Let’s unbox, review and test this lens to find out why it is one of the best bang for your buck deals in astrophotography! I’ll walk you through all this incredible lens has to offer as we go outside to test it with some deep sky imaging. If you own the Samyang or Rokinon version of this lens please let me know about your experience using it and what your imaging in the comment section below.

One important thing to mention off the bat regards the confusion over any differences between Samyang and Rokinon lenses.  From what I’ve read, the 135mm f2 versions of each lens are identical. The difference in their names simply comes down to a marketing decision. If both are available to buy where you live, do what I did and go with the cheaper one, that ended up saving me about 20 dollars for this the Samyang model.

When researching what lens to buy for astrophotography, there were several things that led me to this Samyang Lens. One of which was its low F number. At F/2, this has a very large aperture which lets in a tremendous amount of light, leading to fainter objects showing up under ideal imaging conditions and shorter individual exposure times needed to collect light for stacking and post processing. The true beauty of this lens comes from the fact that even shooting at F2, you can still get incredibly sharp images across the entire field of view and that’s not always the case for lenses.

The second thing that sold me on this lens was the fixed 135mm focal length. Prime lenses that don’t zoom often lead to sharper results for astrophotography due to the design of the lens. 135mm is also a nice sweet spot for my current tracking mount. At a little less than 2 pounds, its light enough for my Skyguider Pro and the amount of sky that it can image will reveal faint details of impressive deep sky objects but also doesn’t push the limits of what my tracking mount is capable of in terms of its tracking accuracy at long exposure times.

Few things test a lens like imaging the nighttime sky with its pinpoint stars and faint deep sky objects, so let’s put this lens to the test and see if it’s impressive claims match up to the real-world rigor of astrophotography by imaging the Constellation Orion. Now the detail of your images will vary from mine due to things like light pollution, exposure times and post processing but the thing I really want to point out is the sharpness of this lens, fully open at F2. From the Flame and Horsehead nebulas near the bright star Altinak, to the Orion Nebula with its nursery of dynamic gas clouds creating stars all the way over the extreme edge of the image where faint stars shine bright, this lens remain as sharp as the center of the image across the entire field of view. The Samyang 135mm F/2 easily lives up to its hype and should be near the top of your list of purchases if you are new or experienced in the field of astrophotography.

If you’re using or are looking to buy the Samyang or Rokinon 135mm F/2, please let me know what you’re imaging with it or any questions you may have in the comment section below. Thank you all so much for your support and clear skies from Late Night Astronomy.

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Astrophotography can seem like an overwhelming addition to amateur astronomy. Over the past several weeks I have attempted to photograph the night sky and will show you what has worked best for me using some entry level equipment and a little bit of research.

Step 1: Buying a Camera and Lens

While I didn’t buy the Canon Rebel SL2 specifically for astrophotography, virtually all new DSLR cameras will provide wonderful results for entry to intermediate level users. The 24 Megapixel CMOS (APS-C) sensor provides more than the necessary minimum for nighttime imaging. It’s standard kit zoom lens featuring an 18-55mm focal length is a nice starter lens and offers fairly sharp fields of view.

Step 2: Adjusting Camera Settings

Be sure to turn your camera dial to Manual Mode. This will give you complete control throughout the entire process. I’ve also configured a menu tab aptly named “Astronomy” which allows me to easily change some of the most important settings involving shooting the nighttime sky.

• Image Quality-Raw and Large jpeg
• Picture Style-Neutral
• White Balance-Daylight (5200K)
• Long Exposure Noise Reduction- On
• High ISO Speed Noise Reduction-Standard
• Drive Mode-2 Seconds

Step 3: Mounting the Camera to the Tripod

The cheapest and easiest way to get into astrophotography involves using a tripod and your DSLR. After connecting the SL2 to the tripod, I chose Orion’s Nebula as my target. Before moving on, I had to determine the proper focal length, focus, aperture, shutter speed and ISO.

Step 4: Setting up and taking the Shot

• Focal Length and Focus:
  How zoomed in do you want your image? This is what the focal length controls. I wanted a zoomed in image of Orion’s Nebula, so I chose to set my lens at it’s maximum 55mm focal length. To focus, make sure that your lens is switched to manual focus and use the digital magnifying feature to show a 10x image of the constellation in the live viewing screen. Slowly turn the focus ring until you get the sharpest stars possible.
• Aperture:
  How much light is going through your lens and into your sensor? This is what the aperture controls. The best possible aperture for my zoom lens set at 55mm is f/5.6.  This is not a strong point of my kit lens. I hope to upgrade this to a fixed 50mm f/1.8 in the near future.
• Shutter Speed:
  How long do you want your camera’s shutter open to allow light onto your sensor? This is what the shutter speed controls. I was looking for as long a time as possible to bring out detail in Orion’s Nebula, without creating star trails. There are a lot of ways to determine how long the shutter can stay open without creating star trails. The website LonelySpeck has an excellent calculator for determining this setting. For my camera’s sensor and zoom lens set at 55mm, 4 seconds was the longest length of time I could afford.
• ISO:
  How sensitive do you want your camera to be when the shutter is open and light is hitting the sensor? This is what the ISO controls. Increasing it will brighten your image, but also increase digital noise. Finding a balance between sensitivity and image quality will vary depending on your camera’s sensor. For my Canon SL2 shooting Orion’s Nebula a setting of ISO 3200 gave me the best results.

Step 5: Post Processing

• How much detail can you bring out of your image? This is what imaging software controls. Canon’s Digital Photo Professional 4 is free software provided by Canon if you buy their products. It is excellent for editing RAW images, which contain much more image information than jpeg files. There are a variety of paid and free choices from Adobe Photoshop to Raw Therapee. The learning curve on these can be pretty steep, but I have found DPP4 to be fairly user friendly and powerful. The most useful settings for me so far have been contrast, shadow, highlight, color tone and color saturation.

The Final Result:
Orion Nebula: 12/27/17
Canon SL2, 55mm, f/5.6, 4 Seconds, ISO 3200
Enhanced and Cropped with Digital Photo Professional 4

There have been several sources that have provided me with a lot of the information presented in this article. “The Backyard Astronomer’s Guide” has been my constant companion as I have expanded my interest in amateur astronomy. That book, along with the websites ImprovePhotography, Astropix and LonelySpeck have given me tremendous assistance in my early efforts at understanding astrophotography. Hopefully, this article helped you as well. Please leave a comment with any questions or suggestions you may have.