Darlot petzval question

[papageno]

What may have been an intended use of this particular lens?

Originally it did not have aperture slot. The slot was cut out just recently. I thought, that I was buying a magic lantern lens. But I can not imagine, that somebody could enjoy watching projected images of such terrible unsharpness. Even in XIX century. Actually, the lens is sharp, but only in the very small area in the center. Move the subject 1 inch on the ground glass, and you will not be able to set the focus there. Another thing is highly pronounced field curvature. Apart from unsharpness, this will also prevent from getting reasonably sharp projected image from magic lantern.

I do not think, that it was suitable for portraiture as well, unless somebody had the patience to unscrew the front element and install a diaphragm inside. People at that time were not swirl and bokeh admirers and pictorialism came much later (as far as I know).

I made only a couple of images with this lens, and always had to stop it down at least to f11. I don't want to say that I do not like that lens, it gives interesting graphic effects. My another petzval, bigger and heavier Gasc Charconnet does not swirl, but is much sharper.

One more thing, that petzval users may find interesting: when I reversed the rear element, the lens got a little bit sharper, but it refused to focus for objects farther than about 2m and edge effects changed from swirl to diagonal smudges.

[Ole Tjugen]

What format are you using it on, and what format was it intended for?
Relatively large 6.5x9cm lantern slides would have been projected with a 40cm Petzval, which doesn't give much swirl.

[Jim Galli]

Projection petzvals typically only used the center sweet spot. Your symptoms sound like someone has reversed the positive element in the rear group. They still work but they get VERY funky. 2 most curved surfaces face each other with the thin one at the very rear. I agree the aperture was added later but looks like they did a nice job. OTOH what happens if you put an aperture on either side of the nodal point?

[papageno]

Thank you for replying to my post.
I use this lens on 5x7 camera, but usually had to crop a little bit. Not because of light fall off, but total blur at the edges. Barrel diameter is about 2 and 7/8 inch, so it's not an easy fit for 4x5 camera. I do not know, for what format it was made for.
I did not bother to measure focal length, but it looks like about 9 inch or so.
It is a classic Petzval design, I checked it. Some manufacturers, like Voigtlander (if i remember correctly) had it modified.
Aperture slot is somewhere near the middle of the lens, I guess close to the nodal point. Frankly, I do not know how to change the position of aperture with regard to the nodal point.

[Jim Galli]

LOL, just looked at your picture. Do you realize people are pulling their hair out trying to get that swirly effect. I still bet your positive meniscus is in backwards. I've reversed them on purpose before just to get the lens to do that. :D:D

[papageno]

"Do you realize people are pulling their hair out trying to get that swirly effect."

That comment made me feel better. Thanks, Jim. I still value my hair quite a lot.

[Gene McCluney]

Your lens was originally used as a projection lens for an early 35mm movie projector. This would only use the very center of the field of coverage, which is very sharp. The petzval design has a huge image circle, but as you discovered only the very center is sharp. Hence, only the center was used. The reason projection lenses were of petzval design is because of high speed. Maximum amount of light on the screen, and the field of sharpness was very adequate for the 35mm frame size.

[Jim Fitzgerald]

Like Jim said, there are people pulling their hair out for this effect. Beautiful swirl in your image.Some people do not like this look. The wet plate friends of mine would love to have your lens. I happen to like the look in your image and I think you could use it to your advantage it portrait work. Different strokes... and all that.

Jim

[eddie]

like jim g said....it is broke! send it to me! :)

[CCHarrison]

Learn more about Petzval's (and Darlot's ) here

http://www.antiquecameras.net/petzvallens.html


Dan

[Jim Noel]

I think you better throw it away. I will be happy to send you the address of my trash can.

Jim

[papageno]

Your lens was originally used as a projection lens for an early 35mm movie projector.

Aaaah, so it is not a Magic Lantern lens. And not from XIX century.
I remember, that there was quite a lot of exactly the same looking lenses for sale on Ebay about a year ago. And they keep appearing from time to time. Certainly, they must have been made in decent quantities, not some sort of rarity.

I tried to make a portrait with that lens, and finally gave up because I was afraid, that the subject would not be able to recognize himself on a photograph. With some help from a subject, I attached with a duct tape Gasc et Charconnet petzval monster lens to the camera and made a beautiful picture with it. Although its construction looks like a petzval, it has completely different characteristic from Darlot, sharp, but with nice rendering and perfect bokeh.

Now I think, that I am going to try that Darlot once again for a portrait. But this time I will place the face (or eyes) exactly in the center of the frame, and crop unused portion later. I do not see the other way to do it right.

[papageno]

Now I think, that I am going to try that Darlot once again for a portrait. But this time I will place the face (or eyes) exactly in the center of the frame, and crop unused portion later. I do not see the other way to do it right.

I do not know, why I did not think about using camera movements to do it without the need for any cropping.

[goamules]

There are a couple of other things to consider. To me it looks like the myriad of magic lantern lenses Darlot made around the turn of the last century, not a 35mm, but a projector is a projector. I think it was Ole that mentioned in another post that some of these projector lenses were not color corrected, or were optimized for one color. A filter may increase your sharpness.

Also consider that with most makers the quality varied. Though the petzval is a simple design, some are slightly better than others, even by the same company. I bet Darlot didn't put the same effort towards quality into projector lenses. I've had 4-5 Darlots, and the sharpest was one that was actually made for photography. Unfortunately, I let it go!

[Dan Fromm]

Your lens was originally used as a projection lens for an early 35mm movie projector. <snip>

Interesting. Gene, why do you believe that?

I ask because the VM, which isn't always right, gives the very strong impression that by the time movies came in Darlot had gone over to making anastigmats.

[Gene McCluney]

Interesting. Gene, why do you believe that?

I ask because the VM, which isn't always right, gives the very strong impression that by the time movies came in Darlot had gone over to making anastigmats.

Because the Petaval is the almost universal "type" of lens used for earlier movie projectors because of extreme sharpness over the narrow field required and the speed of the lens, which could be faster than other designs of the period. It "is" possible that the lens is for a magic lantern (slide projector)...but the same design criteria holds. (Speed, sharpness in a narrow field)

As a Petzval comment in general, the early photographers did not use their Petzvals in such a way as to use the edges of the field of coverage. Modern photographers tend to use these lenses on larger-format film sizes which shows the swirly edges.