Canon EOS Ra – Full Frame Mirrorless Astrophotography Camera

The Canon EOS Ra has just been announced! What is the EOS Ra? It’s a mirrorless camera aimed directly at the astrophotography niche. So you bet your jiffy that I’m going to be all over that and seeing what I can see about it. so let’s get focused in on the Canon EOS Ra.

This release was so quiet that I’m struggling whether to find if it was announced on the 5th or 6th November…

I’m about to scrape together what small morsels I can find about this new Mirrorless camera – and do my best to not refer to it as a DSLR. There’s a few images that have been released and an announcement video: which I shall share in due course.

One disclaimer: I don’t own any of the images I’m about to feature. They’re all published from Canon about the EOS Ra.

Canon EOS Ra

Building from the framework that is the Canon EOS R – a full frame mirrorless camera – Canon decided to re-enter the astrophotography camera scene again and have announced the Canon EOS Ra. This is a camera that has a modified IR pass filter already. The IR Pass filter is what we would traditionally open our cameras up to remove. But Canon now has decided to offer one with a pass filter that already has the sensitivity in place.

How much more sensitive? 4 times more sensitive. This means that the reds in your images will be more deeper and lush as Hydrogen Alpha sits in the red end of the spectrum over at about 656nm. The effect is similar to that of what we try to do anyway when we modify our cameras by removing the IR filters and either leaving them ‘naked’ or inserting a modified bandpass IR cut filter usually from Baader or Astronomik.

Main Features

  • 30.3 Mega Pixel Sensor

  • Modified IR Filter For Better Hα Transmission

  • Full Frame Sensor 36mm x 24mm

  • 5.36um Pixels

  • High ISO noise control, ISO values 100-40000

  • 5x and 30x Live View Zoom

  • Single SD Card Slot

  • Vari-Angle LCD display (flippy screen)

  • 7 Hours or 350 Shots Battery Life

  • SD Card

  • USB 3.1

The raw image sizes are 6720×4480 pixels. That’s pretty substantial. Before cropping that means you could make 22×14” prints! I think the resolution would be a nice thing, although I can only imaging the file sizes are going to enormous. As well as I’ve heard that the Canon EOS R (and by extension the Canon EOS Ra) will use .CR3 format files. Which often used softwares like Deep Sky Stacker don’t currently support (at time of writing 06/11/19)

Increased Hydrogen Alpha Sensitivity

If you’ve been at astrophotography for a bit you may have heard people banging on about hydrogen alpha. This is the juicy part of the colour spectrum for astrophotographers and is where many of the intricate and gorgeous details of emission nebula lie in wait. Hiding in plain sight to unmodified stock DSLRs. Increasing your sensitivity to Hα means you can capture more detail and more vibrant, succulent reds within your nebula.

Visible Light Spectrum for Ha
Hydrogen Alpha is down around 656nm in the reds.


I talk more about this on my California Nebula image page.

So the main point of this camera is the modified IR filter they use on it. This sits immediately in front of the CMOS imaging chip and allows an impressive 4x the regular amount through without having to Full Spectrum Modify the camera.

As mentioned above instead of people now modifying their existing cameras and voiding the warranty (cus oh boy does it void your warranty), you can now just buy one ready modified out of the box that has its warranty intact. To some, this may be the route they want to go rather than a third-party doing the modification. I do this modification myself though so a factory modified sensor doesn’t appeal that much.

ISO Performance And Range

I’m going to immediately address the elephant that I see with the Canon EOS Ra’s ISO room: who the heck is going to use ISO 40000?

With that out of my system, the stated ISO range is 100-40000. That’s quite the spread and allows plenty of flexibility. Most DSLR users will use 800-3200 ISO, 6400 at a push. I’m not entirely sure how good this sensor is anyway – there’s no way I’ll be able to get my hands on one ever to test it myself. However DXOMark‘s report of the standard EOS R suggests good ISO control (as it rates good for indoor sports).

In the Canon EOS Ra Announcement Video from B&H it is said that

High ISO noise is extremely well controlled”.

Your guess is as good as mine, really. It could just be more lies that camera companies tell you. However this North America Nebula image is quite nice and clean. But that doesn’t tell the full story.

The North America Nebula, NGC 7000, in Cygnus, taken with the new Canon EOS Ra factory-modified “astronomical” version of the Canon EOS R mirrorless camera. Taken as part of testing. This is a stack of 4 x 6-minute exposures, with LENR on and at ISO 1600, through the Astro-Physics Traveler 105mm f/6 apo refractor with the Hutech field flattener. Copyright Alan Dyer/


I still am sitting here wondering who uses ISO 40000…

The EOS Ra Sensor

So as mentioned the EOS Ra uses a 30.3mp, full frame sensor. I saw in passing from a very poor source that it’s a Sony sensor. But I can’t find any information for or against that. Not only does it have a 36x24mm footprint, the pixel sizes are 5.36 microns big, which means this sensor has a good pixel size for most astrophotography applications. Though when using it wide field it’ll undersample significantly resulting in lost fine detail and softer images. But at like 18mm or even 50mm focal lengths it wouldn’t make a difference.

It has a Digic 8 image processor on board so that should really result in high fidelity images. It being a mirrorless it doesn’t have a mirror that will slap up and shake the camera when beginning an exposure as well. That will help your photography, however you can also use the Silent Shutter mode which further reduces vibrations.

With this sort of sensor size as well as the pixel size, if you’re going super widefield, like <100mm focal lengths then you’ll have an enormous field of view, and super high resolution images as mentioned further up in the article. For telescopes though to get the optimum suitability chart for OK seeing then you’re going to want to stick to 600-1600mm focal lengths (after things like barlows and reducers are considered).


As stated by Rudy for Canon USA

“The camera has excellent light gathering capability along with good resolution and detail”


The Trifid and Lagoon Nebulas in a sample shot from the EOS Ra


I’ve seen in online discussions that the camera will export .CR3 files. Not the .CR2 files you may be familiar with. So they’re a bit unfamiliar perhaps in the astrophotography scene, and as such popular stacking programs such as Deep Sky Stacker may not be able to handle them just yet. Also, try running 4k videos through applications such as RegiStax, PIPP or AutoStakkert. I’m sure they’ll appreciate it. Meaning that initially your files from the Canon EOS Ra may not be all that wieldy until the software developers catch up. So take that as a reading note.


That Live View Focus

In your DSLR you probably already have 5x and 10x live view magnification. Depending on the lens you’re using this may be enough still to do your focusing on a star. The EOS Ra takes this up a notch – or 3.


If you’re new to the premise of Live View focusing, it basically means using live view, and using the zoom function on the live view to zoom in on a bright star – Like Vegas or Betelgeuse – to nail your focus before locking it down or taping it down. I never had too much issue with the 10x zoom function at 250mm+ focal lengths, but I do concede that at 18mm or 50mm I definitely sometimes struggled. The 30x zoom aspect will help combat that.


Though it is just that. It’s either 5x or 30x. Nowhere have I see it say 5x, 10x, 30x. So you’re either far or near. But it should be workable.

The Canon EOS Ra not only has an Electronic View Finder, but a flip out LCD display.

The fact this is a mirrorless camera and has an electronic view finder means that you can use the 30x zoom with the eyepiece. Why would you do this is well beyond me – especially when there’s a perfectly fine Vari-Angle LCD Display. Or, to you and me, a flip out screen. You know what weird angles we get ourselves in using a DSLR on a telescope. If you have a flip out screen – use it! Make your life easier. Though, watching someone try to look through the eyepiece whilst focusing on a target near the zenith may be entertaining.

Battery Life

To me, one area they’re trying to target with this camera are the hikers and campers who indulge in astrophotography. So that’s people who may use a Star Tracker like the Skywatcher Star Adventurer or the iOptron SkyGuider Pro, as well as the Canon EOS Ra and lenses. Making for an entirely portable set up. So, if you’re going camping and aiming for portability them battery life is going to be a factor.

It is stated that the battery life can last “up to 7 hours of bulb exposure time per battery”. Of course the key part there is “up to”, as I can easily see the battery life dropping from 7 hours quite quickly as the temperature drops, and it doesn’t even get that cold in England, unlike in places like Russia, Canada and the northern Scandinavian countries.

If timescale per charge isn’t your thing, then it’s also stated that you can take 350 shots per battery at 0˚c.


Additional Bits

The EOS Ra is slated for release mid-December 2019, so if you fancy getting me a Christmas present then I’d love to review this.

The Carina Nebula as shot through the Canon EOS Ra

So aside from the photography side. This thing is capable of taking 4k video and 4k timelapses. I know that in my video making side I would be interested in a camera that could shoot night time video nicely, but the fact it’s readily mentioned the camera is practically a dedicated astro camera then it wouldn’t be ideal for terrestrial videography. For planetary or Lunar/Solar work you don’t really need a modified camera (and the sensor size will actually work against you in terms of Field of View).

It weighs only 660g with the SD card and the battery within it. So not too much different to your bog standard DSLR that you may already be using (like a Canon EOS 600D or 450D).

Astrophotography Camera History

Canon is slowly building up a back catalogue of astrophotography cameras. This being the”fourth” in the entry. I say “fourth” as there is reports of a 6Da, but I can’t verify it aside from this third-party modification service from PrimaLuce Labs. So, to me, it doesn’t count.

  1. Canon EOS 20Da (2005)

  2. Canon EOS 60Da (2012)

  3. Canon EOS Ra

You can also utilise the Canon Mirrorless Drop In Filter Slider (EF-EOS R) if you can find filters that fit it. I don’t know what size the filter is. The examples I can find offer an ND or a polarizing filter – not what you really want. Plus they’re adding an additional £300-£400 on the price tag.

Speaking of price…

The Price

Okay so in fairness all seems well up until this point. It sounds like a good camera with nice features, it’s considerate that Canon decided to modify the camera already. So how much does this thing cost? Keep your credit card at bay for now.


The price for this beauty is a whopping $2499! At time of writing that converts to £1944.45.


£1944.45! This is why, at the start of the article, I mentioned it may be a bit misplaced. For the same money you can get a nice dedicated astrophotography camera, one that is cooled to boot. However, those dedicated cameras probably aren’t going to be full frame capable of 4k.


As I’ve called back to, I think this camera is a beast, but it’s a beast that may be misplaced. It’s a niche item, catering for niche people within another niche. I believe this camera is going to be very good for hikers and campers wanting to use star trackers and take advantage of the full frame. If you’re imaging from the back garden or somewhere you can get mains power, then there is a lot you can do to upgrade your astrophotography game when it comes to the camera for just shy of £2000. Like a dedicated mono cooled camera, with filters and an autofocuser. Or even just a really beautiful cooled one shot colour dedicated camera and an autofocuser.

The price makes this hard to justify and swallow, really. Yes, the sensor size is nice of course and yes 4k is all the rage these days. But I just think that, unless you really like camping, there’s so much more you could do for your hobby with the same money than invest in this camera.

Maybe I’m entirely wrong, though. But I don’t think I’m going to be rushing out any time soon to buy one. Besides, I’m planning my next telescope purchase anyway. Since I’m never going to get a chance to use a Canon EOS Ra, then I won’t lose sleep over it anyway. I do that enough with this hobby and just being a night owl anyway.

What’re your thoughts on the EOS Ra? Do you think it’s going to be a good camera? Would you pay £2000 for it? Let me know!



Further Reading

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