Rifle shooters have been using bi-pods for years for prone, sitting, and standing, but I've never any version for photographer use...do they exist? Seems like a nice compromise, more stable than a monopod but less trouble than a tripod...have you seen/used one?

I've never used one, but it would be an interesting alternative to a bean bag or ground plate, assuming it has short legs. I think that a long-legged bi-pod would be difficult to pan. Of course, I'm thinking of using it for support near the front of the lens, certainly forward of the focus ring. The panning problem would disappear if you used a head on the bi-pod, but its inherent stability would be compromised by using it at the tripod mount foot with a head. How do you figure you'd use a bi-pod?

Novoflex Forked Joint - "V" Shaped Tripod Head for Long Lenses

Henry Posner
B&H Photo-Video

Interesting. Sort of the upside down version of a bipod.

Interesting device, Henry, but I am not sure about its relevance to the topic.

Kind of relevant to the question of panning, the lens fits in the fork and can be moved pretty freely in pan or tilt. There are a variety of shooting
sticks" which use something like this and a bipod could as well, again, increases the ability to move around. A "fixed" bipod can do some tilting but panning's tough. One hand gripping the base of the v/top of the bipod holds the support and allows for the motion.

Craig Gillette wrote:
Kind of relevant to the question of panning, the lens fits in the fork and can be moved pretty freely in pan or tilt. There are a variety of shooting
sticks" which use something like this and a bipod could as well, again, increases the ability to move around. A "fixed" bipod can do some tilting but panning's tough. One hand gripping the base of the v/top of the bipod holds the support and allows for the motion.

True.Maybe the complexity of panning just does not lend itself to a useful product.

I shot with a guy who rested his 500 on one and shot BIF a bit using the support. He'd lift and let it fall when going for
tougher pans and overheads. Kinda cool, but he finally gave in to a BushHawk and that's all I ever see him with now.