Petzval, Hemispherique Rapide, etc?

[RdEoSg]

I have a couple of old lenses sitting at the shop here that I am curious about.

One of them is a Hemispherique Rapide #2 Made by Darlot Paris


The other is Benj French and Co Boston and appears to have once been part of a stereo set up.

My end result is I love the look of the wet plate process and want to try to somehow get a similar result. That and it seems like a fun project to build some sort of a bellows for use on either my Canon 5D or my Hasselblad 503

Can someone tell me about these lenses? From what I understand, a Petzval lens is what is commonly used for the wet plate and tintype portraits? What makes a lens this style? Is there some difference between it and the Hemispherique Rapide?

I notice neither of these lenses have an aperture, though they seem to have a slot on them where something could possibly drop in?

 

[sevo]

The Petzval was the first useable fast photographic lens design. It marked the breakthrough of tintypes and wet plates, which both were initially slow, slower than Daguerrotypes (which could be surprisingly fast, but were complex to prepare and toxic as hell), and needed the push of a faster lens to become competitive. Post 1860's, Petzvals were replaced by superior designs and only survived as projection lens designs (where high speed was desirable and narrow angles did not matter). Petzvals have been the subject of many recurring "soft" fads - there are whole stretches of flicker consisting entirely of "swirly bokeh" flowers shot with abused Petzvals...

As far as I can make out, Hemispherique Rapide was merely the Darlot name for their wide-angle Rapid Rectilinear/Aplanat variation - every lens maker had to have some of these in the 1880-1930 time frame.

 

[RdEoSg]

Thank you for the info!

Is there some way I can tell by looking at lenses what type they are other than the ones that are labeled like the Hemispherique Rapide?

What is a Rapid Rectilinear lens? would it create the sharp center area with the quickly falling off edges or is that something specific to the Petzval design?