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Canon EOS Ra

Why I Bought the Canon EOS Ra

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In early May 2020, I decided to purchase a Canon EOS Ra camera from B&H photo. This is Canon’s latest astrophotography camera, and it has some seriously impressive specs (like a  full-frame 30.3 MP astro-modified sensor).

For a complete rundown of the Canon EOS Ra, you can read my full review from January of this year. Essentially, it is a clone of the popular Canon EOS R mirrorless camera, with a specialized IR cut filter optimized for astrophotography.

In this article, I want to discuss why I purchased the EOS Ra, and share my results from the backyard. 

Is the Canon EOS Ra Worth it?

With a price tag of $2500 USD, you’ll want to think long and hard before taking the plunge on a niche camera like the EOS Ra. 

After all, there are plenty of affordable options available in the DSLR line-up, although these are not sensitive to hydrogen-alpha like the Ra is. 

You could modify your DSLR for astrophotography, but unless you’re comfortable dissembling your camera, that task is better left to the professionals.

I considered purchasing a professionally modified Canon EOS 6D Mark II as an upgrade to my Canon EOS Rebel T3i (and Canon EOS 60Da), but the price was not substantially less than a brand new EOS Ra. 

Canon EOS Ra body

I also wanted to “future-proof” myself to a degree, and be able to utilize Canon’s new RF lens mount lineup in the future. 

The EOS R (and RP) were attractive options, but ultimately the ability to record deep-sky images (nebulae regions) sold me on the Ra version.

Another consideration was the ability to utilize the 4K video mode of the EOS Ra. The EOS R version will capture “normal” looking colors in the daytime, while the EOS Ra will have a red cast to them due to the modified IR cut filter.

The EOS R would be a better choice if the camera was primarily to be used for filming my YouTube videos, but this camera is destined for the stars.

Milky Way Photography

The Milky Way. Canon EOS Ra with a Sigma 24mm F/1.4 lens attached. 

I can still use the EOS Ra during the day for photography and filming, but I will need to correct the white balance in post-production.

To be totally honest, I didn’t want to be left behind like I was with the EOS 60Da. This camera quickly sold out and was no longer available unless you could find one used.

I don’t think there will be any new Canon EOS Ra’s left by the end of the year, but we will see. As an example, finding a used Canon EOS 60Da is nearly impossible.

Compared to a Dedicated Astronomy Camera

Many of you may be in a situation where you are deciding whether to invest in the Canon EOS Ra or a dedicated astronomy camera. I currently shoot with all types of astrophotography cameras from a CMOS one-shot-color, to a monochrome CCD.

Each camera will have its own strengths and weaknesses, and much of the decision comes down to the user experience you are looking for.

DSLR vs. dedicated astronomy camera

For example, a nightscape photographer that is used to shooting with a DSLR or Mirrorless camera on the road will have a hard time justifying the purchase of a dedicated CMOS camera that requires a slew of new software and hardware to run.

Dedicated astronomy cameras have their place, and for many projects, I wouldn’t dream of using the Ra over my Starlight Xpress SX-42 or ZWO ASI533MC Pro.

Rather than a long list of strengths and weaknesses, I’ve highlighted the aspects of each camera (good and bad) that are unique to each one:

Canon EOS Ra 

  • Full-Frame Sensor
  • Battery Powered
  • Portable and Lightweight
  • Native Lens Mount (RF and/or EF with adapter)
  • No External Hardware Required to Take Pictures
  • Produces RAW/Jpeg files Instantly
  • Live View Display Screen
  • Framing/Focusing Can Be Done On-Camera
  • All Camera Settings Can Be Adjusted On-Camera
  • No On-Board Cooling

Dedicated Astronomy Camera

  • On-Board Cooling (TEC)
  • Back-Illuminated Sensor
  • Low Noise Images
  • Designed for Long Exposure Imaging
  • Calibration Frames Easier to Replicate/Produce
  • Full-Frame Models (Eg. ZWO ASI 6200) Are Expensive
  • Requires Additional Hardware/Software to Run (eg. PC, ASIair)
  • No On-Camera Control (Live View, Camera Settings)
  • Requires External Power Source
  • Produces FIT files that Must be Converted to Edit

In the end, I would recommend a DSLR or Mirrorless camera to a nightscape photographer who uses lenses, and a dedicated astronomy camera to someone that primarily shoots through a telescope at home.

There is a third category of imager (that I am a part of), that enjoys the DSLR/Mirrorless experience too much to stop using them for all types of astrophotography. 

Compared to the EOS 60Da?

The Canon EOS 60Da is a fantastic astrophotography camera. I’ve taken countless images through my telescope with the 60Da, and it is currently my best DSLR camera for astrophotography.

Canon EOS 60Da

The Canon EOS 60Da DSLR.

Until the Ra came along in November 2019, the 60Da was Canon’s latest official camera for night sky imaging.

However, the features and specifications of this 2012 camera have become outdated, although many of them are largely ignored for long-exposure deep-sky imaging.

For astrophotography purposes, the biggest differences between the two cameras are the size of the sensor, and the lens mounting system.

  • Canon EOS 60Da Sensor: 18 MP CMOS (APS-C)
  • Canon EOS Ra Sensor: 30.2 MP CMOS (Full-Frame)

In the end, chances are that many owners of modified DSLR cameras will not feel the need to upgrade to the Canon EOS Ra.

Make no mistake, a talented amateur astrophotographer will be able to produce results as impressive as ones taken with the Ra using an affordable, astro-modified DSLR.

Telescope setup

My wide-field deep-sky astrophotography setup.

Results Through a Telescope

I recently attached the Canon EOS Ra to my William Optics RedCat 51 refractor in the backyard. A wide-field instrument like this really utilizes the full-frame sensor of the camera.

I chose to photograph a “fool-proof” area of the night sky, the Sadr region. At a focal length of 250mm, several deep-sky nebulae objects are available. 

The image below includes 15 x 5-minute exposures at ISO 3200. The images were stacked and registered in DeepSkyStacker, and processed in Adobe Photoshop 2020.

Triad Ultra Filter test

Nebulae in Cygnus. Triad Ultra Filter and Canon EOS Ra (Click for larger image).

The Radian Telescopes Triad Ultra filter is a superb match for the EOS Ra, and I plan I using it extensively with this camera this summer. It possesses the qualities of a narrowband filter, with the added ability to create “almost” natural-looking colors (with some color correcting in post). 

When reviewing the data shot using the EOS Ra and Triad Ultra filter, the colors focus at the same point. I regularly process my images on a per-channel basis, and often have to control the star size in certain channels (usually blue). 

That is not the case when shooting with this filter as each channel looks sharp in a single RGB image. 

Triad Ultra Quad-Band Filter

Photo Details:

  • Total Exposure: 1 Hour, 15 Minutes
  • Integration: 15 x 5-minutes @ ISO 3200
  • Calibration Frames: 15 Darks, 15 Flats, 15 Bias
  • Image Acquisition: Astro Photography Tool
  • Pre-Processing: DeepSkyStacker
  • Final Editing: Adobe Photoshop 2020

Equipment List:

Tips for EOS Ra Owners

Astro Photography Tool really shines when you’re using a DSLR or mirrorless camera. The latest version recognizes the EOS Ra, and I can do important tasks like framing and focusing on my laptop.

Alternatively, you can use the beautiful articulating LCD screen on the Ra.

You may just choose to focus and frame your target directly on the camera rather than through software on your computer. Use the helpful 30x live view to really nail your focus.

I use a Canon EF to EOS R adapter (picture below) to connect my camera to the telescope. You will also need this to pair the EOS R with any existing Canon EF-mount lenses.

EF To EOS-R Adapter

The Canon EF – EOS R lens mount adapter.

An important camera setting you’ll need to use when the Canon EOS Ra is attached to a telescope is to enable the “Release Shutter W/O Lens“. The camera doesn’t recognize your telescope as a lens, so you’ll need to set this to take a picture.

Another tip I should mention is that the camera comes with a USB Type-C to Type-C cable, so if you plan on connecting the camera to your laptop, you’ll need a USB Type-C to USB 2.0 cable or an adapter.

Lastly, you’ll want to use the Adobe DNG converter to create RAW files that your pre-processing software will recognize. At the time of writing, the RAW CR3 files the camera produces are not recognized by pre-processing software such as DeepSkyStacker.

Adobe DNG converter

The Adobe DNG Converter software.

Final Thoughts

A lot of people seem to think that the EOS Ra is an odd choice considering the price tag and the fact that it’s not a dedicated Astro camera.

I totally get it, and I don’t think it is for everyone. Not even close. I think this camera was designed to meet the needs of a very specific type of amateur astrophotographer.

One that has progressed through this hobby using DSLR’S, lenses, and wide-field refractors.  

With about 10 images using the Ra under my belt now, I can confidently tell you that this camera feels like it was designed just for me.

Mirrorless Camera

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Canon EOS Ra Review

|Camera|15 Comments

The Canon EOS Ra camera is Canon’s first full-frame mirrorless camera dedicated to astrophotography. It is suitable for deep-sky imaging with a telescope, and night sky photography with a camera lens.

Based off of the extremely popular EOS R, the EOS Ra boasts unique features such as 30x magnification (viewfinder and Live View) for precise focusing, and roughly 4x more transmission sensitivity to the hydrogen-alpha (Hα) wavelength.

  • Name: Canon EOS Ra
  • Based on: Canon EOS R
  • Release Date: November 2019
  • Type: Mirrorless System
  • Resolution: 30.3 MP
  • Sensor size: Full-Frame
  • Sensor type: CMOS (specialized IR filter)
  • Lens Mount: Canon RF
  • Features: 30X Live View, Vari-angle LCD touchscreen

In the following video, I share my results using the Canon EOS Ra camera attached to a small telescope. This camera is suitable for high-resolution deep-sky astrophotography using a variety of optical instruments.

Canon EOS Ra Review

In late December 2019, Canon USA reached out to me to test their new astrophotography camera, the Canon EOS Ra. The “a” in the name of this camera stands for astrophotography.

That is because, unlike the regular Canon EOS R, this camera is 4X more sensitive to the h-alpha wavelength of the visible spectrum (656.3 nm). This helps collect the important deep red hues of many nebulae in the night sky. 

As Canon puts it, positioned in front of the CMOS imaging sensor, The EOS Ra’s infrared-cutting filter is modified to permit approximately 4x as much transmission of hydrogen-alpha rays at the 656nm wavelength, vs. standard EOS R cameras.” 

Canon EOS Ra Astrophotography

The North America Nebula. 5+ Hour Exposure Using the Canon EOS Ra.

The Canon EOS Ra also includes astrophotography-friendly features such as a unique 30X live-view mode on the vari-angle touchscreen LCD display screen. It’s a color astrophotography camera that was intended to be used for both deep-sky astrophotography, and wide-angle nightscapes.

In this article, I will review the Canon EOS Ra from the perspective of an “ordinary” amateur backyard deep-sky astrophotography enthusiast. As with every review I post, I was not compensated to endorse the product in any way. All of my opinions about this camera are my own. 

Before using the EOS Ra for astrophotography, I previously enjoyed using Canon’s last astrophotography camera, the (APS-C sensor) Canon EOS 60Da DSLR. The EOS Ra, on the other hand, is a full-frame mirrorless camera. 

Canon EOS Ra body

The Canon EOS Ra is a full-frame mirrorless astrophotography camera that is capable of producing APOD worthy astrophotography images. It is not a “one-trick-pony”, so to speak, as many of the other options available to amateurs are. Not only can the Ra take incredible deep-sky images through a telescope, but also using a wide variety of lenses, and without computer control. 

Having a camera with a long-lasting internal battery and a touchscreen display means that you are able to make adjustments to your exposures and key settings on the fly. You do not rely on third-party software to run this camera, although it can be used with popular software such as Astro Photography Tool, or Canon EOS Utilities.

The tactile experience of the EOS Ra camera body inspires you to focus on creative photography that excites you, and less on micro-adjustments and graphs on a computer screen. To be perfectly honest, the Canon EOS Ra is just more fun to use than any other astrophotography camera I’ve experienced. 

Orion Nebula using the EOS Ra

The Orion Nebula using the Canon EOS Ra (40 x 4-minutes at ISO 800).

Camera Features

At the heart of the Canon EOS Ra, is a 30.2 megapixel full-frame CMOS sensor. That’s a massive 36 x 24mm sensor, an uncommonly large size in the realm of astrophotography cameras.

This translates into an extremely wide field of view when used with a compact refractor telescope. It utilizes the native focal length of the optical instrument rather than cropping the image as smaller sensors do. 

So, if you use a telescope like the Sky-Watcher Esprit 100, you are shooting at the listed focal length of 550mm. This determines the magnification of the deep-sky object and the resolution of your image. 

The EOS Ra includes all of the advanced features of the EOS R, including a self-cleaning sensor unit, dust delete data function, and an OLED color electronic viewfinder

Canon EOS Ra box

Through this viewfinder, you can monitor key camera settings including exposure information, battery level, ISO speed, histogram, white balance, and much more. 

Bluetooth and WiFi connectivity are standard features of the EOS Ra, too. Does your dedicated astronomy camera offer this? 

 The Canon EOS Ra includes Dual Pixel CMOS autofocus. This advanced focusing system found in the original EOS R will not be utilized in many astrophotography-related shoots, but for video work, AF modes like Face+Tracking are incredibly useful. 

Canon EOS Ra camera body

Specifications

  • Format: Full-Frame
  • Sensor Type: CMOS
  • Sensor Size: 36 x 24mm
  • Pixel Size: 5.36 microns
  • Max. Resolution: 6720 x 4480 (30.2 MP) 
  • ISO Sensitivity: 100 – 40000
  • Lens Mount: Canon RF
  • Video Modes: 4K up to 30p, HD up to 60p
  • Memory Card: Single SD
  • Weight: 1.45 lbs.

When comparing the price of the Canon EOS Ra to a dedicated astronomy camera, consider the sheer amount of features this camera has that the latter does not (onboard touch-screen LCD, WiFi, 4K video, dual pixel AF, etc.). Will you use all of these advanced features for deep-sky astrophotography through a telescope? Probably not.

But the Canon EOS Ra is a multi-function camera that was designed to meet the needs of a broad range of amateur astrophotographers from wide-angle nightscape shooters to prime focus deep-sky imagers.

RF Lens Mount

The Canon EOS Ra features the new Canon RF lens mount, which allows you to use the latest RF mount lenses from Canon including the RF 85mm F/1.2L. If you already own Canon glass with the EF lens mount system, you simply need to use the EF-EOS R lens mount adapter to attach them to the EOS Ra.

Yes, the adapter is an added expense to use your existing Canon glass, but you will now be able to experience the impressive RF Lenses available. According to Canonwatch.com, the RF lenses are an improvement over their EF counterparts, as shown in the DxOMark testing (at least on the RF 50mm F/1.2L lens).  

RF - EOS R lens mount adapter

The Canon EF – EOS R lens mount adapter for EF-mount lenses. 

Canon EOS Ra review

Canon EOS Ra with RF 85mm F/1.2L lens attached.

I won’t go too into detail about the 85mm F/1.2 lens Canon included with the EOS Ra for my testing, but an 85mm prime is certainly an attractive focal length for astrophotographers. In terms of deep-sky imaging, this lens is best enjoyed under dark skies rather than an orange-zone backyard in the city.

Test Images using the 85mm F/1.2 Lens

I had a brief opportunity to test the Canon RF 85mm F/1.2 under semi-dark skies (Bortle Scale Class 5) on a moonless night. The photo I captured that night (watch the video) was really nothing special, until you realize that it was accomplished in about 10 minutes. 

Nightscape photographers with access to a dark sky site and enough time will capture amazing images with the EOS Ra this spring. Milky Way season should be very interesting. 

nightscape photography example

The Heart and Soul Nebulae, and the Double Cluster in Perseus. 10 x 30-seconds at ISO 800. 

The image quality of the photos taken using the EOS Ra and 85mm F/1.2L lens was impressive. Each exposure was 30-seconds long, and the noise was minimal despite using ISO 800. 

The following example image shows the star quality you can expect using this lens at F/1.6, and it is quite impressive if you ask me. Only the top corners show stars that are not absolute pin-points, which is admirable considering the monster-sized image sensor of this mirrorless camera. 

Image quality

Click the image for a large version of the image to inspect the star quality.

New RAW Image Format

The Canon EOS Ra shoots RAW images in .CR3 format. This slight number change (from the previous .CR2 format of Canon DSLR cameras) is actually a big deal. All of the software you use for registration, calibration, and image editing must be able to work with this new file format. 

For example, the pre-processing software I use (DeepSkyStacker) accepts .CR2 RAW image files, but not .CR3. That means that I must convert the native RAW image format from the Canon EOS Ra to a .TIF file for the application to recognize it. 

Adobe Photoshop 2020 has no trouble opening up the .CR3 files in Adobe Camera Raw or Bridge (or Lightroom for that matter), but I still use DeepSkyStacker for the registration and calibration stages of my images. 

CR3 format

The .CR3 RAW image format is not yet supported by popular stacking software like DeepSkyStacker.

This adds additional time to the processing stages of astrophotography, and I hope that the software available at the time of writing “catches up” to the new image format. PixInsight users will also need to wait for LibRaw to support CR3 files to integrate data (the PixInsight RAW format support module uses LibRaw as a back-end to support digital camera raw formats). 

A potential workaround for this matter is to register all of your exposures in Adobe Photoshop, but I am unaware of a way to calibrate images with dark frames or flat frames using this method. 

Full Frame CMOS Sensor

The full-frame CMOS hydrogen-alpha sensitive sensor is likely the biggest appeal of the camera overall. If you want to shoot using the field-of-view you are accustomed to with a crop-sensor camera body, you have the option of switching to “crop” mode in the settings. 

Until now, the only full-frame camera sensors I had ever used for astrophotography were the Canon EOS 5D Mark II, and the Canon EOS 6D Mark II. Both of these camera bodies, however, were stock. 

With the EOS Ra, I was finally able to utilize the large image circles of my apochromatic refractor telescopes like the William Optics RedCat 51 and Fluorostar 132. 

You can manually change the cropping/aspect ratio of the image in the camera settings if desired. Most photographers will simply leave the camera in “FULL” (full-frame) mode, but the option of capturing images at a 1.6X (crop-sensor), 1:1, 4:3, or even 16:9 is there.

image crop

Setting the Cropping/Aspect Ratio on-camera.

A full-frame (6720 x 4480 pixel) sensor demands a flat field and large image circle, which should be kept in mind when considering the EOS Ra. If your optical instrument does not have an image circle large enough to accommodate the large sensor, you could always manually set the crop factor on the camera as shown above.

Key Camera Settings

For those using the EOS Ra for astrophotography, there are a few essential camera settings to remember. The most important, in my opinion, is to turn off the built-in long exposure noise reduction and the high ISO noise reduction.

This is a hot topic with amateur astrophotographers and night photographers, as some nightscape shooters that process single exposures may prefer it. For deep-sky imagers that stack multiple exposures, however, you will not want the camera to do any noise reduction before you integrate the data.

If you’re looking for a reliable way to reduce noise in your astrophotos, I recommend giving the Topaz Labs DeNoise AI software a try. 

camera settings

Most astrophotographers will want to turn off long exposure noise reduction and high ISO speed NR.

The other important setting to remember is to ensure you have enabled the setting that allows the camera to take an exposure without a lens attached. When you have connected the EOS Ra to a telescope, it will not recognize that the optical tube is acting as a lens. The feature can be found in the custom settings menu, and it is called Enable Release Shutter w/o lens.

For a detailed look at all of the features this camera includes, you have the option of spending a weekend reading the EOS R Advanced User Guide

Imaging Sessions and Results

If you are like me, a typical astrophotography imaging session will vary in length depending on the amount of clear sky time available. Some sessions last less than an hour due to incoming clouds. The EOS Ra excels in these situations, as a quick setup process is one of its specialties.

The Canon EOS Ra includes a feature I have never experienced before, one that allows you to take exposures longer than 30-seconds in bulb mode. This is something amateur astrophotography enthusiasts can appreciate, especially when using this camera with a portable star tracker such as the Sky-Watcher Star Adventurer, or iOptron SkyGuider Pro. 

Being able to quickly set up the Canon EOS Ra and a wide-field lens on a small star tracker means that you can enjoy spur-of-the-moment astrophotography sessions while traveling. For me, this means being able to escape the light pollution from home and bring the kit to a dark sky site. 

Canon RF 85mm F/1.2

The Canon EOS Ra mounted to a Sky-Watcher Star Adventurer at the side of the road.

I find that camera lenses of all focal lengths are best used under dark skies. The wide-field nature of most camera lenses can create challenging image processing scenarios under light-polluted skies, especially if no light pollution filter is used.

Gradients in the night sky due to the glow of the city can make it very difficult to neutralize the background sky across large areas. That is not to say that it isn’t possible to correct harsh gradients due to light pollution in Photoshop, but it can be very time consuming to achieve a natural result. 

The best remedy for this scenario is to try and reserve your wide-field, camera lens astrophotography for dark sky excursions during the new moon phase. 

Deep-Sky Imaging Through a Telescope

If you want to watch me experience the thrill of unboxing the EOS Ra for the first time, and some backstory behind my image of the Orion Nebula shared at the top of this post, feel free to watch the following video. If my music selection or the sound of my voice annoys you to no end, read on.

For many people using the Ra for astrophotography, you will be capturing a sequence of long-exposure images through a telescope (Here are the ones I recommend). This is standard practice for creating images with a strong signal-to-noise ratio. 

But to do this, you will need to expose your images for longer than 30-seconds, and automate the process to maximize your time under the stars. You have a few options here, including a remote shutter release cable, third-party acquisition software, or using the handy standalone feature on the EOS Ra mentioned above.

The EOS Ra includes a USB Type-C input connection (this is the cable you’ll want), which allows you to control the camera from your computer if desired. You can also run a sequence of exposures using a remote shutter release cable. I was delighted to see that the remote shutter cable input was the same one used on my Canon EOS Rebel DSLR’s. 

deep sky astrophotography

Using Astro Photography Tool (APT) to run an imaging session with the Canon EOS Ra.

For my deep-sky imaging sessions attached to a telescope, I chose to use Astro Photography Tool (APT) to run my deep-sky imaging sessions with the EOS Ra. The camera was recognized by the latest edition of APT (as a Canon EOS R), which meant I could use the software to help focus the camera and telescope, present a live-view image, and set a sequence of long-exposure images. 

The CMOS sensor of the EOS Ra is so sensitive using high ISO’s, that the live-view image mirrored the experience of a dedicated astronomy camera. Dim stars, bright nebulae, and galaxies appear in real-time. This makes finding and framing deep-space targets much easier at the beginning of your session.

Focusing with 30X Live View

Focusing the Canon EOS Ra on dim stars is easier than with any DSLR I have used in the past. This is largely due to the new 30X live-view mode, which allows me to really look closely at how tight the stars are. 

When using a Bahtinov mask, the process is even more precise as you can see the subtle changes in the central diffraction spike as you focus in and out in real-time. The vari-angle display screen makes it easy to tilt the display to a comfortable angle when the telescope is pointed upwards. 

The touchscreen means that you can quickly scroll across the frame with a finger swipe to find more stars or your deep-sky target in the field. I found the focusing experience on the camera body itself to be almost as practical as feeding the information to my computer screen using camera control software. 

Wide-angle nightscapes shooters or deep-sky astrophotographers running their imaging sessions on-camera will benefit most from this feature.

focusing with a telescope

4K Video at 30 FPS

One of the features many people like to ignore when complaining about how expensive this camera is, is the 4K 30 fps video mode. That’s stunningly high-resolution video footage from a full-frame mirrorless sensor.

Is this feature much less likely to be used by astrophotography enthusiasts? Perhaps. Being somewhat of a videographer myself (I have filmed and edited over 100 videos on YouTube), I consider this to be an exciting option – and what I would put to good use.

In fact, I tested the Canon EOS Ra’s video abilities for some daytime filming for one of my videos. I was quite astonished to observe that the colors were not far off of a “normal-looking” scene despite having nearly 4x the sensitivity to H-Alpha over a standard EOS R.

Surely a natural color correction could be achieved in post, especially if the video is shot in a neutral/flat color profile. The EOS Ra includes a handy color temperature compensation feature that corrects the images/videos’ current white balance setting. The adjustment settings are a blue/amber bias, or magenta/green bias with 9 levels of control for each.

EOS Ra 4K video mode

The Canon EOS Ra is a capable video camera with impressive options.

There are a staggering amount of video recording options on this camera, maxing out at 30P shooting in 4K (ALL-I compression). The most practical choice for my style of filming and editing is to shoot in 4K at 23.97 FPS in IPB format.

Shooting at 4K in ALL-I format demands a lot of CPU power and RAM to edit.

Attaching the EOS Ra to a Telescope

For anyone that has ever attached a DSLR camera to a telescope using a t-ring and an adapter, you’ll just need the RF to EOS R lens mount adapter to connect the Ra to a telescope.

This provides the right spacing needed between the camera sensor of the Ra and your field flattener/reducer. You simply thread your existing t-ring to the EF-EOS R adapter and attach the camera as you normally would.

This was the exact configuration I used when I attached the Canon EOS Ra to the field flattener of a William Optics Fluorostar 132 refractor. As you may be able to tell from the photo, the lens mount adapter adds the exact right amount of spacing between the CMOS sensor inside of the mirrorless camera body, and the glass element of the flattener/reducer.

attach EOS Ra to telescope

The EOS Ra attached to the field flattener of my telescope using the RF-EOS-R adapter and a Canon t-ring. 

I also attached the Ra to a smaller refractor, the William Optics RedCat 51. This was a promising imaging combination for wide-field projects. This telescope offers an incredibly wide 250mm focal length and utilizes the glorious full-frame sensor of the Ra. 

My favorite aspect of this setup, however, was how simple it was to put together and start imaging. This is the type of imaging kit that would be perfect for deep-sky astrophotography while traveling. 

mirrorless camera and telescope

The Canon EOS Ra attaches to the RedCat 51 easily using the EF – EOS R adapter and Canon T-Ring.  

Using Filters with the EOS Ra

If you are planning on using a filter with the Canon EOS Ra, there are limited options available. Astronomik offers a CLS filter (city light suppression) for the Canon EOS R (and Ra) in a clip-format. I was not aware of this broadband light pollution filter until it was brought to my attention in the comments section of this article (thank you)! 

The great thing about body-mounted filters is the option of using them with a camera lens attached. It also comes in handy in telescope configurations where there is no convenient location for a threaded filter. 

Astronomik EOS Ra filter

The Astronomik CLS XL-Clip Filter for EOS R Bodies. 

For a wide variety of filter choices (such as narrowband filters), try using a 2″ round mounted filter in the t-ring adapter or field flattener if possible.

The first image I captured using this camera through a telescope did not use a filter in place of the sensor. There was no practical location for any of my 2″ filters within the imaging train. 

The second time around, however, I was able to thread a 48mm round mounted filter to the inside of the camera adapter of the William Optics RedCat 51 (Optolong L-eNhance). 

Optolong L-eNhance

Astrophotography Results

When it comes to testing cameras, I often get an overwhelming feeling of “imposter syndrome”. I am not a professional photographer by any means, and my test images often leave a lot of room for improvement. I partially blame the imaging conditions I shoot in, which regularly include high clouds and a lot of moisture, on a good night.

Regardless, I like to think that I make the most of my situation. The images I take from my Bortle Scale Class 6/7 backyard are a realistic example of what you can expect. Here is an image captured using the Canon EOS Ra and a small refractor telescope (William Optics RedCat 51).  

Canon EOS Ra example image

The Flaming Star Nebula and Tadpole Nebula in Auriga. Canon EOS Ra and 51mm refractor. 

Image Details:

  • Total Exposure: 2 Hours, 30 Minutes (50 x 3-minutes)
  • ISO: 1600
  • White Balance: Auto
  • Filter: Optolong L-eNhance
  • Telescope: William Optics RedCat 51
  • Stacking and Calibration: DeepSkyStacker
  • Processing: Adobe Photoshop 2020

The image of the Flaming Star Nebula region shown above was captured on a night of average seeing, with a 25% illuminated moon present. The filter used was a dual bandpass filter that helps isolates the light emitted in the hydrogen-alpha and oxygen wavelengths of the visible spectrum. 

You can see this image in higher resolution on AstroBin. For a complete breakdown of the way I process my astrophotography images, consider downloading my image processing guide

Noise Performance

It is no surprise that many people would like to know how the Canon EOS Ra handles noise, particularly when using higher ISO values of ISO 800 or more. This camera is not cooled, which means that it is subject to thermal noise due to a warm ambient temperature.

All of my testing with this camera took place during a Canadian winter, so the camera never really got above 5-10 degrees Celcius. However, even under these conditions, the noise performance seemed better than that of my Canon EOS 60Da.

Here is a test image for you to review up close (click on the image). You’ll notice that the noise is minimal in a single 3-minute exposure at ISO 800. Furthermore, this noise is reduced significantly through image stacking.

ISO noise performance

I do not see noise being a problem in the warmer months with this camera, as long as you stack your images to improve the signal to noise ratio. 

Alan Dyer (in this Sky and Telescope article) reported that when using the Canon EOS Ra with higher ISO levels, it exhibits noise that is as good as, if not slightly lower than Canon’s 6D MkII (despite the 6D Mark II’s larger pixels). 

Final Thoughts

The Canon EOS Ra stole my heart from the very moment I revealed the California Nebula on the astrophotography-themed box. In the past, I have professed my love for Canon’s astrophotography cameras such as the Canon EOS 60Da. 

The experience I have had with the EOS Ra was full of memorable moments under the stars. The type of astrophotography that this camera inspires reminds me of why I got into this crazy hobby in the first place.

Now, I have not experienced Nikon’s full-frame astrophotography camera (the D810A DSLR), nor have I ever used a full-frame mirrorless camera from Sony such as the popular A7. So take that for what it’s worth, this is not a detailed comparison between competing cameras in this category.

EOS R for astrophotography

The only negative aspects of the camera I have found are that the large full-frame sensor can result in substantial vignetting with certain optical systems, and the lack of compatibility in certain software to the new .CR3 file format. If you own a telescope that does not feature an image circle designed for full-frame cameras, you will need to crop your images.

Hopefully, DeepSkyStacker will update soon with the ability to stack, register, and calibrate .CR3 RAW images. Other third-party applications will need to support this file type too, for the best overall experience with the Ra.

The Adobe DNG Converter is a great workaround for the time being, as this tool converts all of the files quickly. DeepSkyStacker accepts Raw DNG files, and you can integrate your data as you normally would. 

Adobe DNG converter

Use the Adobe DNG Converter to create Raw files that DeepSkyStacker will recognize.

All in all, the EOS Ra is a monumental step up from Canon’s previous astrophotography inspired camera. Fans of the DSLR/Mirrorless camera experience (especially if you own existing Canon glass), will adore the EOS Ra. I purchased my Canon EOS Ra at B&H Photo Video

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The Canon EOS Ra Announced

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On November 5, 2019, the Canon EOS Ra was announced and is now available for pre-order at various retailers including B&H. This is a 30.3 MP full-frame mirrorless camera designed specifically for astrophotography. 

The Canon EOS Ra shares nearly all aspects of the EOS R camera body, with 2 key differences for astrophotography. Increased sensitivity to the 656nm (h-alpha) emission line, and a 30X live view focus mode.

For a niche hobby like astrophotography, the Canon EOS Ra has sure attracted a lot of attention from the photography world. I pleaded my case to my contact at Canon for an early unit to review but was not successful in my efforts (and I’m not even bitter about it).

Update: Canon USA reached out to me in December asking if I would try out the Canon EOS Ra and let them know what I think of it. Here is a short video showing one of my first experiences with this camera and an RF-mount lens:

Thankfully, some new and exciting example images have already surfaced from those that were granted early access to this camera body, and from Canon themselves.

canon astrophotography camera

In this article, I’ve put together all of the information I can find about the EOS Ra, and included the limited number of example images shared thus far. To see the full slideshow of images shared by Canon with this camera, see this article by Todd Vorenkamp of B&H. 

The Canon EOS Ra

The CMOS sensor found inside of the Canon EOS Ra is 4x more sensitive to the hydrogen-alpha wavelength, which is extremely useful for astrophotography. As many of you know, some of the absolute best deep-sky nebula in the night emit a strong red signal in the 656 nm wavelength.

Historically, amateur astrophotographers that wanted to collect the powerful deep reds found in many emission nebulae with their generic DSLR cameras had to remove the stock internal IR cut filter. This is called modifying your camera for astrophotography and is offered professional from several vendors. 

Canon began offering “pre-modified” DSLR cameras from the factory for astrophotography use in 2005 with the revolutionary EOS 20Da. The Canon EOS 60Da followed in 2012, and now, the mirrorless EOS Ra in 2019. 

The first example photos I saw using the Canon EOS Ra were courtesy of fellow Canadian, Alan Dyer. He posted the following example images using the EOS Ra on Twitter late Tuesday night:

Canon EOS Ra astrophotography examples

Images shot using the Canon EOS Ra by Alan Dyer (Read his review here)

This camera is aimed at landscape astrophotography enthusiasts (such as wide-angle Milky Way photography), and deep-sky imagers using an equatorial telescope mount. The mirrorless design of the EOS Ra is a massive change from Canon’s last astrophotography camera. Not only is it a different style of camera mechanically, but it also accepts Canon RF Lenses

The 30.3 MP full-frame CMOS sensor found inside of the RA is beneficial for amateur astrophotographers that use wide-angle lenses. If you own Canon EF mount lenses as I do, you’ll need to buy the EF-mount adapter to attach your lens. 

I must admit, it will be hard to justify purchasing the “a” version of the Canon EOS R for many multi-discipline photographers that take photos in the daytime as well as night. This camera has some impressive specs for photography and videography including shooting 4K at 30p with Canon Log. 

I have always shot my videos with Canon DSLR cameras (most recently the Canon EOS 6D Mark II), and am a little confused as to how I would fully utilize the video features of the EOS Ra. As Canon has stated numerous times about their “a-series” cameras, they are not suitable for daytime photography. In my tests with the 60Da, the colors are slightly off and create unappealing daytime images without serious adjustments in post. 

Canon EOS Ra

Increased Sensitivity to Hydrogen-Alpha

If you are new to Canon’s astrophotography camera line-up, you may be wondering what the difference between the EOS R and Ra is. 

The reason this version of the camera has an “a” in the name is simply due to the specialized infrared-cutting filter that sits in front of the CMOS sensor. Canon lists that this change allows a transmission in the hydrogen-alpha (Hα) wavelength that is approximately 4 times greater than a regular Canon EOS R camera. 

The example images from Canon USA illustrate this capability on the North America Nebula. I found it very interesting to note that Canon’s engineers report an even greater sensitivity to Hα in the EOS Ra than previously achieved in the 20Da and 60Da camera bodies. 

EOS Ra vs. R

Essentially, the Canon EOS Ra is a modified version of the EOS R for amateur astrophotographers that want to collect more signal in the important Hα emission line. For the same reason I invested in the Canon 60Da, I like the idea of Canon handling the astro-modification and not voiding the warranty with a third-party service. 

The infrared-cutting filter (positioned immediately in front of the CMOS imaging sensor) is modified to permit approximately 4x as much transmission of hydrogen-alpha rays at the 656nm wavelength, vs. standard EOS R cameras. This modification allows much higher transmission of deep red infrared rays emitted by nebulae, without requiring any other specialized optics or accessories.

30X Live-View Magnification

If you’ve experienced what it is like to focus a camera at night, you’ll know how important the live-view zoom feature is. The best way to focus your camera lens or telescope with a DSLR or mirrorless camera attached is to zoom-in on a bright star and magnify it. Traditionally, this would be at a magnification of 10X, but Canon has upped the ante. 

The Ra features Canon’s first-ever 30x magnification, and it can be done on both the LCD screen and viewfinder. Because the EOS Ra is a mirrorless camera system, the electronic eye-level viewfinder is able to provide the magnification feature. As a DSLR shooter, this would feel very strange to me and I doubt it would be a useful as the much larger LCD screen.

Speaking of the LCD screen on the back of the camera, it’s a vari-angle design. This is extremely useful for astrophotographers, as we regularly point the camera in all sorts of awkward angles. 

ISO Performance

Any amateur astrophotographer with experience using DSLR cameras will tell you that the amount of noise in your image will increase as you bump up the ISO. This creates a challenging trade-off, as we often want to collect as much light in a single exposure as possible. 

However, modern cameras have got a lot better and keeping noise at bay using higher ISO settings, and the Canon EOS Ra is no exception. 

In this video from B&H, the host states:

“high ISO noise is extremely well-controlled, particularly at the high ISO’s that are common in astrophotography”

It’s impossible to tell exactly how well “controlled” the noise is from the example photo shared (below). The same vague statement was said about the Canon 60Da, and I found it to be true when shooting at an aggressive ISO 6400 on warm nights in the summer. 

sample photo

Sample image from Canon USA. Canon EF 400mm F/2.8L IS III USM Lens.

Canon EOS Ra Core Specifications

  • Format: Full-Frame
  • Sensor Type: CMOS
  • Sensor Size: 36 x 24mm
  • Pixel Size: 5.36 microns
  • Max. Resolution: 6720 x 4480
  • ISO Sensitivity: 100 – 40000
  • Lens Mount: Canon RF
  • Video Modes: 4K up to 30p, HD up to 60p
  • Memory Card: Single SD
  • Weight: 1.45 lbs.

The following video released by B&H and Canon USA covers many of the core specifications of the Ra, and what separates it from a regular mirrorless camera. I appreciate the improved battery performance of this camera over the previous models. Canon states that the battery will last for 7 hours of bulb exposure time, although I expect this to time to diminish on a cold night. 

Canon’s Astrophotography Timeline:

The EOS Ra is the third installment (not the 4th, as I have seen a non-existent “6Da” reported) in Canon’s line of dedicated cameras for astrophotography.

  • Canon EOS 20Da (2005)
  • Canon EOS 60Da (2012)
  • Canon EOS Ra (2019)

Let’s not forget Nikon’s contribution to the astrophotography community. The Nikon D810A is a fantastic DSLR for astrophotography and was the first full-frame camera body built specifically for night photography. I would not be surprised if Nikon (and Sony) release dedicated mirrorless camera bodies for astrophotography in the future.

Just like in the daytime photography world, the number of lenses you own in a particular brand is a big deciding factor when upgrading your camera body. 

Final Thoughts

The Canon EOS Ra is clearly a big step up from the last astrophotography camera released, the 60Da. More megapixels, bigger pixel size, better ISO performance, more sensitive to Hα, a better viewfinder, a mirrorless body – so what’s not to love? 

In my eyes, there are two reasons why an amateur astrophotographer will look elsewhere for their next camera. The first one is that there are many practical dedicated (CMOS) astronomy cameras available now, ones that offer cooling and sensitive monochrome sensors. 

The other is that modifying an older Canon DSLR is still a very practical way to collect impressive astrophotography images for a fraction of the price.

RF lens mount

The Ra accepts Canon RF lenses (full-frame mirrorless)

However, I think there are many people that enjoy the familiarity of a DSLR/mirrorless camera system. If you travel a lot for astrophotography, a mirrorless camera and lens are much more practical than a dedicated astronomy camera and software to run it. 

Another great point that has been brought to my attention about this camera is the file types created and their compatibility with stacking software.

The Canon mirrorless cameras create CR3 file format images, which are currently not supported in software such as DeepSkyStacker (at the time of writing). This might be a great reason to hold off on the EOS Ra until these applications catch up with the technology.

Another big change is the opportunity to use filters between the camera body and lens via the Canon Drop-In Filter Mount Adapter (EF-EOS R). Daytime photographers use this attractive feature for drop-in variable ND filters, but perhaps the astronomy companies will begin to manufacturer astrophotography filters for this configuration. 

I think this would big a much better option over the clip-in style filters currently offered for full-frame DSLR’s.

EOS R Ef mount adapter

The Canon EF-EOS R Drop-In Filter Mount Adapter.

The big question is, will I be ordering the Canon EOS Ra for astrophotography in the backyard? Probably.

At the time of writing, the price tag for the body only is $2,499 USD, and it will be released on December 19, 2019. I order my photographer gear on Amazon almost exclusively, and the package offered by Canon includes a battery charger, strap, and a few extras.

whats included

I am interested in testing the camera from both a hobbyist perspective and to provide useful information to amateur astrophotographers looking to purchase this camera. The interesting thing is, if I do purchase the Ra, it will be my first mirrorless camera.

As an ambassador of the hobby, I feel obligated to share my experiences with the latest official astrophotography camera from my favorite brand, and yes, you can go ahead and label me a Canon fanboy.

Here is an image I managed to capture in just 10 minutes using the EOS Ra and 85mm F/1.2 lens.

Canon 85mm F/1.2 astrophotography

The Heart and Soul Nebula in Cassiopeia using the Canon EOS Ra and 85mm F/1.2 Lens.

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