Nikkor AF-S DX Micro 40mm f/2.8G Thomas, January 2012
 

Nikon AF-S DX Micro-Nikkor 40mm f/2.8G review

The AF-S DX Micro-Nikkor 40mm f/2.8G is the most affordable macro lens for Nikon's range of DX format DSLRs, and as an AF-S model, it'll autofocus on any Nikon body. Yes you read this right: it's even cheaper than any lens capable of 1:1 magnification from Sigma or Tamron. If you think that doesn't bode well for the performance of this little lens read on: there's a pleasant surprise waiting for you!

Announced in July 2011, the 40/2.8G is the latest addition to an impressive line-up of six macro-lenses from Nikon. It's the shortest of the bunch and one of only two macro lenses from Nikon which is specifically designed for DX format bodies.

Mounted on a DX body, the 40mm delivers an equivalent focal length of 60mm, making it only slightly longer than a so-called 'normal' lens, and with a maximum aperture of f2.8 it is brighter than most zooms. So it could double up as a standard-prime, albeit not as bright as Nikon's 35/1.8G but with the key benefit of going far beyond the meager 1:6 magnification of that lens. This sounds like a compelling option for owners of DX bodies and in this review you'll find out whether it delivers decent performance despite its low price.

   
   


Facts from the catalog

Let's have a look at the technical data. We've rated the features with a [+] (or [++]) when it's better than average or even state of the art, a [0] if it's standard or just average, and [-] if there's a disadvantage.

Size and weight: 69x65mm at 235g = relatively small and light, similar to one of those 50 or 35mm f/1.8 primes. Smaller and lighter than any other macro-lens. [+]

Optics: 9 elements in 7 groups. Only the old Micro-Nikkor 60/2.8D has less elements. The design of the lens is quite simple with no exotic glass, aspherical elements or special coatings. [0]

 

Nikon Micro Nikkor cross-section
   
DX Micro-Nikkor 40mm f/2.8G
 
DX Micro-Nikkor 85mm f/3.5G VR
  VR Micro-Nikkor 105mm f/2.8G
         
         
   
         
         
 
   
The three Micro-Nikkors
Form left to right: 40/2.8G, 85/3.5G VR, 105/2.8G VR


Closest focus distance/max. magnification: 0.16m / 1:1. Magnification of 1:1 is standard with Nikon's Micro-Nikkors, but other manufacturers call some of their lenses "macro" while only reaching 1:4 magnification. So this is a clear [+] for the Nikkor. But the other important thing with magnification is the working distance from the front lens at 1:1, a figure that is rarely published in the technical data. When I measured the 1:1 working distance on this lens I was quite shocked to find it at only 3cm from the front. This makes proper lighting of the front of your subject a very special challenge and is much too close for the comfort of many small critters! [-]

Filter-thread: 52mm = same as the 50/1.8D, DX 35/1.8G, and 85/3.5G. The small size makes filters cheaper. [+]

Image stabilization: No = a pity! With its short focal length it might not be as prone to shake as longer macro lenses, but the closer you focus the stronger the magnification of any shake becomes. So if you want stabilization in a macro lens you have to go for the larger and more expensive Nikon 85/3.5 VR or the Nikon 105/2.8 VR. [-]

Auto focus: AF-S with SWM (silent wave motor), so it works on any Nikon DSLR and you also get manual-focus override by turning the focus ring. The focus scale has a third line that shows magnification in addition to the shooting distances in m and ft. [+]

Covers only DX-sized sensors = you have to upgrade your lens (or shoot in DX-mode) should you buy an FX body. [-]

Comes with a flexible lens pouch, snap-on front lens cap, rear lens cap, and revertible bayonet hood, like any standard Nikon lens. [0]

Price: around 230 EUR new (incl. 19% VAT) = very reasonable. This is by far the cheapest "real" (meaning 1:1) macro lens you can get for a Nikon body! The next Nikon macro-lenses price-wise cost almost twice as much, even the Sigma AF 50mm 2.8 EX DG Macro is around 20% more expensive. [+]

Distance information is relayed to the camera, so the Nikon body can do all the advanced exposure-related stuff with this lens. But this is true for all the alternatives too. [0]

Aperture ring = no, just like all Nikon G-lenses. [0]

Sealing: yes! There's a rubber grommet on the lens-mount. [+]

Focus limiter switch: Yes, 0.2m - infinity. This can be pretty helpful to avoid hunting. [+]

So the score in the "features-department" is 3[-] / 4[0] / 7[+]. That is pretty good considering the low price of this lens. Only the DX-format, the very short working distance at 1:1, and the missing image stabilization are deficiencies that you need to take into account when you consider buying this lens.

 

Motivation:

A 40mm macro-lens is for getting close to your subject and showing details other lenses can't show. And it also doubles up as a standard fixed focal lens. Plus there are expectations that macro-lenses are pretty sharp. But you have to wait just a little bit to see whether the lens fulfills this expectation.

 

Alternatives:

- The AF-S Micro-Nikkor 60mm f/2.8G ED. Larger, more expensive, covers FX-sensors.
- The Sigma AF 50mm f/2.8 EX DG Macro. A little larger and a bit more expensive, covers FX-sensors, no silent AF-drive.
The alternatives are said to perform pretty well, so if you want a longer focal length and/or the guaranty that the lens works on your next FX-body, have a look at those contenders.

 

Testing: Longitudinal Chromatic Aberration

Axial color (longitudinal CA, loCA) is a very common problem with large aperture primes and is not as easy to correct in post processing (or in-camera) as lateral CAs. Longitudinal CAs create some greenish tint with background subjects and a magenta tint on foreground subjects. The 40/2.8G is certainly not a very large aperture prime but as you can see in the following test-shots it is also affected by this problem.

Below left is the result for the 40/2.8G showing a 100% crop at f2.8. The effect is reduced by stopping down and at f5.6 the greenish (background) and reddish (foreground) hues are almost gone. Processing was done in Capture NX 2 with standard settings meaning lateral CA removal was ON, loCA removal = OFF. Below right you see the results from setting loCA removal to 50% in Capture NX.

 
Nikon AF-S DX Micro-Nikkor 40mm f/2.8G Longitudinal Chromatic Aberration (loCA)
100% crop, f2.8, loCA removal OFF in Capture NX2
  100% crop, f2.8, loCA removal 50% in Capture NX2

   

 

Sharpness and contrast

Let's have a look at the theoretical performance (MTF-charts) of the new lens before analyzing the results from the test-shots:

Nikon Micro-Nikkor MTF
   
DX Micro-Nikkor 40mm f/2.8G
 
DX Micro-Nikkor 85mm f/3.5G VR
  VR Micro-Nikkor 105mm f/2.8G

These charts show the lens-performance at the largest aperture. To read these charts you only have to understand that higher values are better and that the closer the dotted and the continuous lines are together the less astigmatism (= resolution depends on the orientation of the test-pattern) the lens displays. The DX-corners where I measure with the D300 are approximately at 12mm on the X-axis.

From the charts the new lens should perform pretty good with very high contrast over the complete image-field and some impressive sharpness in at least half of the image with a graceful roll-off towards the corners. But to really understand what this lens can produce we need to look at real test-shots with a challenging target, the Siemens-stars, with different apertures and different shooting distances. Because performing well at larger magnifications is no easy feat - otherwise people would be only buying extension tubes.

This comparison comes in two parts: center- and corner-performance at normal distances (around 1.4m, 1:35 magnification), followed by center- and corner-performance at macro distances (around 20cm, 1:2.6 magnification).

Processing was done in CaptureNX2 at standard settings, with white-balance adjusted to a neutral white and some exposure compensation to make the brightness match. CA-removal is ON. Focus was achieved as usual live-view based with a little optimization by hand and it was done separate for the center and the corners to avoid any effect from field curvature.

These are all 100% crops!

 

Part 1: Center- and corner-performance at standard (1:35) magnification (around 1.4m)
Shot from a printed test-target

 

AF-S DX Micro-Nikkor 40mm f/2.8G with Nikon D300
100% crop from center
AF-S DX Micro-Nikkor 40mm f/2.8G with Nikon D300
100% crop from corner
 
f2.8, 200 ISO
f2.8, 200 ISO
     
 
f4, 200 ISO
f4, 200 ISO
     
 
f5.6, 200 ISO
f5.6, 200 ISO
     
 
f8, 200 ISO
f8, 200 ISO

As already expected from the MTF-chart contrast and sharpness of this lens under standard conditions is very good. The corners are just a tad soft at f2.8, but that's it. A very impressive performance, indeed!

 

Part 2: Center- and corner-performance at around 1:2.6 magnification (around 20cm)
Shot from a test-target on a black&white negative 24x36 mm film

 

AF-S DX Micro-Nikkor 40mm f/2.8G with Nikon D300
100% crop from center
AF-S DX Micro-Nikkor 40mm f/2.8G with Nikon D300
100% crop from corner
 
f3.3, 200 ISO (max aperture at 1:2.6)
f3.3, 200 ISO (max aperture at 1:2.6)
     
 
f4, 200 ISO
f4, 200 ISO
     
 
f5.6, 200 ISO
f5.6, 200 ISO
     
 
f8, 200 ISO
f8, 200 ISO
     
 
f11, 200 ISO
f11, 200 ISO
 

 

At larger magnifications the center of this lens is also pretty good straight from the largest apertures, which was f3.3 at 1:2.6. But the corner is quite mushy and not up to the standard that you're used to see at normal shooting distances. So stopping down is required to achieve better image-quality at close-up shots. This normally is not so bad as you might expect: at a magnification of 1:2.6 depth-of-field is razor-thin at f2.8 and normally no natural subject is flat enough to be in focus, coupled with field-curvature of the lens also adding to the challenge of corner to corner sharpness. My own experience says that for getting a pleasing distribution of sharpness across the frame of a shot of 1:2-1:3 magnification you need at least f5.6 or f8.0 for depth-of-field alone. And if you look at the corner-performance of this lens at f8 you see a much improved image-quality which certainly does not stand in the way of producing very sharp macro-shots.

If you'd like to compare the quality of this lens to the Nikon DX Micro-Nikkor 85mm f/3.5G VR and the Nikon AF-S VR Micro-Nikkor 105mm f/2.8G IF-ED, see my Nikon Micro-Nikkor lens comparison.

 

Nikon 40mm Micro-Nikkor sample images gallery

The following images were taken with the Nikon AF-S 40/2.8G. Each image was recorded in RAW and converted with Capture NX 2 at standard settings. Some images have White Balance set to a standard daylight value to make them comparable. No extra sharpening, tone, color or saturation adjustment was used.

The first shots show the performance near infinity on a D300. This is important for all landscape shooters. The three 100%-crops are taken from the middle of the f2.8, f4.0, and f5.6 version of each image while the main image shows the shot at f8.0. You can click on each image to access the large original. These files are for personal evaluation only and cannot be used in another publication or website without permission.

Trees: infinity shot with Nikon Micro-Nikkor 40/2.8G on a D300
f8.0, 200 ISO
 
   
f2.8, 200 ISO
 
f4.0, 200 ISO
  f5.6, 200 ISO

The next row shows 100%-crops from the right border.

Trees: border performance with Nikon Micro-Nikkor 40/2.8G on a D300
 
   
f2.8, 200 ISO
 
f4.0, 200 ISO
  f5.6, 200 ISO

 

These images are proof that the lens delivers very good performance with sharp and contrasty images center and border even at f2.8. Stopping down to f4.0 results in excellent performance and also reduces the light fall-off in the corners considerably. This lens performs better at infinity than the DX Micro-Nikkor 85mm f/3.5G VR.

Two other observations can be made from these shots: The 40mm macro-lens renders images with a bit more blue and clearly deeper shadows than either the 85/3.5 or the 105/2.8. As to the shadows you don't need to fear that information is lost: you can easily retrieve details from the dark areas like they can be seen with the other lenses. This very high contrast even against a bright sky might be a bonus from the simple lens-construction with only seven optical groups (vs. 10 groups with the 85mm and 12 groups with the 105mm lenses) that is less prone to light scattering inside the lens.

The next shot should give you an impression of the close-up performance that this lens can deliver. Magnification is around 1:2.5 and I've chosen f8.0 here to get a decent depth-of-field. Clicking on the image gives you access to the large original. The three small crops below are displayed at 100%. When you compare these crops to the same shots in my Nikon 85mm macro review please allow for small focus variations. This real-life test confirms what we've already seen from the test-charts: This lens is a pretty good performer under close-up conditions. But one thing is pretty obvious: The isolation of the figure from the background is not as pleasing with the 40/2.8G as with its longer cousin(s), although the shots have the same magnification and use the same aperture - so depth-of-field is identical across these shots.

 

Wizard: close-up shot with Nikon Micro-Nikkor 40/2.8G on a D300
f8.0, 200 ISO
 
   
f8, 200 ISO
 
f8, 200 ISO
  f8, 200 ISO

 

Focus and build quality

Focus accuracy and repeatability is critical for people relying on AF. Repeatability (=accuracy of focus on the same subject after repeated focus-acquisition) is excellent with no outliers over a series of 14 shots. There are only very slight focus-variations that correlate with the direction the focus was coming from (infinity or minimum focus distance). The 40/2.8G focuses reasonably fast: around 1 sec from minimum focus distance (MFD) to infinity. Sometimes it hunts in the wrong direction (typically when close-up) first but the focus limiter switch prevents this.

The focus ring of the 2.8G turns about 170 degrees from infinity to MFD. This throw should be good enough for manual focusing (in live-view), but unfortunately there is a slight hysteresis/slack/play between the focus-ring and the focus-action, which makes accurate focus under critical conditions pretty hard. The movement of the focus-ring is also quite tight and there is some humming noise when the AF is operating. The AF-S DX Micro-Nikkor 85mm f/3.5G ED VR is clearly better in this respect. This is supporting the general impression of budget build quality that this lens conveys: plastic construction (but with a metal lens-mount), only seven rounded aperture blades, and a lens-shade that does not fit tightly. If you shake the lens there is quite some noise to be heard, which is astonishing for a non-stabilized lens.

Three things happen when you focus towards MFD: the front-end of the lens extends around 18mm (while the lens-hood doesn't move), the effective maximum aperture shrinks to f4.2 (f3.5 at a magnification of 1:2), and the smallest aperture goes from f22 to f32. The shrinking of the effective aperture is nothing to lament about, with a non-IF design those values would be f5.6 resp. f44 at 1:1 magnification.

So all-in-all the latest AF-S DX Micro-Nikkor 40mm f/2.8G delivers a very decent performance for the money, which only leaves me to wrap things up in my Nikon 40mm macro lens verdict.

 

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