Selecting prime lenses for DX

With two DX cameras, a D5600 and a D7500, I use a couple of lenses and wrote about zooms already, but often prefer a fixed focal length. These are my observations, written in blog style. This is not a review trying to be balanced.

The prime DX prime: DX 35 mm 1:1.8G

Usually the questions is 35 or 50 mm? I borrowed the Nikkor 50 mm 1.8 lens several times and find it very sharp and useful for head-shoulder portraits. But I bought the DX 35 mm 1.8 lens, because it provides a field of view usable for almost anything: Travel, landscape, portraits of individuals and small groups.

The optical quality is good, but not outstanding. Especially in close range below one meter, I recommend to stop down. For focusing into the far, I also like to stop down to f/5.6 if I can, or f/2.8 if the light is low. If the light is really now, I have no worries to use the full 1.8 aperture.

Don’t just go f/1.8 mindlessly for background blur, as close-ups can appear quite soft. But for portraits, one might even want to have a sharpness “issue” in order to mitigate some small skin problems. Or when a shallow depth of field is more important than pixel-perfect 1:1 sharpness. Or when it is quite dark and one needs every bit of light.

Low-light application

The D5600 autofocus is not build for very low light, using it under these conditions can result in blurry images. I talk about dimly lit rooms at night while there is no high-contrast edge to focus on. I used the lens on a D5600 on a public Halloween party, of course without flash, and most images were sharp enough.

The D7500 performs a bit better, but a certain miss rate is still there. It takes experience to learn to use the right image part for the autofocus. The first DX 35 mm lens I got was defective, with a high misfocus rate in any light. The replacement works much better. There still seems to be a small chance of missing the focus.

The lens is not stabilized, I use a minimum shutter speed of 1/60 in low light and 1/125 during the day. I rather deal with some iso noise than shake blur.

Experimenting with settings: 1/90 s, f/2.4.

The 35 mm 1.8 lens is the all-purpose prime, and quite affordable. It does not get you perfect detail resolution but there is more to an image than sharpness. I find the rendering overall pleasing and the soft background shows a nice kind of blur (“bokeh”.)

I feel limited rather by my experience as a photographer, than by the physical limits of this lens. The lightweight construction makes it easy to carry, but it feels a bit plasticky and cheap. At least the mount is made of metal, and the lens even has an autofocus switch. This is useful especially on the D5600.

DX 40 mm Micro 1:2.8G

The shortest Nikkor Macro lens. I am not sure if alternatives exists. For macro with 40 mm, one has to get close, which allows unique perspectives. The other DX macro lens is DX 85 mm VR. Also a Nikkor 60 mm lens exists, supporting even FX. I have no experience with either of those two.

For an AF-S lens, the autofocus on the 40 mm is not very fast but the slower pace helps to get a precise focus which is important because this lens resolves a lot of detail if in focus. It allows 1:1 reproduction, meaning something 1 cm long in reality can be projected as 1 cm on the sensor. This, and the high resolution, while being compact and light, yet with a slightly more serious feel than the 35 mm 1.8, makes it my favorite DX lens.

Close-up product shot with the DX 40 mm. Taken at f/13, still only the “Nikon” label is truly in focus.

But I don’t use it as often, because the field of view is a bit too narrow – 35 mm is not much wider but enough to make a difference for me. The 35 mm lens is also more than a full stop faster.

But when the 40 mm lens can be used, it delivers sharp photos with high contrast. Images are so sharp that the bokeh is not very good until the background is really out of focus. The focal length of 40 mm projected on a DX sensor makes it excellent for portraits of all kinds. The lens has a switch to have the autofocus exclude macro range, which sometimes improves the focus speed for normal shots. In very rare cases I experience focus hunting.

The lens is too long for most architecture shots. For landscape it is somewhat useful. If the need arises, one can get extremely close, for example for macro flowers shots. For actual macro one has to get so close that the lens often shades the subject. Insects usually flee if one gets close enough for 1:1 reproduction. This is why I would not recommend the lens for macro work unless one wants to photograph motionless objects, and has control over the light. But for not-yet-macro close-ups I like the lens a lot, which includes Italian shots, meaning close-up portraits showing not much more than the eyes.

The DX 40 mm requires more experience than the 35 mm 1.8, but if applied correctly, it gets images I didn’t know were possible with a crop-sensor camera. There is a learning curve and one needs a steady hand.

50 mm 1.4G

This lens, or the 85 mm 1.8? Both are FX lenses but of course can be put on DX cameras as well. I borrowed the 85 mm several times and it is a serious bokeh machine. Images get very sharp when stopping down to 2.8. This aperture also helps with color fringes caused by chromatic aberration. Looking the cost of the 85 mm lens, I find the image quality very good. But I opted for the 50 mm 1.4 instead, because of the wider field of view.

On a DX camera, 85 mm is just too long for me. The 50 mm 1.4 lens is faster but has less background blur because it is shorter. Chromatic aberration, meaning purple and green color fringes, can be very ugly at open aperture. Stopping down helps. With f/5.6 this lens is pleasantly sharp, at least in the center. The DX image corners get softer. The much cheaper 1.8 version of the 50 mm Nikkor, stopped down to f/5.6 as well, has fully sharp corners on a DX camera.

Sharpness enthusiast would probably prefer the 1.8 version, and if you must have a lot of background blur, the 85 mm 1.8 Nikkor delivers – but the field of view of a 85 mm lens is really narrow on a DX camera.

Regarding the 50 mm 1.4, the aforementioned softness is even the least of the issues when using it wide open at f/1.4, because digital postprocessing can get a lot of the detail back. I was surprised seeing how much can be recovered. However, those color fringes cause problems which are not easily addressed in post. Those fringes don’t appear in every situation, making 1.4 usable in sometimes without color fringes.

50 mm wide open f/1.4. Taken with D5600.

This is not a pro lens providing creamy results wide open. For me personally, the 50 mm 1.4 lens is a good choice because it excels at lady portraits using f/2. The parts in focus show enough detail without being too harsh, while the other parts smoothly get softer, creating an overall pleasing appearance. The depth of field is shallow enough to get a nice blurry background. Also the bokeh quality improves with stopping down to f/2, the sharp bokeh-disk edges with 1.4 are gone.

Autofocus is the slowest of all AF-S Nikkor lenses I have, but still fast enough even for outdoor usage. Using it wide open in bad light sometimes benefits from live-view instead of viewfinder in order to nail the focus. In many cases, stopping down helps to get better images but when needed, the 1.4 f-stop is available. From experience, the t-stop also seems to be great, meaning the lens construction causes very little loss of light.

The manual focus ring has almost no play and turns quite smoothly. The lens itself feels serious.

The 50 mm 1.4 is my secret weapon for events because the results are quite different from typical cellphone shots. My photos with his lens stand out.

Bonus: 50 mm 1.8

After borrowing a 50 mm 1.8G lens several times, I feel experienced enough to comment. Even as DX camera user, you might want to get this lens. It is good for head-shoulder portraits. It can also be used on events, keeping in mind that the field of view it too narrow to get a photo of everything. But if others are there, taking cellphone shots, why redo those with your DSLR? Using a light telephoto lens with the option to get physically blurry background instead of computational blurry background, allows you to get photos your smartphone-using friends cannot. Especially on hair and other complex edges, computational bokeh can create artifacts.

A couple of cups. 50 mm 1.8 wide open. All example images in this article are straight out of camera.

Practical use of these primes

I like to use a prime lens for a full day, because it gives me a a frame. The attention then focuses on that frame. There are occasions where I need zoom flexibility and a prime lens is only a low-light backup option.

The DX 35 mm 1.8 can be used as the only lens all day long, or as low-light backup or for late-night events. The field of view is optimal to portrait one to three people.

The optical construction of a 35 mm lens for F-mount is a challenge because the flange is some 46 mm, meaning shorter lenses rely on retrofocus which complicates the design. Still getting this affordable but fast 35 mm option is great. Image resolution is good but not excellent, though looking at the size and weight, I consider it a reasonable performance.

The 40 mm 2.8 lens can be used as macro but getting 1:1 reproduction is difficult because one has to get so close that the lens hood should be taken off. As an all-purpose portrait lens it offers a nice field of view but the optics are somehow too sharp: Image parts which are slightly out of focus still try to be somewhat sharp. It takes experience to use this lens correctly, with the reward of a lot of detail in images.

If focused very close, the lowest possible f-stop number increases up to f/4.2 at 1:1 reproduction, because the inside lens-group movement causes higher f-stop. This is not an issue in practice because one has to stop down even further to get a useful depth of field. However the meter sometimes seems to overcompensate, for macro shots of moss or tree bark I usually put the exposure compensation to -1.

Zooming in on a tree bark means to enter weirdness. Taken at 1/640 s, f/11, auto-iso 7200.

For younger persons with smooth skin, this lens can do good portraits. Images can get very sharp, while added digital sharpness reveals even more detail. Resolving a lot of detail also means shake blur gets easily visible. I usually prefer faster shutter to lower iso, to avoid any shake blur.

50 mm on a DX camera is quite good for portraits, but not so good for general purpose photography because of the narrow field of view. I still find myself leaving the house with this lens mounted quite often. For travel I preferred the D5600 because it is substantially lighter. Since I dropped the camera into water, the screen no longer functions so I have to use the D7500. (Or use the D5600 without screen, which is possible, but not practical.)

For prepared portrait shootings, I tend to select the D7500 anyway, because the autofocus is a bit quicker and offers the Group-Area mode.

Using the 50 mm lens with f/2 means the fine detail is there but not in high contrast. This works well for skin. I sometimes use this effect also for objects, defying today’s trends of “microcontrast” woo woo.

FX advantages

In order to unlock the full potential of the 50 mm lens, an FX camera is needed. Vignette is quite visible at open aperture if used on a full-frame sensor, but is easily corrected in post. Corner sharpness issues on an FX image are quite visible but who cares? The center is the important part and sharp enough. Especially when using an FX sensor with common pixel count like 24 megapixels, the f/1.4 sharpness issue is less visible anyway. The tests were done using a borrowed D750,

If I had an FX camera, the compact Nikkor 50 mm 1.4 could be the only lens I need for a long time. However I am invested in the DX world.

For a true vintage look I use an AI 50 mm 1.8 pancake, with manual focus. On D5600 and D7500, there is no automatic metering. This slows me down, but makes me think before taking a photo. The manual focus ring turns very smooth. Using this pre-AF era 35-mm-film lens, when stuff was build for eternity, is an experience in itself. Do I always want to get the best possible images in the shortest amount of time, or can this be a hobby worth taking more time than technically necessary?

With fast aperture settings, the pancake AI 50 mm lens cannot compete with today’s optics. On an FX body with a lower pixel pitch than today’s DX sensors, the difference is not as visible, and the FX cameras even meter. The pancake Nikkor can be used to generate a classic photo look on digital cameras, but works best on film cameras with a split-image viewfinder.

Summary

My personal preferences seem to be inverse to the objective properties. The DX 35 mm 1.8 is a bargain lens and practical, somehow even too useful because it is too easy to get a useful composition. I recommend this lens for what it offers considering the low price, but personally don’t use it that often anymore. Sometimes I need it, like for full-length portraits in a confined space. It it also still use it for travel every now and then, with no other lens in the bag! The DX 35 mm is that versatile. And I took a lot of personal photos with it. Also the lens survived some abuse, like being dropped (two small dents in the front lens, still works but shows two small marks in bokeh disks) and heavy rain (after a day of drying, autofocus began to work again.)

On a side note, I used the DX 35 mm lens on a film camera, the Nikon F65. Though there is visible vignette in the corners especially if shooting wide open, it works good enough for me.

The DX 40 mm is more limited in its application being a little bit too long for general usage, and not as fast, and having slower autofocus. It offers 1:1 reproduction for macro, however the close range is not always practical.

But if I could keep only one DX lens, it would be this. It is sharp to begin with and stopping down reveals even more detail. It does not zoom but one can “zoom” with getting very close.

When using the 50 mm 1.4, I normally stop down, so I paid for the aperture without using it a lot. According to my tests the 50 mm 1.8 lens is optically superior when comparing the same f-stop. The 1.8 is also much cheaper, and of course smaller and lighter. But the 1.4 lens has a more serious feel and I like the overall look of the images. This is subjective of course.

The 50 mm 1.4 costs as much as the DX 35 and DX 40 mm combined. It is the fastest, but on a DX camera also the overall least useful of those three. Still, I put it on quite often.

Snap shot taken at f/2.

Recommendations?

The Nikon lineup for DX prime lenses is not very extensive, beside 35 and 40 mm there is an old 10.5 mm fisheye wide-angle, and a modern 85 mm macro, the only Nikkor DX prime lens with Vibration Reduction (VR).

Generally, Nikon does not often put VR into any prime lenses, not even the FX ones. The FX line-up compatible with DX cameras is still impressive and there are a couple of Nikkors which I would like to own – knowing I would rarely use them. And then, there are older, D-type lenses, still made, cheaper than G-lenses, and whisper “buy me to fill the prime-lens hole in your heart!” However especially for DX, many wide-angle needs can be sufficiently met with a standard zoom lens: There is not much background blur anyway, and low-light situations can be addressed with optical stabilization instead of wide apertures.

The more lenses you have, the less you use each one. This is another reason keeping me from buying more stuff for now.

Overall, I found that experimenting with a lens, see were its weak points are and what the strengths ares, and over time learn to apply it correctly, is the satisfying part.

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