A macro lens that is not a macro lens - Radionar 50mm


davidwozhere

Link Posted 09/12/2021 - 18:36
There is a whole series of Schneider Kreuznach Radionar lenses, all of which have quite a following. I have shown
results from the 1:4.5 105mm in the past and I have now found time to have a play with my latest acquisition -
a 1:2.8 50mm. Here it is on my K1. (image taken with a 1936 105mm Trioplan).



It came off a completely wrecked post war Balda folding camera and, consequently, didn't cost a fortune. Luckily
the glass was not damaged and the Prontor shutter was mechanically sound. I converted it to an M42 mount but,
since it is a 50mm it is impossible to get it sufficiently close to the sensor of a DSLR to attain infinity focus. But
going the other way, a 20mm extension tube worked wonders and by putting the whole ensemble onto a BPM
Focuslide (their spelling, not mine) I had an absolutely excellent macro lens with a very convenient working distance
of about 9 inches !

All of these subjects are around 1 inch in size and were photographed with the aid of a tripod, the focuslide and an
IR remote. Lighting is extremely dim daylight from a north facing window under dark, cloudy skies, requiring long
exposures. (So I went whole hog with ISO100 and mainly f11).

A damp acer leaf from the garden.



Having taken 20 consecutive images of this for a focus-stack it became apparent that the leaf was busily curling up
as it dried out, making the entire exercise futile - use a dry one next time! I have to ask, "was it necessary, however?"
because the depth of field at f11 in this single shot is just amazing.

This ballpoint pen is much smaller at its business end but the lens has resolved the smear of ink on the ball very well.



And finally, a Polo mint. You would imaging these to be very smooth and shiny if asked to describe one but the
reality is somewhat different. Again, this was taken from a distance of about 9 inches.



What the heck is this?



It was a TeePee interdental brush but has had the brush bit replaced with a 5/8" panel pin
to provide a necessary tool. This particular shutter does not have a 'T' setting but only has a 'B' setting
which will keep the iris open only for as long as the shutter release is depressed. As soon as you release it,
it snaps shut. You can get round this by means of a screw-in, locking cable release but this shutter has no
provision for one. How to hold the release lever down ???

If you look at the very first image, above, you will see a tiny hole just to the left of the word 'Prontor'. Fortunately,
there is nothing behind the front plate just here so by drilling that hole I could insert a locking pin to hold the
release lever in place, thus providing an open shutter until it is removed. The panel pin works fine on its own
but is quite tiny - hence cannibalizing a toothbrush for a handle.

There is always a way to resurrect 'old glass'.
Both the *istDS and the K5 are incurably addicted to old glass

My page on Photocrowd - link

Urbanmeister

Link Posted 09/12/2021 - 18:39
What a fascinating post! So informative. And what a great job you did, davidwozhere. Kudos.
Be well, stay safe.

davidstorm

Link Posted 09/12/2021 - 19:07
Just fantastic and fascinating! The image quality from those old lenses is astounding and the lighting is spot-on. I would be interested to see what happens if you re-did the shots under an artificial light source, such as an LED photo light, in particular whether there would be any chromatic aberrations apparent.

Kind Regards
David
Flickr

Nicola's Apartments, Kassiopi, Corfu

Some cameras, some lenses, some bits 'n' bobs

Defragged

Link Posted 09/12/2021 - 21:06
Urbanmeister wrote:
What a fascinating post! So informative. And what a great job you did, davidwozhere. Kudos.

+1
C.O.L.B.A.S victim
(Compulsive Obsessive Lens Buying Addiction Syndrome)

What you need are lenses, more lenses, bigger lenses, better lenses, faster lenses, and when you have these, your pictures will be perfect!

jeallen01

Link Posted 10/12/2021 - 13:13
Ref the locking pin, if only one could cut the same sort of thread as found in most older shutter release buttons then an old-style locking release cable could be fitted to make timed long exposures easier - alternatively, remove the actual button and superglue it to the shutter panel and screw the cable release directly into that????
K-3 II, K-3 and a K-70 from SRS (having now relegated the K-30 /"K-50" to a backup body), & some Sigma and Pentax lenses (and a lot of old 35mm gear!)

davidwozhere

Link Posted 11/12/2021 - 01:11
There is no provision for a cable release of any kind on this particular shutter. The 'button' on the top is for the electrical contact on the old-style flash guns (I think). Others that only have a 'B' setting do have a screw-in facility for a cable and it works a treat to keep the shutter open. Alternately, you can set the DSLR to B and simply use the original controls on the shutter if you have a cable release. I haven't done that yet - but I will.
Both the *istDS and the K5 are incurably addicted to old glass

My page on Photocrowd - link
Last Edited by davidwozhere on 11/12/2021 - 01:15

drofmit

Link Posted 16/12/2021 - 20:58
Wow! Now this looks fun…. And wonderful resolution. Thanks for sharing this.
Never be afraid to talk about your techniques...
"Give a thousand photographers...
the same camera, lens and scene...
and you'll always get a thousand different takes!!"
Anon.

K10D

Link Posted 18/12/2021 - 11:47
Well done. Impressive work.

Best regards

davidwozhere

Link Posted 18/12/2021 - 14:36
Thank you Tim, Gary - and everyone else who has found my tinkering interesting.
Both the *istDS and the K5 are incurably addicted to old glass

My page on Photocrowd - link
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