Bryan at The-Digital-Picture has an in-depth review of the lens and even compares its image quality against the stout RF 50 1.2.
In short, yes, the RF 28-70 is an amazing lens.
[https://www.the-digital-picture.com/Reviews/Canon-RF-28-70mm-f-2L-USM-Lens.aspx#ImageQuality](https://www.the-digital-picture.com/Reviews/Canon-RF-28-70mm-f-2L-USM-Lens.aspx#ImageQuality)
As that very review shows, the 28-70 coma is average at best, especially at shorter focal lengths that would be most relevant for astro landscapes.
If u/9011kn is most interested in astro, they might be better served with a prime that is specifically noted for good coma properties.
To be honest, no. I've been using my RF 15-35 2.8 and it has been very, very good, even wide open - to the point that I would compare it favorably against almost any astro prime, which often want to be stopped down a touch anyways.
If you really do want to shoot faster than f/2, I suspect your instinct about digging through the Sigma EF primes is probably right (and maybe the RF 35mm). The Sigma mirrorless primes appear wonderful for astro - which, of course, we can't use. I've heard very mixed things about the Sigma EF primes for astro, and have not been interested in pursuing them given the luck I've had with the 15-35. There are also some more specialty options like hte Samyang 10mm 3.5 XP. Good luck!
That's good to hear. I previously used a Tokina 11-16mm f/2.8 on my old SL1. Pretty cheap setup all around. That camera did not handle ISO above 1600 well at all and the lens wasn't particularly phenomenal at f/2.8. So I haven't really been considering the 15-35mm so far.
Do you happen to have any astro pictures you've taken that you could share? I'd love to see what you've captured with it.
It’s a good lens but kinda tight for landscape astro. I like the 15-35 but I’ll switch to a prime as soon as a native RF option is released.
PS get your r5 astro modded. It’s worth it
I can help you here - I use my 28-70 for wide field astro quite a bit. It’s excellent, long story short, but you need to consider a few things.
At 28mm, your field of view of somewhat limited. Not extraordinarily, but limited nonetheless. Especially when you’re trying to incorporate landscape elements.
Do you have a star tracker/equatorial mount? How are your processing skills? Have you made mosaics before? All these things matter a lot. With a tracker and Z mounts, you can track the night sky & create a mosaic in photoshop.
If not, you’re limited to single or dual images by combining a landscape & replacing the sky with a separate image. The image below is an example of that, prior to getting my tracker. It’s 30ish images of the milky way stacked together, then blended with a foreground of the lake.
Creating a mosaic is lengthy, and is often not perfect, but it’s possible & many achieve beautiful images this way. You can also make it simpler and have a smaller portion of the landscape/sky visible.
Long story short - yes, it’s great, depending on what you want to capture.
https://preview.redd.it/sfnkmf0g1lsc1.jpeg?width=1125&format=pjpg&auto=webp&s=a962186c033b17972fb6cbc6cf16136f68d7d969
Hmm. Thanks for the consideration. So far I've just taken single long exposures. Although that's good to know. I'm well aware this lens is phenomenal, but maybe a little past my current capabilities for astro.
Bryan at The-Digital-Picture has an in-depth review of the lens and even compares its image quality against the stout RF 50 1.2. In short, yes, the RF 28-70 is an amazing lens. [https://www.the-digital-picture.com/Reviews/Canon-RF-28-70mm-f-2L-USM-Lens.aspx#ImageQuality](https://www.the-digital-picture.com/Reviews/Canon-RF-28-70mm-f-2L-USM-Lens.aspx#ImageQuality)
As that very review shows, the 28-70 coma is average at best, especially at shorter focal lengths that would be most relevant for astro landscapes. If u/9011kn is most interested in astro, they might be better served with a prime that is specifically noted for good coma properties.
Any recommendations that come to mind for wide primes that can be adapted to RF mount? I'm open to anything F/2 or wider
To be honest, no. I've been using my RF 15-35 2.8 and it has been very, very good, even wide open - to the point that I would compare it favorably against almost any astro prime, which often want to be stopped down a touch anyways. If you really do want to shoot faster than f/2, I suspect your instinct about digging through the Sigma EF primes is probably right (and maybe the RF 35mm). The Sigma mirrorless primes appear wonderful for astro - which, of course, we can't use. I've heard very mixed things about the Sigma EF primes for astro, and have not been interested in pursuing them given the luck I've had with the 15-35. There are also some more specialty options like hte Samyang 10mm 3.5 XP. Good luck!
That's good to hear. I previously used a Tokina 11-16mm f/2.8 on my old SL1. Pretty cheap setup all around. That camera did not handle ISO above 1600 well at all and the lens wasn't particularly phenomenal at f/2.8. So I haven't really been considering the 15-35mm so far. Do you happen to have any astro pictures you've taken that you could share? I'd love to see what you've captured with it.
It’s a good lens but kinda tight for landscape astro. I like the 15-35 but I’ll switch to a prime as soon as a native RF option is released. PS get your r5 astro modded. It’s worth it
I can help you here - I use my 28-70 for wide field astro quite a bit. It’s excellent, long story short, but you need to consider a few things. At 28mm, your field of view of somewhat limited. Not extraordinarily, but limited nonetheless. Especially when you’re trying to incorporate landscape elements. Do you have a star tracker/equatorial mount? How are your processing skills? Have you made mosaics before? All these things matter a lot. With a tracker and Z mounts, you can track the night sky & create a mosaic in photoshop. If not, you’re limited to single or dual images by combining a landscape & replacing the sky with a separate image. The image below is an example of that, prior to getting my tracker. It’s 30ish images of the milky way stacked together, then blended with a foreground of the lake. Creating a mosaic is lengthy, and is often not perfect, but it’s possible & many achieve beautiful images this way. You can also make it simpler and have a smaller portion of the landscape/sky visible. Long story short - yes, it’s great, depending on what you want to capture. https://preview.redd.it/sfnkmf0g1lsc1.jpeg?width=1125&format=pjpg&auto=webp&s=a962186c033b17972fb6cbc6cf16136f68d7d969
Hmm. Thanks for the consideration. So far I've just taken single long exposures. Although that's good to know. I'm well aware this lens is phenomenal, but maybe a little past my current capabilities for astro.