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Jul 28

Lens review: Nikon AF 20mm f/2.8D

The Nikon 20mm f/2.8D AF is a small wide-angle lens which was originally design for film camera and which fits well for full-frame and APS-C sensors of digital camera. I write this review because since I bought my FF camera (Nikon D610) it was not so straight what kind of wide lens to choose. Basically your choice is limited to some fixed lenses like Nikon 20mm f/2.8D AF
, Voigtlander Color Skopar 20mm f/3.5 SL-II Aspherical or best-in-class (highly expensive) zooms like Nikon 16-35mm f/4G ED VR II AF-S IF . If you are looking for a lens dedicated to landscapes and street photography, the 20mm is probably very interesting focal because it is not too wide so the geometric distortions can be manage quite well while the angular of view is high enough (94° on FX  / 71° on DX cameras) to enables great  compositions.

 

Distortion

According to results published on Phtozone.de, distortion is high (-2.26% barrel) with a mustache sub-frequency, very uncomfortable to correct accurately with standard tools (Photoshop, Adobe Photoshop Lightroom 5
) but which can be well manage with a tools such as PTLens PS plugin. This distortion is hardly noticeable for natural landscape photography but could get annoying if you are planning to dedicate this lens for architectural photography.

Vignetting

The falloff is very strong at f/2.8 (2.1EV according to Photozone.de) and becomes very complex to correct during the post-processing. This becomes acceptable from f/5.6 (less than EV) and hardly noticeable at f/8 – f/11. By reading a lot of forum, it seems that a lot of people has noticed a icreased falloff by adding a filter onto the lens. I personally use a clear filter on my lens and did not notice any additional falloff… Nevertheless this drawback is apparently not affecting the Voigtlander Color Skopar 20mm f/3.5 SL-II Aspherical

Chromatic aberrations

They are quite pronounced (about 2px) throughout all apertures but can be easily corrected by software or even within the camera for JPEG format. By comparison chromatic aberration on Carl Zeiss DISTAGON T*2.8/21mm and Nikon 24mm f/1.4G ED AF-S RF is about 1px and 1.6px respectively over the full range of apertures.

Sharpness

The lens is very sharp in the middle and lake of sharpness at full opening due to the coma aberration. The sharpness becomes quite uniform between f/8 and f/11. Note that this lens is very sharp, as a comparison the sharpness of the Nikon 20mm f/2.8D AF is quite as high as the Carl Zeiss DISTAGON T*2.8/21mm at f/8 albeit $1500 less expensive !

By comparison sharpness is far better than on Voigtlander Color Skopar 20mm f/3.5 SL-II Aspherical , which is the most comparable lens in term of price, according to results obtained by Photozone.de on Canon EOS 5d MkII.

Here are a picture to illustrate the sharpness of the lens (no correction here). The strong chromatic aberration is well displayed on the borders but the center remains sharp and detailed.

Fit for night sky photography ? No… but

The 20mm focal and the f/2.8 aperture is clearly a great advantages for night sky photography. However the pronounced falloff in extreme corner and the loss of resolution due the coma aberration make this not not very adapted to nigh sky photography. Let say that if you are looking for a lens dedicated to nigh sky photography you can dismiss this lens but if this kind of photo is occasionally it will be OK (see my photography as example).

 

Nightsky photography using Nikon AF 20mm f/2.8D

Nightsky photography using Nikon AF 20mm f/2.8D

Highlight reflexion

The 7 blades apperture render beautiful 14-pointed sunstars on bright points like you can show on the picture below. Highlight reflexio are quite moderate for the price of this lens.

DSC_3555

Price

This lens is currently sold new for $569 on (Nikon 20mm f/2.8D Amazon, US) (550€ on Amazon FR) which could seems a little bit expensive but, as I said before, there is not man solutions available at this range of prices for such ultra wide angle lens. You can find an used one on Ebay for about $300 in the US (medium price is 290€ on Ebay France)

First version of the AF-D version appeared in 1994 and the lens is still produced by Nikon in 2014. The optical configuration has not changed over the years. As a consequence if you planned to buy a used one you should care about the product serial number to estimate the date of fabrication. You will find useful information below. Of course this work also for the AF and AI-S versions.

 

Serial number for Nikkor 20mm f/2.8

Ai-S 20/2.8 MIJ 62mm filter, CRC, SIC coating from 257xxx

200001

200004 – 266369 Oct 84 – 2005
Ai-S 20/2.8 MIJ 2006 serial no

300001

300009 – 304075 2006 – >
AF 20/2.8 Japan  

200001

200800 – 269471 Feb 89 – Apr 94
AF 20/2.8 D Japan  

300001

300117 – 400656 Mar 94 – 2005
AF 20/2.8 D Japan 2006 serial no

500001

500120 – 536157 2006 – >

 

Summary

This 20mm is close to perfect for street photography on an APS-C sensor, the sharpness is high enough to reveal the true potential of recent sensors while the crop enable to mask the main drawbacks of the lens: distortion and falloff. If you are an APS-C sensor, seriously consider this discrete lens as being a major piece of your bag for only $569.00.

If you are a FF user who absolutely needs a discrete lens let’s say you don’t have the choice because all current pancake-type wide lenses are affected by the same symptoms: distortion, falloff and loss of resolution on the borders. The only lens that stands out is the Carl Zeiss DISTAGON T*2.8/21mm for about $2500… By conception you will never get the same image quality on a full frame with such small length and you will need to consider bigger lens like Rokinon 24mm F/1.4 Aspherical or Nikon 24mm f/1.4G ED AF-S RF.

Main advantages

Drawbacks

  • Coma aberration which limits the resolution on the borders and make it non suitable to night sky photography
  • Not suited to architecture photography due to a complex geometric  distortion (barrel with mustache sub-frequency)
  • Strong falloff between f/2.8 and f/5.6 which might be increased if you use a filter

 

Where to buy:

Amazon (US): Nikon 20mm f/2.8D AF Nikkor Lens for Nikon Digital SLR Cameras

Amazon (FR): Nikon AF 20mm f/2.8 D Objectif super grand angulaire

DSC_2257

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