How to focus a soft focus lens

[Tin Can]

Some times what you see is not what you get

[jnantz]

Focusing technique will vary slightly between lenses. What aperture to use can not be adequately judged on the groundglass. You really have to try some different apertures on different subjects to fine tune what you like for sharp versus soft, as the aperture choice affects softness as well as focus. After 50-100 sheets of film, you'll find an aperture choice you like best for that lens and learn to keep the lens at that aperture.

yup. like everything experience is the key because WYSIWYG might be WYSMNBWYG

[cowanw]

One thing that becomes apparent with these lenses is that wysiwyg on the GG is not really true.
I have found it very heplful to use a sharp specular light source such as a old maglight with the top screwed off, with the older style of bulb, not LED.
With various soft focus lenses, I find a real difference in the nature of the depth of field in front of and behind the subject (the light filament)
The Universal Heliar, Kodak Portrait, Verito, Imagon and Veritar all maintain the central core of the filament when the bellows are focused closer. Focusing towards Infinity the filament changes to a diffuse circle with a dark core. This suggests that the most appealing use of the increased depth of field is found if these lenses are focused on the nose to use the depth of field to extend back to the catch light of the eyes.
The Kodak portrait lens manual on Camera eccentric agrees with this, describing racking the bellows out to focus "the tip of the nose to bring the face into the depth of field". It is a bit confusing about the depth of field being behind the lens focus but it is clear the bellows is racked out to the nose so the face is in the depth of field. "The lack of depth of field is in front of the focused plane." (not behind)
The Kodak manual for the Portrait lens says to use the normal focusing point and then apply a correction for the lack of depth of field in front of the lens, focusing at the working aperture. The plane of focus is moved forward say to the tip of the nose to include the face in the depth of field. Rack out 1/8th inch for a 2 inch head; 3/8th in for a 3 inch head and ½ in for a 5 inch head.
Or just focus on the nose.
The Graf Variable, the RVP and the Komuranon SF maintain the best use of extended depth of field when the bellows are focused towards infinity or shortening the bellows. The manual of the Graf suggests focusing on the eyes and the instructions warns against too much bellows extension.
The Cooke soft and the Velostigmat soft favour neither front or rear depth of field.
Whether you focus forward or behind your chosen focal plane depends on the nature of the soft focus lens you are using.

[xkaes]

the WOllensak Veritar instruction manual it says to stop the lens down a little and then open it up afterwards to the desired level of softness. works well with imagon, vitax, verito, vesta, fast tessars and homemade Wollaston .. might work with others too .. can't be sure ..

That's exactly what Fujinon says as well. If nothing else, it's a great place to start. Kind of like the manufacturer's recommended ISO.

[xkaes]

I have found it very heplful to use a sharp specular light source

That's also what Fujinon suggests.

[Tin Can]

Many dislike Fujinon SF as Harsh

So I never bought one

Cooke SF changed instructions way back, I have 2, I like both Knucklers

1 big Verito almost mounted

2 Wolliston modern, affordable

! huge SF KODAK the most difficult

I really like my 3 Imagon as they have better tricks

more are waiting for time

[Daniel Unkefer]

Imagon Tiefenbildner 1 by Nokton48, on Flickr

Imagon Tiefenbildner 2 by Nokton48, on Flickr

Notice how the "belt of focus" is slightly forward in terms of DOF.

Imagon Tiefenbildner 3 by Nokton48, on Flickr

Notice the low values remain sharp.

[jp]

Here's what I've enjoyed with sufficient practice (wasted film and worthwhile images)
Gundlach Hyperion 9"
Verito 7.25"
Kodak 305 on 8x10
Wollaston Meniscus
Magnifying glass with spaghetti measure aperture

I've tried the Fujinon with 4x5 and didn't find it soft enough but depth of field didn't drop off a cliff like a tessar/planar. If you want a gentle smooth triplet like the meyer trioplan, this is a good shuttered option.

I still have to spend some quality time with a wider Verito and a Spencer port-land.

[Daniel Unkefer]

Rodenstock Imagon 1 by Nokton48, on Flickr

Rodenstock Imagon 2 by Nokton48, on Flickr

[russyoung]

Here in ENGLISH are Heinrich Kuhn's instructions for using his Imagon invention: https://www.cameraeccentric.com/stat...s/imagon_2.pdf

Russ