Typical lens / field of view for Civil War era stereo camera?

Hello-
I'm curious about what type of lens would be commonly be found on stereoview cameras from the American Civil War era (in part to help answer someone else's question on a Civil War forum that has piqued my interest).

My guess is that in the 1860s "normal" to slightly telephoto lenses were most prominent in general. In looking at the images of the day there doesn't seem to be a lot - or any, really - of obvious very wide angle images. I imagine that the overwhelming number of images made were studio portraits, and these cameras were, I'd guess, mostly outfitted with slightly long lenses (or that's my guess).

But back to the stereos, which were most likely shot in the field. Would the relatively small image area of a stereo half make them more or less likely to have a tight - as opposed to wide - field of view? Did they make lenses meant for stereos that had much of a wide field? Was there a focal length that would have been a standard for stereos then?

Funny, my two greatest interests are probably CW history and photography, but I'm still feel weak in regards to my knowledge where those two subjects intersect. Thanks for any insights!

I suspect that you're correct in your observations. Until panorama cameras were brought out & I don't think it was that early.

In that time, there simply were no decent wide-angle lenses. The Goerz Hypergon (ultra wide large format lens) was only developed around 1900 and still had lots of flaws. There may have been some moderate wide-angle lenses before (maybe 35-40mm equivalent for 35mm film), but those had massive vignetting, because they were basically scaled down versions of lenses with normal focal length. Truly usable wide- and ultrawide lenses with completely new formulas only came about in the 1930s and 40s, as far as I know.

So, yes, a normal focal length is most probable, maybe a little on the long side, to enhance the image circle and only use the "sweet spot" for the picture... not an uncommon practice in the early days of photography.
Especially stereo cameras tend to have a normal lens, because that's what the human eye is used to see. These pictures where viewed in stereo viewers were each eye only sees one of the pictures. Just try to take stereo pictures with a wide angle lens and view them that way - it's confusing to say the least, because it's not, what the brain expects the eyes to see.
What exactly is considered standard for the camera in question is of course dependant on the picture format. There is a difference between whole plate and quarter plate, no matter if it's stereo or not. And I don't even know, if there were standardized sizes back then. Probably not.