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Best fast astro lenses 24mm to 50mm - what is your favorite?

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#1 nathanm


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Posted 01 October 2020 - 03:06 PM

What are your favorite fast lenses in the 24mm to 50mm focal length?


The key question for me is what f-stop do you need to be at to get decent (but perhaps not perfect) stars in the corners of a full frame?


The "usual suspects" are  Canon (or Nikon for Nikon shooters) and some Zeiss lenses.  However, mostly the big-name lenses are terrible at Coma and thus for stars.


Meanwhile Sigma ART, Samyang/Rokinon, and a select few Zeiss lenses do have good coma correction.


Here is a start of a list


Canon 24mm f/1.4 II

Sigma 24mm f/1.4 ART

Samyang/Rokinon  SP 24mm f/1.2

Samyang/Rokinon  24mm f/1.4


Zeiss Otus 28mm f/1.4 - I think that has lots of coma despite high price, but maybe somebody has a different notion


Canon 35mm f/1.4 II - this lens has a lot of coma.

Sigma 35mm f/1.4 ART lens - this is reputed to have decently round stars at f/2.8 as shown here https://www.peterzel...strophotography


Samyang/Rokinon  35mm f/1.2 SP lens 


Samyang/Rokinon 35mm f/1.4


Canon 50mm f/1.4  II

Sigma 50mm f/1.2

Samyang/Rokinon 50mm f/1.4

Samyang/Rokinon SP 50mm f/1.2


Other makers lenses are certainly welcome.


Almost all of these are f/1.4 or f/1.2 lenses wide open.   Almost all of them aren't really usable wide open because the stars are poor quality in the corners, and like most other lenses they improve as you stop them down.


The big question is this - how much stopping down do you need to do to get them to be decent?





#2 Jim Waters

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Posted 01 October 2020 - 03:18 PM

My best 50mm lens Sigma Art f/1.2 also the Canon 50mm f/1.4 II.  (Stopped down to f/4 for 'sharp' stars in the corners.)


Rokinon's are OK but many are hit-or-miss...!  They suffer from QC issues.  They MUST be stopped down to f/4 or greater.  Below 35mm are very problematic.  

Edited by Jim Waters, 01 October 2020 - 03:20 PM.

#3 tkottary


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Posted 01 October 2020 - 03:39 PM

Just the Sigma 40 art.


40 art works wide open, but I use it at 2.2 just for sharpness.


Both my 35 and 50 art needs to be at 3.2 and higher to get round stars through out full frame.


Other good contenders are Sigma 28 1.4 and new Tamron 35 1.4

#4 erictheastrojunkie


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Posted 01 October 2020 - 03:44 PM

Sigma Art 40mm, nothing else comes close, it's the sharpest and most aberration free lens wider than 100mm, the only reason I stop mine down to f1.8 is to reduce vignetting. 


I have used many many many lenses from 11mm up to 600mm for astro, I'm probably sitting at ~75 total lenses used quite extensively now. IMO the best lenses per focal length are:

14mm: Sigma Art 14mm f1.8

20mm: Sony 20mm f1.8 or Nikkor 20mm f1.8S

24mm: Sony 24mm f1.4 or Nikkor 24mm f1.8S

28mm: Sigma Art 28mm f1.4

35mm: Tamron 35mm f1.4 

40mm: Sigma Art 40mm f1.4 - best lens wider than 100mm

50mm: Sony Zeiss 50mm f1.4 ZA (although I'm probably going to try the new Voigtlander 50mm APO which is supposed to be close to it)

65mm: Voigtlander 65mm f2 APO

85mm: Sigma Art 85mm f1.4 (the new one I haven't tested yet, but have read some good things, I'll try it next year)

100/105mm: Sigma Art 105mm

135mm: Take your pick, Rokinon 135mm f2, Sigma Art 135mm f1.8, Zeiss Apo Sonnar 135mm



I've used quite a few Samyang/Rokinon lenses, I still use the 14mm for time lapse, IMO stay away from them except the 135mm, the QC issues are too frustrating to deal with. The 24mm is ok, a bit soft wide open, but little to no LoCA or coma. I have the 35mm sitting in my closet, for a $250 lens its quite good, little coma, some LoCA, needs to be stopped down to f2.8. I've used the 85mm, it's junk, skip it. The 135mm is obviously a "benchmark" lens in terms of value and I use it with an ASI183mm to do some widefield imaging. 


Sigma doesn't make a 50mm f1.2, their Art f1.4 is a solid lens, but needs to be stopped down to get rid of coma, mine was fantastic at f2.8. 


I think if you've got no budget limits you should look at the Sigma Art 28mm or Tamron 35mm f1.4 if you want a wider lens, the Art 40mm is the benchmark for all lenses now IMO, but it is huge and heavy and some people don't like that. The Tamron 35mm f1.4 I had was incredible and IMO it is the best 35mm lens available, I kind of wish I had kept it instead of the Art 40mm just for size/portability sake. 

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#5 Blackbelt76


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Posted 01 October 2020 - 03:54 PM

IMO if you're a Nikon shooter, the Nikon AF-S NIKKOR 50mm f/1.4G Lens is probably the best kept secret.

If the budget doesn't allow, the same at 1.8 is still pretty amazing.

#6 nathanm


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Posted 01 October 2020 - 05:30 PM

I am interested in what is out there regardless of budget.   Obviously cost does matter but each person can evaluate cost on their own - we all know what it means.  


But only somebody who has tested lenses on actual Astro subjects  knows how well they work.  Many very expensive lenses - such as the super premium Zeiss Otus line - are poorly corrected for coma.


Samyang/Rokinon does have QA problems - I have sent several back myself.


I had somehow overlooked the 40mm Sigma ART - based on the strong endorsement and some additional feedback online I am ordering one!



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