Training a horse to 'stay'

What is the best way to train a horse to 'stay?' Meaning, training a horse to stand in one spot as you move away...not holding them with a lead rope. I love taking photos of my horse, but as I move away from him to take pics from farther away, he tends to just follow me. Is there a method for training him to 'stay' like you could do for a dog? Thanks!

I bet some people would know how to do that. I have to start with hobbling my horses. Many of them never go beyond that. Others ground tie quite well. I tie to sagebrush. Really I just drape a rein over the brush, but for some that is enough. After they get used to that I can just drop a rein on the ground.

I dunno, I just say "wait there" and back away with my horse. Brock doesn't follow me then. He only follows if I ask him to follow. If he looks at the camera and makes the shot all funky I say "look there" and point him in the right direction, and he does, then I take the photo. I'm a dreadful photographer though, so I'm not sure why I bother lol.

ETA: as far as training them to stay in the one place without holding the lead, I had to do that with Brock because he can undo knots and clips so tying up was kind of pointless if it was going to be longer than 5 mins. I just started by draping the rope over a fence and pretending to turn my back - if he tried to move away I'd turn and say "stay/wait there". Once he'd stand at the fence and not move away even though he knew he wasn't tied I did the same in the middle of the paddock by draping the lead over his neck. He caught on quickly, but he's so lazy he can't be bothered moving around much anyway

What I do is start by teaching the command "stand." I use it every time I am asking them to stand still, tied, in the cross ties, with the farrier, and any time else I want them to not walk off. After I can see a reaction to the word, usually I look for them to prick an ear to me and relax, but you will have to read your horse, I will take them to places that they already know to stand still, but not tie them, like the cross tie area, give the command and then go about my normal routine. If they start to wander, I bring them back to where I had them, give the command again and resume my actions. Depending on the horse, I may exaggerate dropping the lead rope to the ground while I give the command. Once they have that part down, I will pick spots at random to ground tie them, always in a fenced off area. I walk to where I want to stop, show them the lead and drop it on the ground as I say "stand."

Using this progression, I had a yearling filly that I could stand up in the barn yard and she would stay in one place for up to 45 min just watching me while I did little odd jobs around the barn.

What has worked well for me is to stand in front, about 3' away and raise my hand like a stop sign and then walk to the neck place my hand and walk to the shoulder. I will turn away and back to the horse and offer a treat. I repeat the raised hand, again to the neck and walk to the hip, always turning away from the horse to the front with a treat. At first the horse may swing it's rump away but just repark him and start again. It took maybe 10 min. At first one hand must touch the horse at all times as you circle. Then I gradually moved farther away as I circled and rewarded. Within 20 minutes I could make a large circle only by not looking at him as the horse may be inclined to turn his hips to follow visually. I then was able to leave the gate, to retrieve a treat and return. That is when the horse may want to follow but just repark him, reinforce the stop sign and try again. This means your back is to the horse and he'll think his treat is leaving. A little persistance will keep him remaining in his spot. I reinforced this the following day which took only a few minutes. Now if I park him he'll stay until he's told otherwise. I should add, this was done in his pasture at liberty. He could have taken off any time he chose, but he chose to stay.