71 replies to this topic

[lucutes]

Very interesting article on the results of the new Nikkor 135mm f/1.8 Plena being used for Astrophotography. Nice corners.

 

http://Using the Nik.../#ixzz8PU1aDkQb

 

Author Dominique Dierick
https://flic.kr/p/2ps1YLe

 

 

Attached Thumbnails

• 

[deansjc]

Hey out west!  Thanks for sharing this.  Can you provide a working link to the article?  

 

Sounds like a nice, if pricey, lens.  I just picked up a vintage Nikon 135mm and would love to compare.  It's a 2.8, but that's fine.

 

The image looks very sharp, corners too as you said.  In fact, I don't recall a prime lense picture being quite this nice.  There is some degree of processing evident, as shown by some halos, but not much else.  It does make me wonder if the stars have been rounded as they are really sharp and round?

 

Thanks, John

 

(Central at 45N :-) 

[erictheastrojunkie]

Another lens that looks to fall to the famed Rokinon 135mm, lol. $2,500! Woof, performance looks "ok", coma looks well controlled, but there's clearly a ton of purple chromatic aberration and honestly...it looks a little soft. Maybe the user missed focus slightly and that's causing the issues, but at that price....color me unimpressed....again. So I'll just keep recommending the Rokinon, because why not, it's cheap, well proven, lots of options for mounting focusers and other equipment, and it performs well. If you've got a bit more money, the Sigma Art 135mm is a slight step up and also has some options. 

[deansjc]

Hopefully I can soon say that my vintage 135mm Nikon lens was fully worth the $125 CDN I purchased it for.

Then I will say "who needs to spend so much for a Rokinon"

If only the clouds permit sometime soon.

Cheers.

[dan_hm]

The corners look decent but let's keep in mind this was taken with a Z6.  One of Nikon's 45MP cameras would be a better indicator of quality.

[Andy Lucy]

The purple fringing on the stars evident in the nebula image is indeed horrible.  However, I wouldn’t write the Plena off too fast, since there are clearly issues with this image.

 

First, the stars are hugely overexposed.  If the same conditions were used as for the flaming star nebula image (on the flickr album), each exposure was 2 minutes at f/1.8 and iso 800.

 

Second, there are very clear processing artefacts:  the bright stars show a dark ring around the blown out core, surrounded in turn by a purple fringe

 

Some other images, less obviously overexposed, are shown by the author in the article on Nikon Rumors and the stars there look very good:

https://nikonrumors....otography.aspx/

 

Andy

[lucutes]

Yeah I am not sure why that link didn't work above. It's from the Nikon Rumors site.  Beautiful lens, but not many options for filters. Optolong haven't really come out with a Z-mount filter yet for their dual bandpass. However at f/1.8 you need something that works on a RASA.

https://nikonrumors....otography.aspx/

[erictheastrojunkie]

The purple fringing on the stars evident in the nebula image is indeed horrible.  However, I wouldn’t write the Plena off too fast, since there are clearly issues with this image.

 

First, the stars are hugely overexposed.  If the same conditions were used as for the flaming star nebula image (on the flickr album), each exposure was 2 minutes at f/1.8 and iso 800.

 

Second, there are very clear processing artefacts:  the bright stars show a dark ring around the blown out core, surrounded in turn by a purple fringe

 

Some other images, less obviously overexposed, are shown by the author in the article on Nikon Rumors and the stars there look very good:

https://nikonrumors....otography.aspx/

 

Andy

Star shape looks ok, all the images have a huge amount of chromatic aberration, definitely not worth the price tag for astro use given those results and the other options available. 

[Whereisclearsky]

Star shape looks ok, all the images have a huge amount of chromatic aberration, definitely not worth the price tag for astro use given those results and the other options available. 

Can you base it off a post processed image nowadays though?

Who knows if something like BlurXTerminator wasn't applied to it?? 

[nhmorgan79]

I agree that the image posted looks to have a ton of fringing, but that wasn't my experience with the lens when I tested it out. I owned it for a couple of months and sold it only because I needed to sell either the 135 or 85mm 1.2 and decided to keep the 85mm. I use both primarily for daytime photography, but did do a quick test with the Plena and didn't see that kind of aberration. I wish I'd kept the files. I think this example may be a byproduct of processing rather than an indictment of the lens. I don't know that the Plena is worth the premium over the sigma or sony GM. In lab tests, the sony GM 135 is supposed to have color fringing, but that is maybe the best lens I've ever used for astro when stopped down to 2.2-2.5. So, I don't know that the Plena is worth 1k more, but the plena does have better rendering and bokeh for daylight use. I wish I'd used it more for astro to get a feel for it.

[lucutes]

I see an almost perfect lens with very little to no distortion. I mean he shot it unguided, wide open at f/1.8 with no calibration frames and just a quick post process. 

I might have to rent this lens and slap it on my Z6iia for further analysis.

[erictheastrojunkie]

I see an almost perfect lens with very little to no distortion. I mean he shot it unguided, wide open at f/1.8 with no calibration frames and just a quick post process. 

I might have to rent this lens and slap it on my Z6iia for further analysis.

This is the beauty of this hobby, you see an almost perfect lens and I see a very very expensive lens with a ton of aberration, ok sharpness, and pretty bad post processing. FWIW, at this focal length I'd expect almost every lens to have little to no distortion. Just looking at other 135mm offerings on lenstip.com reviews, I can't find a single one with more than 1% distortion, and again...the Rokinon 135mm has some of the lowest distortion measured. Maybe the author of that article got a bad copy, but I certainly wouldn't be yearning to test that lens given those results. 

[primeshooter]

Apart from some outliers, nikon tune their lenses to people. So stuff like what we are looking for, is low on the list for the designer.

Still, I noticed this from the corner of the plena, I assume wide open. Looks like focus was missed by a hair - easily done.

It definitely beats their 50 1.8S lens as he shows (below). The CA that seems apparent may be due to his over blueing of this area, which naturally isn't these colours. The stars look all mostly blue, which indicates some mangled colour IMO. This along with the slight focus miss I see here, I don't think we can judge it on CA just yet though...

 

That said -

 

Rok, and Sigma win, especially when price comes into it.

Exceptions - 14-24/2.8S at 14mm. If you want a 14mm lens for a star tracker, this one is incredibly good at f/2.8 for star shapes, even slightly better at f4. It's pretty good at 24mm too. 70-200/2.8S. I use this alot at 200mm and the star shapes around 3.5 are decent. I use it for daylight too, so it is a win win for me.

 

Sigma, and Voigtlander and to an extent Samyang, or Rokinon or whatever they name themselves in each country are where the game is at for this mostly though...Now to pick up that 50 APO lanther. Soon...

This image has really hit home how much better the APO is at f/2 - (this is the 50 1.8S at 2.2) -

 

See the full res downloadable plena shot here on flickr - some dark halos around the stars and slight focus miss make it hard to judge. If wide open as he states, this is pretty good star performance, given you could shoot this all day at 2.5 if good focus prevents CA. https://www.flickr.c.../in/dateposted/

Edited by primeshooter, 24 January 2024 - 07:19 AM.

[nhmorgan79]

I wouldn't judge the corners too carefully. I've seen many many modified Z cameras that exhibit some problems from tilt after modification. I think that 50mm 1.8s shot might be more due to a poor copy. I'm pretty happy with mine, but I'm almost always doing mosaics with it. Here is a corner crop from a single frame of a pano shot at ISO 1250 f2.5 45 seconds on a star adventurer. Stopping down to 2.8 it's really good, which is where you want to shoot the voigtlander 50mm too.

I do agree that these nikon lenses can be all over the place for quality control. The good copies are very good astro lenses though.

 

I know people praise the sigma 135mm 1.8, but I've seen pretty nasty corners on that lens too. Much worse than what that plena is showing.

Attached Thumbnails

• 

Edited by nhmorgan79, 23 January 2024 - 09:26 PM.

[primeshooter]

I wouldn't judge the corners too carefully. I've seen many many modified Z cameras that exhibit some problems from tilt after modification. I think that 50mm 1.8s shot might be more due to a poor copy. I'm pretty happy with mine, but I'm almost always doing mosaics with it. Here is a corner crop from a single frame of a pano shot at ISO 1250 f2.5 45 seconds on a star adventurer. Stopping down to 2.8 it's really good, which is where you want to shoot the voigtlander 50mm too.

I do agree that these nikon lenses can be all over the place for quality control. The good copies are very good astro lenses though.

 

I know people praise the sigma 135mm 1.8, but I've seen pretty nasty corners on that lens too. Much worse than what that plena is showing.

Yes, true but like you allude to, it's not just modified cameras I'm seeing a similar problem in - it's the lens having a tilted or decentered element. I've seen some wild copy variation of the 50/1.8S and the 20/1.8S to the extent one edge frame is unusable to me. Great to claim the fancy pants Z mount is this or that, but if you can't get basics like alignment right, it's all for nothing.

 

Re your crop, nice one, have you got the full size for me to look at?

What puts me off buying that 50/1.8S personally is, for me the voigt looks a shade better - and it's deffo built better and I don't care about AF. That and realistically, the 50/1.8 is another boring 50mm lens and I have two already (not suited to astro tho) for portraiture and other purposes. It's also quite an ugly looking thing, not that this really matters, but for me, I like the aesthetics!

Edited by primeshooter, 24 January 2024 - 07:18 AM.

[nhmorgan79]

Yes, true but like you allude to, it's not just modified cameras I'm seeing a similar problem in - it's the lens having a tilted or decentered element. I've seen some wild copy variation of the 50/1.8S and the 20/1.8S to the extent one edge frame is unusable to me. Great to claim the fancy pants Z mount is this or that, but if you can't get basics like alignment right, it's all for nothing.

 

Re your crop, nice one, have you got the full size for me to look at?

What puts me off buying that 50/1.8S personally is, for me the voigt looks a shade better - and it's deffo built better and I don't care about AF. That and realistically, the 50/1.8 is another boring 50mm lens and I have two already (not suited to astro tho) for portraiture and other purposes. It's also quite an ugly looking thing, not that this really matters, but for me, I like the aesthetics!

Here is a link to the full version of that one: https://images-pw.pi...b48811-2500.jpg

Here is one from the same night but earlier shot at 2.8: https://images-pw.pi...2d540c-2500.jpg

Both of those are straight out of camera with a kolari HA modified z6ii

 

2.8 is the best aperture to shoot that lens, but if I'm doing panos with overlap, which both of these were for, then 2.5 is perfectly suitable. I used a focusing filter for both, so the focus should be dialed in to optimal sharpness. I think I focused on the center for both of those, but have found with most lenses it's preferable to focus a little outside of center to help the edges.

 

Also worth considering is that the Voigt is over 2/3 of a stop darker in the corners at f2 than the 50mm 1.8s

 

I've got a copy of the voightlander z 50mm apo, but havent had a chance to test it out under dark skies yet. I had the 35mm version, but it wasn't great even at 2.8, so I sold it and picked up the 50mm. I agree that the Nikon 50mm 1.8s is an ugly lens, but these days you can find them used in the $350 range so at that price they are an absolute steal.

Edited by nhmorgan79, 24 January 2024 - 08:43 AM.

[primeshooter]

Here is a link to the full version of that one: https://images-pw.pi...b48811-2500.jpg

Here is one from the same night but earlier shot at 2.8: https://images-pw.pi...2d540c-2500.jpg

Both of those are straight out of camera with a kolari HA modified z6ii

 

2.8 is the best aperture to shoot that lens, but if I'm doing panos with overlap, which both of these were for, then 2.5 is perfectly suitable. I used a focusing filter for both, so the focus should be dialed in to optimal sharpness. I think I focused on the center for both of those, but have found with most lenses it's preferable to focus a little outside of center to help the edges.

 

Also worth considering is that the Voigt is over 2/3 of a stop darker in the corners at f2 than the 50mm 1.8s

 

I've got a copy of the voightlander z 50mm apo, but havent had a chance to test it out under dark skies yet. I had the 35mm version, but it wasn't great even at 2.8, so I sold it and picked up the 50mm. I agree that the Nikon 50mm 1.8s is an ugly lens, but these days you can find them used in the $350 range so at that price they are an absolute steal.

Thank you for that link. It's pretty good. Far corners show astigmatism which is making the stars larger - but not too bad. I think the voigt at 2.5 is a little better from the copies I've seen reviewed though, and like I said it seems much less of a gamble to get a good copy of that lens that it does a 50/1.8S from Nikon. Nikon have a real problem with alignment in some primes. But oddly, the zooms of theirs I own are spot on. All f/2.8 lenses that cost an arm and a leg - perhaps they undergo more rigorous alignment than the el cheapo primes; however it is something that they should be sorting out as I am not the only person noticing this. Re the voigt: I am aware the caveat of worse vignetting, but it quickly goes away stopping down, which is like you - where I'd be using it. f/2.5-f/4.5 is where I would be at with it (4.5 for deep sky shots, no landscape).

 

Let's see your voigt when you get time, the 50 is better than the 35 for starlight...

Edited by primeshooter, 24 January 2024 - 09:40 AM.

[nhmorgan79]

Thank you for that link. It's pretty good. Far corners show astigmatism which is making the stars larger - but not too bad. I think the voigt at 2.5 is a little better from the copies I've seen reviewed though, and like I said it seems much less of a gamble to get a good copy of that lens that it does a 50/1.8S from Nikon. Nikon have a real problem with alignment in some primes. But oddly, the zooms of theirs I own are spot on. All f/2.8 lenses that cost an arm and a leg - perhaps they undergo more rigorous alignment than the el cheapo primes; however it is something that they should be sorting out as I am not the only person noticing this. Re the voigt: I am aware the caveat of worse vignetting, but it quickly goes away stopping down, which is like you - where I'd be using it. f/2.5-f/4.5 is where I would be at with it (4.5 for deep sky shots, no landscape).

 

Let's see your voigt when you get time, the 50 is better than the 35 for starlight...

I agree with you on the 70-200 2.8s. At 3.2-3.5 it was impressive for a zoom, but that's a lot of light to lose. The 14-24 is a great lens but I was unimpressed with it wide open. It was better stopped down, but like the 70-200, once you stop it down, I'd much rather just use a fast prime stopped down and have have much better correction and more even illumination of the frame. I just don't use zooms for work so I sold them both. I do think that the Nikon lenses are among the best for astro, but the Sony 50mm 1.2 GM is really good even at f2 and the 135mm 1.8 GM is exceptional at 2.5. The 24mm GM was horrible in my opinion and I don't know why it has such a good reputation. The 35mm 1.4 GM was better, but both have bad fringing, but so does the Nikon 35mm 1.8s. 

[primeshooter]

I agree with you on the 70-200 2.8s. At 3.2-3.5 it was impressive for a zoom, but that's a lot of light to lose. The 14-24 is a great lens but I was unimpressed with it wide open. It was better stopped down, but like the 70-200, once you stop it down, I'd much rather just use a fast prime stopped down and have have much better correction and more even illumination of the frame. I just don't use zooms for work so I sold them both. I do think that the Nikon lenses are among the best for astro, but the Sony 50mm 1.2 GM is really good even at f2 and the 135mm 1.8 GM is exceptional at 2.5. The 24mm GM was horrible in my opinion and I don't know why it has such a good reputation. The 35mm 1.4 GM was better, but both have bad fringing, but so does the Nikon 35mm 1.8s. 

Granted it is a light loss, but there are no telescopes that I know around that arena are 2.8 so at least, at a push I can use it there and easily at f/3.5 I've shot comets with it and they came out well. I don't know of a scope that is around 200-250mm that has a fast aperture, which is why I am using the Nikon. The Redcat51 is 4.9. That's pretty slow, the stars are good though. Anyhow, I use the Nikon for landscape photography too so it fits the bill for me. I've seen some of your 70-200 mosaics. (at least I think it was you). No one can argue that the lens delivered the goods so as far as I am concerned - it's academic.

 

Surprized re the 14-24mm 2.8. I've never seen a better 14mm on starlight, and I've used a pile of them. (The Z mount should excel at this stuff, if the designer drives the lens towards top performance. Obviously pricing and bokeh favouritism can sway it). Then we have to come at it with the caveat that 14mm doesn't gather much light with such a small clear aperture, but for what it is, I felt that Nikon nailed the starlight on the wider end with it. (Still generally prefer using longer lenses for MW work though - but I can't resist the odd 14mm shot).

 

Re sony - they have some good ones. Their 20 1.8S might beat nikon actually. But I simply cannot deal with green stars, the shots look ok til you punch in...

Edited by primeshooter, 24 January 2024 - 10:51 AM.

[Kevin_A]

Unfortunately the Nikon Z6 is not the best camera to test a lens like this on. Besides it having a lower resolution big pixel sensor than the Z7, it also has an Anti Aliasing filter to blur it even more. When I tested new lenses I could easily see this big difference between my Z6 and Z7 cameras. The Z6 faired much better at longer focal lengths but it still had the blurring effect from the AA filter. 

[lucutes]

Isn't the filter removed when they modify it for H-Alpha?

[Kevin_A]

Isn't the filter removed when they modify it for H-Alpha?

Yes it is removed for modification…. my comments are just for general testing of any lens. Even with the removal, the almost 6uM pixels still do not resolve well for these new very sharp lenses. This sensor is absolutely fabulous when paired with a 600mm plus scope as can be seen in the asi2400mc pro camera. I had the D5300, D7200, D750, Z6 and Z7 and used my D750 and Z6 on only my biggest scopes as the images looked very rich on those.

Edited by Kevin_A, 25 January 2024 - 06:46 PM.

[nhmorgan79]

Plena update. I've got one of these for work so did some really quick tests under very light polluted skies last night vs the 135mm sigma. Long story short, the Plena is ok, but better than the copy of the sigma I have. There is definitely a little wierdness at the edge of the frame and some indication of a little decentering, esp looking at the lower left corner. I tested it with both a z8 and modded z6ii. I've linked to the Z8 files as the results were almost identical. Similar star shapes on both cameras. The lens definitely has some blue and purple fringing. Due to the high light pollution I opted to just evaluate the star shape, so I did a 90 second exposure at 1.8 with both lenses at ISO 64 and a 180 second exposure with both lenses at 2.5 ISO 64. Both images were guided on an HEQ-5. 

 

Plena at 1.8 90 seconds ISO 64

https://www.dropbox....ewjn97sc3t&dl=0

 

Plena at 2.5 180 seconds ISO 64. 

https://www.dropbox....ewjn97sc3t&dl=0

 

Sigma ART 135mm at 1.8 90 seconds ISO 64

https://www.dropbox....py7q2t73g0&dl=0

 

Sigma ART 135mm at 2.5 180 seconds ISO64

https://www.dropbox....mwemp91jp4&dl=0

 

I realize this isn't a great test. Just had a few spare minutes to look at star shape and vignette on both. 

[dan_hm]

Plena update. I've got one of these for work so did some really quick tests under very light polluted skies last night vs the 135mm sigma. Long story short, the Plena is ok, but better than the copy of the sigma I have. There is definitely a little wierdness at the edge of the frame and some indication of a little decentering, esp looking at the lower left corner. I tested it with both a z8 and modded z6ii. I've linked to the Z8 files as the results were almost identical. Similar star shapes on both cameras. The lens definitely has some blue and purple fringing. Due to the high light pollution I opted to just evaluate the star shape, so I did a 90 second exposure at 1.8 with both lenses at ISO 64 and a 180 second exposure with both lenses at 2.5 ISO 64. Both images were guided on an HEQ-5.

Plena at 1.8 90 seconds ISO 64
https://www.dropbox....ewjn97sc3t&dl=0

Plena at 2.5 180 seconds ISO 64.
https://www.dropbox....ewjn97sc3t&dl=0

Sigma ART 135mm at 1.8 90 seconds ISO 64
https://www.dropbox....py7q2t73g0&dl=0

Sigma ART 135mm at 2.5 180 seconds ISO64
https://www.dropbox....mwemp91jp4&dl=0

I realize this isn't a great test. Just had a few spare minutes to look at star shape and vignette on both.

Pretty good for an f/1.8 lens. For someone who needs an advanced lens with AF for terrestrial photography I can see it being a good option. For an astro-only person, it’s still hard to compete with the Rokinon.

[erictheastrojunkie]

Plena update. I've got one of these for work so did some really quick tests under very light polluted skies last night vs the 135mm sigma. Long story short, the Plena is ok, but better than the copy of the sigma I have. There is definitely a little wierdness at the edge of the frame and some indication of a little decentering, esp looking at the lower left corner. I tested it with both a z8 and modded z6ii. I've linked to the Z8 files as the results were almost identical. Similar star shapes on both cameras. The lens definitely has some blue and purple fringing. Due to the high light pollution I opted to just evaluate the star shape, so I did a 90 second exposure at 1.8 with both lenses at ISO 64 and a 180 second exposure with both lenses at 2.5 ISO 64. Both images were guided on an HEQ-5. 

 

Plena at 1.8 90 seconds ISO 64

https://www.dropbox....ewjn97sc3t&dl=0

 

Plena at 2.5 180 seconds ISO 64. 

https://www.dropbox....ewjn97sc3t&dl=0

 

Sigma ART 135mm at 1.8 90 seconds ISO 64

https://www.dropbox....py7q2t73g0&dl=0

 

Sigma ART 135mm at 2.5 180 seconds ISO64

https://www.dropbox....mwemp91jp4&dl=0

 

I realize this isn't a great test. Just had a few spare minutes to look at star shape and vignette on both. 

I'd say it's better than the Sigma in this comparison, definitely in terms of vignetting and edge performance. Looks like your sensor has a bit of tilt going on, the stars on the left side with both lenses are elongated and softer compared to those on the right side.