Zeiss Flektogon 20/2.8 vs Sony FE 28/2 + 0.75x = 21/2.8

[chudy128314]

I did quick comparison of famous Flektogon 20/2.8 (best copy from my entire collection) and Sony FE 28/2 with dedicated 0.75x converter - you get 21/2.8. Sony A7R, same JPG settings for each shot, no post-processing, crops 1:1.




Sony is an obvious winner for me, it's always sharper anf I don't care about CA at the edges wide open - when I want sharp edges I close it down, at f/8 it rules.

[TrueLoveOne]

To be honest: i am surprised. Simply because i would have never thought that a lens combined with any converter/turbo could produce a better image than just a lens on it's own.

I must add though that i do not know how good or bad that Flektogon performs, i never owned one.

[chudy128314]

Yes, I was also surprised. But Sony FE 28/2 was designed to work with converters from the beginning I think.

[y]

TBH Flektogons are really overhyped lenses (mainly 20mm and 35mm). Their corners are pretty bad compared to anything more recent.

[Gerald]

I think there's something wrong with your Flektogon, or with your test. The image on the edge looks worse at F8 that at F2.8, which does not seem reasonable. With my Flektogon 20mm F2.8, the image quality increases quite dramatically when going from F2.8 to F8, as can be seen in the 100% crops below. As expected, the quality of image in the center is not as sensitive to the closing of the diaphragm. The pictures were taken with a Sony A99 and then upscaled to 34.2 MP to allows a direct comparison with Sony 7r.

The Flektogon 20mm F2.8 was one of the best lenses of its time, but, of course, there was much progress in lens design in the last 40 years. That said, no doubt the Sony 28mm F2 plus the wide-angle converter is a better solution for owners of a Sony A7 camera.

[TrueLoveOne]

[chudy128314]

[stevemark]

[chudy128314]

I was not surprised that modern lens is better than old Zeiss, I was surprised how well works the additional converter.

[miran]

[Gerald]

Some additional remarks:

1) Classic ultra wideangles for SLR in the range of 18 to 21mm are not recommended for use on APS-C or M43 cameras. A 18mm-xxx kit lens would be a better option.

2) The Sony 28mm f2 was specifically designed for FE mirrorless cameras, which means it has a much smaller back focal distance than, for example, the Flektogon 20mm F2.8, which is a lens designed for SLR cameras. It's much, much easier to design a wide angle lens for the Sony A7 than for a SLR camera.

3) The Sony 28mm F2 plus its wide angle converter lens becomes a complex 21mm F2.8 lens of 13 optical elements, with three aspherical and two ED elements. In contrast, the Flektogon is a lens with a relatively simple design of "only" 9 spherical elements, all made from conventional optical glasses.

4) The Flektogon 20mm F2.8 cost about $200 in the US in 1980, which would be almost $600 today when the inflation in the period is considered. On eBay, a Flektogon in excellent condition costs today something between $400 and $600. The classic retrofocus Angenieux lenses are even more expensive today. Blame the collectors!

5) To be fair, the Flektogon 20mm F2.8 should only be compared to other extreme retrofocus lenses for DSLR, like the Sony 20mm F2.8 for Sony A99 and the Nikkor 20mm F2.8 for cameras Nikon FX. Both lenses are still in production and they cost $600 or more. The Sony 20mm F2.8 is in fact a Minolta design, but its performances at edges and corners are not better than the Flektogon, as Kurt Mungen tests suggest:


extracted from: http://kurtmunger.com/sony_20mm_f_2_8_reviewid257.html

[woodrim]

Never underestimate Sony. Didn't realize there was a fractional converter.