Short Petzval

[RedGreenBlue]

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I have this Petzval lens that I find odd, but then maybe it's not. I'd appreciate feedback.

All measurements are approximate. The focal length appears to be 195mm, the entrance pupil is 43mm or so, indicating an aperture of 4.53. The engraved stops are 4.5 5 5.5 6 8 11 16 22. Pretty much a modern sequence. The image circle is 11 inches. The barrel length seems short to me at 52mm, with attached cells it's 62mm. I also have the flange - not shown.

The aperture engraving is shallow. I thought there was no maker's name but then I noticed what looked like scratches at the front edge of the barrel. I tried to show these in the first photo. I'm pretty sure they are the remains of an engraving which, if so, would lead me to think that the barrel had been shortened. So I took other photos with the cells removed to show the condition of the barrel openings and threads.

The lens shows lots of swirl moving away from center wide open, and is moderately sharp at center. Stopped down the center is sharper and sharpness extends farther out. I removed the lenses from the cells so I know it's a Petzval. Only slight corner vignetting on 8x10 and it fully covers 8x10 stopped down a bit.

Besides the question of the barrel, the other thing I noticed is it seems to me that the angle of view is quite wide. I can only say that it covers a field that's equivalent to a 24mm lens on 24x36mm format in the narrow dimension.

Scott

[Ron (Netherlands)]

Indeed looking at the engraving, the barrel has been shortened.
Why do you think it is a Petzval? a Petzval has 4 lenses (as you probably already know), two of which are cemented.
For a Petzval your barrel has an unusual iris diaphragm; most of them have the WHS or no variable aperture at all.
If you have the two cemented lenses then this might perhaps work as a nice landscape lens with an aperture in front of the lens.

[RedGreenBlue]

Hi Ron,

Yes, the the front cell has a cemented achromat and the rear has the usual two air-spaced elements. There was 100 years of dirt on the lenses so I cleaned them up. But I would have disassembled it anyway to ID the type. The elements are clean - that's a reflection in one of the photos.

So assuming the barrel was shortened, what was the goal? Could this be why the field of view is so much greater than with my other Petzvals?

I can't imagine who would shorten the barrel and then cut new internal threads? Would the maker have done this? It's a professional job.

I can think of a number of interesting photo opportunities using this lens just as it is but you've also made an interesting suggestion.

Thanks,
Scott

[seezee]

Indeed looking at the engraving, the barrel has been shortened.
Why do you think it is a Petzval? a Petzval has 4 lenses (as you probably already know), two of which are cemented.
For a Petzval your barrel has an unusual iris diaphragm; most of them have the WHS or no variable aperture at all.
If you have the two cemented lenses then this might perhaps work as a nice landscape lens with an aperture in front of the lens.

FWIW, the longer of my 2 Petzvals has an adjustable iris. It is definitely a Petzval — 2 doublets, cement in front, air in back.

[carylee2002]

Probably shortened to reduce vignetting when using larger format cameras thereby increasing the image circle on the back end. If you do the light and white paper and have the light shine thru to the paper you will know exactly how much back focus freedom you have on that lens.