Heads up: Canon FDn 50mm f/1.4

[JKT]

I don't recall seeing this tested, so I had some fun with the FDn 50mm f/1.4. It required making a small part used to wedge the aperture lever open and to modifying a lens cap by removing the back surface and the small notch that prevents the lens cap from rotating all the way.

All the lines in test images consist of 1:1 crops from center, top, side and corner of landscape image taken by Canon RP (FF, 26MP).

The first set was with FDn 500mm f/4.5, but that was taken before I had figured how to open the aperture. As a consequence I have no idea what the aperture actually was. A bit soft, but also pretty clean I'd say.

Then I tried with S-K Makro-Symmar 120mm. The tested apertures are 2.0, 2.3, 2.8, 3.3 and 4.0, but the first is omitted due to max image size. The field is not quite enough in the 50mm ... or it is just too large for the aperture in S-K. However, d24 circle seems nice starting from f/2.8.

That leaves two 180mm lenses: S-K Componon 180 and Canon EF 180mm f/3.5. The first is tested with apertures 1.4, 2.0, 2.8 and 4.0. The second with only 2.0 and 2.8. The first is pretty good at 4.0. It might have worked with 3.3 as well. There is some vignetting and softening at the corner, but otherwise the result is good. With the Canon the aperture 2.8 is almost enough - the vignetting seems to be due to the 180 as it is pretty much similar with many lenses.

I'd say the FDn 50 shows promise. With FF the selection of tube lens would be critical, but with APS-C it might work well with a number of tube lenses. Too bad the wider apertures won't work.

[chris_ma]

interesting idea. I take it from the description that these are stacked setups?

I don't quite see why the 50mm 1.4 FDn would be more promising than pretty much any other 50mm though.
I mean, it looks to me that best results are with F4 (or possibly smaller since IQ was still on the upslope), so why not take a lens like the Nikkor Ai 55mm 3.5 (or the Nikkor Ai 50mm F2 or any high quality 50mm)?
My first guess is that this would very likely result in higher image quality, but maybe I'm missing something?

[JKT]

interesting idea. I take it from the description that these are stacked setups?

Yes.

I don't quite see why the 50mm 1.4 FDn would be more promising than pretty much any other 50mm though.

Well, the results were better than my results with two S-K C-S 50mm lenses and THAT is something I have not been able to understand. I suppose I have to re-check the makro-iris both ways just to see I have not messed it up that way.
Nikons may be better, but I don't have any. If you have, have you tested them?

[chris_ma]

Well, the results were better than my results with two S-K C-S 50mm lenses and THAT is something I have not been able to understand.

yeah, that's certainly strange. first thought that maybe it has something to do with the combination of the tube lens, but my only experience with stacked setups is through carefully reading Robert tests.

Nikons may be better, but I don't have any. If you have, have you tested them?

I haven't tested them as stacked combos (or rather any stacked combos). I somehow assumed that by F4 or F5.6 the differences between different 50mm vintage lenses won't be very big, but maybe it is.

[RobertOToole]

Hi JKT, Chris,

Well, the results were better than my results with two S-K C-S 50mm lenses and THAT is something I have not been able to understand.

yeah, that's certainly strange. first thought that maybe it has something to do with the combination of the tube lens, but my only experience with stacked setups is through carefully reading Robert tests.

I agree about the SK 50mm lenses. I have not been able to generate any good results from them stacked, especially corners. I've wasted a lot of time trying. That said, I haven't given up yet, I have a M-Componon 50mm that I need to try out with about 5 or 6 other 50mm lenses, on extension and in a stacked setup.

M-Componon 4/50
Lecia Photor 4/50 late model (loaner)
Componon-S 2.8/50 Makro-Iris
Rodenstock APO-Rodagon N 2.8/50
Rodenstock-P (plain Rodagon optics)
Tominon 4.5/50 (gift)

Nikons may be better, but I don't have any. If you have, have you tested them?

The 120mm? The Nikon 120mm AM was excellent as a macro lens but not so good as a tube lens. The MS-120 was excellent at both.

The 55mm Nikon macro lenses, in my tests the front lens element is setback and it causes issues. The fast Nikon 50s, they have some issues with CAs even stopped down. I'm pretty sure thats on my site, not 100% sure though.

I haven't tested them as stacked combos (or rather any stacked combos). I somehow assumed that by F4 or F5.6 the differences between different 50mm vintage lenses won't be very big, but maybe it is.

I've tested fast 50mm lenses and the CAs were an issue even stopped down. That has to be somewhere on my site. I'll take a quick look!

For me the very best quality in a stacked setup has been from 28-35mm lenses. 40mm and 50mm lenses have been disappointing.

Best,

Robert