Author Topic: Lens "porn" with the Df: A Pair of Voigtländer APO-Lanthar 125 mm f/2.5 lenses  (Read 10211 times)

Bjørn Rørslett

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[ Posted 09 January 2014 - 14:58 Reposted and edited by agreement ]

Here something to warm the heart of the manual-lens friends: my pair of Voigtländer APO-Lanthar 125 mm f/2.5 lenses with the Df. Both are CPU-modified of course. I realised a backup sample was needed as my primary copy has been pretty beaten up by now. This is a lens I simply cannot be without. Once again 'Dr. Lens' aka NG member Erik Lund to the rescue. He rebuilt a Canon FD version of the famous and elusive 125 APO-Lanthar to have F-mount and added the CPU while he was at it. So, now the APO-Lanthars join the growing ranks of lenses coming in pairs for redundancy (UV-Nikkor 105/4.5, 35/1.4, 50/2, 200/2 etc.).

The hood on the oldest copy is permanently fixed (red tape). I have had many questions about that and now you know the simple answer.

Be aware that the external appearance of solidity and ruggedness, often touted on various forums as indication of the quality of this lens,  does not extend entirely into the deepest innards of the APO-Lanthar. It is liable to have issues with knocks and bumps in particular to the front, to the extent that some of the internal holding screws can shear off and almost make the lens split into two. Alternatively, annoying focusing wobble can develop. Whenever I visit Erik in Copenhagen, an event taking place several times per year, he always looks the lens critically over and brings it up to par again.

The other APO-Lanthars of the fabulous Trio (90/3.5, 180/4) haven't exhibited similar issues, but to be fair, they haven't seen the extensive use as their 125 APO brother either. So the jury is still out.

Erik Lund

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Re Voigtländer APO-Lanthar 125 mm f/2.5 lenses
« Reply #1 on: June 29, 2015, 14:52:27 »
A very capable set this one!

If anyone is interested the conversion of these lenses to Ais Nikon F-Mount ia not so difficult unless you off course try to make it difficult for yourself as I did the first time...

The lens is from the outset by Voigtlander Cosina design made as a modular design, so the Canon FD, m42, Olympus, Nikon F et all, are all made up from a standard housing with Helicoil, aperture, optics etc. and a rear control part that contains the aperture lever and couplings and of course the mount itself.

The distance from the mount to film plane is the easily adjusted to fit the camera, no problem in that...

So far so good - except Canon and Nikon have opposite directions for control and activation of the aperture functions so the Nikon version has a reversing mechanism build-in for this into the rear control part...

The first time I did the conversion I used an really old Pre-Ai F-Mount without screw holes, since they are completely different for Voigtlander lenses drilled the holes and and build the reversing levers by hand, it was a rather time consuming work, luckily I had a original 125mm 2.5 Ais Mount to copy the measurements from and in the end I got it to work many hours later and with a CPU G-Type from Bjørn it was perfect...

By chance some time later I got a Voigtlander 40mm f/2 mark I, with Nikon Ais F-Mount and noticed that the mount looked familiar...
Imagine my surprise when I took it apart and saw that the mount was exactly the same as on the 125mm 2,5 - 5 minutes later I had switched the mount to the 125mm 2.5 and it was a perfect fit!

Naturally the aperture ring show 2.0 but it's not needed to be adjustable since it's a G-Type CPU...

Small warning, make sure to check for internal interference when modifying these 125mm 2.5, in Bjørns sample there was a little leaver that rotated when vibrated and got caught form time to time we had to fix.

And yes they look strong on the inside but believe me, I have repaired Bjørns 125mm 2.5 since the first day we met at the NikonGear safari in 2009 and I have repaired/adjusted it almost every time we have been together since - That is about 2 to 3 times a year!

I have converted/repaired this lens for several people over the years it is very fragile inside so please try to take care of your samples out there!

Probably the optically finest general use close-up optics out there.
Erik Lund

Jethro Sang

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Wow, it is already rare enough, and you have got second copy? It is such a shame that voigtlander does not produce more. Surely the raw material is not that expensive...

Bjørn Rørslett

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[ Posted 12 January 2014 - 23:28 ]

I used the 125 mm f/2.5 APO-Lanthar for the first time with the Df today. Suffice it to say  was not disappointed ...
The APO-Lanthar produces vibrant  colour which just jumps off the screen. An example,

One cannot complain about sharpness of detail (100 % crop),

The 125 APO-Lanthar will enter the core lens set for the Df. I already have allocated the second CV 125 copy to my D800 as the main lens for that camera. Saves valuable time when you plan lens kits for an upcoming trip.