the last word

Photography meets digital computer technology. Photography wins -- most of the time.

  • site home
  • blog home
  • galleries
  • contact
  • underwater
  • the bleeding edge
You are here: Home / a7RIV / 20mm f/1.8 Nikkor S initial testing

20mm f/1.8 Nikkor S initial testing

March 27, 2020 JimK 3 Comments

It is a rare  occurrence that two rival camera manufacturers viewing for the top of one market (in this case full frame MILCs) introduce two lenses of the same focal length and aperture simultaneously. Yet that is what has just happened with the Sony 20 mm f/1.8 G E-mount lens and the Nikon 20mm f/1.8 S Z-mount one. It’s a little like two women showing up for a dress ball in the same outfit.  I’ve already some testing on the Sony lens(here, here, here, and here), but I’ve been holding back a bit, wanting to test both lenses together. [Added later. It turns out the lens is slightly tilted, but that won’t affect the results posted here.)

Now I can.

Yesterday the 20/1.8 Nikkor S arrived. It’s a big — mostly long — lens. It’s so long that, as I opened the box, the thought crossed my mind that I’d gotten the wrong lens.

The Nikon lens has sparse controls. There are just two: the programmable ring and a manual auto/manual focus switch. The Sony has both focus and aperture rings, a switch to set the aperture ring to clicky or clickless operation, an AF/MF switch, and a programmable button. The Nikon lens is about $150 more than the Sony one.

The weather is preventing me from doing my lens screening test on the Nikkor, but I should be able to do it today. Informal testing found nothing amiss, so I pressed on with my indoor low-contrast Siemens Star test of both lenses with the Sony lens mounted on an a7RIV, and the Nikon one on a Z7.

Here’s the scene, at f/1.8 with the target centered:

20/1.8 Nikkor S on Nikon Z7, center, f/1.8

The protocol:

  • Distance: 8 meters
  • Star in the center and the lower left corner.
  • AF-S, small spot (not pinpoint, in the case of the Z7.
  • Three shots at each setting, focusing anew for each shot, picking the best. This method calibrates out focus curvature.
  • Developed in Lightroom
  • Sharpening set to amount 20, radius 1, detail 0, which is quite a bit less than Lr’s default sharpening.
  • White balanced to the gray surround of the target (mixed lighting — daylight from both sides of the target — made this ineffective).
  • Adobe Color Profile
  • Minor exposure adjustments, with same adjustment applied to all images from each lens, so corner darkening is unaffected.
  • Everything else at default settings
  • They are presented at the same field of view, which is about 250% for the Sony, and slightly more for the coarser-pitched Nikon.

In the center:

20/1.8 Nikkor S on Nikon Z7, center, f/1.8

 

Sony 20 mm f/1.8, center, f/1.8

The Sony lens is a tad slower than the Nikkor, and quite a bit sharper.

Stopping the Nikkor down a third of a stop helps:

 

20/1.8 Nikkor S on Nikon Z7, center, f/2

 

At f/2.8:

20/1.8 Nikkor S on Nikon Z7, center, f/2.8

 

 

Sony 20 mm f/1.8, center, f/2.8

Both lenses are doing fine here. The Sony is a bit sharper, even without considering its finer pixel pitch.

20/1.8 Nikkor S on Nikon Z7, center, f/4

 

 

Sony 20 mm f/1.8, center, f/4

Not much to choose between these.

20/1.8 Nikkor S on Nikon Z7, center, f/5.6

 

 

Sony 20 mm f/1.8, center, f/5.6

Very similar.

20/1.8 Nikkor S on Nikon Z7, center, f/8

 

Sony 20 mm f/1.8, center, f/8

Diffraction is taking its toll on both lenses.

In the lower-left corner:

20/1.8 Nikkor S on Nikon Z7, corner, f/1.8

 

Sony 20 mm f/1.8, corner, f/1.8

Sharpness is similar. The Nikkor has a lot more corner falloff. I had vignetting correction turned off in both cases.

There’s less fall off if we stop the Nikkor down to f/2.

20/1.8 Nikkor S on Nikon Z7, corner, f/2

At f/2.8:

 

20/1.8 Nikkor S on Nikon Z7, corner, f/2.8

 

Sony 20 mm f/1.8, corner, f/2.8

The sagittal/tangential nature of the aberrations is more symmetric for the Nikkor. The increased aliasing is probably more of a function of the sensor than the lens.

At f/4:

 

20/1.8 Nikkor S on Nikon Z7, corner, f/4

 

Sony 20 mm f/1.8, corner, f/4

Pretty close to a tie. The increased aliasing and false color of the Nikon is at least partly a function of the sensor pitch. The Nikkor is more contrasty.

20/1.8 Nikkor S on Nikon Z7, corner, f/5.6

Sony 20 mm f/1.8, corner, f/5.6

Very close.

And here’s the last pair:

 

20/1.8 Nikkor S on Nikon Z7, corner, f/8

 

Sony 20 mm f/1.8, corner, f/8

I’d say that f/4 or f/5.6 is the best stop for across-the-frame sharpness if DOF is not an issue.

a7RIV, Nikon Z6/7

← An apology Focus curvature with the 20mm f/1.8 Nikkor S →

Comments

  1. JeremyGreen says

    March 27, 2020 at 5:34 pm

    You mean Z mount, not F mount

    Reply
    • JimK says

      March 27, 2020 at 5:38 pm

      Fixed now. Thanks.

      Reply

Trackbacks

  1. Nikon, Sony 20/1.8 foliage test says:
    March 28, 2020 at 1:16 pm

    […] I noticed the Nikon onces weren’t quite as sharp as the Sony ones, which was different than the Siemens Star testing indicated. I said a few choice words, then reshoot the Nikon series using its abysmal — at […]

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

February 2023
S M T W T F S
 1234
567891011
12131415161718
19202122232425
262728  
« Jan    

Articles

  • About
    • Patents and papers about color
    • Who am I?
  • Good 35-70 MF lens
  • How to…
    • Backing up photographic images
    • How to change email providers
  • Lens screening testing
    • Equipment and Software
    • Examples
      • Bad and OK 200-600 at 600
      • Excellent 180-400 zoom
      • Fair 14-30mm zoom
      • Good 100-200 mm MF zoom
      • Good 100-400 zoom
      • Good 100mm lens on P1 P45+
      • Good 120mm MF lens
      • Good 18mm FF lens
      • Good 24-105 mm FF lens
      • Good 24-70 FF zoom
      • Good 35 mm FF lens
      • Good 60 mm lens on IQ3-100
      • Good 63 mm MF lens
      • Good 65 mm FF lens
      • Good 85 mm FF lens
      • Good and bad 25mm FF lenses
      • Good zoom at 24 mm
      • Marginal 18mm lens
      • Marginal 35mm FF lens
      • Mildly problematic 55 mm FF lens
      • OK 16-35mm zoom
      • OK 60mm lens on P1 P45+
      • OK Sony 600mm f/4
      • Pretty good 16-35 FF zoom
      • Pretty good 90mm FF lens
      • Problematic 400 mm FF lens
      • Tilted 20 mm f/1.8 FF lens
      • Tilted 30 mm MF lens
      • Tilted 50 mm FF lens
      • Two 15mm FF lenses
    • Found a problem – now what?
    • Goals for this test
    • Minimum target distances
      • MFT
      • APS-C
      • Full frame
      • Small medium format
    • Printable Siemens Star targets
    • Target size on sensor
      • MFT
      • APS-C
      • Full frame
      • Small medium format
    • Test instructions — postproduction
    • Test instructions — reading the images
    • Test instructions – capture
    • Theory of the test
    • What’s wrong with conventional lens screening?
  • Previsualization heresy
  • Privacy Policy
  • Recommended photographic web sites
  • Using in-camera histograms for ETTR
    • Acknowledgments
    • Why ETTR?
    • Normal in-camera histograms
    • Image processing for in-camera histograms
    • Making the in-camera histogram closely represent the raw histogram
    • Shortcuts to UniWB
    • Preparing for monitor-based UniWB
    • A one-step UniWB procedure
    • The math behind the one-step method
    • Iteration using Newton’s Method

Category List

Recent Comments

  • Brian Olson on Fuji GFX 100S exposure strategy, M and A modes
  • JimK on Picking a macro lens
  • JimK on Picking a macro lens
  • Glenn Whorrall on Picking a macro lens
  • JimK on What pitch do you need to scan 6×6 TMax 100?
  • Hatzipavlis Peter on What pitch do you need to scan 6×6 TMax 100?
  • JeyB on Internal focusing 100ish macro lenses
  • JimK on How focus-bracketing systems work
  • Garry George on How focus-bracketing systems work
  • Rhonald on Format size and image quality

Archives

Copyright © 2023 · Daily Dish Pro On Genesis Framework · WordPress · Log in

Unless otherwise noted, all images copyright Jim Kasson.