My favorite Nikkor lens? I like them all for something. That something can be more rational. Or more emotional, like with the Nikkor 50 mm 1.4G. This blog entry talks about technical minutiae first. Then it goes into cons and pros.
The technical side: Designs compared
A lens with just one element cannot change focus, and even if the focus by chance is correct, it would get it right for a single wavelength only, meaning one spectral color. We want to change the focus distance, while getting all colors sharp in a flat projection on the film or sensor, without much sharpness or brightness falloff towards the edges. This is done with additional elements which create optics much more complex than a single element. In the end it still functions a lot like a magnifier glass, but corrected for good image reproduction.
Making fast lenses complicates the design as it has to process light rays from more angles. Manufacturing costs set a practical limit.
The standard Nikon 50 mm option for SLR cameras is the 1.8G version. Affordable, lightweight, sharp. It has an aspherical lens element, which allows to perform multiple corrections by using a more complex – and harder to manufacture – surface.
The 1.4G is much more expensive and just a bit faster. It is Nikon’s cheapest f/1.4 option within the G-series. Unlike the 1.8, it has as no aspherical lens element! Just an additional spherical element. How can that even work, then?
Here is the trick: A lens element which is flat on one side is easier to make, but gives up potential for optical correction. Both 50 mm designs use a couple of such elements which are flat on one side, but the 1.4 has more elements which are spherical on both sides. These additional curvatures, and the one additional lens element, allow to get acceptable optical correction.
Older, pre G-series 50 mm 1.4 designs use one lens group less than the G version. I don’t know which, if any, optical properties suffer in comparison.
This is the challenge of building a fast lens: 50 mm f/1.8 means the absolute aperture is 50 / 1.8 = 28 mm. For 1.4 the calculation is 50 / 1.4 = 35 mm. (Both results are rounded.) This is a substantially bigger aperture which has to be projected on the film or sensor with acceptable quality. Area is diameter squared, meaning at least the front lens elements are by area much bigger, by some 55%. Also the model is in lower demand and produced in smaller batches, that increases cost per each part. This seems to justify the price of the 1.4G lens from a technical perspective.
But does it deliver?
Why it is not as popular
Already having the DX 35 mm 1.8, I wanted something more different than 50 mm with the same 1.8 aperture. Of course, a 50 mm lens with 1.8 also provides a lot more background blur compared to 35 mm because 50 mm is longer. But then I wanted something even more different and ordered the 1.4 version.
Then put it on, took a couple of test shots wide open. And liked the result. Close inspection revealed several issues, but I was already sold.
A couple of weeks later I took the lens out to photograph a historic Nuremberg cemetery and discovered more optical issues. The post-processing for wide-aperture shots took more time than with other prime lenses. I understand why this lens is not often recommend. But still like the overall look.
Color fringes
If used wide open in broad daylight, or at night pointed at bright lights, color fringes are very prominent. Stopping down to f/2 helps to makes it manageable in post. Under direct sunlight, f/1.4 is unusable for me anyway because the fastest shutter of D7500 is 1/8000s, resulting in over-exposure. Again f/2 helps.
In the night, car lights shot at 1.4 get a thick blue ring. Correcting that in post involves a lot of work to get natural-looking results. Daylight shots which show blue, or green fringes also need quite some time to remove those without leaving visible artifacts. Global image adjustment doesn’t do it, local editing is required.
Sharpness
Color fringes rarely appear shooting on cloudy days, allowing to use f/1.4 under those conditions? Only if! Images taken with f/1.4, even if in perfect focus, come out visibly soft. Digital sharpening can get a lot of detail back. It appears that the lens is technically not soft, it just renders fine detail in low contrast. An aperture of f/2 gets some improvement, f/2.8 is visibly better, f/5.6 seems optimal.
At least in the center. The edge part of the image get softer again. Also some small color fringes, while quite under control at f/5.6, can be there. And this is on a DX sensor which cuts off the FX corners!
Used with an FX camera and a typical resolution of 24 megapixels, the issues shift. Even f/1.4 provides almost acceptable details now. Color fringes, counted in pixels, are thinner and thus less an issue. The absolute thickness does not change of course but the overall frame is bigger on FX, so compared to the final image, color fringes are smaller.
In other words, those results are created by the different pixel pitch of the FX sensor used in the D750. While the high pixel density of modern DX sensors magnifies all the lens issues.
As the frame on an FX camera is larger, one is much more flexible and it is possible to get more background blur because one can move closer to the subject in the foreground. Sharpness and fringing issues are visibly worse looking at the FX-frame corners though. Digital post processing does help, and is even required when used wide open, in order to get proper results if used at 1.4 aperture. Again, the lens performance peaks at f/5.6.
Long story short, 1.4G comes with issues on any camera, but using a current DX camera almost requires you to stop down a bit.
Bokeh
Used wide open, bokeh disk edges are harsh and distracting. Stopped down to f/2, they get a lot softer. We see a pattern: 1.4 is offered but quality improves visibly with f/2.
Looked at it objectively, we can conclude that the 50 mm 1.4G lens should be used with an f-stop of 2 or higher. Why then pay a premium for the f/1.4 aperture?
First, the 1.4G model has nine aperture blades, the 1.8G lens only seven, resulting in a somewhat angular-shaped disks when the 1.8G lens is stopped down. The 1.4 lens on the other hand can be stopped down while keeping an almost round shape. The difference is not drastic and not in itself a reason to go for the 1.4G lens.
And I have to admit that the open-aperture performance of the 1.8G version is really good. Still, if you compare bokeh at same aperture, the 1.4 lens is a little bit better.
When light is needed
Shooting portraits in a quite dark room is possible thanks to being a 1.4 lens. All the issues when using the lens wide open are there, but iso is low and motion blur kept in check. It is a trade-off, but a trade-off which is not available with an 1.8 lens.
Looking at other, more high-end 50 mm 1.4 lenses, it is clear that the comparatively cheap and small Nikkor version has its limits. It is an 1.4 nonetheless and its construction with relatively few lens elements means that little light is lost. It might not be the best 50 mm 1.4 lens, but at least it is bright!
However in closer range, the depth of field is too shallow with 1.4, one has to stop down in order to have enough of the frame in acceptable focus.
Looking at results
With the right settings I get a creamy appearance with a smooth transition from in-focus parts to out-of-focus parts. And the lens issues gracefully increase towards corners, leading the attention to the best part, the center. NOT using aspherical elements seemingly can be a weird advantage sometimes.
My 50 mm lens took some beating, once I ran against a wall, breaking one of the lens hood brackets. When the lens later dropped to ground by mistake, focus broke (both auto and manual). I ordered a new 50 1.4G, though by then I got more realistic about its performance. For example, colors are not spectacular. But for me, this lens provides the balance of performance and traditional photographic output which I like. And if needed it is very fast.
Looking at the gear
From the outer appearance, I think this lens looks like a good fit the D7500. Judged objectively this combination is not optimal because the crop-sensor uses less than half of the projected area of an FX lens.
On the D5600 the 50 1.4 lens makes a good impression, too, judged from the outside looks. On a borrowed fullframe camera, the D750, the lens appears almost tiny.
Your mileage may vary, but I like the look and the balance with this lens on each of my Nikons DX cameras. Of course it well with the Nikon F65 which I bought used. The lens barrel surface feel is nice, the focus ring turns smooth. Everything feels a bit more serious than the 1.8G version. For me, such things help to justify the price.
The front lens element is quite big, the rear lens, too. Seemingly there is a lot of glass in there. This also helps to enjoy the purchase, as the lens just radiates “I gather a lot of light”. And then the experience when using the aperture dial. I was used to have 2.8 or 1.8 as smallest number depending on the prime lens. Being able to go lower feels great. It might not help the photo directly if one enjoys toying around with the gear. But liking the gear for whatever reason means to use it more often. This can turn into practice and eventually yields a couple of hopefully useful photos.
Autofocus compromises
Both automatic and manual focus is slower than with the 1.8G. This should improve precision. While not always perfect when using viewfinder autofocus shooting wide open, the lens usually does get in focus. For consistently perfect results, I use the contrast-based focus in live-view used with enlarged preview, if I can. Because of the low-contrast rendering of fine detail one still would do some work in post.
Not sure about differences within the series. The new copy I got seems to nail focus better, but that could also be because I handle it more carefully.
In most cases I work with the viewfinder and find the focus precision good, and the speed good enough. I use the lens for outdoor portraits while the model is not holding still, and get nice results with the camera’s AF-C mode. In other words, yes the Eye-AF of recent cameras might get higher yield but with a bit of practice I feel confident to use this lens for portraits when it matters.
What about premium lenses?
Nikon marks its best lenses with a gold-colored outside ring. The 50 mm 1.4G has no such gold-colored mark. But the NPS terms (Nikon Professional Services) still consider it a pro lens.
The DX 16-80 mm does have the golden honor, and is also part of the NPS terms, but only as a group-2 item (in this nomenclature, that means lesser). The 16-80 mm is very good, but a blog entry would be short: If quality is not already excellent, stop down a bit, but unlike standard DX zoom lenses you can expect good results even wide open. Color fringes are well under control. You get many switches on the lens, and VR works well. One can do almost everything with the 16-80, even portraits because the bokeh is nicely soft. Color rendering is extraordinary. Sadly, the focus ring has a bit of play and the exterior, while okay, does not feel pro-grade like the 50 mm 1.4G.
The 50 mm 1.4G is roughly half the price of the 16-80, but of course much more limited in application. For use on a DX camera the 50 mm 1.4 seems overpriced. Especially because for less than half of the 1.4G cost, one can get the 1.8G version which is a bit slower but sharper over the entire frame and it has less issues with color fringes. The 50 mm 1.8 is an entry-level item in the FX world, but still solid in DX terms as it of course comes with a metal mount, dust seal, distance indicator and MF switch, all missing on current DX kit lenses.
Using the 50 mm 1.4 with a modern high-resolution DX camera stretches the capability of that design, while wasting half of its image area and thus image information. Yes the center crop gets the best part but optical limits are still there. Having more area on FX means more information gets captured.
Long story short: This lens is good but using it correctly requires practice.
Personal preference
Okay nine aperture blades, like a portrait lens should have. Otherwise nothing special. A standard “silent” (actually, low-noise) wave motor like any AF-S lens. But no ED, nor aspherical lens elements. No inside, nor rear focus, instead the front element moves. No nano coating, just standard stuff. No VR of course.
With f/2, this lens is able to get nice portraits: Optical issues are there but dialed back so that they even contribute to the image giving a classic photographic look. The depth of field is where I need it: Shallow, but not to the extreme. Bokeh is soft. Image edges might be a bit blurry and darker as some vignette is still there but that also helps to get a traditional appearance. For more sharpness I stop down, for more light I stop up.
Just cranking up the aperture and expecting perfect results – not happening. It took some time to discover all the weak points and how to avoid them – or how to apply them just enough to avoid a sterile, digital look.
Using the lens
I couldn’t use photos of a social event for this blog and I picked this landscape or rather cloudscape. The narrow field makes landscape photos more difficult, but can also serve as a force of creativity. It is not a very useful lendscape choice of course.
For events, the fixed and narrow field of view can also be a limitation. However in a good way: When others use their cellphones, usually with a wide-angle lens, they get the standard social-media results. Using a 50 m lens on a DX camera all the time gives the resulting image gallery a different look. Compared to the other photos it stands out. Especially as one gets real background blur instead of computational blur.
So far, my best work (non-commercial as I am not a pro) was when I brought this lens only. No backup with a wider angle. Instead having to walk more.
In post, I sometimes don’t use lens correction (geometric distortion, vignette) for Raw files taken with this lens, as it looks more natural than a digitally applied filter.
Some aperture recommendations
I prefer 5.6 for landscape or architecture or everything where I need the in-focus part tack-sharp. Also for close-ups of flowers, as it gives a reasonable depth of field.
For single portraits, f/2 seems to be optimal in many cases. Group portraits often benefit from 2.8, as it increases the yield where everyone is fully in focus. With 50 mm, one still gets some background blur if the background is far enough.
The lens has no VR, using short exposure times helps. Even for still objects I use 1/160 or less, for objects in motion 1/500 or less. For events, I sometimes use 1/250 to keep iso low and accept some unusable results with too much motion blur.
In-door at night, I push my luck with 1/125 needing the light because f/2 is the widest practical aperture if two or more guests are in the photo.
Talking about 1.4. I try to avoid it as it can result it busy bokeh with harsh edges, f/2 is much better.
By mistake I used 1.4 for an outside portrait shooting in snow. It was quite some work to smoothen the background and even more work to address color fringes in post, and except the very few parts which were fully in focus, the images have a dream-like haze. Luck had it that the hazy appearance turned out to be atmospheric.
For a 12-month-in-a-year portrait project I used the DX 40 mm lens and the DX 16-80 mm lens for the first months, and only the 50 mm 1.4G since then. Using it correctly requires practice but then it gets me results which are to my taste.