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Using a Sigma 24mm F/1.4 for Astrophotography

Sigma 24mm F/1.4 Lens for Astrophotography
|Camera Lenses|4 Comments

The Sigma 24mm F/1.4 lens is an interesting choice for astrophotography, particularly wide-angle Milky Way photography. With an f-ratio of F/1.4, this Sigma art series lens can pull in a lot of light under a dark night sky.

Over the years I have used a number of great camera lenses for astrophotography from the Rokinon 135mm F/2, to the Canon EF 300mm F/4L. The Sigma 24mm F/1.4 is perhaps the most impressive lens for astrophotography overall, rarely due to its incredibly fast aperture. 

I’ve used the lens on my Canon DSLR and Mirrorless cameras, and have found it to be one of the most useful lenses I own. The reviews on B&H Photo indicate that Nikon and Sony camera owners have had a positive experience with this lens as well.

The lens isn’t perfect, but it is an exceptional value and has impressive qualities that amateur astrophotographers can appreciate. The lack of image stabilization will likely be a deciding factor for those looking to use this lens for video work, but I have found it to be very useful when filming in low-light situations despite this feature. 

In this article, I will share my results using the Sigma 24mm F/1.4 Art lens for astrophotography. The photo shown below was captured using the Sigma 24mm F/1.4 lens and my Canon EOS Ra mirrorless camera.

The Milky Way

The Milky Way under a Dark Sky. Canon EOS Ra + Sigma 24mm F/1.4.

To create the image above, I capture multiple 90-second exposures on a portable star tracker (Sky-Watcher Star Adventurer). My wife and I rented an Airbnb at a dark sky location (Bortle Scale Class 3), to enjoy an unspoiled night sky. 

24mm is an ideal focal length for astrophotography applications, particularly nightscape photography. When paired with a full-frame astrophotography camera, the results are simply stunning. 

For the image above, my exposures were shot at ISO 3200 at F/2.8. Take a look at the example image below to see the difference between a single frame, and the final stacked image.

single exposure vs. stacked image

I have used the Sigma 24mm F/1.4 Art Lens on my full-frame Canon cameras for astrophotography. I have a Canon EOS 6D Mark II (stock), and a Canon EOS Ra (astrophotography) camera. 

The stock 6D II is used mainly for videography with the Sigma lens, while the EOS Ra is used for long-exposure night sky imaging exclusively. 

Sigma 24mm F/1.4 Art Lens

The Sigma 24mm f/1.4 Art lens is a professional-grade wide-angle lens part of the overall Art-series by Sigma, which are great budget-friendly alternatives to similar, and more expensive Canon, Nikon, and Sony lens options.

The lens I use includes the Canon EF-mount, which I can also use on my RF-mount Canon EOS Ra using a Canon EF – EOS R adapter

The 24mm lens is the second widest prime lens in the Sigma Art series, ideal for low-light photography. An aperture of f/1.4 is a very attractive spec for amateur astrophotographers that capture images and videos at night. This is lens is also suitable for many other types of photo/video work, such as weddings, landscape photography, and event photography.

One of the big selling features for me was the 77mm lens diameter, which allows me to utilize my existing collection of UV and ND filters. 

Sigma 24mm F/1.4 lens

The Sigma 24mm F/1.4 Art lens attached to my Canon EOS Ra Mirrorless body (using an adapter).

The Sigma 24mm F/1.4 offers impressive sharpness characteristics and offers an optical formula comprising 15 total elements in 11 groups, four of which are low dispersion, three that are low-dispersion (FLD), and two that are aspherical. The premium glass elements bring aberrations and distortion to a minimum, which is a common issue with many wide-angle lenses.

The focus ring, located on the front of the lens barrel, is very smooth and easy to rotate which is important for manual focusing. The lens focuses fast and is equipped with a high-quality hyper-sonic motor, found on other Sigma lenses, providing fast and quiet (i.e. barely audible) autofocus.

Like some of the other Sigma Art-series lenses, the 24mm f/1.4 Art, unfortunately, does not have a rubber gasket on the mount, meaning there is the risk of dust, moisture, and other debris to get between the lens and the camera mount. It is important to be mindful of this while using the lens to ensure the area is clean at all times.

While I did not experience any issues with auto-focus, others have indicated that they had auto-focus issues when shooting at wider apertures, which was solved by using a Sigma dock and some auto-focus adjustments.

Overall, the lens had low distortions, normal vignetting, fast/reliable auto-focus, pro-level build quality, and construction and is great in low-light situations. It is also considerably more affordable than other 24mm f/1.4 wide-angle lenses.

lens construction

The lens construction diagram of the Sigma 24mm F/1.4 Art lens. 

Sigma 24mm F/1.4 Art Complete Specs:

Focal Length: 24mm
Maximum Aperture: f/1.4
Minimum Aperture: f/16
Lens Mount: Canon EF
Format Compatibility: Full-Frame
Angle of View: 84.1°
Minimum Focus Distance: 9.84″ / 25 cm
Maximum Magnification: 0.19x
Optical Design: 15 Elements in 11 Groups
Diaphragm Blades: 9, Rounded
Focus Type: Autofocus
Image Stabilization: None
Filter Size: 77 mm (Front)
Dimensions: (ø x L) 3.35 x 3.55″ / 85 x 90.2 mm
Weight: 1.46 lb / 665 g

creative night sky photography

A creative shot with out-of-focus stars using the Sigma 24mm F/1.4 Art Lens. 13-seconds, ISO 400, F/1.4.

Uses in Astrophotography

Although I find the autofocus system on the Sigma 24mm F/1.4 to work exceptionally well in low-light video situations on my Canon EOS 6D Mark II, this feature is not used in my long-exposure imaging projects. That is because you must manually focus the lens on a bright star before taking the picture. Autofocus just won’t work pointed up at a dark night sky.

To focus the lens, I simply use the 10X live view mode on the camera’s display screen and find the brightest star in the field of view. It is best to use the maximum aperture (F/1.4) and a generous ISO setting (ISO 3200 or above) when focusing the lens on a star. Once you have it dialed in, you can stop the lens back down to F/2.8 or slower for a sharper image. 

Compared to other lenses I have used for Milky Way Photography, such as the Rokinon 14mm F/2.8, the Sigma 24mm F/1.4 is noticeably sharper at the edges of the frame. This is not surprising, as the Sigma is a higher-quality lens overall and not “ultra-wide-field” like the fully manual Rokinon. 

The following image was captured using the Sigma 24mm F/1.4 Art lens attached to my Canon EOS Ra and a Sky-Watcher Star Adventurer tracking mount. The image on the left is a single frame, while the one on the right is a processed stack of images to enhance color and clarity.

To learn how I process my astrophotography images, consider downloading my premium image processing guide

image processing

The Milky Way. Single Exposure vs. Processed Stack.

Clearly, the focal length of this lens lends itself well to capturing large portions of the night sky at once. With a crop-sensor camera, expect the field to be significantly reduced. To fully utilize the benefits of this lens, stick to full-frame camera. 

I enjoy the framing a 24mm focal length provides, but if you’re looking for something even wider, consider the Sigma 14mm F/1.8 Art Lens. The 14mm versions enters “ultra-wide” territory and would be a great fit for capturing the Milky Way, timelapses, meteor showers, and star-trail images.

There are a few secrets I would like to share about using the Sigma 24mm F/1.4 lens for astrophotography. These tips include techniques to apply in the field while shooting, as well as post-processing steps to take.

The first one is not such a big secret if you’re accustomed to processing astrophotography images in Adobe Photoshop.

Lens Profile Correction

I used the lens profile correction feature found inside of Adobe Camera Raw before stacking the images manually in Photoshop. The Sigma 24mm F/1.4 lens was recognized to have an associated profile in Adobe Camera Raw, as is the case for every lens I’ve ever used for astrophotography.

The main benefit of this technique is that it helps correct the curvature of the image that was evident in the RAW image files out of the camera. When comparing the image before and after the profile correction, I noticed that it flattens the field quite substantially.

lens profile correction

 I recommend applying the lens correction profile to all sub-exposure images before stacking, as opposed to a global application of the stacked/calibrated final. You can easily copy and paste your develop settings in Adobe Camera Raw and “paste” them to all of the images in the folder.

 This technique also helps to reduce any chromatic aberration of the stars in the image, which is a huge bonus.

Correcting color fringing in the image processing workflow is a standard procedure, but it certainly helps to apply a specific lens profile to the data at the onset.

Focusing the Lens

The Sigma 24mm F/1.4 has an impressive autofocus system, even when using the lens at its maximum aperture of F/1.4. This, of course, is in the daytime. For all astrophotography purposes (including video work), I use manual focus on this lens.

For daytime (and even dusk) filming on my Canon EOS 6D Mk II, the continuous autofocus capabilities of this lens are a lifesaver. I can simply tap the flip-out LCD screen to refocus on my face or any equipment I happen to be talking about.

However, at night, all of this goes out the window and the lens will not focus on stars in the night sky. For photography purposes, I simply use the manual focus ring to achieve a tight focus on the stars in the night sky.

For most lenses, it is best to “stop down” the lens for a sharper image. You will lose light-gathering power, of course, but your stars will likely look better at a slower f-ratio. On the Sigma 24mm F/1.4 Art lens, I find F/2.8 to be a good balance between aperture and image quality. 

Advice When Stacking Images

Depending on the way your individual sub-exposures were captured, you may notice some rotation in your final stacked image. This can be very difficult to overcome, but I believe that applying the lens profile to your sub-exposures before stacking will help. 

For nightscape astrophotography, I like to use Sequator to stack my images. This is a simple, free software that allows you to improve the signal-to-noise ratio of your final image by integrating several exposures together. 

This program allows you to select the areas of your image you would like the stack (such as the stars), and the areas you wish to leave alone (the landscape). It’s not perfect, but with some trial and error, you may find it to be a useful tool for your nightscape photos. 

I prefer to keep the default setting applied for the most part. I do not utilize the auto-brightness, high dynamic range, reduce light pollution, or enhance star light options, but you may want to try those settings out on your image.

Sequator Image Stacking

Stacking images in Sequator.

There are a few challenges that may arise when attempting to stack your individual light frames in Sequator (or DeepSkyStacker for that matter). The issues are not exclusive to camera lens astrophotography, but you will need to keep them in mind when taking photos with the Sigma 24mm F/1.4 Art Lens. 

Some tips for anyone looking to use the Sigma 24mm F/1.4 DG HSM Art lens for astrophotography are:

  • Capture long-exposure images (30-seconds +) on a star tracker mount
  • Capture a series of exposures to stack using software such as Sequator or DeepSkyStacker
  • Stop the lens down to F/2 or slower for sharper stars, especially near the edges of the frame
  • Use a bright star to manually focus the lens before capturing your subject
  • Capture your stationary foreground details in a separate exposure and blend with your stacked/tracked images

Milky Way astrophotography

The Milky Way. 10 x 30-seconds using the Sigma 24mm F/1.4 and Canon EOS Ra. 

The Bottom Line

The Sigma 24mm F/1.4 Art lens was a welcome addition to my ever-growing line-up of lenses for astrophotography. It is my fastest lens I own, at a convenient focal length for most projects. 

A “nifty-fifty” (50mm, F/1.8) lens is comparable, but I find a 50mm to be a bit too long when you want to capture a large area of the night sky in a single shot. However, an entry 50mm lens will get you the light-gathering power at a much more affordable price. 

The Sigma Art Series of lenses offer impressive quality and are a great value, and the astrophotography community seems to agree on this. 

In my experiences with the Sigma 24mm F/1.4, the images are impressively sharp and flat when paired with my full-frame Canon DSLR and Mirrorless cameras. I usually stop the lens down to F/2.8, but getting creative at F/1.4 can be useful for certain projects as well. 

For video work, this lens is quiet and focuses quickly (with adequate lighting). I have used this lens for the majority of my YouTube videos in 2020. If you notice scenes that include stars and constellations in the night sky, the Sigma 24mm F/1.4 was used. 

Sigma lens bokeh

The beautiful lens bokeh of the Sigma 24mm F/1.4 wide open. 

The Sigma Art Series Lens Line-up

The Art Series lenses are available for Canon, Nikon, and Sony camera bodies. The “DG” in the name stands for “digital full-frame and APS-C”, and the “HSM” stands for “hyper-sonic motor”. 

Here are the lenses I believe most astrophotographers and nightscape photographers will be interested in:

  • 14mm F/1.8 DG HSM
  • 20mm F/1.4 DG HSM
  • 24mm F/1.4 DG HSM
  • 28mm F/1.4 DG HSM
  • 30mm F/1.4 DC HSM
  • 35mm F/1.4 DG HSM
  • 35mm F/1.2 DG DN
  • 40mm F/1.4 DG HSM
  • 50mm F/1.4 DG HSM

Sigma offers Art series lenses beyond 50mm (including an enticing 50-100mm zoom lens). I am looking into the 14mm F/1.8 as an alternative ultra-wide-angle lens. The 35mm F/1.2 Art lens is the fastest lens of the bunch but is currently only available for Sony camera bodies. 

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This Post Has 4 Comments

  1. Judit Fabian says:

    Trevor,

    Could you post a close-up of one of the corners of a star field that shows the coma of the lens at f/1.4 and f/2.8?

  2. Andy Ross says:

    Great review, I finally bought this lens 2 months ago after seeing it on your YouTube channel. My Samyang 14mm hasn’t seen the light of night since. Looking forward to next years core season and I use it on stock 6d mkii and modded 600d.

  3. Jesse D Beatty says:

    Trevor,

    Thank you for the valuable information. Really enjoy learning more from watching your You Tube programs. I am expanding my learning curve as I, again, venture into astro imaging after a 30 plus year hiatus. Making use of my Canon i6 for prime focus on my 1986 era Meade 10in. 4.5 Newt and original pier mount. Had the primary mirror refigured and coated by Carl Zambuto in Washington state. Keep up with the excellent videos and valuable information they contain.

    Thank you, sir….

  4. Doug Griffith says:

    Trevor:

    Totally agree on how good Sigma Art lenses are for Astrophotography.
    My preferred lenses for Milky Way imaging are the Sigma Art 35mm f/1.4; and the 40mm Sigma Art f/1.4.

    For wider field, the 85mm f/1.4 and 135mm f/1.8 are both excellent choices (albeit expensive ones).

    Here are some examples:

    35mm Sigma Art
    https://www.astrobin.com/420573/?nc=user
    https://www.astrobin.com/386252/?nc=user

    40mm Sigma Art
    https://www.astrobin.com/np3v87/?nc=user

    85mm Sigma Art
    https://www.flickr.com/photos/[email protected]/49927439722/in/dateposted-public/

    135mm Sigma Art
    https://www.astrobin.com/mx4hyy/B/?nc=user
    https://www.astrobin.com/ov0285/?nc=user

    Keep up your excellent posts; and stay safe in these uncertain times.
    Best,
    Doug

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