Friday, May 16, 2014

Pixel-peeping: Comprehensive (Zoom) Lens test on Sony Nex 5N & A6000 / ILCE-6000: SEL1670, SEL1855, SEL1650PZ, SEL50

UPDATE: For a 1:1 comparison of 1650 versus 1670 both on the A6000, check here: Blog -the-16-something-zoom-shootout-on-a6000)

Guilty as charged - did another lens test to assess the performance of the currently available zoom lenses for the the Sony APS-C mirrorless camera line: SEL1670, SEL1855 and SEL1650PZ. The SEL50F18 was added on the spur of a moment.

If you are interested, you can find here crop comparisons of those lenses both on the Sony Nex 5N camera body and on the A6000. These comparisons are at different apertures: wide-open, f5.6 and f8. Crops were taken from the center of the image, and another set is for the left upper corner.

Just for illustration, a downsized picture of one of those comparison:
Just a small example
Since Google and Flickr mess up the files, I have ZIPped them and added the links below. File size is 5 to 10 MB, so have patience!

My personal summary based on my copies are:
My SEL1670 is a very sharp lens in the center and the edges even wide open at f4. The sharpness wide-open allows good shots in lower light as well as good subject isolation. Contrary to some other reviews, it appears to me as well-usable for landscape photos. Weakest point seems to be edge sharpness at 35mm & 50mm wide open at f4. Further bonus points are the tele range and a silent & fast AF drive. Very well-built.

My SEL1855 needs f5.6 or f8 to perform best, edge sharpness above 24mm is not the best. For the low price a good allround lens. But the 1670 outperforms it in central sharpness by two stops at the wide end and else by one stop, as well as in edge sharpness by one stop. The SEL1650PZ easily outperforms it too, is smaller, and also cheap. So for me, the SEL1855 is ripe for retirement.

Unfortunately, I forgot to test the SEL1670 on the A6000 and therefore had to compare the results of the SEL1670 on the 5N to the SEL1650PZ on the A6000, giving the latter a slight advantage in resolution. See my following lens-shootout between the 1670 and 1650 both using the A6000 here: LENS SHOOTOUT 1670 & 1650
My SEL1650PZ is a compact lens and easily outperforms my SEL1855. Weakness is edge sharpness below 24mm unless f8 is used. Also strange is the dip in sharpness in the mid-aperture range at 16-18mm, similar to the odd behaviour of the FE2870 kit zoom for FF.
If the SEL1650PZ is used at f8, it is a good lens over its entire range, better than the SEL1855. In the wideangle range it is sometimes outperformed by the SEL1670 but at f8 can achieve comparable results. This is impressive for such a small and inexpensive lens. Lacking a lens hood, flare can impact image quality. See my solution using the hood of the SEL1855 and some inexpensive stuff here.

Download links:
SEL1670 at 16, 18, 24, 35, 50 and 70mm on 5N:   Center crops

SEL1670 at 16, 18, 24, 35, 50 and 70mm on 5N and SEL1855 at 18, 24, 35, 50 mm on 5N: Crops from left upper edge

SEL1855 at 18, 24, 35, 50 mm on 5N: Center crops

SEL1855 at 18, 24, 35, 50 mm on A6000 / ILCE-6000: Crops from Center and upper left edge

SEL1650PZ at 16, 18, 24, 35, 50 mm on A6000 / ILCE-6000: Crops from center  &  Crops from upper left edge

SEL50F18 on A6000 / ILCE-6000: Crops fromcenter and upper left edge

Detailed evaluation of lens performance:

SEL1670 (on Nex 5N)
16mm sharp from f4, contrast good, improves to very good at f5.6.   18mm sharp from f4, contrast already very good at f4 f5.6.  24mm same (changing contrast due to clouds).   35mm, 50 and 70 mm sharpness and contrast improves slightly from f4 to f5.6.  At 50mm, sharpness decreases somewhat at f8 compared to f5.6
16mm good at f4 with slight improvement at f5.6.  18mm and 24mm ok to good at f4, slight improvement at f5.6 and good at f8.  35mm soft at f4, ok at f5.6 good at f8.  50mm slightly soft at f4, good at f5.6, very good at f8.  70mm ok to good at f4, good at f5.6 and f8

SEl1855 (on Nex 5N):
18mm weak at f3.5 and f4, ok at f5.6, good at f8      => SEL1670 at f4 beats SEL1855 at f8.
24mm slightly soft at f4, ok-good at f5.6 and f8.       => SEL1670 at f4 still slightly better than SEL1855 at f8.
35mm quite good at f4.5, good at f6.3 and f8            => SEL1670 at f4 is reached by SEL1855 at f5.6.
50mm f5 and f5.6 soft, at f8 acceptable                     => SEL1670 at f4 clearly better than SEL1855 at f8.
18mm: ok to good at f3.5 and f4, good at f5.6 and f8   24mm: slightly soft at f4, good at f5.6 and f8   35mm soft at f4.5, ok at f6.3, good at f8   50mm soft at f5 and f5.6, ok to good at f8

SEL1855 (on A6000)
Same observations as on the 5N, but the pictures are somewhat better on the A6000 (higher resolution?)

SEL1650PZ (on A6000)
16mm excellent sharpness and contrast at f3.5, drops to good at f4 and f5.6 and becomes very good at f8
18mm good sharpness at f4, drops to ok at f5.6 and becomes good again (or better) at f8
24mm ok sharpness at f4.5, good sharpness at f5.6, very good at f8
35mm and 50mm starts at f5.6, good sharpness, very good at f8
=> The 1650PZ (at least my copy) outperforms the SEL1855 everywhere.
=> The 1670 on the 16 Mpx 5N is as good or better if both are on f5.6.
16mm soft at f3,5 and f4, still somewhat soft at f5.6 ok to good at f8 
=> 1670 is always sharp, the 1650 at f8 is still less sharp than f4 on the 1670
18mm soft at f4, somewhat soft at f5.6, good at f8           => 1670 is sharper at f4 and f5.6, about the same at f8
24mm slightly soft at f4.5, good at f5.6, very good at f8   => 1670 better at f4, draw with the 1650PZ both at f5.6 and f8.
35mm soft at f5.6, good at f8                                               =>1670 offers f4, f5.6 and f8 are as good or better than f8 on the PZ
50mm ok at f5.6, good at f8                                                 => 1670 offers f4, is better at f4 and f5.6, draw at f8

SEL50 (on A6000)
Slightly soft at f1.8, improves at f2.8 to good, at f4 better, at f5.6 and f8 bitingly sharp :-)
At f1.8 slightly soft, improves at f2.8 and further at f4 to good, f5.6 and f8 very good

Focus was on windows, NOT on the ladder. Central point was used. Changing clouds, so don't overvalue the colors and contrast. AWB, OOC, JPG, ISO 100, 2 sec shutter delay, tripod. OSS off. Keep in mind when comparing that wide-open on the variable-aperture zooms SEL1855 and SEL1650PZ is different from the constant f4 of the 1670. 
The FILE NAMES of the first three comparisons are wrong regarding center or left edge crop. What IS correct is always the text within the comparisons. Sorry for the potential confusion. 

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