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Tips & Tutorials >> All Tips & Tutorials In Focus: EOS R- Part14

Astrophotography Techniques to Try with the EOS R

The optimal exposure for capturing a starry sky is about four million times of that on a clear and sunny day. When you can barely see your surroundings, it can be hard to compose shots and focus on the stars, but the EOS R makes it surprisingly easy. In this article, we share some astrophotography tips and ideas to try with the EOS R. (Reported by: Shigemi Numazawa (Digital Camera Magazine))


3 reasons the EOS R is great for astrophotography

1. If you prefer using a viewfinder: The EVF lets you "see" and focus in the dark
For those who like the direct feel of shooting through a viewfinder, the EVF provides a viable option for shooting in the dark. It displays the same information that you see in Live View, and you can preview exposure settings too.


2. When using Live View: Shoot more comfortably with the Vari-angle LCD screen
Instead of constantly tilting your head up to see the LCD screen as you point your camera up at the sky, you can simply rotate the screen to the most comfortable angle, reducing the strain on your neck. 


3. Lighter tripod load
For astrophotography, you want your setup to be as sturdy as possible.The smaller, lighter body of the EOS R helps to achieve better balance even with a lighter tripod.


Scene 1: Using the AF to capturing a glittering starscape

EOS R/ RF35mm f/1.8 Macro IS STM/ FL: 35mm/ Manual exposure (f/1.8, 20 sec, EV±0)/ ISO 1600/ WB: 3900K
Extra equipment: Soft filter

In this shot taken in the pitch-dark sky of the mountains, the winter constellations including Orion and the Pleiades sparkle brightly. Focus was done with AF, with the focal point set on a magnitude 1 star in Orion. I used a soft filter to blur the starlight, which makes the stars look bigger and brighter. This technique is frequently employed in astrophotography.

With the EOS R, using MF is no longer your only option

The usual way of taking a shot like the one above would be to magnify the Live View/EVF display to the maximum, and then focus using MF. However, it can be difficult to identify peak focus with this method, and I’m sure many find it challenging to control the lens, especially with the shorter focusing ring stroke on recent lenses.

The EOS R’s low-light focusing capabilities make it possible to use the AF to achieve focus on the stars. It’s more precise than finding focus with the naked eye—the only prerequisite is a fast lens.


3 keys to easier AF on stars

1. Find a bright star to set focus on

If the star is bright, the AF should be able to achieve focus on it even at maximum aperture f/2.8. Stars can be classified by their magnitudes. The lower the magnitude number, the brighter the star.

Note: It is more difficult for the AF to achieve focus on reddish stars than other stars with the same level of brightness.

Brightness (magnitude) of stars around Orion

Magnitude of different stars in Orion


I am using XXmm focal length and my maximum aperture is f/YY. What kind of stars does my AF work on?

The table below shows the star magnitudes that the AF can establish focus on at various focal lengths and maximum apertures, when a soft filter is attached to the lens*.

Key: 〇 = Yes; ×= No; △= Maybe

Focal Length Aperture EVF/Live View display Apparent magnitude of star
-1 0 1 2 3
16mm 2.8 Normal × × × × ×
10x magnification × × × ×
35mm 2.8 Normal × × × × ×
10x magnification × × × ×
24mm 1.4 Normal × × ×
10x magnification ×
35mm 1.8 Normal × ×
10x magnification × ×
50mm 1.2 Normal × ×
10x magnification

*Ability to achieve AF is subject to factors such as the type of soft filter, position to which it is attached and atmospheric conditions.


2. Use a fast lens

The larger the maximum aperture of a lens, the easier it is for the AF to establish focus on darker stars. Ideally, the maximum aperture of the lens should be f/2.8 or brighter.

If you are unable to achieve focus on any of the stars but there are street lights visible in the distance (a few hundred metres away), focusing on those lights can be quite effective too.

EOS R with EF16-35mm f/2.8L IS III USM

Read about the benefits of using an f/1.4 lens for star photography in:
Astrophotography: Capturing Clear Starry Skies with f/1.4 Lens


3. For easier focusing, magnify the EVF preview image

The EOS R’s touch screen allows you to simply tap on a bright star to set the AF area around it. Magnifying this focus area helps to make focusing more accurate. The higher the display magnification, the easier to achieve focus, so use the highest magnification (10x) where possible.

AF frame with no magnification

Normal view

AF frame with 10x magnification

10x magnification

Tip: To magnify your view quickly, customise your buttons
I assigned the Magnify/Reduce function to the AE Lock button, which happens to be one of the most accessible buttons on the EOS R. This lets you toggle the 10x magnification on and off with just one button press.


Scene 2: Using star trails to express the flow of time

Star trails

EOS R/ EF16-35mm f/2.8L III USM / FL: 16mm/ Manual (f/2.8, 30 sec x 30 shots, EV±0)/ ISO 2500/ WB: 3700K

Star trails are another popular technique for photographing starry skies. On the EOS R, you can do so by carrying out continuous shooting with a cable release, and then merging the resulting shots.

Tip: Shoot for a longer duration to get a better picture
If your shooting duration is too short, the star trails will be less defined. On a wide-angle lens, you should shoot for at least 20 minutes. For more dramatic results, shoot for at least 1 hour.

Canon EOS R with Remote Switch RS-60E

A cable release with a shutter lock mechanism ,such as the Remote Switch RS-60E, keeps the shutter release button locked down for continuous long exposure shots.


Star trails with EOS R

EOS R/ EF16-35mm f/2.8L III USM / FL: 16mm/ Manual (f/2.8, 30 sec x 53 shots, EV±0)/ ISO 2500/ WB: 3900K


2 steps to creating amazing star trails

1. Make sure your camera settings allow uninterrupted star trails

- Set the drive mode to “H” (High-speed continuous shooting).
- Set Long Exposure Noise Reduction to “Off”, as noise reduction processing could cause lag between exposures.

Drive mode Quick Control menu

Set drive mode to “H”

Long Exposure Noise Reduction settings menu

Set long exposure noise reduction to “Off”


2. Create star trails by merging images with a software program

Star trails can be created by merging only the bright areas of an image. This can be done easily using special software programs such as StarStaX (a free software that is compatible with both Windows and Mac).

Screenshot from StarStaX


Here’s something else you can try to create star trails with a difference:
Slow Shutter Art: Using Zoom Burst to Transform Stars in the Sky into a Meteor Shower

For more astrophotography tips, check out:
Introduction to Astrophotography - A Beginner's Guide
Astrophotography: What To Avoid When Shooting Stars


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Digital Camera Magazine

Digital Camera Magazine

A monthly magazine that believes that enjoyment of photography will increase the more one learns about camera functions. It delivers news on the latest cameras and features and regularly introduces various photography techniques.
Published by Impress Corporation

Shigemi Numazawa

Shigemi Numazawa

Born in 1958 in Niigata, Numazawa specialises mainly in astrophotography and astronomical illustrations. He has been involved in numerous science-related TV programme projects by the NHK. He is also appointed as the photographer for the National Geographic Tour and a recipient of Good Life Award presented by the Ministry of Environment (Japan).