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Crazy bokeh from a hybrid lens
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PostPosted: Mon Nov 13, 2017 9:36 am    Post subject: Crazy bokeh from a hybrid lens Reply with quote

Hi folks, long time since I visited here. I wanted to show you something pretty crazy. The story is that I got an old Dallmeyer Octac 80mm f1.5 Oscillograph in a trade, but when the lens arrived I found out that it was only the front element group. Instead of returning it, I decided to try an experiment.

A couple of years ago I bought an Ilex Oscillo Paragon 56mm f1.2 lens very cheap, mounted in a weird electronic shutter. The lens was in great shape, but was pretty useless, because even with the rear element flush on the mount of my Sony A7RII the focusing distance was only centimeters. However the design was similar to the Dallmeyer (two groups separated by a shutter), so I wondered what would happen if I mated the front group of the Octac with the rear group of the Ilex.

The results were pretty surprising. The lens does have a lot of glow, but it is very sharp, and just covers the full 35mm frame with very minimal vignetting in the extreme corners. It has remained a 56mm f1.2, interestingly enough, but I am now able to focus out to several meters using a helicoid. And oh, did I mention the bokeh? Like nothing I have ever seen. Here are the first tries from a walk in the park.
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PostPosted: Mon Nov 13, 2017 9:46 am    Post subject: Reply with quote

Like Dog


PostPosted: Mon Nov 13, 2017 10:36 am    Post subject: Reply with quote

surprisinly harmonic "crazy"
I find the effect best with the red berries, just because of the round shapes
would like to see architecture this way


PostPosted: Mon Nov 13, 2017 10:59 am    Post subject: Reply with quote

You saved a lot of bucks for making a replacement of Super-Six. Congrats


PostPosted: Mon Nov 13, 2017 11:12 am    Post subject: Reply with quote

Like Dog

does the lens have some shiny internals?
I think the bokeh is result of inner reflections


PostPosted: Mon Nov 13, 2017 12:36 pm    Post subject: Reply with quote

Very nice kymarto. In particular I like the lavender coloured poppies. Can you achieve infinity? I ask because I can't help wondering what landscapes may look like under the gaze of such an impressionistic lens.


PostPosted: Mon Nov 13, 2017 12:53 pm    Post subject: Reply with quote

No it’s not a Super Six. I actually have one of those and it’s quite different.

There are various issues with this: one is that the rear inner concave element is smaller than that on the Dallmeyer and has exposed ground glass around the outside. I may try to blacken that and see what happens.

In addition the front surface of the Octac seems to be covered with a fine film of lacquer or acrylic spray. My friend thought it was coating wear but it is definitely raised from the surface. I will have to get some solvent and see what happens. That obviously reduces contrast but also affect highlights.

At distances beyond a meter or so it looks like crap. These Oscillo lenses have heavy negative field curvature and are corrected for close work, usually from 1:0.5-1:1. Focus too far and it just looks bad, with the edges going super soft. You can see that starting to happen in the pic of the cosmos flowers already.

But it is quite fun anyway. As I have (still to my great surprise) a Super Six 8” f2.0 lens, I will post a set from that soon. The Super Six is from a different galaxy.


Last edited by kymarto on Mon Nov 13, 2017 1:51 pm; edited 1 time in total


PostPosted: Mon Nov 13, 2017 1:16 pm    Post subject: Reply with quote

Interesting bokeh effects, a bit too much for me in some shots, but selected ones may work very well!
I had expected the definition to fall apart rapidly with increasing distance, and you already confirmed that.
Those CRT lenses with negative image plane all do...I have a few myself, like the CRT Nikkor-O 1.2/55mm Wink


PostPosted: Mon Nov 13, 2017 1:30 pm    Post subject: Reply with quote

WOW looks like a camera on LSD Like 1 small