Prewar - Fed 50mm f/3.5 macro m39 mount PT5620

mfkita · Joined: 29 Jul 2007 Posts: 222

...it's a winner!

GP · Joined: 12 Jul 2013 Posts: 29

Your lens looks so stern on your Olympus. I don't know why, but somehow it reminds me of battleship Potemkin.
Now, if someone made a similarly robust looking digital camera .... that would be a cool thing to walk around with.

Lightshow · Joined: 04 Nov 2011 Posts: 3669 Location: Calgary

Any chance we can get the pictures reuploaded? I'd love to see them. Thanks in advance.

Nordentro · Expire: 2015-01-29

A7R

OMD

Lightshow · Joined: 04 Nov 2011 Posts: 3669 Location: Calgary

Thankyou very much. Smile

Seems to have good resolution for such an old lens.

Alex Kraus · Posted: Fri Jun 02, 2023 8:11 am Post subject:

I was also able to get hands on a sample of this rare lens Smile

The lens was in unusuable condition when I bought it (the damage was known and I got it cheap). The cemented rear element was extremly scratched (like an ice hockey field after the game) and the cementing had started to separate.
It was absolutely clear that the rear glass lens pair needed to be replaced in order to make the lens usuable again. Fortunately, I owned an ordinary FED-10 collapsible (postwar production) that should have the same optical formular. However, it turned out that the brass fitting of the rear element of the collapsible FED had a different thread than that of the Macro version. So I had to take the glass out of the brass fitting and "transplant" it into the original brass fitting of the macro. This was not easy because the brass was crimped over the glass edge, but with a cutter blade I could bend the rim out and replace the glass! After the new glass was in place, I crimped the brass back over the glass edge in order to fix its position (I used a wooden rod as a tool).
Now it is working again like new Smile

Here are two tests shots I took yesterday evening (@f:6.3) after the repair was finished:

Test shot by Alexander Kraus, auf Flickr

kiddo · Joined: 29 Jun 2018 Posts: 1120

Beautiful results, can you post a pic of the lens?

Alex Kraus · Posted: Fri Jun 02, 2023 9:13 am Post subject:

Alex Kraus · Posted: Sun Jun 04, 2023 9:07 am Post subject:

Here are some pictures of the lens:

This lens is NOT rangefinder coupled and the flange distance is NOT the expected 28,8mm for Leica M39, it is actually 35,5mm! Strange...

Alex Kraus · Posted: Sun Jun 04, 2023 1:26 pm Post subject:

Some more pictures:

Iris germanica by Alexander Kraus, auf Flickr

Wide open my specimen shows a lot of spherical aberations, which quickly disappear at f<4.5. This might be a consequence of the exchange of the rear element from another FED-10 (collapsible) 3.5/50mm. I don't know. On the other hand, the sharpness drop towards the corners is now definitely less as with the original collapsible FED-10. Also the lateral chromatic aberations in the corners, visible with the collapsible version (post war), is not visible withe the FED Macro after the "transplatation".

Stopped down to f:6.3

Iris germanica by Alexander Kraus, auf Flickr

Anyhow, since the lens was totally unsuable before the surgery, I'm very happy with the result Smile

Alex Kraus · Posted: Sun Jun 04, 2023 1:27 pm Post subject:

f:6.3

Hieracium aurantiacum by Alexander Kraus, auf Flickr

Alex Kraus · Posted: Sun Jun 04, 2023 4:56 pm Post subject:

It seems that exchanging the rear element did lead to an increase of the focal length and hence the increased flange distance of 35,5mm instead of 28,8mm.
I therefore also exchanged the front element (took it from the same collapsible FED-10 as for the rear element). Now the focal length is back to 50mm and the flange distance is 28,8mm as it should be.

Alex Kraus · Posted: Sun Jun 04, 2023 6:26 pm Post subject:

The exchange of the front element not only reduced the focal length, it also had a siginificant impact on the wide open performance:

Iris Germanica by Alexander Kraus, auf Flickr

This picture was taken at f:3.5 and the strong spherical aberation is now reduced and the bokeh is much smoother!

Alex Kraus · Posted: Sun Jun 04, 2023 6:32 pm Post subject:

A bit closer and stopped down to f:6.3:

Iris germanica by Alexander Kraus, auf Flickr

Side effect of the element exchange: 3 of 4 elements are now coated Smile

serkol · Joined: 26 Aug 2012 Posts: 896 Location: Belarus

Intrestihg result

caspert79 · Joined: 31 Oct 2010 Posts: 2921 Location: The Netherlands

Beautiful pictures!

Alex Kraus · Posted: Wed Jun 07, 2023 8:35 pm Post subject:

Thank you.
The color rendering of the lens is now much more vibrant due to the fact that 3 of 4 elements are now coated. Smile

Alex Kraus · Posted: Fri Jun 09, 2023 8:34 am Post subject:

Yesterday, I finally figured out how to completely disassemble the FED Macro. I cleaned the helicoids and I cleaned and blackened the aperture blades as well (they are made of brass and were quite golden shiny at some spots. On this occasion I also took the opportunity to exchange the last remaining uncoated lens element against a coated post war one. The the lens is fully coated now Smile

Some fresh examples:

Relaxing by Alexander Kraus, auf Flickr

Wild rose by Alexander Kraus, auf Flickr

Geranium by Alexander Kraus, auf Flickr

First roses in my garden by Alexander Kraus, auf Flickr

Alex Kraus · Posted: Fri Jun 09, 2023 4:02 pm Post subject:

Corn flowers / Kornblumen (Centaurea cyanus) by Alexander Kraus, auf Flickr

Alex Kraus · Posted: Fri Jun 09, 2023 4:02 pm Post subject:

Summertime by Alexander Kraus, auf Flickr

Ultrapix · Joined: 06 Jan 2012 Posts: 551 Location: Italy

Your pictures are forcing me to try better my collapsible Industar... really good samples thanks for sharing

Alex Kraus · Posted: Sat Jun 10, 2023 9:30 pm Post subject:

FED Macro f:3.5 / 50mm by Alexander Kraus, auf Flickr

Unfortunately I accidentally polished the front engraving partially off in an attempt to restore the chrome finish. Since the partial engraving looked bad, I decided to remove the engraving completely and regalvanize it.
Maybe I find a way to replicate the the engraving later... Sad

Alex Kraus · Posted: Sat Jun 10, 2023 9:32 pm Post subject:

Candles by Alexander Kraus, auf Flickr

Alex Kraus · Posted: Sat Jun 10, 2023 9:33 pm Post subject:

Potentilla palustris (Sumpf-Blutwurz) by Alexander Kraus, auf Flickr

Alex Kraus · Posted: Sun Jun 11, 2023 2:58 pm Post subject:

Sarracenia purpurea by Alexander Kraus, auf Flickr