20mm f/1.8G AF-S FX Nikkor Review
Leonard Taupier (Leonard62)
Keywords: resolution, flare, 20mm, prime, wide, angle, fx, nikkor, nikon
Ever since Nikon filed for a patent in Japan in early 2012 for an 18mm f/1.8 and a 20mm f/1.8 FX lenses, I started to get excited at the possibility of having more low-light and high optical quality ultra wide angle options.
While waiting to see if such a patent would become a lens on the shelves, I kept occasionally shooting with my 20mm f/2.8D AF when moving around light and mostly with the extraordinary 14-24mm f/2.8G ED IF AF-S Nikkor.
It was eventually announced and it came to market. Being a big fan of prime lenses I felt I had no choice but to order one immediately when it became available.
As soon as I received my new 20mm f1.8G AF-S prime lens I spent most of an afternoon walking around taking photos but, before that, I did some side by side resolution testing of the 20mm f/2.8D AF, the 14-24mm f/2.8G AF-S and the new 20mm f/1.8G AF-S, using the classic USAF chart and protocol.
Above, the charts of all three lenses at f/2.8 using the Nikon D800 and LiveView focusing for all photos at ISO 100, shot from a sturdy, heavy aluminum tripod and a pro-class ball head.
The lines per millimeter resolution numbers from the 20mm f/1.8G AF-S were the most consistently high numbers from f/1.8 through f/16 I had ever seen from a wide angle lens.
Being a previous design, the older 20mm f/2.8D AF lens couldn't match the resolution of either the new 20mm f/1.8 lens or the 14-24mm zoom at any aperture. This became more obvious when checking for edge resolution.
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Frederic Hore (voyageurfred) on May 9, 2015
Thank you Leonard for your followup response and the PM - much appreciated. The 20-35 I own was sourced on eBay from another owner. I would love to do a side by side to compare my older 20-23 with the new 20mm 1.8 Cheers, Frederic in Montréal
Leonard Taupier (Leonard62) on May 7, 2015
Hello Frederic. The last line on page 2 mentions the low barrel distortion. I wish I had the AF 20-35mm zoom. It's been on my wish list for a couple years now. Historically Nikon engineers have designed wide angle lens with very little distortion. This design philosophy has been followed up through the AFS 14-28mm f2.8 lens on the pro lenses. It's difficult to correct for linear distortion on a wide zoom lens. One of the best zoom lenses for distortion is the AF 28-105mm. I just tested the 20mm for edge distortion and it's as good as I've seen. Len
Frederic Hore (voyageurfred) on April 17, 2015
Superb review! Unless I missed it, there appears to be no mention about how little distortion there is when held level. Other online reviews mention this. Not sure how close the edge distortion is compared to my old 20-35 f/2.8D rectilinear zoom lens, which is really good for architecture interiors, however I'm sure the sharpness will blow it out of the water! Will be investing in this new lens for my night photography work. That extra stop, and the corner-to-corner sharpness wide open at f/1.8, will make capturing the vast sky.... a real high! Cheers, Frederic in Montréal
Carman Pagano (the diewrecktor) on February 16, 2015
Leonard, Thanks for responding, and sadly you were correct. This lens is not part of the annual Nikon lens only rebates this year. So I bit the bullet and ordered it. Now all we need is for the weather to warm up around here so I can take it out and use it. I'll post again after I get to try it out. Carman
User on January 28, 2015
Good review also. But as I understand you have the 14 - 24! When considering a wide angle, this lens is a good buy for landscape and architecture. Thnx!
User on January 18, 2015
Got mine last week and tested it out on some shots around the house last night. I'm very impressed with the 1.8 performance of this lens and how well it does on the D750. I am going to use this lens a lot and feel it is a great addition to my other 1.8 Nikon primes -- 35, 50 and 85. Let's hope we see a 135 f/1.8 soon!
Leonard Taupier (Leonard62) on January 14, 2015
Thanks for your comments, Jim. For my testing I used the highest resolution full frame camera I own, the D800. I find that with many of the newer lenses the resolution numbers I can read on my 27" Apple monitor will reach a ceiling which is about 112 LPMM. I reached that number at f1.8 with the AFS 20mm f1.8 lens. What I did see was a slight loss of contrast at f1.8 compared to f2.8 so the chart would look to have the same contrast as the AFS 14-24mm lens but with ever so slightly higher sharpness, like what you see at f2.8. From f2.8 to f11 the charts look the same which tells me the lens out resolves the D800 sensor when evaluated on my monitor or on the web. I hit the ceiling of my testing at these apertures. I measured the same center edge resolution of 80 LPMM that I did at f2.8. Len
Jim Stamates (Jimi) on January 14, 2015
Thans for the review Leonard. Testing is a lot of work and I appreciate you for doing it. What's missing for me is how is it at 1.8? I know the lenses you were testing against are 2.8 but how does it compare? 1.8 vs 2.8, and how does it compare to itself? 1.8 vs 2.8 or 5.6? Thanks Jim Stamates
Mike Banks (unclemikey) on January 3, 2015
Recently received this lens and put it right to work last night at an event shoot. Very pleased with the results and the weight is no problem to carry around on the D750. I think I'm really going to like this new 20mm f1.8.
Gerard P (slalom002) on January 2, 2015
Thanks for this review. I have had the 20mm f/2.8 for about 15 years. It was a good lens in film days, but in front of my D800 the limitations are quite noticeable. A couple of years ago I bought the 16-35 f/4 VR. It has been a good lens both for landscape and inside cathedrals and castles where you can't always step back very far. I ordered the new 20mm on sale a few weeks ago but I am customer 31 on the list so I shall be waiting a while. Hopefully it will arrive before my next trip (February).
User on January 1, 2015
Thank you for the review Leonard. I have been looking seriously at this lens, so your summary has helped. It seems to be a reasonably priced lens for a fast prime and your test shots seem to justify that. Richard
David Kinston (DKinston) on December 25, 2014
I bought this lens - very happy. Very interested to see the Tamron 15-30 zoom when it arrives!
Leonard Taupier (Leonard62) on December 24, 2014
That's a valid request, David. I didn't use the AFS 17-35mm in my original review as I thought a comparison to the AFS 14-24mm would have more interest. So today I compared the new AFS 20mm f1.8, AFS 14-24mm and the AFS 17-35mm, all at 20mm and at f2.8. I used my same setup to test the center resolution of the three lenses and was quite surprised to see the the AFS 17-35mm and the AFS 14-24mm had nearly the same resolution with a very slight advantage going to the 17-35mm lens. Both lenses fell slightly behind the new 20mm f1.8 lens. Compared to my original test of the AF 20mm f2.8 lens, the 17-35mm is better. Where I see the difference with the 17-35mm lens is in the sharpness falloff as you move towards the edges of the frame. While it is not awful, it is bested by the AFS 20mm f1.8 and the AFS 14-24mm f2.8. In this area the AF 20mm f2.8 has much more falloff than the other three lenses and should be stopped down for best performance by f5.6. Len
User on December 24, 2014
How about comparing against the 17-35mm 2.8 zoom? Have always found it to be as sharp if not sharper than the 20mm 2.8, especially from 20mm up.
Leonard Taupier (Leonard62) on December 24, 2014
Rohinton, thanks for your comment. The LPMM numbers are published for these charts and are based on the smallest set of line pair groups that can be resolved visually when viewed at 100% in a high resolution digital photo or a 20X loupe when viewing a negative from a fine grained film. There is a set distance from lens to chart for each focal length in order to correspond to the LPMM numbers. This is 50X the lens focal length so the size of the photographed chart is always the same for all lenses regardless of focal length. The chart is composed of 6 groups with 6 pairs in each group. Generally it is the 2 groups with the smallest line pairs that modern lenses fall into. The LPMM ratings for these 2 smallest groups range from 50 LPMM to 176 LPMM. When using the highest resolution camera that I have the best LPMM numbers I see peak at 128 LPMM. In very rare cases will I see a higher number and that is only with an exceptional lens at only one f stop, normally around f5.6. Regards, Len
Rohinton Mehta (Rohinton_Mehta) on December 24, 2014
Thank you for your frank opinion on the 20mm f/1.8G and the comparison with the 14-24mm. I have a question for you. You have shown the lines per millimeter resolution of the 3 lenses. Since I have never used such a chart (USAF chart), could you please explain how you arrived at the lpm figures? Thanks once again for the excellent review.
Joe Allen (juicesqueezer) on December 24, 2014
Thanks very much for your review on this lens. Looks like a late Santa present to me! lol
Gerard P (slalom002) on December 20, 2014
I bought the 20mm 2.8 many years ago. It was a good for the time, shooting film. I ran some tests with it on my D800 and found that it was not sharp enough for my liking. These test shots support my observations. I looked at the 35mm 1.8 and it was not wide enough. The 28mm 1.8 was disappointing and the 24mm 1.4 was out of my budget. Based upon these and other reviews, I have now ordered the 20mm 1.8. The local dealer has 31 on order but no ETA.
Leonard Taupier (Leonard62) on December 19, 2014
Robert, I like fast prime lenses and use them on all my bodies including the D7100. With the exception of the AFS DX 35mm f1.8G there aren't any fast, wide Nikon DX lenses. If you someday think you'll be getting into a full frame body, sure, why not get it if you find the focal length useful. Carman, I don't think you'll see this lens on sale anytime soon. It's also not a lens that's likely to be put into a bundle like the AFS 24-120mm f4 lens. Len
Robert Demers (shipsdrummer) on December 19, 2014
Would you say that this lens would be a good choice for a D7100 owner who wants a sharp and fast prime lens for general landscape and city travel photography? Or should I wait until I buy a FF camera instead...Thanks!
Carman Pagano (the diewrecktor) on December 18, 2014
Leonard, Thanks for the review. Your review is not helping my NAS affliction. Seriously, this lens has been on my wish list since it was announced and your review has confirmed that it belongs at the top. I'm hoping Nikon puts it on sale soon.
Frank Villafane (frankmv) on December 18, 2014
I have the 20mm f/1.8 and I can say it is everything Nikon advertises and more. Extremely good at low light, I have used the lens now for the last 3 weeks and I'm more and more enamored with it's results. You can see some of the images, both day and night, on my website in the Recent Work gallery. (http://www.urbanindustrialimaging.com/p118771442)
Mike Banks (unclemikey) on December 18, 2014
Leonard, thanks for this review. I have this lens on order and am waiting for notice that it is back in stock.
Peter Geran (gearsau) on December 18, 2014
" Would I recommend you to switch your 14-24 for this 20mm f/1.8? No, not at all. The 14-24mm f/2.8G AF-S is very impressive too. Although heavy (35.3oz/1Kg), bulky and needing a special setup for use of Neutral Density Graduated and other filters, it nevertheless remains the performance king of the wide angle zoom lenses ever made by Nikon, with its 11 groups and 14 elements. And it saves you from carrying a 14, 18, 20 and 24mm set of primes. I have no intention of getting rid of my 14-24mm lens nor would I choose the 20mm lens to take a series of photos where a change in focal length may be required " I'm staying with my Nikon 14-24mm f2.8. A much more versatile lens to take with me when I am travelling . :-)
philippe ned baba (nevan) on December 17, 2014
Thanks a lot dear Leonard. I would love to have this prime lens for my D700. I've never shoot that wide. I'm experiencing great shots with the Nikon 35mm f1.8 on my D300/D7100 when focus is sharp! My D700 is so impatient. May be my next lens. Thanks again. Ned