SEL50F18 ves SEL18-55 versus FD lenses
EDIT: Due to some comments having difficulties with my conclusion the SEL being the better lens wide open, I have appended the original text with some lines describing my line of thought.
The availability of Sonys lenses for the Nex series is limited, to say the least. I have ordered this lens in the beginning of January and it has now arrived, after 2.5 months. For a Leica lens, this would probably be fast :-)
Anyway, up to now I have used a Canon FD 50/1.4 lens for low light scenes, so it was natural to make some comparisons to evaluate sharpness and bokeh rendering.
The Nex was tripod mounted and set to daylight WB. The FD lens was of course manually focussed, whereas the SEL 50 was using AF and I tried to get the same focus points (not always successful, though).
The SEL renders warmer, however I don't know if the camera would compensate for this if I would have used auto WB. CA (red/green shift) is stronger at 1.8 (Sony) versus 1.4 (Canon lens).Though the Sony lens was 2 cm farther from the subject due to the adapter lens mount used for the FD lens, its magnification is larger. So at this distance, the effective focal length is larger than that of the FD lens.
Overall, the lens is about as sharp as the FD lens, not quite as light sensitive but much sharper at open apertures and it does offer AF as well as OSS. Real-life experience will show the performance benefits.
Below the pictures are two links for downloading 100% crops of aperture series comparison of both lenses.
Stay tuned :-)
============== Conclusion based on the aperture comparisons linked below!===========
As I already stated, it was difficult focusing the SEL. Therefore, if you closely observe the provided pictures, the SEL is focussed on the scale at "50" except for the f2.0 shot, which is at about scale "15". Now the FD was always focussed on "50"!
Some have claimed that the FD at f2.0 was not focussed on the scale at all. This errorenous conclusion may have been caused by comparing it to the SEL f2.0 picture which shows the dust behind the scale much less sharp. But that is due to the fact that the SEL was front focussed (operator error) in that shot which is clearly visible on the scale delivering max sharpness between "10" and "20". If you compare the "dust" continously from f1.4 to 4.0, you can see that the FD really is well focussed. And if you compare the FD 50 at _f2.0_ with the SEL 50 at _f1.8_ (!), you can easily see that the SEL is more contrastier and sharper, while showing more CA (reddish tinge).
But the CAs almost have disappeared entirely at f2.0 for the SEL, so the conclusion is that the SEL50F18 will be even better IQ-wise at f2.0 compared to f1.8.
My conclusion is therefore that the SEL is the better lens wide open f1.8 - 2.0.
At f2.8 -4, the differences are practically nil, with the FD color rendering a bit warmer.
The FD has the advantage of having f1.4, but the pictures also show that using the lens wideopen. will deliver rather soft shots. IF the scene allows to use the OSS + lower shutter speeds at f1.8, the SEL will render significantly (!) better IQ.
If you consider that lens coatings have improved a lot and modern lens coatings take into account the reflections of the sensor, it was to be expected that wideopen. the SEL would deliver better. Since the FD50/1.4 was a reference lens at its time, it also was to be expected that closed down 2 stops (so that lens internal reflections become negligible), the FD lens will perform very well indeed and still is competitive with a lens 30 years younger.
For anybody with a budget or tolerant targets :-), the FD is a great lens. Its MF and aperture operation are very pleasing in their smoothness. But let's be objective (haha) and accept that there are limits to these legacy lenses. And the usual issue is wideopen. where the lens coatings reveal their limits.
|Sony Nex 5N Canon FD 50/1.4 at 2.8|
|Sony Nex 5N Sony SEL 50F1.8 at 2.8|
Link to full size aperture series crop comparison 1.4 to 4.0
Link to full size aperture series crop comparison 5.6 & 8