KenProspero

Living in an imperfect world, where one makes trade-offs.

I just bought a Nikon z-5 and am looking for a lens for astrophotography, though I'll also be using it for landscapes, general photography, etc. Currently, I have the Samyang 14mm f/2.8 Pentax Mount (from my old camera) and a Pentax to Nikon z adapter. This works fine -- though I find the distortion to be unacceptable -- esp for landscapes, and to be honest, it's not the sharpest lens there is.

I've been looking at the Nikon Z 20mm f/1.8 -- which as far as lens quality/speed will meet my needs. However, the downside is that there's a significant difference in fov from my 14mm lens. Alternately, there's the Nikon z 14-30mm f/4. Which gives me the fov, but is >2 stops slower, and from what I can glean not quite as good optically (though given my photo skills, the difference may not be significant). There's also the Nikon z 14-24mm f/2.8, but this is out of my price range.

My initial thought is that since I've moved to the Nikon Z infrastructure, and over time will be getting a whole new set of lenses anyway, get the best/fastest lenses I can and make do with what I have until I can get what I really want -- which would tend towards the 20mm lens.

OTOH For my next night shoot, I can probably borrow the 14-30 from a friend -- and after a couple of nights shooting with it, I suppose I'll have my answer whether this meets my needs.

I'm beginning to think that this is a classic case of 'pick your poison'. But am wondering, am I missing anything obvious.

Longshadow Loc: Audubon, PA, United States

What's more important to you? FOV or light gathering ability.

I myself would pick the 20 ƒ/1.8.
But that's just me...

line_and_shadow Loc: ATL

In my limited experience with shooting stars, I find that I'm always trying to keep my shutter speeds as fast as possible in order to avoid star-streaking, and trying to use as low ISO compensation as possible to avoid noise.
I'm using a Canon DSLR & glass (6D2 body), and don't have any experience with Nikon mirrorless, but with my kit, ideally I'm looking to stay around 12-15 sec max shutter times and ISO ~3200, and compensating for any shortfall with boosted exposure. I've had good results with a 50mm 1.4, but would love something wider FOV. I have a 100mm 2.8 macro lens that works beautifully in the right composition, but my shutter times creep up to 20 sec or so and the streaking starts to get noticeable. My 24-105 f/4 is the widest lens in my kit, but I'm having to boost the ISO so much to compensate for the aperture that those shots require a good deal more post-processing. I've got my eye on a Rokinon 35mm f/1.2.

chasgroh Loc: Buena Park, CA

Borrow your friends Z 14-30, I have absolutely no complaints about mine. The stop difference might not be ideal but it's worth a try? Sorry, I can't attest to its efficacy for astro stuff...not my cup o' tea.

Mac Loc: Pittsburgh, Philadelphia now Hernando Co. Fl.

I don’t do much in the way of astrophotography, but I agree with Longshadow. The 2 1/2 f/stop difference means the 20mm f/1.8 will gather about four or five times as much light as the 14-30mm f/4. I think the light difference is more important than the field of view difference.

Edited

larryepage Loc: North Texas area

Ken...I saw your post as I was stopping by to close out a few loose ends here, so probably won't be available for any follow-up discussion. Night sky photography is a tough challenge. I've been to several workshops and watched out of the corner of my eye as folks struggled to learn how to capture images like the ones we have all seen. The Nikkor 14-24mm f/2.8 really is a gold standard for this activity.

Anything longer than 16mm on a full frame camera is going to be pretty limiting when trying to capture the galactic core in a single shot with room to include anything else, and f/4 is going to push you to shutter speeds that are way longer than you want to use, even with the most advanced cameras available today (D850, Z7). Your choice is going to be to underspose significantly, then rely on the dynamic range of the camera to dig out the image that you want. It can work, but it is tough.

The other issue is lens distortion. If you shoot panoramas, you are going to need to be overlapping by 50% or so. If your lens has much barrel or pincushion distortion, software is going to have a really rough time putting the pieces together. The edges will be either too short or too stretched to match up with the same area when it is in the center of the adjacent image.

Your idea to borrow the f/4 lens is a good one. It will let you see and decide if you can live with the exposure. And with the 20mm lens, just be prepared to need to shoot panoramas to get what a wider lens could capture in a single shot. I'm not familiar with the level of distortion in the lens you are looking at, or if it has a lot of brightness falloff in the corners, which also creates a problem.

Just experiment and see what might work. It may be worth saving up a few more rolls of quarters for the 14-24mm.

ELNikkor

Since it is a Z camera, any other lens than one designed for a Z will give you less than the camera was designed for. The advantages will be noticeable in final image sharpness wide open, especially at the edges and corners. Since you have already invested in Nikon mirrorless, don't go the adapter route, get the Z 20 1.8. It might help to see some astro-photography on Flickr or elsewhere already done with that lens wide open.

tcthome Loc: NJ

For Astro

KenProspero

Thanks -- I agree with that, Going with lenses designed for the Z mount for new purchases is one of the reasons I ruled out getting the Nikon 14-24 f/2.8 F mount + the FTZ adapter

jayluber Loc: Phoenix, AZ

I have the Rokinon 14mm and 16mm and have used them with success. I picked up a Sigma Art 14-24 2.8 lens a year ago. First - the Sigma far outperforms the Rokinon lenses in sharpness and corner to corner. No coma at all. And secondly - I find I use the full range of the lens. It is so much more versatile than the prime lenses. Of course it depends on what is in the foreground and what I'm shooting, but for MW I find its fast enough to eliminate star trails and long enough to bring the MW a bit closer. I'm only keeping the Rokinons as backup lenses. I'm wondering how a prime 35 would do.
Mirrorless and lens for them I can't comment on.

tienws

I have both, but use the 20 F1.8 due to its light gathering and shorter shutter speed to avoid star trail.
However, if composition requires a wider FOV and star trail is not an issue, then I use the 14-30.

JBRIII

Besides noise and shutter time, Astro presents big problems with area viewed. For exampke, a lens perfect for Andromeda will be pretty useless for planets (too small), but good for sun (special filter needed), or the moon. Also sun and moon are plenty bright, while many deep sky objects are large, but very dim.

Orphoto Loc: Oregon

I would vote to get the 20 and either stitch as needed or use the older 14 until you can pick up another option. I would expect high quality ultrawides primes in the Z mount within a year or two.

baron_silverton Loc: Los Angeles, CA

If you are using it for astrophotography it is a no-brainer - the 20mm 1.8 smokes the 14-30 f/4.

If it was just for landscape then I'd say 14-30 as you will be mostly shooting at around F/8-16 anyway. Once you add astro to the mix there is no question - 20mm 1.8 is the right lens of the two. It is 2.34 stops faster - this means much lower ISO and faster shutter speeds - both necessary to excellent astro photography.

Hope this helps.
-B

Grahame Loc: Fiji

If you don't want stars that look like flying saucers towards the edges I would also be having a close look at the 'coma' results of any lens you are considering.