A Lens for the Left-Hand Side of the Town

... and for the Lens Weight or Price Challenged

The Schneider-Kreuznach Radionar 2.9/50mm looks quite diminutive glued onto the M42-to-EOS adapter
and weighs only about 60g, which beats even the Carl Zeiss Tessar T* 2.8/45mm weighing 90g.
I paid only 3.50 Euros for the Radionar vs. 125.00 Euros for the Tessar.

Canon EOS 350D with Schneider-Kreuznach Radionar 2.9/5cm

extracted from an old 35mm folder camera, a 1938 Balda Jubilette like this one

Veijo Vilva

(Page under Construction)

  • uncoated lens with a low contrast and a certain amount of lens flare
  • FOV corresponds to a 80mm lens on a 35mm camera,
  • manual focus, front cell focusing
  • The Compur shutter was retained, set at T position
  • AV (aperture priority) or M (manual)

  • the lens complex is presently glued straight on an M42-to-EOS adapter. The lens to sensor distance is slightly too short so the lens will focus considerably past infinity and loses the ability to focus any nearer than 1.5m (the original focus range starts at 1m). I'll have to insert a suitable spacer to improve the situation, a spacer of about 0.5mm ought to do it.
    Update: Well, it did. However, I didn't take into account the thickness of the glue and now I'm not quite sure the lens reaches optimum focus at infinity at the full aperture -- probably not as the near limit is about 80cm.
  • changing the aperture is quite awkward -- the lens must be unmounted as the aperture ring is only accessible at the inside of the M42-to-EOS adapter due to the thin spacing. It doesn't matter much, however, as the idea is to shoot mostly at the full aperture.


  • my test procedure isn't very rigorous
  • bad results may be caused by bad focusing as manual focusing in dim lighting isn't any too easy when the DOF for this level of expected sharpness is just a few millimeters in either direction
  • the test only shows that the specific tested lens is at least as good as my results -- even that individual lens might be better, and others of the same make and model may be better or worse
  • anyhow, the equivalent magnification of the 100% crops is just plain sick, i.e. about 48x on a typical 17", 1024x768 CRT. Normally, 8x has been considered a reasonable maximum for critical sharpness from film. At 48x magnification, a 35mm film frame would be about 172cm (68") wide, and even a 1.6x crop factor dSLR frame would be 107cm (42") wide!

At f/5.6

The off-center is soft, but the center is sharp enough for most purposes. (full size)

A 100% crop:

Contrast is rather low. Front cell focusing isn't any too easy as it is quite difficult to prevent fingers
from getting in front of the lens.

A 100% crop from a local contrast enhanced version:

This is pretty good though, of course, no match for a Zeiss Planar 1.4/50mm -- or any other
high quality MC lens for that matter. (Note: the illumination is different.)

For a street lens, however, even this level of sharpness is an overkill.
On a 12" wide print, the above section would be about this size:


A Comparison with my Carl Zeiss Planar T* 1.4/50mm

Schneider-Kreuznach Radionar at f/2.9, full frame scaled down:

Note: slight front focusing due to inaccurate mounting! Contrast is quite reasonable at this image size.

Carl Zeiss Planar at f/2.8, full frame scaled down:

Better contrast, more or less correctly focused at infinity.

Schneider-Kreuznach Radionar at f/2.9, 100% crop:

Reasonably good resolution although not quite properly focused at infinity, lowish contrast, lens flare.

Carl Zeiss Planar at f/2.8, 100% crop:

Blooming in the camera sensor due to the high contrast!
(Not a fault of the lens)

Schneider-Kreuznach Radionar, the same crop after some local contrast enhancement:
Not bad for the price, practically no artefacts at all!
However, the railing at the edge of roof at the lower left corner mostly disappears due to lens flare along with some of the thinner twigs against the sky, but the lower contrast of the lens helps to minimize blooming - even after the applied local contrast enhancement. The Planar definitively looks worse here. Of course, a careful inspection even of the scaled down photos reveals that the Planar is a much better lens than the Radionar -- just as expected. The lowly Radionar, however, does surprisingly well -- especially with some post-processing help.

The above crop as viewed on a 17" CRT at 1024x768 corresponds to a 48x magnification,
and the whole image would be 41" wide. More realistic magnifications would give:

on a 10" wide print

on a 20" wide print

Schneider-Kreuznach Radionar, the whole frame after some local contrast enhancement

All the photos below have been taken at the full f/2.9 aperture, local contrast has been enhanced

I took the following photos under very low contrast conditions, and the focusing is in no way any too perfect. Anyway, using f/2.9 with an old triplet lens is a wee bit silly, but it gives the results I'm after. The Radionar doesn't have the sharpness and contrast of a Carl Zeiss Tessar T*, but all the out-of-focus areas look much better, more peaceful, mostly without any disturbing artefacts. There is some vignetting, but that is at least partly caused by my fingers getting in the way while focusing - front cell focusing on a SLR requires a little bit of getting used to.

In this photo, there is nothing, and yet there is something.
(compare this with a photo taken with a Carl Zeiss Planar T* 1.4/50mm)

A quite reasonable amount of post-processing artefacts in the out-of-focus background.

Even the out-of-focus foreground looks quite nice.

The foreshortening of the perspective given by a 50mm lens seems just right for
street scenes. Focus at the crossing.

(compare this with a photo taken with a Carl Zeiss Planar T* 1.4/50mm)

With a little bit of post-processing with LightZone, the result is quite nice.
Not much use for a more expensive lens, here.
(compare this with a photo taken with a Carl Zeiss Planar T* 1.4/50mm)

A quick, hand-held shot at 1/25s (Vantaa, Finland, 5 Apr 2006, 6.30 a.m.)
The illuminated track numbers (3, 4) flare out being relatively bright.

7 a.m.

A couple of shots at f/5.6, giving an even more favourable impression

Well, the Radionar is no Planar, and the mounting is slightly slanted (the upper ends of the
vertical shots and the right-hand ends of the horizontal ones are a little bit out of focus).
Anyway, the lens still succeeds in giving rather a good account of itself.

A 100% crop

The yellow building is about 700m from the camera, the tram at the end of the street about 800m. This shot was rather underexposed which is why it is a little bit noisy after relighting with LightZone.

(Compare with a photo taken with a S-M-C Takumar 3.5/135 under better circumstances.)

A 100% crop

Levels adjusted.

A 100% crop

At f/8:

A 100% crop

A 100% crop

A 100% crop

The limited resolution and AA filtering of the 350D takes it's toll, and so does the ever so slight haze. Anyway, a quite good performance given the lens flare of the uncoated lens. Also, let's keep in mind that the on-screen crop magnification is quite sick at 48x. On a 20" x 13" print, the size of the above segment would be about

Focus at about 1 m.

A 100% crop

Note the rather nice bokeh behaviour.

Straight against the Sun:

A 100% crop

There is a lot of lens flare, but note the consequently almost total absence of distractive blooming!


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