That Elusive "Swirly" Bokeh

[Jim Galli]

hello jim,
i am interested in an old lens that give s a nice swirl effect when shot wide open. i plan to use it on a 4x5 and an 8x10.
how can i be sure i get what i am looking for? does it need water house stops? will a projection lens of that era do the same? how can i be sure? if it has a built in iris is it too new to give good swirls? is it safe to assume any lens of this type made before the year 1900 will give me these effects? can i estimate the focal length given the overall length and diameter of the lens?
any tips you can give me to help guide me would be great. that old 2d i bought from you sees a lot of use!
do you have any of these lenses in your mine? for me it does not have to be pretty or perfect. i just want to use it so "beater" is good for me.
thank yo u for your time and knowledge.

eddie




Hi Eddie. Ahh, the elusive swirly bokeh. Impossible to define and more impossible to formulize. It seems to happen only in the portion of a petzval lenses image circles that were never intended to be "in the image" in the first place. So the only way to get it on purpose is to get a petzval type lens that just vignettes the corners on the format in use. Roughly this might be 4-6 inches on a 4X5 and 10-12 inches on an 8X10. The larger the aperture the better too. You would pick the shorter of the lenses for nearer subjects as the bellows goes out. So at 6 feet from the lens a 10" petzval would give nice swirley bokeh on the 8X10 camera. Then your composition needs to have elements that will show the swirling, like bushes and tree branches. The busier the better. It's hard to portray a swirley blank sky. Wollensak Verito's have the same properties in the same conditions. Rapid Rectilinears mostly do not. So just because a lens is old means very little. The Goldfield Courthouse series (http://www.largeformatphotography.info/forum/showthread.php?t=23148) I posted was all done with lenses that are 90 to 110 years old and the photos are tack sharp. Hope this helps some. Best, Jim

Note: This is from a private e-mail but there is a lot of general interest so I thought to bring the discussion here. Hope Eddie doesn't mind too much. More to learn from others in any case. jg

[Neil Purling]

I liked the courthouse photographs. Not a PC in sight and check out those ancient typewriters! The Protar was incredibly sharp, I liked the shot of the judge at her desk. That Rochester Optical R.R at full bore had quite nice bokeh, but got pretty sharp stopped down.
I would like to add a Petzval of around 6"to my "Lens Library".
Is the Wollensak verito also a Petzval type, or just prone to major coma (which causes the swirl effect)?

[Jim Galli]

Hi Neil. Thanks. The Verito is a modified achromatic meniscus?? Someone will correct me if that's innacurate, but no definitely not a petzval but with built in non corrections that seem to have a similar effect although still different. A Verito can never achieve the center sharpness that a petzval inherently has.

[Frank Petronio]

I swirl more than you do... ;)

[Jim Galli]

I swirl more than you do... ;)

Nice job in Photoshop Frank. Everyone know where the swirly bokeh button is in photoshop?? :D

[Neil Purling]

That image of the tree looks like a representation of: The morning after, after someone spiked your beer that is.
If you want to see examples of the Petzval swirl look for Domenico Foschi's work and sort through the 'Stock' folder till you find the child_at_penn_park, or carraie_italy in the Italia folder. Wonderful photography.

[Hugo Zhang]

That Vitax portrait lens from Jim's mine could produce nice swirly Bokeh with its curved field. Here are a few pictures with a Kodak 8x10 2D. Of course, they are shot wide open because my Vitax has no aperture blades.

[Lazybones]

I use a bottle of Patron Silver to get swirly bokeh. Never eludes me.

[Neil Purling]

Re, the Vitax lens... What maker? Really great bokeh, just what I want.
What aperture is it? F3, 3.6, something of that order? I bet it's a brute of a lens (if it is a Petzval) to cover 8x10.

[Jim Galli]

Re, the Vitax lens... What maker? Really great bokeh, just what I want.
What aperture is it? F3, 3.6, something of that order? I bet it's a brute of a lens (if it is a Petzval) to cover 8x10.


The Vitax is a Wollensak product of the 1910's - 30's. It was f3.8. The one Hugo mentions is here; (http://www.largeformatphotography.info/forum/showthread.php?t=23182)

http://www.largeformatphotography.info/forum/showthread.php?t=23182

Thanks Hugo!

[eddie]

nope. i do not mind at all. thanks for all the help and info.

eddie

[Erich Hoeber]

What Jim said. Here's a 5" petzval on 4x5:

[Jim Galli]

What Jim said. Here's a 5" petzval on 4x5:

Erich, those are spectacular. Personally I go for the shorter lens and feel the vignette just adds to the character.

[Neil Purling]

I note that the Vitax, while it has the bokeh... Well it just isn't sharp enough in the centre of the field. Can you vary the central sharpness, or is that just how it always is?

[Ash]

Dammit... now I HAVE to get a swirly-bokeh lens!

[Paul Fitzgerald]

Hi Neil,

"I note that the Vitax, while it has the bokeh... Well it just isn't sharp enough in the centre of the field. Can you vary the central sharpness, or is that just how it always is?"

I have all 3 Vitax and they are brutally sharp in the center at the 0 setting. Dialing up the soft focus setting does induce abberations and changes the focal length quite a bit. The petzval all have a curved depth of field AND a curved depth of focus so the GG has to be in exact register with the film. The 10.5 inch Vitax does NOT cover 8x10 to the corners at inf, just checked.

Good morning people.

[Neil Purling]

I heard that a photographer would ask the outer members of a group shot to step forwards so as to be as sharp as those in the middle. I take it that the zone of sharpness would curve towards the camera in the dge of the field?

[Christopher D. Keth]

I heard that a photographer would ask the outer members of a group shot to step forwards so as to be as sharp as those in the middle. I take it that the zone of sharpness would curve towards the camera in the dge of the field?

Yup. The curved field will move toward the lens on the edges on both sides of the lens (that is in front of, and behind.)