Let me offer a bit of insight so you know what to expect. The "Upper" is the more popular of the two and is typically very crowded. Try to be at the front or the rear of the tour group you're in so you can get shots without people in them. Also, this is monsoon season in Southern Utah and Northern Arizona. Don't be shocked if your tour is canceled. This is footage from a week ago in Southern Utah:
https://www.abc4.com/news/wasatch-front/footage-flash-flooding-southern-utah/
So I suggest you have some backup options (other than slot canyons). The Navajo (who provide the guides and control access) will be hard-ass about water threats--if there is a risk of rain (or if it rained hours before) they'll shut down tours--I had two tours booked that got canceled because there was a risk of rain. So have backups.
The Upper Antelope Creek Canyon is short, flat ground (easy to walk) and is referred to as an "A" slot: wide at the bottom and narrow at the top. Expect temps to be much cooler in the canyon than outside. Do NOT plan on changing lens--it will be very dusty. Because it's an "A" slot, light will be low--your best photos may be from your phone (if you've got a recent cellphone camera). If your tour is between 10:30am and 2pm, you've got a good chance of getting shots of "god beams" (a beam of light streaming through the narrow opening up top).
If the weather allows it, look at the Lower canyon (a little less crowded, different experience--it's a "V" shape), or Canyon X (really two slots, part of the Antelope Creek Canyon system and the least crowed of these options) or Peekaboo Slot Canyon in kanab Utah (you'll need a tour for any of these). I've been to each one of them and they're incredible. Do not try Cardiac Canyon unless you're really athletic--it's a serious workout (you get out of it at the end by rope) but it's outstanding and the least crowded of the 4 Antelope Creek options (Upper, Lower, X, and Cardiac).
Since you're going to be in Page, AZ there are a gazillion things to see or do (many of which are not slot canyon related). Plan on getting pictures of Horseshoe Bend. South of Page is White Pocket (incredible surface). There are some great places (Belly of the Beast, Coral Pink Sand Dunes State Park) in Kanab, maybe 40 minutes from Page. There is a place just across the border from Page in Utah called the "New Wave" or "The Beehive" (not to be confused with "The Wave" in Coyote Buttes). No permit required, not underground and it's supposed to be lovely.
If you're flying into SLC and driving South (to get to Page), I have more recommendations. Let me know if you have any other questions.