Update 6.5.15: I compared distortion-corrected JPGs against other lenses and found that for the 18105, this results in approximately 18mm of the 18105 being about 19mm in other lenses, 22->24mm, 35->38, 46->50mm, ...and 101->103 mm.
Update 8.5.15: There is another comparison with 1670 and 1650 now available
Update 16.9.2015 The current Capture One does a better job in terms of lens correction for the 18105.
Alright folks, for all of you fellow-addicted pixel peepers out there, here is some real stuff to wear your eyes out with.
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| The test candiates |
What I did.
I shot my standard scene with the A6000 on tripod, OSS off using most of the lenses available to me, among them the zooms SEL1018, SEL1650, SEL18105, SEL1855 as well as two FD primes, the FD35/2.8 and the FD100/2.8. For the zooms I went through most setting of the available range, like 10, 12, 16, 18, 24, 35, 50, 70, 90, 105 mm and apertures mostly f4, 5.6 and f8.I then cropped the left upper edges and compiled a comparison JPG file. In another file are the center crops. From my previous test of the SEL1670, I added some crops, too, though of course weather and light conditions were different then, thefore no comment on those. Some few shots apparently were shaken like the 50 mm f5.6 and 70mm f4 18105 shot, probably by accidentally touching the tripod.
There is also a special section on the distortion of the SELP18105 which may be of interest.
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| The scene at 10 mm |
How to properly peep.
To not get lost in the complexity of the available pictures, check the legend where which lens is located. It follows (my weird sense of) logic, so it can be understood with some effort :-)The resulting files are large and blogger does not render the images properly. Therefore it is best to download and view locally. For comparison, I recommend to open and crop to the lens you are interested in, and then do the same once more with the lens you want to compare it to.
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| The roadmap where which lens is located |
What I noticed aka Executive Summary.
The SEL1018 is a good lens, should be used at f5.6 to f8. At 18mm it has the best edges but the weakest center.My SEL1855 is ok from 18 to 35 mm but needs stopping down and still has the lowest contrast and sharpness.
The SEL1650 is good when stopped down once, at f8 it is about equal to the SEL18105. The latter however usually is as sharp at about one stop more open.
6.2.15 Update after comparing both 1650 and 18105 in a landscape test f4-8, 18-50mm: From 18-35 mm edges are better with the 1650 with most improvement seen at 18mm and then declining. At 50 mm things have inverted with the SEL18105 clearly sharper than the SEL1650. So if you own both, you might prioritize to use the 1650 from 16-35, and the 18105 from 35 to 105mm.
The SEL18105 is better at 105mm f4 than the FD100/2.8. The latter is sharper at f5.6 and f8.
The SEL18105 can be used all over its range. Recommended aperture is f5.6 to f8. AF-C sets this lens at f4.5 and this will already deliver sharp results within the zooms range. Lens distortion is not corrected well from 24-35mm, see section on distortion.
The inexpensive, light weight FD35/2.8 is one great lens from 2.8 to f8. A FF lens that can be well used on a high-resolution APSC sensor.
The files.
Remember to download and view with your viewer of choice since blogger/google messes up JPGs. |
| Center crops |
Download (30 MB!)
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| Edge crops |
Distortion of the SELP18105.
The SELP has quite a big range at a low cost, especially compared to the SEL1670. This apparently was achieved by using more inexpensive optical design, mandating a stronger degree of SW based lens distortion correction to compensate. A similar approach as with the SELP1650.This can be done either incamera, using firmware information from the lens, or in post-processing in the raw converter.
So far, so good.
However, the implementation of Sony seems to be not that effective. Taking into account that my setup may not be perfectly rectangularily aligned to the building front, the distortion at 24 and 35 mm is weird, to say the least.
In my view, Sony should update the lens firmware with a more accurate correction profile.
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| 18 mm |
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| 24 mm |
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| 35 mm |
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| 50 mm |
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| 70 mm |
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| 90 mm |
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| 105 mm |
Because
- it is SW correctable in Adobe Camera Raw and in Capture One
- it is not that noticable in real life shots
Here what ACR does at 24mm when you set lens correction to 134%:
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| 24 mm from RAW with Adobe CR, 134% correction |
Update 18.2.2017 With Capture One v10, Distortion correction works now excellently. One can pick either the Phase One profile or the ARW-embedded one. The Phase One profile additionally allows to correct sharpness dropoff at the sides of a lens.
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| 24 mm from RAW, using Capture One with Lens correction |
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| 35 mm, out-of-camera |
Back to reality.
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| Taken by an imperfect human, using imperfect equipment. |
