Top 6 Best Nikon Z Lenses for Astrophotography

Astrophotography is a unique and rather specific genre of photography.

This means that some of the rules that apply when selecting a lens for other types of photography have little relevance here.

Meanwhile certain aspects of lens design and construction that are of only minor importance in other areas of photography become fundamental when photographing the night sky.

In this section we break down the main technical points you will want to consider when choosing a Nikon Z lens for astrophotography.

Maximum Aperture

When it comes to lenses for landscape photography, achieving a deep depth of field will be most photographer’s main priority.

As a result, for landscape photographers fast maximum aperture is rarely a selling point.

But skyscapes are another matter entirely; here a lens’s light-gathering abilities count like nothing else. 

In any case, the long exposure times necessary to correctly expose a nighttime scene at a small aperture such as f/16 just aren’t practical for astrophotographers, who are effectively photographing stationary objects (stars) while they themselves are standing on a giant rotating ball (planet Earth).

The earth’s rotation isn’t detectable to the naked eye, but if the exposure time is too long, it will clearly show up in a photograph of the night sky as blurred stars.

Using a faster ISO will of course permit shorter shutter speeds, but this also comes with increased digital noise. Not a good solution.

The best tactic for astrophotography, then, is to use a fast lens, so as to keep exposure times to a minimum and ISOs low.

How long an exposure you can get away with before you start to see star trails (motion blur) depends on a number of different factors, such as sensor size, lens focal length (see below), and even the direction in which you point your camera.

Thankfully there’s a handy rule for determining which shutter speed you should use in any given situation.

To recap then, one of the most important attributes of a good astrophotography lens is a fast maximum aperture.

However, there are also other important considerations to keep in mind when choosing a Nikon Z lens for astrophotography, and they in turn cannot be considered in total isolation from maximum aperture.

Read on to learn what these factors are and how they affect the apertures you can get away with using when photographing the night sky.

Sharpness

In effect, astrophotography involves photographing tiny pinpricks of light. The sharper and better defined those pinpricks are, the prettier they tend to look. Clearly then, lens sharpness is extremely important to the astrophotographer.

But when we say that a lens is sharp, this can actually mean a variety of different things.

Most lenses tend to be fairly sharp at the center of the image, at least when used at medium apertures; indeed, if a lens can’t manage this basic feat, it’s unlikely that anyone will buy it.

Trickier to find are lenses that are not only sharp in the center of the frame, but also at the edges.

Rarer still are those lenses that are sharp from edge to edge even when used at their widest aperture. 

As you will take most of your night sky photographs at the lens’s widest aperture setting, and will want to capture sharply defined detail across the entire image, obviously it’s this last kind of lens that you need for doing astrophotography; sharp across the frame, even at its widest aperture.

This is the holy grail of astrophotography lenses.

Coma

Designing camera lenses is a challenging job. Lenses contain numerous pieces of precision glass that must be perfectly aligned in such a way as to capture and focus light with as few reflections, optical errors, and areas of uneven illumination as possible.

Some optical faults are almost inevitable and, while perhaps noticeable, will make little practical difference to the performance of a lens (a degree of flare, for example, is to be expected when shooting into the light). 

Other optical defects will be totally undetectable under most common shooting circumstances (e.g. in the middle of the day, under bright sunshine), but will only become apparent when the lens is used in a particular way.

Coma is one such error. It’s fairly common, but isn’t a problem when using a lens in the way that 95% of photographers will use it. Unfortunately, astrophotographers don’t fall within that 95%.

But what is coma? 

Comatic aberration is a kind of optical imperfection, a misalignment caused when rays of light entering a lens don’t refocus to a perfect point.

It’s most noticeable when photographing small points of light – such as stars – and will be visible as a kind of flare or trail behind the point of light. In effect this will make the star look like a shooting star or a comet (hence the name “coma”). 

Coma affects off-axis light, meaning that it tends to be more noticeable the further you move away from the center of the image.

It also tends to be more evident when shooting at wider apertures, and may clear up once the lens is stopped down by a stop or two.

Unfortunately though, this is rarely an option that is open to the serious astrophotographer.

If you’ve followed the 500 Rule (see above) to determine the best shutter speed for your camera/lens/subject, and yet still notice what look like star trails in your photos of the night sky, this may in fact be coma.

Coma can be caused by an inherent fault in the design of a lens. I.e. the lens is just made that way, so there’s nothing you can do about it other than buying a different model lens..

Alternatively, a particular lens may display coma due to a manufacturing error.

In which case you should send the lens back to the manufacturer and demand a new, coma-free, one.

In theory, Nikon Z lenses are ideal for astrophotography, in that they are not only extremely sharp, but also tend to be very much free of comatic aberration.

Unfortunately, though, the Nikkor S line suffers from one major defect that will likely deter most astrophotographers.

We’ll look at this problem in the next section.

Focusing

Nikon Z-mount lenses generally feature great autofocus. Unfortunately, as autofocus doesn’t easily permit precise focusing on tiny objects positioned at infinity (i.e. stars), it is of little use to astrophotographers. 

Of course, Nikkor S lenses also offer manual operation, don’t they?

Kind of. 

While it’s true that S lenses come with a manual focus ring, this is actually what is known as “focus-by-wire;” a system that doesn’t provide genuine manual (i.e. mechanical) control of the lens elements.

Instead, turning the focus ring sends an electronic signal to the lens motor, which moves the elements for you.

Effectively this is just autofocus controlled by a different means.

And sadly the difficulty of making minor, precise adjustments to focus remains exactly the same as with regular autofocus. 

To be clear, it’s not entirely impossible to focus sharply on stars using AF. It just involves a lot of extra hassle. 

Unfortunately though, the Nikon Z lenses have another problem that makes them even less appropriate for astrophotography. 

Namely, once you do find the right focus point, you better pray that your camera battery doesn’t run out, or that you don’t need to turn your camera off for any other reason.

Because if you do, you’ll only have to start all over again, as in the meantime the camera will have reset focus for you.

*** 2021 update: This is no longer an issue with the latest firmware update on Nikon Z cameras, make sure to update to the latest firmware to avoid this de-focusing problem! ***

In short, the ideal astrophotography lens is a truly manual focus lens. 

And with the exception of the very expensive Noct 58mm – which is in any case unsuitable for astrophotography due to its longer focal length (see below) – Nikon Z-mount lenses do not currently offer this capability.

Focal Length

If you’ve ever used a telephoto lens handheld, you’ll have discovered that a longer focal length lens is harder to hold steady than a wide-angle lens; increasing the risk of camera shake.

It’s kind of similar with astrophotography.

Only here you’ll be using a tripod, so it’s not shaky hands you need to worry about, but instead star trails caused by the movement of the earth. And this movement will be more noticeable the longer the focal length of lens.

As a general rule, when using a full frame camera you should stick with lenses that are 40mm or wider.

This rule becomes 24mm or wider when using an APS-C sensor camera.

While it is possible to use longer focal length lenses than this to photograph the night sky, doing so will require the use of a “tracker”; an electronic rig that moves the camera to compensate for the movement of the Earth.

The only drawback to this solution is that any landscape features that you might want to include in the foreground of your shot will be blurred by the movement of the camera.

Meaning that a tracker is only really appropriate when photographing just the sky and nothing else.

In short, stick to wider lenses, and star trails will be much less noticeable. Simple.

Primes vs Zooms

As ever, prime lenses tend to have the upper hand over zooms when it comes to image sharpness.

Zooms are complicated pieces of optical engineering, and so it’s hardly surprising that manufacturers can’t always maintain the same degree of precision over the entire zoom range. 

For some genres of photography, sharpness is only really a secondary consideration.

But as mentioned above, for astrophotography it’s almost everything.

As a general rule then, prime lenses are probably the first place you should begin your hunt for an astrophotography lens. 

But it’s important to keep in mind that this piece of advice is only a guide, not a hard and fast rule. Some prime lenses perform relatively poorly on sharpness, whereas some zooms excel. As they say, the proof of the pudding is in the eating. And there’s absolutely no reason not to go with a zoom if you identify one that performs well in this area and fits your needs on all other fronts too. 

As case in point, Tamron’s 15-30mm zoom (above) is undoubtedly one of the best Nikon Z lenses for astrophotography out there right now – of any kind. In part this is precisely because it is so exceptionally sharp, despite being a zoom.

Lens Mount

Although in itself the type of lens mount you use for astrophotography will make no practical difference to your photos, the fact is that the majority of the most useful lenses for astrophotography are simply not available in native form for the Nikon Z-mount system.

Given that the Nikkor S line of lenses are generally excellent, this may come as something of a surprise to learn.

And hopefully Nikon will eventually resolve this problem by adding a few more true manual focus lenses to the range. But for now the problems caused by Nikon’s use of the focus-by-wire system far outweigh any advantages that Z-mount lenses may otherwise offer the astrophotographer. 

In short, the best Nikon Z lenses for astrophotography are mostly not Nikon Z lenses at all.

This being the case, unless you are willing to put up with the fiddly focusing and frequent missed shots caused by focus-by-wire operation, you will likely want to make use of third-party lenses such as those listed above.

This invariably requires the use of an adapter; do not expect a Nikon F-mount lens, such as the ones from Samyang, Tamron, and Sigma that we’ve recommended  here, to work on your Z6 or Z7 right out of the box.

The good news is that Nikon’s FTZ adapter works very well and doesn’t result in any compromise in the performance of these lenses.

Nonetheless, this is an extra expense that you will need to budget for when putting together your Nikon Z series astrophotography kit.

Final Thoughts

Despite the generally exceptional quality of Nikon’s native Z-mount lenses, choosing a Nikon Z lens for astrophotography is a surprisingly difficult affair.

Or rather, there are several fantastic options available for astrophotography, it’s just that they tend not to come from Nikon at all, but instead from third-party manufacturers.

Do you have experience of shooting astrophotography with Nikon’s S-series lenses? Have you been satisfied with the results? How have you found focusing? We would love to hear your tips and opinions in the comments section below.