• Ultraviolet Photography

Canon FD 50/3.5 macro, a simple UV macro lens?

UV Lens
3 replies to this topic

#1 UlfW

    Ulf W

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Posted 15 August 2019 - 14:49

By chance I started with the Canon FD manual focus system, when I got my first SLR in the early eighties, last century.
One of the lenses that was very special for me was the FD 50/3.5 macro.
It replaced any faster normal lens for me and was a real pleasure to use.
I liked it because it was quite sharp and easy to use, focusing directly to 1:2 with its long helicoid.
To reach 1:1, there was a 25mm extension ring, normally delivered together with the lens.

This lens type can now often be found at eBay with prices around US$50.
The only extra part needed will be a cheap suitable camera mount adapter.

Recently I have tried to use it for UV-photography and found that it works quite well, even if the transmission is not as good as the EL-Nikkor 80/5.6 (old version) or the Noflexar 35/3.5.
The Canon FD 50/3.5 lens does not reach quite as far into the UV as either of those lenses and is not suitable for experiments with 340 nm filters.
It is also slightly more than a 1/2 stop slower than the EL-Nikkor 80/5.6.

For imaging flowers where a tripod is used it will still work quite well.
On most DSLRs it will not focus to infinity as the Canon FD system has a short back flange distance of 42mm, but that will not be important for macro. :smile:

Attached Image: IMG_1866 (2).JPG Attached Image: IMG_1864 (2).JPG Attached Image: IMG_1865 (2).JPG

Transmission spectra around 370nm for the lenses mentioned above:
Attached Image: Screen Shot 2019-08-15 at 15.34.27.png
Red: 100% measurement verifications after each measurement.
Green: El-Nikkor 80mm, general measurement setup verification.
(This transmission graph is slightly better then my original integrating sphere-measurement, due to a cleanup of the lens and some method tweaks.)
Magenta: NOFLEXAR 35/3,5
Blue: Canon FD 50/3.5 Macro

The Canon FD 50/3.5 lens is quite sharp.
I could not see any big difference in sharpness compared to reference images I took with the El-Nikkor 80/5.6, placed a bit further away from the flowers to compensate for the focal length difference

The images below are 100%-crops of images from the Canon lens. The images are direct from RAW, only white balanced against a PTFE disc and slightly adjusted for exposure levels.

Attached Image: Screen Shot 2019-08-15 at 15.46.10.png
SS8612, 2mm + BG25, 2mm

Attached Image: Screen Shot 2019-08-15 at 15.45.30.png
SS8612, 2mm + UG1, 1mm

Camera: Canon EOS60D, full spectrum modified.
Flash: Godox AD200, UV-modified.

Edited by UlfW, 21 August 2019 - 04:55.

Ulf Wilhelmson
Curious and trying to see the invisible.

#2 JMC


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Posted 15 August 2019 - 15:26

I've often wondered about the FD lenses, so thanks for testing Ulf. Much better than the newer EF mount EOS 50mm f2.5 macro. By 360nm that's down at around 5% transmission.

#3 Andrea B.

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Posted 15 August 2019 - 16:51

Quite a nice find, Ulf.
Thank you for the topic.
Andrea G. Blum
Often found hanging out with flowers & bees.

#4 Andy Perrin


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Posted 15 August 2019 - 20:49

I got a couple of these from my sister. Good to know they are sharp.