Author Topic: ISCO-GOTTINGEN ISCONAR 100mm f/4  (Read 897 times)

Ian R

  • NG Member
  • *
  • Posts: 92
  • You ARE NikonGear
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #15 on: February 25, 2019, 13:56:38 »
The F mount is 1mm longer in register plus the adaptor so any lens able to reach infinity on the F mount with adaptor would well overshoot on an M42 camera. I used a micrometer to set my adapter, and with a 50mm f/2.8 M42 Zeiss Jena, that overshoots infinity just a little. I don't think lens calibration was that exact back then. I calibrated my 100mm shown here by using the moon. Now just before the lens hits the focus stop I can feel the helical just starting to bottom out.

I used to spend hours with a ground glass and a loupe calibrating my old rangefinder cameras. Bit of a waste of time really, but at least I learnt something - and got the cameras working their best.

Roland Vink

  • NG Member
  • *
  • Posts: 1051
  • Nikon Nerd from New Zealand
    • Nikon Database
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #16 on: February 25, 2019, 22:51:16 »
Lovely images and nice rendering. Shows you don't need a super-fast lens to get nicely defocused backgrounds.

rosko

  • Homo erectus manualfocus
  • NG Supporter
  • **
  • Posts: 884
  • France/Uk
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #17 on: February 26, 2019, 09:09:44 »
There are a number of M42 lenses which can reach infinite focus with a very slim F-M42 adapter, especially if the focal length is longer than 85mm.

We can say that. in my experience, I get infinity provided with F bodies if you stop down toward f/22 thanks a deeper DOF. At full aperture I don't. (using the 100mm f/2.8 trioplan)

This is why I am expecting a true infinity with a M42/Z adapter ring I ordered recently for my Z6 I bought few days ago.

Wait and see, but I am glad Ian confirmed it... :)
Francis Devrainne

Ian R

  • NG Member
  • *
  • Posts: 92
  • You ARE NikonGear
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #18 on: February 26, 2019, 20:55:17 »
We can say that. in my experience, I get infinity provided with F bodies if you stop down toward f/22 thanks a deeper DOF. At full aperture I don't. (using the 100mm f/2.8 trioplan)

This is why I am expecting a true infinity with a M42/Z adapter ring I ordered recently for my Z6 I bought few days ago.

Wait and see, but I am glad Ian confirmed it... :)

Did you order the Pixco adapter? That reached infinity perfectly, however a couple of points. The Pixco is exactly 0.1mm too short. This is by design, but its good that it is an exact figure as by adding a 0.1mm shim under the metal threaded insert you are now spot on to M42 standard. Coper tape is conveniently 0.1mm. Also the internals are not treated with any anti-reflective material. I added my own high quality flocking.

Now I feel happy that I have got it right as can be and I can hunt down some more M42's.

rosko

  • Homo erectus manualfocus
  • NG Supporter
  • **
  • Posts: 884
  • France/Uk
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #19 on: February 26, 2019, 21:58:40 »
I've ordered this one : https://www.ebay.co.uk/itm/M42-screw-mount-lens-to-Nikon-Z-mount-full-frame-mirrorless-camera-adapter-Z6-Z7/401646385553

This is Roxsen stuff which I know already the quality. But it is written ''Pixco'' on the item. It seems black inside but no mention on the description. Will see when I get it.

I love the aluminium body lenses : I am seeking a primagon 35mm (meyer optics) in M42 mount. Unfortunately, there are mostly in Exacta mount. ::)

Francis Devrainne

Ian R

  • NG Member
  • *
  • Posts: 92
  • You ARE NikonGear
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #20 on: February 26, 2019, 22:30:47 »
That's the one Rosco. Very nice machining - I appreciated that - but do add some internal light damping if you can. I had some black 1mm light trap felt which was just enough to do the inside. If you don't, you may run into instances where the light bounces about inside.

FGAng

  • NG Member
  • *
  • Posts: 86
  • Mixing the old and the new Nikkors
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #21 on: February 28, 2019, 01:53:30 »
I am guessing the rear element of this lens is recessed in and thus won't hit the mirror of a FX Nikon when adjusted to infinity, is that correct?

Can you describe how with a screw driver infinity is adjusted?

Thanks.

Ian R

  • NG Member
  • *
  • Posts: 92
  • You ARE NikonGear
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #22 on: February 28, 2019, 11:46:59 »
I am guessing the rear element of this lens is recessed in and thus won't hit the mirror of a FX Nikon when adjusted to infinity, is that correct?

Can you describe how with a screw driver infinity is adjusted?

Thanks.

Absolutely no mirror interference - there is only the lens mount at the rear.

To set infinity you remove the front lens ring with a rubber lens wrench, then loosen the three screws underneath - this allows the focus collar to move independently from the optics. You can then set up the focus to match your adapter and re tighten the screws.

FGAng

  • NG Member
  • *
  • Posts: 86
  • Mixing the old and the new Nikkors
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #23 on: February 28, 2019, 13:12:54 »
Absolutely no mirror interference - there is only the lens mount at the rear.

To set infinity you remove the front lens ring with a rubber lens wrench, then loosen the three screws underneath - this allows the focus collar to move independently from the optics. You can then set up the focus to match your adapter and re tighten the screws.

Thank you that is very helpful.  So long as the movement range is not too big this is a simple way to achieve infinity focus.

Bent Hjarbo

  • NG Supporter
  • **
  • Posts: 1002
  • Hvidovre, Denmark
    • Hjarbos hjemmeside
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #24 on: March 12, 2019, 08:38:24 »
I've ordered this one : https://www.ebay.co.uk/itm/M42-screw-mount-lens-to-Nikon-Z-mount-full-frame-mirrorless-camera-adapter-Z6-Z7/401646385553

This is Roxsen stuff which I know already the quality. But it is written ''Pixco'' on the item. It seems black inside but no mention on the description. Will see when I get it.

I love the aluminium body lenses : I am seeking a primagon 35mm (meyer optics) in M42 mount. Unfortunately, there are mostly in Exacta mount. ::)
Have a look here: https://www.photohaus.de/shop/meyer-optik-primagon-45-35mm-m42/

rosko

  • Homo erectus manualfocus
  • NG Supporter
  • **
  • Posts: 884
  • France/Uk
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #25 on: March 12, 2019, 14:20:27 »
Have a look here: https://www.photohaus.de/shop/meyer-optik-primagon-45-35mm-m42/

Thanks for the link, Bent !

I had a look (with the help of Google translate ! :))

Price is correct but the postage is too expansive (29)

I just got an adapter (Exacta to Z) in case... ;)
Francis Devrainne

Bent Hjarbo

  • NG Supporter
  • **
  • Posts: 1002
  • Hvidovre, Denmark
    • Hjarbos hjemmeside
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #26 on: March 12, 2019, 16:06:46 »
You are welcome Francis.
The postage is too high for items that cost 69 :o

rosko

  • Homo erectus manualfocus
  • NG Supporter
  • **
  • Posts: 884
  • France/Uk
Re: ISCO-GOTTINGEN ISCONAR 100mm f/4
« Reply #27 on: March 13, 2019, 11:42:32 »
The postage is too high for items that cost 69 :o

And regarding the size/weight (155gr.) ! :P :D
Francis Devrainne