Canon m39 RF lens test /comparison

[belgiumreporter]

Because of the persisting bad wheather i was unable to take on the canon 7 test run. To know what i could expect i mounted the canon 50mm 1.8 RF lens on the samsung NX1000 and compared it with some other 50mm lenses.

After the test it became painfully clear the Canon 50mm isn't OK... It hasn't got any contrast and on close inspection i noticed the lens has some haze on the internal elements probably caused by evaporation of the helicoid grease.

I will have to take it apart as in this condition it is rather useless. Further more i compared it to a russian jupiter 8 50mm f2 this one isn't very good at f2 but improves a lot from f4 and up. Just out of curiosity i've put on the samsungs kit 20-50 zoom wich isn't bad at all but starting at 5.6 at 50mm dosn't make it very usefull in low(er) light.

Than as ea reference i've used a Nikkor 50mm 1.8 maybe a well known fact it's somewhat soft at 1.8 but stopping it down to f2 things get very good.

I've put the comparing shots at full res on the IMGBB site so clicking on them hopefully will allow for detailed comparing. The whole test naturally is only limited by the DX sensor of the NX1000.

This was the test subject maybe i should mention focus was on the 3th guitar



and these are the cut outs for comparison:

[julio1fer]

Results for the Canon lens are way below what the lens can do. Hope you can get it sorted out.

[belgiumreporter]

Jun 5, 2021 13:14:33 GMT -5 julio1fer said:

Results for the Canon lens are way below what the lens can do. Hope you can get it sorted out.

They are indeed. meanwhile the Canon 7 project is on hold, i've made some 20 shots with it with the different lenses at my disposal but i haven't got the right screw driver to open up the Canon 50mm (removing and cleaning front and back elements wasn't a problem). i would like to use it on the roll of film wich is currently in the 7 but either i need to find the right tool or make one myselve. I hope to get it fixed in the upcoming week. Things wich need to be fixed are piling up (the Contaxes, Minolta's and some Pentax)

[belgiumreporter]

In order to get on with the film/ camera combination test i had to take the Canon 50mm apart (made the right tool).

There was (is) mould on the middle elements, however after cleaning the elements traces of the mould are still there. I wonder is the glass etched by the mould or do i see it wrong and is what is thought to be mould is actually the separation of the lens block?

So i've put the lens back togheter resting in the fact it will be one for display not for use. To be sure if my cleaning attempt did anything at all i've put it back through the guitar test and much to my surprise it is now producing more than acceptable results (even with the bad middle element).

I think it is now good enough to be worth a try with film ad see what comes out as film will be full frame where as the digital testing is done on DX format.(this is due to change in the nearby future).


Here's the 50mm in parts.


This is the best i could get the middle elements.


And these are the results at f1.8 and 5.6


With a little post processing some nice results can be obtained.