for Nikon (F-mount) is a great value, and used appropriately, is quite capable of capturing high-quality images of wildlife, even in less-than-ideal lighting conditions. The zoom range is a great utility, especially when traveling, and I've found it to be sharp at all focal lengths for at least some apertures at each. You can see from the examples that f/6.3 @600mm produces results which are plenty sharp.

After all has been said and done, I believe I would have regretted leaving this lens behind for this trip. I had been tempted to focus on macro photography if I hadn't brought it. However, it turns out flash is prohibited in many of the national parks and reserves I visited, even with a diffuser, so I didn't end up shooting as much macro as I had wanted to anyway.

While I'm quite pleased with the photos I've captured, the ones I missed are nagging at me a bit. A 400mm or 600mm f/2.8 would be a welcome addition to my quiver of lenses...