RF 16 f/2.8 for Astro Landscapes ?!?

[Andreas_F]

I view the 16mm f/2.8 primarily as lightweight wide-angle solution for travel when I don't want to carry my WA zoom. It nicely complements the 24-105 in that role. It would be great if it could double as astro lens when more establishes solutions like my Rokinon 14mm are not available.

Below is a shot I took a couple of days ago and a screen grab from a 100% view. No corrections were applied. Also shown are images of the same scene with the Rokinon 14mm f.2,8. The images are not processed exactly the same way but the comparison might still be useful. The RF16 clearly shows a lot more coma and pretty serious vignetting, which leads to stars disappearing on the edges and in the corners. However, I am quite pleased with the results considering the price and weight of this lens. I think it'll do in a pinch. Let me know what you think...


Canon R5, RF 16mm at f/2,8, ISO3200, 20s


same as above; 100% crop, upper left corner


Canon R5, Rokinon 14mm at f/2,8, ISO3200, 30


Same as above; 100% crop, upper left corner; some star trailing visible at 30s. Should have stuck to 20s

 

[Marco Nero]

I view the 16mm f/2.8 primarily as lightweight wide-angle solution for travel when I don't want to carry my WA zoom. It nicely complements the 24-105 in that role. It would be great if it could double as astro lens when more establishes solutions like my Rokinon 14mm are not available.

Below is a shot I took a couple of days ago and a screen grab from a 100% view. No corrections were applied. Also shown are images of the same scene with the Rokinon 14mm f.2,8. The images are not processed exactly the same way but the comparison might still be useful. The RF16 clearly shows a lot more coma and pretty serious vignetting, which leads to stars disappearing on the edges and in the corners. However, I am quite pleased with the results considering the price and weight of this lens. I think it'll do in a pinch. Let me know what you think...

The results look good and your observations seem dead on. I suspected coma would be inevitable with a lens that sits in this price range - and the same applies to the RF 35mm Macro lens as well (which has coma even towards the center of the frame of shooting astro with it). Yet some of Canon's best wide-angle L-series lenses produce notable coma towards the edges of the frame... sometimes even much stronger than this lens. So price doesn't always enter into the equation. Coma is an element of Lens Character and it's also going to appear with wider FOV lenses. Some journalists that have taken astrophotography shots for publication don't bother worrying about coma at all.
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As you observed, you should start seeing star movement (star trails) at around 30 seconds with a lens like this on a Full Frame camera. Either way, it's bright enough and wide enough to be able to produce some excellent Astro-landscape images if you choose.
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I have a feeling that the popularity of the RF 16mm f/2.8 will enable many people to dabble with wide-field astrophotography for the first time. It's certainly an affordable lens from Canon and that too should draw in more fence-sitters contemplating the R system.

 

[Dan_168]

I view the 16mm f/2.8 primarily as lightweight wide-angle solution for travel when I don't want to carry my WA zoom. It nicely complements the 24-105 in that role. It would be great if it could double as astro lens when more establishes solutions like my Rokinon 14mm are not available.

Thanks for sharing your Astro experience with the RF 16mm F2.8, I am an astro ( milky way ) shooter but currently not using my Canon system for this application simply because I don't have a great Astro lens on my Canon system, your sample image looks very decent for a $300 lens. most of the Canon fast prime I had before had much worse Coma even they costs 4 times as much as this little guy, so Coma is totally expected for lens at this price level, let's see if Canon will bring out lens like the Sony 14mm F1.8GM. or at least something like Sigma 14 F1.8.

 

[Andreas_F]

Thank you Marco and Dan!
A couple of additional thoughts:

- Coma of the RF 16/2.8 is comparable to what I see with the Laowa 12mm f/2.8, which doesn't keep me from using that lens.

- Uncorrected, the angle of view of the RF 16mm is probably more equivalent to 15mm.

- Manual focussing is quite easy when choosing MF in the menu and using the virtual distance scale on the rear screen

 

[Marco Nero]

- Manual focussing is quite easy when choosing MF in the menu and using the virtual distance scale on the rear screen

I did not know there was a digital scale on the rear screen when focusing the R5 (and presumably R6 cameras). Was that buried in the menu? I assume you simply select "infinity" on that scale to nail the manual focus?

 

[Andreas_F]

Marco,

When you're in manual focus (I think either by selecting on the lens or in the menu) and press the Info button, you get that scale. ...and yes, I just selected infinity. It would probably more accurate if I did it manually using a planet or bright star or whatever. On the Rokinon, I have the focus ring taped at the infinity setting.

I stumbled on the distance scale when I was trying to shoot a lightning storm at night a few weeks ago.




Canon R5, 24-105 f/4, blend of 45s and 15s exposures