It's probably presumptuous of me to give any advice about shooting slot canyons. I've only shot in four, and all those were packed into one photography workshop. Instead of advice, then, think of this perhaps as just a recounted experience. YMMV. For real advice, based on years of experience and likely tens of thousands of frames, check Gary Hart's tips here and a few others  here, here, and here. I found Gary Hart's tips especially useful, particularly the primary tip: have a plan.I chose the shot above to headline the post because it illustrates several fundamentals of slot canyon shooting: scale, lighting, and general conditions and challenges. Scale and composition were the first challenge. A lot of slot canyon images tend toward the abstract, and it can be difficult for the viewer to determine what they are seeing. Sometimes, that is intentional, but there are images where a sense of scale can add a lot to an image. The one above is not much more than a snapshot, but the people in it provide an impression of scale. You may not always want people in your shot [almost certainly not], but in order to get the shots you want, you almost certainly will want a lens wide enough to get those people. You can always crop or remove them if they or a stray hat or head or camera enters your frame. What's wide enough? Well, in HBSC, I shot technical with the Cambo 1600, a Phase One Trichromatic back, and the Rodenstock 23mm lens [13.8mm equivalent on a full frame DSLR]. That's pretty wide; predictably, for some shots, too wide, while for others, too narrow. That's the nature of shooting with prime lenses, and especially a single prime lens. That's also one of the reasons I love having just one lens with me: it forces me to dig really, really deep to find some artistic eye to see the compositional possibility. But it's also true that shooting with the Trichromatic's 101 megapixels affords some cropping luxury. Still, having shot all four canyons, and because of some of the challenges discussed below, if I could only have one camera on the trip, and I was visiting multiple canyons, I would take a quality, wide dynamic range DSLR or mirrorless equivalent, and a 24-70mm wide aperture zoom [preferably with IBIS or lens vibration control]. You'll find that wide dynamic range camera a real asset in the canyons. But even the widest dynamic range sensors—and I had two of the widest in the Trichromatic and the D850—can't solve all the lighting you will encounter in a single shot. I strongly recommend three approaches. The first, harped on by our instructors, is to learn how to access and read your cameras histogram. And not just the overall histogram, which can mislead you, but also the individual channels, so you can determine which light is properly exposed, what's underexposed and, most importantly, what is being blown out. Be careful with the ETTR rule of thumb, because if you don't check each channel, you will have blown highlights. The second is bracketing. If your camera has the capability, shoot 3 to 5 bracketed images with each shot [with as much as 2 stops of range off you only shoot 3 images], and consider an EV adjustment of anywhere from -⅓ to -⅔ of a stop. I am a big fan of shooting manual, but in the canyons, with other groups breathing down your neck, shooting in either aperture or shutter priority has its respective advantages if you bracket, and you set a floor and a ceiling for your exposure values. It can also be very useful to use auto ISO, again, with a floor and a ceiling. These are judgment calls you will learn to make if you really take time to learn how to use your equipment, both from its manual [you have read it, right?], online tutorials, in the field, and at your computer screen in post where the follies of your judgment can be ruthlessly exposed. The third approach is to shoot RAW; I skip JPEG altogether, because it conserves card space. RAW is the only way you will really boost your shadow detail with the minimum noise, and it receives you of any need to worry about white balance. I also like "Flat" mode in the Nikon for its color neutrality.That brings us to the criticality of focus. The AF function on many cameras will simply not work very well in the canyons with their light range, and intersecting planar and curved surfaces. Sometimes it might lock on, but even with my D850, which has very good AF, i often found manual focus much more accurate and true to my composition. Try it both ways, but know how to focus your lenses quickly in manual mode; if you are working at wider apertures and higher ISO settings to permit hand-held shutter speeds, this ability will serve you well. In Upper Antelope, I shot the Nikon D850 and a Zeiss Milvus 25mm f/1.4 lens. It's not quite the resolution beast that the Otus 28mm is, but it is smaller, lighter, wider, and weather-sealed—every one a significant advantage. It is also a fast manual focus lens.Interestingly, shortly before our workshop, we learned that we would not be able to shoot with tripods in Upper or Lower Antelope. This cheesed off some of our group, and I wasn't exactly thrilled to hear it either. But it turned out to be—at least for me—a blessing to be forced to shoot handheld. I'll explain why in a minute. Of the four slot canyons I visited, only Waterhole [also called, incorrectly it appears to me, Water Hole and Water Holes] was unguided. In the first, Horseshoe Bend Slot Canyon, I was part of a very small group of five [two other couples]. We had the canyon to ourselves, and our guide, Hope, even played her flute that echoed throughout the canyon while we wandered, stared slack-jawed, and made pictures. It was tailor-made for shooting with a tripod. And I loved it. For reasons I have blogged about in other posts, I thoroughly enjoy the deliberate process of setting up and shooting a technical camera on a tripod. But it's not the only way to fly. HBSC was my first slot canyon, and I visited the day before my workshop started. It was not part of the workshop itinerary. The next day, our workshop's first slot canyon was Upper Antelope. And for us, it was tripod-free. But not for everyone as it turned out. Some groups were permitted to use tripods, because they had paid an extra fee [one can imagine this annoyed some of our group even more to learn that tripods were not in fact in banned, but were merely "more expensive"]. But it turned out to be a better experience without tripods. Upper and Lower Antelope Canyons are pretty crowded. They aren't quite the "madhouses" that some sites describe—at least not in April 2018, though I could see it being really bad in the summer or in the future—but they are crowded, and for the tripod photo groups, those crowds became oppressive. Because the tripod groups have to set up, shoot, break down, and move, their guides have to shield them from the crowds in front and behind. This makes for serious logjams around the tripod groups, and lots of pressure, and even occasional yelling to keep them moving. This is not a fun way to shoot. I am glad, I was glad, both in the moment and in retrospect that I was not trying to shoot on a tripod there. [I have recommended to Alain and Natalie that they "feature" the tripod-free element of their workshop as a positive, learning experience, but . . . photographers can be a whiny lot; it might not work.]After Upper Antelope, our next canyon was Waterhole [permitted, but unguided]. We had the place mostly to our group, and it is beautiful. After the UA experience, I decided to go into Waterhole with nothing but the Nikon D850 and Nikkor 24-70mm zoom, and the Sony on a Black Rapid harness. A very enjoyable, fast way to shoot. As good as that Nikon lens is, it does not hold a candle to the Zeiss or Rodenstock lenses. But it is more than good enough. And you can choose to AF, and it has vibration control. All those are features that expanded my shooting opportunities. Unless you are fanatic about primes and medium format, I wholeheartedly recommend this approach. I shot the Nikon without the battery grip [which is little more than a balance counterweight, and a spare battery holder, and an expensive one at that], and it worked well from a balance perspective. I used this same setup in Lower Antelope, and it rewarded me well.All groups are guided in the ULA Canyons, along with HBSC, and the Navajo guides are truly superb, pointing out compositional opportunities, and even illustrating the shot with their own phone or camera. It's worth noting that it was inspirational to me how much the Navajo love their land; their respect for the natural wonders that surround them is instructional in the best possible way. That love was also reflected by Alain and Natalie who have spent decades in this region. It's a great way to feel as well as see what one is photographing.NB: some people will try to tell you there is no such thing as Horseshoe Bend Slot Canyon, or that it's "really called Secret Canyon," or that it's part of Waterhole Slot Canyon. or some such. It is true that it was once called Secret Canyon, though with its own website, it would be hard to call it that any more. But it's not a part of Waterhole Slot Canyon. It is smaller than the others, but still staggeringly beautiful. And I mean that literally, without hyperbole. There are views in all these canyons that will make you weak in the knees. if I had to choose only one to see again, it would be Horseshoe Bend. And when I taker Mary there, HSBC is the one we will see. Waterhole is also beautiful, but it's accessible to anyone who paid the permit fee and parked by the highway for the hike in. You may find it quiet, as our workshop group did at first, or you might not. For Horseshoe Bend Slot Canyon, HBSC Tours controls access to the canyon, and they limit it. So, you will rarely if ever feel crowded, and you can choose to shoot on or off tripod.