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Kevin Klazek
25-Nov-2009, 14:21
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
25-Nov-2009, 14:44
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...

http://i55.photobucket.com/albums/g139/Owen21k/Jennasleeping.jpg

Kevin Klazek
25-Nov-2009, 15:37
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
25-Nov-2009, 15:38
Mark, how did you get to the screw? I haven't been able to get to mine to take it out.

Mark Sawyer
25-Nov-2009, 17:27
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
25-Nov-2009, 19:57
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
26-Nov-2009, 06:06
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
26-Nov-2009, 10:56
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
26-Nov-2009, 11:49
"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
26-Nov-2009, 12:10
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

Mark Sawyer
26-Nov-2009, 14:45
"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.

I've never seen one where you can get at it from the rear, but don't doubt it. These lenses were made for various shutters and barrels over several decades, so there may be numerous versions...

On my 12" I removed the front ring and element, and that let me get to the screw from the front and unscrew it part way. Here's what it looked like from the back with the front element unscrewed:

http://i55.photobucket.com/albums/g139/Owen21k/L1000068.jpg

The little machine screw is still there because the threads on its end were badly buggered from hitting the opposing pin, and I couldn't remove it all the way. Since I had to scew it back in flush to replace the front element and ring, I dremeled off the opposing pin. (That's the shiny little brass spot.)

It lets you unscrew the front element about this far. (Here it's hanging on by one full revolution.)

http://i55.photobucket.com/albums/g139/Owen21k/L1000072.jpg

I can't get to the screw on my 9.5" from either direction. I think I could just make a good solid pine holder for my vise (so I don't chew up the barrel) and force it til the pin or screw shears off. It's under consideration...

Don't know if this helps or not...

goamules
26-Nov-2009, 17:25
...I can't get to the screw on my 9.5" from either direction. I think I could just make a good solid pine holder for my vise (so I don't chew up the barrel) and force it til the pin or screw shears off. It's under consideration...

Perhaps a tiny charge of black powder?

Kevin Klazek
27-Nov-2009, 06:29
Thanks for the pics and explanation Mark. How did you get that front retaining ring off? What tool did you use?

Kevin

Mark Sawyer
27-Nov-2009, 10:20
The front ring I got off with just friction from my fingers unscrewing it, but I cleaned the exposed threads and let a little bead of penetrating graphite soak in a bit, and it was still a challenge.

I have another very badly scratched up 12", and on that one, I had to drill two small holes on opposing sides of the ring to fit a spanner wrench, and I still couldn't screw it all the way out because of an almost imperceptible dent in the barrel.

Getting rid of that little screw is not an easy job, at least in my limited experience. If anyone else has advice, please chime in!

Kevin Klazek
27-Nov-2009, 17:19
Your advice was right on Mark. My lens must be in good shape as the lens retaining ring screwed off very smoothly. Once off I could see the TINY set screw, which also screwed out easily. I took the opportunity to clean the inner glass surfaces and relube the diffusion ring. Overall a simple job...when you know how!

I now figure the diffusion adjustment has gone from a range of 0 to 5 to 0 to 25. There is about 4 or 5 more turns, but that should be the safe zone to stop the diffusion ring from falling off.

It could take a while to to figure out the subtleties of this lens now that it's full potential is unleashed!!!

Thanks for your help.

Kevin

Andrew O'Neill
18-May-2014, 20:57
I have a 12" Velostigmat and have been trying to remove the front diffusion ring. I have been unable to locate any set screws so it looks like I will have to try forcing the ring off with a vice and spanner wrench...hopefully if I'm gentle enough, I won't damage it.

Jon Shiu
18-May-2014, 21:07
I have a 12" Velostigmat and have been trying to remove the front diffusion ring. I have been unable to locate any set screws so it looks like I will have to try forcing the ring off with a vice and spanner wrench...hopefully if I'm gentle enough, I won't damage it.

If you can't get the beauty ring off, you can take out the rear element of the front group and file down the pin from inside.

Jon

Andrew O'Neill
18-May-2014, 21:57
Thanks Jon. I looked at doing that but I cannot figure out how to take the rear element out...any ideas?

Jon Shiu
18-May-2014, 22:15
Thanks Jon. I looked at doing that but I cannot figure out how to take the rear element out...any ideas?
Usually there is a smooth metal ring holding the element in. You unscrew that and it comes apart.

Jon

Andrew O'Neill
19-May-2014, 11:24
I was able to remove the smooth metal ring with my fingers and thought I was home free. The element still won't come out. If the ring is actually holding the element in, you would think it would just drop out. Could it also be cemented in?

Louis Pacilla
19-May-2014, 11:59
I was able to remove the smooth metal ring with my fingers and thought I was home free. The element still won't come out. If the ring is actually holding the element in, you would think it would just drop out. Could it also be cemented in?

Hey Andrew

The element is not glued in but with the front element in place the rear element develops a bit of a vacuum making hard to remove. It will work out enough to get a grip on it for removal.

Hold the cell upside down with a soft surface directly under the work area (just in case it falls out when you start tapping ) then tap on the side of the barrel/cell repetitively with a rubber hammer or something alike Shoe with rubber soul. You don't need to hit the barrel hard just tap it several times and keep an eye on the element to see if progress is being made. Do this until the rear element works out enough that you can get a hold of it and then good luck with the grinding filing of the stops.

Hope this helps.

Andrew O'Neill
19-May-2014, 14:55
Thank you Louis! I tried hammering gently on its side as you suggested but it just won't budge.

Jim Noel
19-May-2014, 15:06
I'm at the same point as Andrew. The element is loose, but just won't fall out. would gentle heating to expand the air between the cells be a wise move?
Jim

Andrew O'Neill
19-May-2014, 15:09
I'm warming up the oven as we speak! Thinking of putting it in for a few minutes at 300F. I'll get back to you... pray for me... and my lens!

Andrew O'Neill
19-May-2014, 16:04
No luck removing after heating. Plan B: Remove adjustable soft focus lens with vice.

Louis Pacilla
20-May-2014, 05:58
No luck removing after heating. Plan B: Remove adjustable soft focus lens with vice.

This is a terrible idea. You'll wreck the lens as you wont be able to break the stops without doing damage to the barrel. Better off using the lens as is if it's in working condition. IMHO.

Andrew O'Neill
20-May-2014, 08:17
Came out fine. No Worries. There is a ring at the front of the lens that unscrews. Slowly working that off, but it's killing my hand.

Andrew O'Neill
20-May-2014, 16:33
Finally got that outer ring off! There was a brass pin and screw inside. I removed the screw and she's done. So, after all that, the trick is to remove the outer ring on the front element.