MGrayson
Subscriber and Workshop Member
This may be obvious to everybody but me, so if your response is "Well, duh!" then I apologize.
The thread on "Aging photographers and weight" got me thinking about my favorite tripod head - an Acratech Panorama. I like it precisely because it is not a ballhead. Once set up, the camera is always level to the horizon. It tilts up and down, swivels side to side, but doesn't twist (pitch and yaw, but no roll), The problem is, it needs to be leveled. On a big tripod, adding a leveling base isn't a (relatively) big deal, so problem solved. But if you're going light, you want to get by with as little hardware as possible.
Well almost every tripod has a built-in leveling mechanism - its legs! The problem is that, as the name implies, tripods have three legs - and they are arranged equally spaced at 120˚ angles around the center. Leveling is easy when your adjusters are at right angles, which is how geared heads arrange things. But 120˚ angle coordinates are what mathematicians call "messed up".
Now if you're going to level your tripod, you have to have ... a level. I'm assuming it's a bubble level. The Acratech head has a very sensitive level, but most tripods have at least something. So! Here's how to level your tripod by adjusting its legs.
Method 1) Just do it. No, a little more here. Almost. Maybe if I shorten that one. Whoops - too much. Etc. etc.
Method 2) Come up with an algorithm that is 100% accurate - only when the tripod is already level. We love mathematical solutions. But it's accurate to first order, so if you're at all close, and your legs are all pointing mostly down, then it will work.
Here's a typical starting point. Don't worry if the bubble is against the edge of the level, it still works.
The lines from the legs divide up the level into three sectors. The center of the bubble will lie in one of them. If you're really lucky and it's smack on the boundary between two sectors, you can skip the first step.
I'm assuming you want to adjust by shortening legs. It's easier to control - and makes the description simpler. We're going to adjust the two legs marking the boundaries of that sector. In this case, Legs 1 and 3.
Important point - shortening a leg moves the bubble 180˚ away from that leg's direction. (This is the part that's only exactly true when the tripod is already level on flat ground, but ¯\_(ツ)_/¯ ). It doesn't matter which order you adjust the two chosen legs, so we start by shortening Leg 1 until the bubble lies on the Leg 3 line.
Now shorten Leg 3 and the bubble will go right to the center.
If the terrain is very uneven, the bubble will move along a different path, but you'll get it closer to the center, and then an iteration will do it. Am I the only tripod owner who hadn't worked this out intuitively? Certainly no one ever told me how to do it. Ok - maybe I'm a frustrated graphic artist and just wanted to draw these pictures.
Well, happy shooting,
Matt
The thread on "Aging photographers and weight" got me thinking about my favorite tripod head - an Acratech Panorama. I like it precisely because it is not a ballhead. Once set up, the camera is always level to the horizon. It tilts up and down, swivels side to side, but doesn't twist (pitch and yaw, but no roll), The problem is, it needs to be leveled. On a big tripod, adding a leveling base isn't a (relatively) big deal, so problem solved. But if you're going light, you want to get by with as little hardware as possible.
Well almost every tripod has a built-in leveling mechanism - its legs! The problem is that, as the name implies, tripods have three legs - and they are arranged equally spaced at 120˚ angles around the center. Leveling is easy when your adjusters are at right angles, which is how geared heads arrange things. But 120˚ angle coordinates are what mathematicians call "messed up".
Now if you're going to level your tripod, you have to have ... a level. I'm assuming it's a bubble level. The Acratech head has a very sensitive level, but most tripods have at least something. So! Here's how to level your tripod by adjusting its legs.
Method 1) Just do it. No, a little more here. Almost. Maybe if I shorten that one. Whoops - too much. Etc. etc.
Method 2) Come up with an algorithm that is 100% accurate - only when the tripod is already level. We love mathematical solutions. But it's accurate to first order, so if you're at all close, and your legs are all pointing mostly down, then it will work.
Here's a typical starting point. Don't worry if the bubble is against the edge of the level, it still works.
The lines from the legs divide up the level into three sectors. The center of the bubble will lie in one of them. If you're really lucky and it's smack on the boundary between two sectors, you can skip the first step.
I'm assuming you want to adjust by shortening legs. It's easier to control - and makes the description simpler. We're going to adjust the two legs marking the boundaries of that sector. In this case, Legs 1 and 3.
Important point - shortening a leg moves the bubble 180˚ away from that leg's direction. (This is the part that's only exactly true when the tripod is already level on flat ground, but ¯\_(ツ)_/¯ ). It doesn't matter which order you adjust the two chosen legs, so we start by shortening Leg 1 until the bubble lies on the Leg 3 line.
Now shorten Leg 3 and the bubble will go right to the center.
If the terrain is very uneven, the bubble will move along a different path, but you'll get it closer to the center, and then an iteration will do it. Am I the only tripod owner who hadn't worked this out intuitively? Certainly no one ever told me how to do it. Ok - maybe I'm a frustrated graphic artist and just wanted to draw these pictures.
Well, happy shooting,
Matt
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