Petzval vs Projection Petzval

[Ari]

Slightly different lens design, right?
Does anyone have images that illustrate the difference in how each type of Petzval renders?
Thank you

 

[jim10219]

Not necessarily. The design of the lens elements are essentially the same, either way. The only common difference is the Petzval used for cameras will usually have some kind of aperture control.

Of course, "Petzval" is kind of a generic term used to describe a certain general formula of a lens that contains two specific types of doublets. How exactly that's implemented, can vary from manufacturer to manufacturer, so they're not all identical. So it's possible that two specific Petzval camera lenses can be even more dissimilar than a specific Petzval camera lens and a specific Petzval projection lens.

Now, it's not unheard of for people to pass of other lenses that exhibit spherical aberrations as Petzval lenses. For instance, I once owned an f/0.9 projection lens that had some pretty severe spherical aberration. It also had something like 10 elements, so it was clearly not a real Petzval, though I had seen that same type of lens sold under the name "Petzval" before by some unscrupulous sellers on the internet.

 

[Ari]

Right, thank you, Jim.
This just makes it harder to know what you're buying unless you know the seller and have photos showing what the lens can do.
FWIW, I think the lens in the photo above could also be a B&L triplet, dressed up as a Petzval.

 

[jim10219]

Right, thank you, Jim.
This just makes it harder to know what you're buying unless you know the seller and have photos showing what the lens can do.
FWIW, I think the lens in the photo above could also be a B&L triplet, dressed up as a Petzval.

That's possible. Some sellers seem to think that all brass barrel lenses are "Petzval" lenses.

And to what you posted before, sometimes, it can be hard to tell how a lens started off. I have a 8 1/4" f/5.6 brass Petzval that has a slot cut out on the top for waterhouse stops. From the outside, it looks like it might be a projection lens that was modified for a camera at a later date. However, on the inside it has an extremely well machined metal ring with a groove cut into it to hold the waterhouse stops in place that appears to be original. If it's not original, someone went to a lot of trouble to modify the internal of the lens where no one would see. There's no lens maker signature on the lenses, nor on the body, and while it looks a lot like every other brass Petzval I've ever seen in general terms, it's also just a bit different in the tiny details from any other Petzval that I've come across in my research. So I don't who made it. I don't know if it was a projection lens that got turned into a camera lens by a highly skilled craftsman, or started off as a camera lens, and was just made by some small, probably American, lens maker.

Either way, the images it takes are really nice! And that's all that matters to me.

 

[Ari]

Either way, the images it takes are really nice! And that's all that matters to me.

Absolutely agree on that! Now if I could just do a comparison of images, or if someone has Projection Petzval images they can share here, I'd be grateful.
Just want to make sure it's worth spending the extra money on a Petzval, or if I'll likely be as happy with a projection lens.
Thanks in advance.