The last word on 1670-1650-18105

Updated 18.2.2017 with some comments on 1018 and 1670. Have fun shooting :-)
After having received my repaired 1670 back from Sony (fix of decentering), I made another and final test round to assess its image quality compared to my 1650 and 18105.

I then compiled the results into some tables (see below) and stored the sample shots on a Google drive.

Here the last words on this subject (at least from me :-) ):

The last word on.......…..the 1670:

+ good central sharpness through entire range except 16 mm f4
+ good range wide 16 mm wide to 70 mm tele
+ f4 throughout
+ low visible distortion in OOC JPGs
+ lens hood included

- poor IQ on sides for 16, 24 and 70 mm unless stopped down to f8 where it gets at least ok
- worst IQ at 24 mm which is a frequently used focal length
- strong amount of CA in OOC JPGs, improved when using ARW in Capture One and manual CA calibration
- regular price is debatable
- notable risk of getting subpar and/or defective copy
- power-up delay 1 seconds

Personal view: The 1670 is a nice, good-feeling all-in-one zoom lens, not too large or heavy with good central image quality throughout the entire focal range. However, image quality on the sides needs stopping down to f8 for the wide and tele end to go from poor to at least ok results. If you want to check the impact of this versus the 18105, take a look here at the examples I posted there. Then there is the risk of a subpar copy and the high list price not really reflected in image quality, since my 1650 is equal or better from 16-35 mm f5.6-f8. Positive is, that if you can live with the CA on the sides, the OOC JPGs are already well-usable. Update on 18.2.2017: Based on numerous sources of information, the percentage of decentered and/or subpar 1670 appears to be in the lower two-digit percentage. For me, this is entirely unacceptable for such an expensive lens. For those who got a good one, enjoy :-).

The last word on.......…..the 1650:

+ good central sharpness through the entire range from 5f.6 to f8.
+ very good IQ on sides at 24 mm at all apertures, for f8 also good at 50 & 35, rest ok except for 16 mm f4.
+ good range wide 16 mm through 50 mm. At 16 mm OOC JPG, it is visible wider than the 1670, effectively 15mm. Using RAW, you can get 14.9 mm focal length picture with lens correction from this lens!
+ low visible distortion in OOC JPGs
+ low amount of CA
+ inexpensive
+ extremely compact and light-weight

- low IQ at 16mm f4
- effectively a stop slower than the other lenses for 35mm and above, low DOF not really possible unless you can get very close.
- lack of lens hood. I use adapted 1855 hood, see other blog post.
- power-up delay 1.5 seconds

Personal view: The 1650 is a impressive zoom lens, considering its collapsible design and low price. If used well, that means always stopping down to at least f5.6, it delivers good image quality all over the frame. It matches or exceeds the 1670 under these preconditions from 16 to 35 mm. It is a shame that no lens hood is provided, since this greatly improves the image quality (contrast). However, this can be fixed with low effort by either buying a screw-on hood or adapting the 1855 hood as I did. Distortion is well corrected incamera and in Raw. I quickly got used to the power zoom, operate it through the zoom ring and actually missed the visual zoom info in the EVF when using the 1670.

The last word on.......…..the 18105:

+ central sharpness: good to very good at 50-70 mm. Very good at 105 mm. Ok to good from 18 to35 mm.
+ good image quality on sides from 22 to 70 mm if stopped down to f8, else ok.
+ good range from 18 to 105 mm.
+ f4 throughout
+ lowest depth-of-field achievable with this zoom lens. Well suited for portraits (low DOF, background compression).
+ lens hood included
+ fixed length design

- visible distortion in OOC JPGs for geometric scenes. Using ARW in Capture One default, well compensated though.
- due to distortion compensation, more like a 19 to 105 mm range.
- some CA in OOC JPGs, improved when using ARW in C1 and CA slider
- largest and heaviest lens. Though for some, lthat helps looking „serious“ :-)
- power-up delay 2 seconds

Personal view: The 18105 is a well-built and affordable zoom lens that handles smoothly. Image quality is enjoyable throughout and this lens can be well used for portraits with low DOF or for getting close with a twist of hand. Due to the distortion compensation, it actually is not really that wide, effectively 19 mm is the starting point. Since in-camera distortion compensation does not work that well, using RAW is recommended to get the most out of this lens if your scene is geometrical. Update 18.2.2017: Using Capture One v10, ARW distortion correction is close to perfect now.

Conclusion:

The combination of 1650 & 18105 equals or beats the 1670 in image quality, but of course requires using two lenses instead. A side effect is of course the versatility to have a small system with the 1650, and have the long tele at effectively FF 155 mm in the second setup. So you have choices to make, all three options will deliver good images if used well.
One thing worth to consider is that with 18105 together with the light-weight 1018, one has a super wide focal range travel zoom kit at hand. For my trips, I personally have found this combo to be great for travelling to cities such as Florence or Hamburg, or abroad to Spain or Portugal. Examples are available on my travel blog posts.

Comparison of the zooms over all range and aperture combinations

If you stick to f8 to get maximum image quality, things look like this:

Just looking at f8

 If you compare the combined image quality of 1650&18105 versus the single-lens option of the 1670, and also only consider where central image quality is at least good and side quality at least ok, this looks like this:

1650 used from 16 to 35 mm, 18105 from 50 mm upwards

And lastly, to lighten up with something like a photo:
I noticed that with Capture One, the shots with the 1650 from 16 to 24 mm actually have more Pixels than the original 24 Mpx. At 16mm it's 28.4 Mpx, at 24 mm still 25 Mpx. So there you go Samsung :-).
Reason is of course that the 1650 has strong distortion in the UWA range. Instead of discarding all of this, Capture One allows you to set cropping to the maximum box possible. Now before you complain that the edge IQ is bound to be low, it is - for f8 - about similar to the 1670 at 16 mm & f4.
In the end, this results in a focal length of 14.9 mm for the 1650 at 16mm. So with the SEL1650, you have an UWA on your fingertips!


I stacked the different pictures of 1650, 1670 and 18105 on top to calculate the effective focal length, with the SEL18105 turning out at 19 mm when set to 18mm (using the 1670 as reference).

1 - corrected 1650 b&w, 2- 1650 same but cropped rectangular by C1 16=14.9mm, 3- SEL1670 at 16 mm, 4 - SEL18105 at 18=19mm