Canon vs sony for astrophotography: In astrophotography, the camera body is quite primordial to the final picture quality and the amount of noise. Sony has gained so much success over Canon cameras for this purpose lately, but now people are switching back! This might be why…
Over the past few years mirrorless cameras, and especially Sony cameras, have become very popular to the point where many people have switched the content of their entire camera bag from DSLR’s like Canon or Nikon to the electronics giant Sony. But now many among of the concerned people want to switch back. There is no doubt that Sony cameras offer performance and versatility, especially in the field of night photography. However when trained eyes linger a bit longer and deeper into the pictures’ data, they realize that Sony cameras are not quite as performant as one once thought.
Picture of the milky way taken with the Canon 6D
ISO
Regarding the ISO capability and versatility, there is no doubt that Sony beats any Canon by a hundred miles. In the full frame series of Canon, the 6D and 5D mk. IV are the best contenders but have an optimal ISO of 6400. The ISO invariance range for these cameras is very limited (3200-6400). The ISO invariance is the ability of a camera to produce the same amount of internal noise (on-chip and off-chip read noise) no matter the ISO value you choose. In the Sony a7s and a7 line, most cameras have an ISO invariant range that is much wider (usually in the hundreds ISO to 12800). With this ability, you can shoot at lower ISO, gain more dynamic range, and boost the signal at will in post-process. Sony alpha line’s high ISO performance is also unmatched for the price and is especially remarkable for low-light filming for the price range.
NOISE
Noise is probably the most important aspect when it comes to astrophotography. It’s any obstacle that prevents photons of light from hitting your sensor, resulting in a ‘false value pixel’. Whether external or internal, there exist several types of noise and we perceive them differently. Some of the most famous types are grain, lines, hot pixels… Sony and Canon cameras have very different ways of handling noise. It mostly depends on the camera that you are buying, of course. Nevertheless when you study the picture you took more thoroughly, you realize that Canon cameras stand out.
Here’s a side-by-side comparison of RAW pictures taken in the exact same conditions with the exact same settings and lens. The left picture was taken with a Sony a7s and the second a Canon 6D. Aside from the color, which we will talk about later, there’s a general trend regarding noise. Over a long period of time and after looking at a lot of pictures in detail, we have noticed that Sony alpha cameras tend to pre-process the picture. Even if you have the built-in noise reduction off, the Sony picture looks cleaner overall. The Canon picture looks grainier. Well, what’s the matter then? Doesn’t one want cleaner photos?
For us, the problem is two fold. Firstly we want to be able to keep the picture as RAW as possible. We do not want to camera to pre-process the picture for us, as we want to be in control of noise reduction in post-process. Sony camera’s algorithms still seem to apply a built-in noise reduction when the photo is taken. And we are not talking about the infamous star-eater algorithm that exists in the older cameras of the line up. For this test we by-passed the star-eater problem with an older firmware and shooting in SILENT mode. Secondly, the noise-reduction algorithm seems to smooth out nebulosity. Instead of having a fine, grainy and detailed nebulosity (which is gas by the way), you get a rough, smudged and diffuse blur. It’s especially true if you take a closer look at the dark lanes of the milky way.
It is to be noted that the Canon 6D appears to produce more line and color noise than the Sony a7s, especially in the shadows. However if you expose your shot properly, you won’t have that problem, even if you shoot time-lapse with the Canon 6D.
Bottom line, if we had to choose between a camera that might be slightly better for shadow noise but destroys the milky way structure, and a camera that has a bit more color noise, but seems to preserve the nebulosity well and not least lets you have full control over your RAW file, we’d prefer Canon over Sony!
With Canon camera, gas clouds of our galaxy are rendered in a better way than Sony cameras. If exposed well, you won’t have trouble with the noise. Canon has remained our #1 choice for milky way timelapse and photography.
COLORS
Color acquisition, rendering and general balance is also paramount at night, especially for colorful phenomena like the aurora, which a lot of people attempt to shoot. Again, Sony cameras can have an edge when shooting the lights because you might be able to preserve more dynamic range, especially since the aurora is constantly changing luminosity. However we found that Sony cameras have a very hard time picking up certain colors of the aurora. They also have a general color balance that is shifted to the far blues and greens. Your blue- hour shots will generally look even bluer and your aurora shots will look desperately greener than usual. Although most of the predominant aurora is oxygen glowing green, there are other colors like red and pinks that Sony cameras fail to show.
The picture above, taken with the Sony a7rII, shows a really nice aurora show over the fjords of Norway. The picture below was taken overhead during the same display and moment, with the Canon 6D.
The Sony camera clearly doesn’t pick up the purple/red canopy, sign of oxygen glowing. It doesn’t appear to display the lower pink glow from nitrogen molecules and ions either. The green also seem to have more color range in the Canon picture, with shades of yellows and green. In the Sony picture, it’s just a uniform lime green.
Canon vs Sony – Conclusion
As a conclusion, there is no doubt that Sony cameras, especially the alpha series, are good cameras for overall astrophotography. They possess nice ISO capabilities, shadow noise control and dynamic range opportunities. However during the long tests that we have run over the past few years, we felt like Sony cameras didn’t deliver real ‘RAW’ pictures, which is what all astrophotographers are after. They seem to alter the night sky in terms of nebulosity, natural grain and color. Even if we have taken beautiful pictures and films with Sony, we stuck to Canon for truer-to-life pictures. So if astrophotography is a big part of your portfolio, don’t switch just yet!
