Wollensak Velo Diffusion Ring

[Kevin Klazek]

I am just getting around to working with my 12 inch Velostigmat Series II 4.5 lens with the diffusion ring. In trying to find the proper use of the ring I find conflicting results. An old Wollensak catalog says to set the diffusion then focus. I recall reading perhaps in this forum to focus , then set diffusion. I have found that setting diffusion then focusing removes the effect. So I have been focusing, then setting the ring. This is done after the appropriate appeture is set.

Can someone confiirm the proper method? Perhaps I am missing something in my tests and searches.

I love the peachy smoooth results from this lens. I see some people advise to remove the stop screw and go beyond the 5 setting. I have not done this and wonder what the benefits are beyond just more softness?

Thanks

[Mark Sawyer]

My experience with several Velostigmats (9.5" and 12") is that the "diffusion" ring shifts the focal length slightly, but introduces very little aberration. If you focus then dial more softness, you get out-of-focus. If you dial in softness then focus, it's sharp.

If you remove the set screw that restricts the rotation of the front element (this is the "diffusion" ring), you can unscrew the ring much farther. The benefit to this is that it introduces enough genuine aberration (probably spherical) to give a genuine soft focus effect where a sharp image is still there underneath. I find the best method is to learn how much softness you get at varying amounts of "unscrewiness", (it's a technical photography term), set the diffusion accordingly, then focus.

It's hard to judge well from an internet scan, but below is one I just posted over in this month's portrait thread, done with the 12" Velostigmat with the diffusion well beyond the restricted range. Used this way, I find the Velostigmat as desireable as other far more expensive soft focus classics. And smooth? My own objective scientific methods show the Velostigmats tested to range from 3.7 to 5.2 times smoother than a baby's behind...

[Kevin Klazek]

Thanks Mark. Looks like I had it all wrong. The results were good with my focus and set approach. I will reshoot some shots I just did with the set and focus approach to see the difference with the additional abberation produced.

Also how do you remove the set screw?

Beautifull shot by the way.

Kevin

[Jeremy Moore]

Mark, how did you get to the screw? I haven't been able to get to mine to take it out.

[Mark Sawyer]

I just plugged in the dead battery for my digital camera, and I'll post a few images tomorrow on where that little screw is, (if someone doesn't beat me to it!)

[SteveKarr]

Hey Mark,
With a 11.5" Verito like we both have is it the same routine? Or is it focus and then stop down 'till it looks good?

Or do you run film tests at different f/stops ... then set to a known "look" and focus?.....

Steve

[goamules]

The Verito is a different type of soft focus, and will remain soft where ever you focus, depending on the aperture setting. It's softness comes from uncorrected aberrations. With Veritos, I find it easier to focus stopped down, at about F8, where it's sharper. Then I adjust the aperture (which adjusts the softness) to get the amount of softness I want.

[Mark Sawyer]

Hey Mark,
With a 11.5" Verito like we both have is it the same routine? Or is it focus and then stop down 'till it looks good?

Or do you run film tests at different f/stops ... then set to a known "look" and focus?.....

Steve

Pretty much what Garrett (Goamules) said, but I work the focus and f/stops (and camera movements and positioning of the camera, subject, lighting, etc) throughout the set-up, sometimes many times, Changing one thing changes other things... But always do a final focus last, as the Verito has a bit of focus shift.

I usually do an image at several stops when I first get a lens, but it takes a while to really get to know a soft focus lens. It's not just "here's how soft it always is at this f/stop". How closely you focus changes the aberrations, (closer is softer), light makes a big difference in how energetically the aberrations and diffusion dance around, and subject tonalities and textures make a big difference in how the softness is perceived. You'll probably learn to make a few adjustments in developing the negatives and prints, too.

But on the other hand, the "mistakes" can be as lovely as the ones you call spot-on!

[Paul Fitzgerald]

"Mark, how did you get to the screw? I haven't been able to get to mine to take it out."

There are 2 versions, first is behind the nameplate/beauty ring on the front of the cell, second is inside the cell, under the rear element.

Have fun and be careful.

[goamules]

On a related topic, Mark and I were discussing the other types of diffusion soft focus lenses, and what they do. This morning this thread reminded me to try something: I adjusted the soft focus on my Dallmeyer 5D, way out, past the IV mark (a la Mark's UberUnschrewen method). I then focused. This is the backwards method, but confirmed my findings on other petzvals - the lens focused sharply.

I compared sharpness with the diffusion off and on at various levels, and didn't notice a difference looking at text on an opposite wall, if I focused after playing with the diffusion. I'm led to believe slightly unfocused petzvals will look the same as one with the soft setting adjusted