Are cheap lenses that much worse than expensive lenses for Astrophotography?
With all the hype over the Sony 24mm 1.4 GM for Astrophotography I wanted to know if this was really the best lens for the night sky for and how it compared with the Rokinon/Samyang 24mm 1.4. I didn’t want to spend a whole lot on an Astrophotography lens, and I imagine I’m not the only one, so I went with the Rokinon 24mm 1.4 GM for my Sony a7iii and rented the Sony.
Out of the box, the Rokinon looked and felt great, but was quite heavy and long. Brand new it was $499, but I was able to find it for $300 on eBay. From what I read it was the best bang for the buck.
Researching more, I found that the Rokinon 24mm 1.4 had problems with lens decentering but with Ebay’s good return policy I decided to go ahead and try my luck. I also heard that the Rokinon was not as sharp at f1.4 with a strong vignette, and the online community was encouraging to use f2 for more usable results for astrophotography.
On the other hand the Sony 24mm 1.4 gm was said to be the best Astro lens available on the market. It had little distortion, practically no coma and rated as the best lens to buy. It also was the most expensive.
Read more to see how the most expensive lens compares to the most budget friendly lens for astrophotography.
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How well does the Rokinon 24mm 1.4 perform for astrophotography?
The Rokinon is solid but almost too solid. It has no weather sealing and it feels extremely heavy. This is not a landscape lens to just carry around. It’s 20.8 oz or 590 grams. The Sony is 15.7 oz or 445 grams but the rokinon is also much wider with a 77mm filter thread vs 67mm (Sony). It has no autofocus and no way to capture metadata which I found annoying when trying to compare apertures. Below is the first photo I took and 1.4.
You can see the vignette is strong in the corners and if your wondering why the background is so bright it’s because I’m about 10 miles from the Las Vegas strip which is probably the worst place for a test shot. The next shot is an 1.5 hours away and almost considered a night sky sanctuary not too far from Death Valley. This is where I really started to notice the problems with the Rokinon.
This is shot at f1.4. If you look closely some stars look sharp while others look blotchy. It almost looks like I didn’t nail focus and I was thinking that maybe the lens didn’t focus correctly. The infinity mark was at the end of this lens but it still seemed to not get sharp focus. However, once I stopped down to f2.0 things started looking better.
This was stopped down to 2.8. I was finally able to feel like the lens got correct focus , but the larger stars still not looking so good. I almost prefer this look too with the larger aperture bringing more depth of field to the foreground.
As you can see in both images the stars appear to be trailing but it’s the coma. The coma was very much pronounced. I was surprised to see such a difference with the next shot I took with my Sony 24-105mm f4.
This was actually the best photo of the night. It’s hardly an astro lens at 10,000 iso, but the optics for astro really weren’t bad. It would have done a much better job with a star tracker.
How well does the Sony 24mm 1.4 gm perform for astrophotography?
Is the Sony really worth the $1400. If all you’re doing is astrophotography I would say no. There are plenty of other lenses that offer great performance and even better coma than this lens, but if you want to do anything other than astro work this lens does not disappoint.
Things to love about this lens are the aperture, sharpness, coma performance, and weight. I love this lens, but to me it’s still not worth the price if you are frugally minded like me. f1.4 is great for the night sky but the depth of field can blur the foreground more than you want. Also the coma is good but not great. In the corners the coma is cross shaped.
In this image you can see the cross shaped coma. It really isn’t that bad unless you are a pixel peeper, but it’s still there and for $1400 and all the hype saying this was the best lens for astrophotography on the market I was a little disappointed.
One last disappointment I had with the sony 24mm 1.4 GM was the manual focus. It is not easy to focus to infinity with this lens because it’s too easy to focus past infinity. I had to shoot multiple shots of the same image just to get the focus; a problem I didn’t have with the Rokinon.
I’m going to go ahead and say the Rokinon 24mm is not worth the money if it’s only used for astrophotography at f1.4 because f1.4 was unusable. What’s the point of buying a f1.4 lens if you have to stop down to f2? For the budget consumer I’d recommend the samyang 18mm 2.8 for $329.
Another option could be any lens with a star tracker. I use the Tamron 17-35 f2.8-4. If you still want a faster lens the Sony 20mm 1.8 is a viable alternative For $899.
Overall, the Sony 24mm 1.4 it’s a great lens and it’s worth it if you have the money. I don’t have a problem with the coma because at the edges it is shaped like a cross and that’s pretty close to a star shape.
Is the Sony 24mm 1.4 the best lens on the market for night photography? No, but it’s good and one of the fastest made for Sony. If I had the extra cash I’d buy the sony 24mm 1.4, 20mm 1.8, or the sigma 14-24mm 2.8. In the end you get what you pay for, so I’d say don’t pay full price for either.
Pros and Cons
Rokinon 24mm 1.4 Pros and Cons
Pros: inexpensive, decent images stopped down to f 2.0
Cons: poor coma, heavy, strong vignette, manual focus
Astrophotography Score: 3/10
Sony 24mm 1.4 gm Pros and Cons
Pros: Lightweight, good overall performance, sharp, good for everything else
Cons: Expensive, coma still exists, difficulty to achieve manual focus.
Astrophotography Score: 8/10
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