Rokinon 14mm F/2.8 Lens for Astrophotography
I purchased the Rokinon 14mm F/2.8 lens for my Canon DSLR for the purposes of wide-angle astrophotography. Over the past 2 years, I have captured many spectacular images using this Rokinon lens on both a crop-sensor DSLR, and full-frame camera.
The Rokinon 14mm F/2.8 is a manual, wide-angle camera lens that comes in Canon, Nikon and Sony mounting options. The aperture of this lens (F/2.8) is a handy feature for those looking to capture astrophotography images of the Milky Way. The 115-degree field of view can only be utilized will a full-frame camera, but I have found it to be impressively wide with a crop-sensor DSLR as well.
Using a Rokinon 14mm F/2.8 Lens For Astrophotography
The Rokinon 14mm F/2.8 lens is an affordable option for wide angle astrophotography, as it is less expensive than comparable lenses made by Canon or Nikon. There are a number of reasons Rokinon was able to offer this lens at this price point.
Features that come standard with any premium lens are not present on the 14mm F/2.8, such as autofocus, and the ability to change aperture using your camera. This is a fully manual lens, with no communication with the camera the way a regular Canon or Nikon lens does.
Fortunately, these missing features do not affect the astrophotography performance or user experience of this wide-angle lens. As most amateur astrophotographers know, the majority of the camera settings will be set once, and remain the same for long periods of time under the night sky.
When it comes to capture wide angle shots of the night sky, a camera lens that is fast and wide can make your life a lot easier. You’ll be able to capture much more sky in a single shot than you can with a standard 18mm lens.
I purchased my Rokinon 14mm F/2.8 on Amazon
Rokinon 14mm Ultra-Wide Angle Lens Specs:
The lens design features 2 ED elements. This includes 1 “hybrid” aspherical element, and 1 glass aspherical element. The field of view is 115-degees when used with a full-frame (35mm) DSLR camera body, and about 94 degrees with a crop sensor (APS-C) DSLR.
The lens construction is 14 elements in 12 groups, utilizing the 2 ED elements mentioned above. The Rokinon 14mm Ultra-Wide Angle ED AS IF UMC is available for Canon EOS, Nikon, Sony Alpha, Pentax & Olympus 4/3. The lens comes with a large plastic front cap that clips onto the lens petal.
- Type: Manual Ultra-Wide Angle
- Focal Length: 14mm (Fixed Prime)
- Aperture Range: F/2.8 – F/22
- Field of View: 115.7° (Full-Frame DSLR)
- Minimum Focusing Distance: 11”
- Lens Construction: 14 Elements in 12 Groups
- Mounting Options: Canon, Nikon, Sony, Pentax, Olympus
The Rokinon 14mm Ultra-Wide Angle IF ED UMC attached to my Canon EOS Rebel T3i DSLR
Manual Aperture Adjustment Ring
Up until I used the Rokinon 14mm F/2.8, I had never used a camera lens that required manual adjustment of the aperture. In fact, when you connect this lens to your camera body, the video mode does not recognize that a lens has been connected at all (similar to when connecting a telescope).
The aperture setting (F-stop) on your DSLR will display “0”, when the Rokinon 14mm F/2.8 is connected. To change the f-stop of the lens you need to manually rotate a ring at the base of the lens. The ring displays each f-stop setting to confirm the current lens aperture.
Luckily, there is a printed display of the aperture setting at the base of the lens, this where you’ll need to confirm which f-stop you are currently using. The lens clicks into place at each stop, but you’ll need to be careful not to inadvertently knock the aperture out of position when holding the camera.
If you are making this adjustment to the lens in live-view or video mode, you will see the amount of light collected by the lens changing as you turn the dial. Setting the aperture wide open at F/2.8 lets the most amount of light into the camera as possible, which can be beneficial in low light situations.
The Cygnus Region of the Milky Way with the Rokinon 14mm F/2.8 Lens
Which F-Stop is Best?
A camera lens with a fast aperture of F/2.8 can collect a lot of starlight in a single exposure. The Rokinon 14mm F/2.8 can certainly create beautiful images at this f-stop, but I rarely use F/2.8 for my wide-angle astrophotography images.
Adjusting the aperture can affect the overall quality and sharpness of the stars in your astrophotography images, especially near the edges of the frame. The lower the f-stop you go, the more critical achieving a precise focus becomes.
For certain situations, such as capturing the summer Milky Way from a dark sky site, you may want to use the lens “wide open” at F/2.8. This is because an image like this focuses on the structure and color of the Milky Way as a whole, rather than the individual stars within it.
For photos of constellations, where capturing more isolated regions of stars is important, I suggest stopping the lens down by 1 or 2 stops. There is no need to go beyond F/4 at this focal length, and I think you will find your photos to be extremely sharp using this aperture.
I recommend using an f-stop setting of F/3.2 with the Rokinon 14mm F/2.8 lens. This is a very versatile setting that can maximize the light gathering ability of the lens, while providing sharper images than its fastest aperture of F/2.8.
Most of the Canon camera lenses I use for astrophotography, such as the Canon EF 300mm have an f-ratio of F/4. The added light gathering power of F/3.2 provides a much-needed boost in signal, and allows me to use lower ISO settings.
Star Quality and Sharpness
You may be interested in the quality of the stars in your image when using the Rokinon 14mm F/2.8 lens for astrophotography. I have found this lens to perform exceptionally well in this regard, as you can see in the image below. I have zoomed-in on a small portion of the image to highlight what the stars in the corner of the image frame look like up-close.
Checking for chromatic aberration and coma at the edges of my image
It’s worth noting, that this image was taken using a crop-sensor DSLR, which effectively produces a field of view similar to a 21mm lens would on a full frame camera. So, the quality of the stars at the edges of a full-frame image are the true test of this lens. I expect that they would be less sharp and coma would begin to really kick in.
However, I do not believe this is an issue if you use this lens for what it was intended for, wide angle nightscape astrophotography. Will you spend time actually zooming in to inspect the stars at the edges of the frame, or will you enjoy the image as a whole from a realistic distance? For me, the answer is clear.
If your images demand sharp stars without a hint of chromatic aberration or coma, perhaps the Canon EF 14mm f/2.8L II USM at 6x the price is a better fit for you.
Have a look at this price comparison of some popular 14mm prime lenses:
|Rokinon||14mm F/2.8 AS IF USM||$299 USD|
|Canon||14mm F/2.8L II USM||$2,000 + USD|
|Nikon||14mm F/2.8D AF||$1,400 + USD|
Focusing Tips and Advice
To focus your DSLR camera with the Rokinon 14mm F/2.8 lens attached at night, it is best to use a distant bright object. A streetlamp or even the moon will make a useful focusing tool. To make these objects easier to see, use the live-view function of your camera and zoom-in 10X.
A common mistake when focusing your camera for astrophotography is to use settings that do not allow enough light to hit the sensor. You won’t be able to see anything on your DSLR display screen to assist in focusing.
Make sure that your camera is in manual mode, with the exposure length set to bulb. Also, crank up your ISO, and set the aperture to F/2.8. You’ll change these settings back to the appropriate levels once you have confirmed that the lens is in focus.
The focus ring on the Rokinon lens is completely manual, and fluid. You may be surprised at how much you need to rotate the focusing ring to achieve focus. At 10X magnification in live-view, you should be able to achieve sharp edges on your focusing subject.
Once dialed in, you can turn the live-view mode off, and your lens is now in focus. You can also use a bright star to focus the lens, such as Aldebaran or Sirius. Again, use the 10X live view, and make sure your ISO setting is high, and your aperture low.
Remember to adjust your camera settings back to your intended levels for the shot, as it can be easy to leave them as they were during your focus routine. When using an f-ratio of F/3.2, the stars in my images with the Rokinon 14mm lens are very sharp.
When Used on a Star Tracker
I have found this lens to be most beneficial when used with a tracking camera mount such as the iOptron SkyTracker Pro. This will allow you to shoot longer exposures that maximize the Rokinon 14mm F/2.8 lenses ability to gather starlight over a wide span of the sky.
The lens is lightweight and compact, meaning a small star tracker can handle this lens without issues. The Built-in lens hood comes in handy for astrophotography, as it helps to reduce any stray light from entering the optical plane.
In my opinion, this lens was built for Milky Way photography. Even when used on an APS-C sensor DSLR camera like my Canon EOS Rebel T3i, the lens is wide enough to capture an impressive portion of the Milky Way core. The photo below was captured using the Rokinon lens under the dark skies of the Cherry Springs Star Party.
The Milky Way (60 x 2 minute exposures)
Camera Settings Used for the Photo Above:
White Balance: Daylight
Number of Frames: 60
Several images were stacked in DeepSkyStacker to improve the signal to noise ratio, and dark frames were subtracted to reduce noise in the resulting image. The image was then processed in Adobe Photoshop to boost the color and contrast of the Milky Way.
The Bottom Line
For the price, you’ll be hard-pressed to find a more capable wide-angle astrophotography lens. If you’re on a budget, and your photography goals include capturing wide panoramic-style images of the Milky Way, the ultra wide-angle 14mm Rokinon is for you.
To fully utilize the extra wide 14mm focal length, you’ll need to use a full-frame camera. However, as you can see in the images shared in this post, the images are still plenty wide when used with a crop-sensor DSLR like the Canon EOS Rebel T3i.
The stars are the edges of the field are impressively sharp when shooting at F/3.2 or above. There are some signs of color fringing and elongated stars (coma) at the edges of the image, but this will not be an issue for users that enjoy sharing their images as I believe they were intended to be seen.