I’ve been shooting with my Canon EOS Ra for a few months now, and while the modified sensor is incredible for capturing those H-alpha emissions, I feel like my current glass is holding me back. I’m looking to upgrade to a lens that truly complements the Ra's capabilities for deep-sky wide fields and milky way shots. I'm particularly interested in something with minimal comatic aberration and a fast aperture, maybe around f/1.4 or f/1.8. I've been eyeing some Sigma Art primes or the RF 15-35mm, but I’d love to hear from fellow enthusiasts. What lens has given you the sharpest stars edge-to-edge on this specific body?
This ^
Seconding the recommendation above! Honestly, after years of shooting wide fields, I've found that the Sigma 28mm f/1.4 DG HSM Art for Canon EF is the real sweet spot for the Ra's sensor. It's much cheaper than RF glass and the edge-to-edge sharpness is incredible at f/2.0. If you're on a tighter budget, the Samyang 14mm f/2.8 ED AS IF UMC for Canon EF is a classic value pick, though teh corners can be a bit hit-or-miss. Hope this helps!
Seconded!
@Reply #6 - good point! Honestly though, I've had some pretty frustrating issues with those big adapted setups on my Ra. The balance is just wonky. It makes the whole rig feel way too clunky for long nights out there. Unfortunately, the sharpness at the edges on those older lenses just hasn't been as good as I expected once you really zoom in. Kinda disappointing tbh.
- Honestly, just go with Canon, you cant go wrong with their native stuff.
- Stick to the native mount glass if you want to avoid adapter issues.
- Look into the newer manual lenses from some of the boutique brands. Its a letdown that the expensive glass still has these quirks. Staying with the same brand usually fixes most of the headache though. Just keep looking at the native options and you'll find something much more reliable for your setup... it's out there!
+1
🙌
Wait really?? Thats actually super helpful. I always thought it was the other way around.
In my experience, you should definitely watch out for the Canon RF 15-35mm F2.8 L IS USM if you're chasing f/1.4 level sharpness. It's a great lens, but for the Ra's sensor, the coma at the edges can be frustrating for the price. Honestly, I've had the best luck with the Sigma 14mm f/1.8 DG HSM Art for Canon EF using the adapter. It’s heavy and pricey, but the light gathering is unreal for those H-alpha regions! Hope this helps!
Saved for later, ty!
To add to the point above: after years of testing glass on modified bodies, I really think people sleep on the Sigma 40mm f/1.4 DG HSM Art for Canon EF. I know, it sounds a bit narrow for wide-field, but the lack of coma is just breathtaking. Its easily the sharpest lens Ive ever put on my Ra. Most wide lenses get mushy in the corners but this one stays tack sharp even at f/1.4. It basically turns your camera into a mini telescope. If you are dead set on something wider for those massive Milky Way arches, the Sigma 20mm f/1.4 DG HSM Art for Canon EF is still the one to beat. Youll need the Canon Mount Adapter EF-EOS R obviously, but native RF options just havent caught up to these specific Art primes for pure astro performance yet. The 20mm has some slight vignetting wide open, but the star shapes are way better than what you get on the zooms. TL;DR: Grab the Sigma 40mm f/1.4 DG HSM Art if you want the absolute best star quality and dont mind stitching panoramas. Its a heavy beast, but the optics are flawless for H-alpha regions.
