How to test Soft Focus lenses

[Paul Ewins]

I commented in another thread that I still haven't tested a lens that I have owned for a number of years. I've got quite a few soft focus lenses along with others that are merely old or "interesting" and they cover a number for formats (35mm, MF, 4x5, 8x10) and I am struggling to come up with a testing method that would give them the best chance of success. I'd rather not be wasting 8x10 negs testing things that were never going to work in the first place.

Since I am most interested in using them for portraits ideally the test would involve a live model. What I would like to do is to find one or two lighting set ups that will work with soft focus and can be repeated easily. I guess that is the first assumption on my part, that only some situations will create the "look" that is associated with these lenses or that shooting in natural light may produce a different result to tungsten lighting or strobes.

So if anybody has some ideas or guidance I'd be interested to read your thoughts on the subject. Also tips for the particular types of lenses - e.g. never do X with an Imagon, or Veritos work best with Y and so on.

[eddie]

it is hard to keep track of which neg is which lens. keep careful notes (i never do!) i change the models, the clothes, and the props to help me keep them all straight. start with 1 or two lenses.

i would shoot them all two stops down from wide open at 1st. this makes most all of the lenses very "easy to use" some of the achromat lenses and the verito lenses are a bit too wild for me to just jump right in an bang away wide open. many people do it very well...check out galli, stephane, and sawyer to name a few. they all got it right on. me on the other hand need a bit of a learning curve.

after you get some decent negs open them up more and see how you do.

after that try changing your exposures and see how this affects the glow. it has a dramatic affect on many formulas. stephane recommends at least 2 stops over exposed.....over and above your calculations including bellows factor. (best part of this is over exposing on fast shutter-less lenses is easy to do....:).

you should print the negs. i find my computer/scanner hates my negs. others have better skills and can scan the neg. i suggest printing some any way. printing exposures have less impact that negative exposures but they do allow for some control.

obviously the exposures will need the appropriate development. (i have not really go that far along but as we all know it controls the highlight value so it is important.).

change the light source. use a soft box. another set up use direct hot lights. both affect the glow in a different way. change the background from light to dark. how the highlights glow can be easier seen with different light and dark values. pay attention how the shadows also soften. this can be seen when they spill onto a lighter back ground.

i hope this helps to get you started. have fun. make prints and sit down and study them side by side.

look at this thread (http://www.largeformatphotography.info/forum/showthread.php?t=69809) about focusing soft focus portrait lenses.

keep us posted

eddie

[Darryl Baird]

I often use paper negs to start, using the first few apertures from wide open to about f/8 or f/11... after that, most SF lenses just get too "sharp." I write down which lens is first, mark my film holder with numbers, then unload and process in the same order... I write down info on the negative storage sleeves for later review. I used to try to make stickers to place into each shot, but it became a struggle to get a good test and worry about the info on the cards...

VC resin paper with a yellow filter seems to give longer tonality to see effects of that softness. For me, film is the next step in testing. I test all the lenses on the same subject, trying to keep the focus and DOF the same... it gets more complicated when you begin to stop down... and harder to see the soft effects... I like to include metal or something shiny to evaluate specular highlights... or at least something very white.

FYI, before beginning on a series last summer, I conducted about 5 or 6 progressive lens tests to determine which of my lenses would work best. I narrowed it to three, but I still have some trouble distinguishing between two SF lenses I use of the same focal length. My 300mm Velo II and Kodak Portrait both perform close enough under medium to low contrast light, but really change when the light is contrasty or there are very white/light value subjects... I have started taking notes on the voice recorder in my phone to help me remember which lens and aperture I use for which shot. It takes time, but its well worth it to better predict the end results.

Keep shooting till you know your lens is my best advice... (and buy cheap or outdated film for testing!)

[Dan Fromm]

Paul, when I run lens tests without cutting corners I include a sheet that indicates the lens and aperture in the shot. Not hard to do, just one more damned thing.

[cowanw]

One problem is that tastes change and are different anyway. For example, vis a vis, Eddie's reference to Stephane suggesting two stops overexposure. This would be at variance with the Imagon's instructions by Heinrich Kuhn, which warn against too much exposure.
I am sure neither is wrong. Each is looking for a different look.
I find the more diffuse a lens the less exposure I want. A fully open Verito will get one half to one less stop than a fully open and fully soft Cooke.
But I am a Luddite who admires the portraiture of the 1930's.

[Stephane]

Using paper will only help you in testing the way you focus. And this could be a tricky part at first. Testing exposure with paper negs and translating to negatives might not necessarily be strait forward.

The 2 stops over-exposure on the negatives works for me, or at least I like the results. I also develop in cold (16degC) rodinal 1:100. Obviously I am after low contrast and nice mid-tones. I chose to over-expose because I was not happy with normal exposure and development "look".

The way I tested was to stick to my over-exposed negatives and find the development times that were pleasing (to me).

You will have to learn from few mistakes before you will be pleased. You can of course start following some of the steps that work for some of us, and choose your path (of departure).

Start with normal exposure and development and see if you like or not the results, and adjust from there.Testing is not wasting, at least in the long run.

And yes, take notes because it is very difficult to remember or guess what lens was used for that shot.
And it is a very good idea, most likely a must, to practice on live models, because inanimate objects are very different to a person's face.

[Mark Sawyer]

If your interest is in portrait work, Stephane is very correct; nothing inanimate replicates the look of living skin. The problem in the "testing" phase is that it's rather difficuly to recreate the pose and focus shot-to-shot. I've noticed Jim Galli often arranges still lifes that allow wonderful and accurate comparisons, especially with the small apecular highlights, but that gets away from the portraits. And the same lens will give a quite different look moving from a still life of a twig in a bottle to a human face.

For that matter, be aware that the same lens will have a different look according to aperture, lighting, and film and processing choices. As far as "testing" goes, I'd just jump right in and start using them. I think the big learning will be in processing and printing the negatives for the print you want, not in how one lens is different from another. A feel for them will come, and then you can comfortably switch between them or start using a new soft lens and know what to expect.


Also tips for the particular types of lenses - e.g. never do X with an Imagon, or Veritos work best with Y and so on.

I break those rules constantly. On an Imagon, one "never" uses soft light or the aperture wide open, but I like them that way. Bob Salomon properly chides me for using the conventional aperture rather than the factory h/stop disks, but I find the Imagon works well both ways. Just goes to show...

As far as focusing goes, if you stay with lenses that achieve softness via spherical (rather than chromatic) aberration and use conventional film without filters, what you see on the ground glass will be pretty much what you get on the negative. I remember Kodak goes into a great deal of detail about different techniques for focusing the Kodak Portrait Lens, but it could all be summed up as "the spherical aberrations are over-corrected, so the faint depth-of-field gain is to the far side". (And that seems to be true for most soft-focus lenses.)

[Darryl Baird]

..SNIP>>>
As far as focusing goes, if you stay with lenses that achieve softness via spherical (rather than chromatic) aberration and use conventional film without filters, what you see on the ground glass will be pretty much what you get on the negative. I remember Kodak goes into a great deal of detail about different techniques for focusing the Kodak Portrait Lens, but it could all be summed up as "the spherical aberrations are over-corrected, so the faint depth-of-field gain is to the far side". (And that seems to be true for most soft-focus lenses.)

Brother-in-Softness Mark, I've got to respectfully disagree here about WYSIWYG as far as SF lenses. I've come to expect that the obvious flare/halation/whatever I experience on my Sinar ground glass is not an accurate depiction of what my film will render. It is usually sharper than I can "see" with my loupe or magnifying focusing hood. I rack the rear focus a lot and look for the "just focused" points as they go in and out of focus while turning the focus knob. I really never COMPLETELY know what I'll get until I've printed the image and I really like that... it makes me feel like I'm hurling myself off a cliff and always expecting a soft landing (wow, a better metaphor than I first imagined - :-} )

Maybe I'm just going blind. I turned 60 last February... lol :eek:

[Stephane]

Hey Paul! And if you are not 60 yet (;)), dont use a loupe, but instead stand as far as you can from the gg to appreciate the effect of diffusion!

[Mark Sawyer]

Hey there, Darryl! Maybe it's just that my young 54-year-old eyes are better than yours! ;) I can usually call the amount of softness off the ground glass pretty well, but having used the soft lenses for quite a while now, maybe I'm subliminally adding some experience to the mix.

But I was speaking more towards focus than effect, and early experiences focusing with the soft lenses can be a little bit of a trick. We use them at near-wide-open apertures where focus is critical, and the softness coupled with the faint spreading of the zone-of-focus makes the desired focus point less obvious than with a sharp lens. My only advice is patience and knowing what to look for. Judicious use of the sings and tilts at the rear become a major part of focusing too, but for all these things, I feel I can trust the image on the ground glass.

[Paul Ewins]

Thanks guys, that gives me a few things to start with. I have done some testing recently for using flash bulbs and usually have a piece of note paper in shot with the appropriate details on it.

I guess I'll just start with a conventional head and shoulders with 2:1 lighting at 45 degrees either side and see how that works. It'll probably be tungsten lighting since that will probably make it easier to focus. Method will probably be wide open, then two stops down (refocus as required) and maybe trying two stops down with two stops over exposure as well while I'm at it. The control lenses for the LF stuff will be plasmats, probably at f11.