Canon FD 17mm F4 or FD 20mm F2.8 or Rokinon 12mm F2 for best IQ?

[shaolin95]

Hi all!
I have decided to get one of those as my ultra wide lens to upgrade from my current SEL16F28 with ultra wide adapter which has nowhere near good corners and wide open is pretty horrible.
You can see the resolution test here:
Sony Wide Angle Converter VCL ECU1 : ERPhotoReview
and the 20mm does a lot better:
Canon FDn 20mm f/2.8 on Sony A7 : ERPhotoReview
Unfortunately I cannot find the same test for the 17mm F4 so I am left wondering how it will compare. My SEL16F28 with the ultra wide adapter was giving me focal range of about 18mm (35mm equivalent). Either Canon lens will be used with a Lens Turbo 2 adapter, meaning it will act almost as a FF instead of having a crop factor of 1.5 thus I will end with about 18mm for the 17mm and about 21mm for the 20mm.
So my preference would be the wider lens.
I currently have an FD 24mm and and a 35mm F2.8 (amazingly sharp!), so likely I will sell the 24mm and stick to one super wide lens so MAYBE the 20mm will be wiser choice as to not have such a huge gap in my lenses from 17mm to 35mm or maybe I will keep the 24mm IF I buy the 17mm.
In any case, anyone has seen any resolution tests between the 17mm and the 20mm or have actual real life experience between the two?

The other option will be a more expensive FD 20-35mm L lens but will that be better than either the 17mm and 20mm in IQ? Usually zooms cannot match primes with exceptions like the 80-200mm F4L of course.

Finally maybe a modern lens like the Rokinon 12mm F2 will be a better choice for me.

Any comments will be appreciated.

 

[Michiel Schierbeek]

The 17 FD has not a very good reputation the 20mm is a very good lens and has no issues what so ever on the A7 's. But the 24 is a whole lot smaller and also very good!

Rokinon 14mm (Samyang) seems to be very sharp.

I do have the FD 20-35 as well. Lovely lens!

 

[shaolin95]

I do have the 24mm F2.8 but I want something wider and with better corner performance though. You can see here that the 24mm is never that sharp on the sides.
Canon FDn 24mm f/2.8 on Sony A7 : ERPhotoReview
While the 20mm is not super sharp wide opened, it does get much better at 5.6 and 8 so I thought that one will be a good choice even if I sacrifice some wideness compared to the 17mm. Also being FF lenses, I can always use them again if I get a FF camera later on without having to use the crop mode
Do you think the 20-35mm can match the 20mm IQ even on corners/edges?
Thanks for the reply!

 

[Michiel Schierbeek]

I have the 21 Voigtländer as well which is a bit sharper but you have to take care of the colour cast on the wide sides on most photo's.

About your question; I never compared them more scientificly with their corners and all.
I am not very good at that, but I quess a prime lens probably wins.

This lens also work great on the A7r with no issues.

This zoom has a rather difficult distortion, that's why I use it less for architectural stuff.

 

[shaolin95]

Those pics look great indeed! Thanks for sharing.
I saw some other posted some more 20-35mm pics with the A7R which look very good too and of course my Nex-6 with 16MP will be less demanding. Decisions decisions!

 

[mbroomfield]

Which Nex do you have? The 12mm VC is very good on Nex 5/6 bodies but has trouble on the Nex 7. Not sure about the a6000.

The 16mm/F2 Rokinon is excellent but I assume you want wider. I agree with Michiel that the 20mm FD is excellent, and the 14mm Rokinon is also a contender. 18mm c/y and 18mm OM as well if wide enough.

Edit .. ah, just saw you're using the Nex 6 so the 12mm Voigtlander is an option.

 

[mbroomfield]

Saturday am with the 16/F2 Rokinon on Nex 5

 

[shaolin95]

I was actually referring to the 12mm F2 Rokinon not 16m as yes I want to keep it as wide as possible.
Is this the Voigtlander you are referring to?
Voigtlander Ultra-Wide Heliar 12mm f/5.6 Aspherical II on Sony NEX - Review / Lens Test Report - Analysis
Thanks!


PS Nice pick btw!

 

[mbroomfield]

I was actually referring to the 12mm F2 Rokinon not 16m as yes I want to keep it as wide as possible.
Is this the Voigtlander you are referring to?
Voigtlander Ultra-Wide Heliar 12mm f/5.6 Aspherical II on Sony NEX - Review / Lens Test Report - Analysis
Thanks!
PS Nice pick btw!

Thanks ...
Yes, that's the 12mm.
Either the c/y or OM 18mm lenses will take adapters to EF so can be used with an EF-Nex lens turbo. There's also the more modern 18mm Zeiss for EF or Nikon (ZF2). I think they'll give you ~19mm FOV on the Nex