Wollensak Cine-Velostigmat F1.5/1 inch tests

[Andy Perrin]

Credits: Earlier discovered by Iggy and possibly others (Klaus, I think), but these are my experiences.

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I will add to this thread as I do more with the lens.

 

My first shot (full spectrum). Have you ever REALLY looked at your shoe? Certainly there is plenty of vignetting. The bokeh on this one does not look particularly nice to me? Perhaps it's just this particular photo and my still-poor photography skills!

 

NEX-7, Cine-Velostigmat, F/1.5 0.00625" iso100

[igoriginal]

Interesting shot.

 

The UV-capable Wollensak lens discovered by Klaus was a different model (different focal length and aperture range, entirely) than the one which I have discovered. Although it is also possible that he later stumbled across the same find, after I did.

 

About the unique "swirly bokeh" (due to the 'Petzval Field Effect' of the optical design) of the Cine-Velostigmat: You will not notice it so much, unless you shoot against a highly patterned or well-textured background (such as tree branches/woods), not against flat, featureless, single-color backgrounds such as walls and doors. This effect is also most pronounced when shooting with the aperture wide open (of course), and the background has to be completely OOF (out of focus) and far removed from the DOF (depth of field) of the focused subject. In the case of your photo, the wall is still relatively close to the DOF of your focused-upon foot.

 

Try this: Go outside, find a dense patch of woods or shrubs which are at a good distance behind your focused-upon subject (and also fill up the entire frame, right to the edges), then shoot wide open, and see what happens. :)

[Andy Perrin]

Noted, Iggy.

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UV test using a small 330WB70 filter (not the same one as the 330WB80 in the El-Nikkor 80mm test from the other thread):

 

Center of the image is reasonably sharp, but there is quite a lot of aberration toward the edges. Many kinds of aberration. Chromatic, spherical...all kindsa fancy stuff! Also, the dichroic filter effects become pretty intense. No lens shade. I should probably do something about that. I bet a toilet paper cardboard thingy would do.

 

F1.5 1/13" ISO3200

[Andrea B.]

And also try some shots from between 5 - 10 feet to make use of that cine swirl for artistic purposes, yes?

[igoriginal]

Since Andy made a post about using his Wollensak 1 inch F/1.5 Cine-Velostigmat on the APS-C sensor of his full-spectrum-modified Sony camera, I felt that it was pertinent to add some of my own findings with regards to comparing the VIS/UV images from the 25mm Cine-Velostigmat up against the images derived from a UV-capable lens of my own design with the same 25mm focal length: My "PUPIL 25mm F/4" UV lens.

 

NOTE: I am not trying to deliberately solicit my own lens, to be clear, but rather that this was the only other 25mm UV-capable lens that I have to compare to, which I design to be specifically dedicated for the Sony NEX/E-mount system and use on a regular basis when I require wider angles.

 

As it turns out by my head-to-head image tests of the Cine-Velostigmat F/1.5 against my PUPIL 25mm F/4 lens (see images below), both lenses transmit equal amounts of UV (down to about 325 to 330nm, roughly), but my own testing confirms that the Cine-Velostigmat does indeed exhibit some moderate corner vignetting on the Sony APS-C sensor, unlike my 25mm UV lens.

 

Furthermore, I was shocked to discover that it also appears that the "1 inch" designation of the Cine-Velostigmat has been a bit exaggerated on the manufacturer's part (Wollensak), because you can very evidently discern by the images below that the Cine-Velostigmat is not a true 25mm focal length, contrary to its stated "1 Inch" designation. It appears to be closer to around 28mm to 30mm, or so (whereas my 25mm F/4 UV lens is a true 25mm focal length).

 

On top of this, with the apertures on both lenses stopped down to F/4 and the ISO remaining at 400 for all photos, to remain as consistent as possible, it appears that the Cine-Velostigmat renders significantly softer results along the edges of the image frame, compared to my 25mm UV lens.

 

Please don't get me wrong: This is not an intentional attempt to strike down the Cine-Velostigmat, generally speaking, but only reaffirms that this lens doesn't fair very well on an APS-C sensor (although it does much better on a Micro-4/3 sensor, or smaller). To be sure, it's a sufficiently uv-capable lens for general, spur-of-the-moment snapshots and such. But in light of these comparison tests, I will not be reaching for the Cine-Velostigmat if and when I want to derive better-quality UV images at wider angles (especially landscape UV photographs) on the Sony E-mount/NEX APS-C sensor.

 

ADDITIONAL NOTE: To be fair, the Cine-Velostigmat does have its strengths, too. For instance, it has a larger starting aperture of F/1.5 (at its "fastest" setting). Thus, it may still be a better choice (vignetting and significant corner-softness notwithstanding) if one requires faster shutter speeds as their priority (e.i. - for tripod-free/lower-ISO UV imaging by hand), rather than image quality and edge-to-edge frame coverage. But again, this strengths-versus-weaknesses assessment only pertains to usage of this lens on the APS-C sensor of the Sony E-mount/NEX system. On other systems with smaller sensors (Micro-4/3 and smaller), one can expect the Cine-Velostigmat to offer whole-frame coverage and improved corner sharpness due to utilization of an increasingly cropped area of the image circle. I should also be additionally fair and consider the fact that some people like having a moderate vignetting effect with some lenses of "character", such as the Cine-Velostigmat. Oh, and there is certainly that "swirly bokeh" effect, too, isn't there? I happen to like that characteristic for certain image project goals, as well.

 

I hope that this quick review adds some additional insight to this thread.

 

(Andrea, please do not kill me. Haha. This was not an intent at solicitation of my own lens offerings, but just to place things into perspective. Obviously, my own 25mm UV-capable lens is not the ONLY 25mm [or even wider] lens out there which is capable of significant UV-pass ability. However, it's the one that I am working with, when it comes to APS-C sized sensors of mirrorless bodies, because it is also the least expensive to put together compared to the majority of the more expensive lens offerings out there).

 

[Andrea B.]

It's OK, Igor. This is a useful comparison and discussion. :)

[Andy Perrin]

(He shared this with me by direct message earlier, so to confirm, this really isn't soliciting. And it was interesting.)

 

Honestly, for my camera (the NEX) I see this as a special-effect lens. I'm hoping for good SWIR transmission also, but really it just amuses me to have an antique lens on a modern camera, and we will see what we can do with that, accepting its limitations and quirks. (Besides, I enjoy posting these shots to Instagram with the "#nofilter" tag, and watching people try to figure it out!)

[Andrea B.]

Klaus has made many interesting and beautiful photos with cine lenses. I love the "swirl" myself.

 

Older lenses certainly do have their fascination in spite of certain features like vignetting or softness or unusual bokeh or whatever. It's all about photographic context. Sometimes we want those effects, sometimes we don't.

 

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