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Wednesday, June 19, 2013

Night Focusing the Rokinon 14mm Lens

MilkyWay over String Lake, taken with the Rokinon 14mm lens ~ © Royce Bair
Many have purchased the Rokinon 14mm f/2.8 lens for starry night photography, at my recommendation, and then have written to me about their difficultly in focusing this lens for night photography.

Focus Frustrations and Fix: I must admit, that the first time I tried to focus this manual lens I was a bit bewildered. It seemed to stay in focus no matter what I did! This is due to the incredible depth of field of this 114º angle lens, even wide open. After considerable tests in the daylight and field testing at night, I can make the following recommendations: Don't focus on the infinity mark (some are even confused as to what position the infinity mark is located on the lens barrel).

Left: This is NOT the infinity position. Right: This is the infinity position.
HOWEVER, I recommend the following focus position below:
This is the focus position I recommend when shooting 'NightScapes':
Shoot at f/2.8, and set your focus halfway between the 10-feet mark and the infinity mark.
Hyperfocal Distance correction: Some hyperfocal charts will recommend focusing on 7-feet (actually, 7.62 feet—saying that everything from 3.81 feet to infinity will now be in focus). I find that I get better infinity sharpness at my focus position, and I still get good depth of field in to about 10 feet. I think this is because most hyperfocal DOF charts are based on the sharpness quality of an 8x10 inch print, whereas I want 16x20 and even 30x40 quality. (Quoting the Cambridge in Colour website about hyperfocal distances: "... it's often helpful to use a more rigorous requirement for 'acceptably sharp,' or to focus slightly further and improve background sharpness.")

Best Ultra-Wide Lenses for Starry Night Photography: The Rokinon 14mm f/2.8 lens has incredible coma correction and quality for a lens of it's price (about $350). It surpasses the coma aberration correction (even wide open) of most lenses in its ultra wide-angle category. I find it has about 1.5 stops of light fall-off in the corners (vignetting), which is easily corrected in the Adobe Raw Converter (via Photoshop or Lightroom). It is also a little soft in the edges, unless you stop down to about f5.6 or smaller; however, I don't recommend doing that if you're using the lens for high-ISO night photography—just keep this lens wide open, and place important areas away from the edges or corners of your composition. When doing daylight landscape photography, I found this lens performed optimally at f/11, with the focus set at 7-feet (f/16 was also very good, but at f/22, I began to notice a little bit of diffraction).  If you're a Nikon user (and can afford to shell out about $2,000), the only other lens I'd recommend in this category is the Nikkor 14-24mm f/2.8 lens. This lens is well-corrected in every area, and is sharper than most prime lenses. It is a little sharper than the Rokinon, especially in the corners. Some Canon users like it so much, they even have the Nikon mount adapted to fit their EOS bodies!

Full-resolution crop of the top photo. Enlarge or download this image to see for yourself the quality of the
Rokinon 14mm when used wide open at f/2.8—just keep in mind that you're also seeing the coarseness of an
ISO 6400 image that has had some noise reduction in the ARC software (which tends to soften shadow detail).



15 comments:

  1. I could have used the lens profile, but in this case, I did nothing. On some images I feel a need to bend or straighten that barrel distortion or "mustache effect" with the use of Photoshop's "Warp" tool (Edit > transform > warp). This allows me to manually adjust only those areas that I think need improving, rather than relying on a built in lens profile formula.

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  2. Is it sharp at minimal focus distance as it is at infinity and in between ?
    Mine is super sharp at min focus distance but cant seem to find infinity at 2.8...but I had it for like 5 hours :) Will check what is going on... Great photo, and great lens.

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  3. I've received my Samyang 14mm f/2.8 last week but didn't have time to take it out yet though! Thanks for the tip Royce and lest hope that July will bring some starry nights as I’m really hungry to use it;)!

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  4. My lens' focus ring was calibrated incorrectly and from what I've read that's a common problem. It's still a great lens, but Samyang's quality control doesn't seem to be all that great.
    But I found this video that explained how to fix it in about 15 minutes.
    http://www.videofy.me/emadeloc/755452
    It's in spanish with english subtitles.

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    Replies
    1. Kevin, I've heard of this quality control issue problem and have seen the video for doing your own re-calibration. Thanks for sharing!

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  5. Can I also recommend the Tokina 11-16mm f/2.8?
    Awesome lens.

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  6. I just got one of these a few days ago. I love it! When I got it, it was dead on sharp using all the focus measurement markers and the infinity focus was perfectly accurate. But then I dropped it :-( it was only from about 3 feet and onto carpet, but it must have been enough to knock something out of alignment because now all the distance markers are way off, and I can only focus down to 1.5 ft. instead of 3" :( Has anyone tried the re-calibration technique above? Any luck?
    This was the first shot I took with the Rokinon http://www.damianvinesphotography.com/portfolio/diablo-lake-milky-way-pano/

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  7. I`ve got Samyang AE version for Nikon, the infinity is correct and sharp.

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  8. I have the Bower copy of this lens, using it with a Pentax K5-II, and extremely pleased with it. My first copy did have a de-centered lens and I returned it to B&H and received a replacement which is great. The focus distance markings are way off, but I just covered the markings with masking tape and setup focus charts and made my own marks at 1.5 feet, 8 feet and infinity. Now I can set it in the dark with confidence that everything I want will be in focus.

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  9. Could you show me infinity focus if you have rokinon 35mm 1.4?
    IT's difficult to me,I have CANON Dslr.
    Thanks.

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  10. After renting a Rok 14mm f/2.8 for several astro outings, I finally broke down and purchased this lens. It is a remarkable and inexpensive lens, but admittedly requires logging some hours to fully appreciate its strengths and weaknesses. I completely agree with your focus comment: "Bewildering." The focus also appears very mushy when using the Live View. Not sure if this is due to a lag in processing the live image on the LCD, but it appears you can keep dialing the focus ring without changing the focus setting very much. I confirm that my "infinity" (Canon mount) falls short of the infinity mark on the ring at about the same distance you note. Performing a focus test is absolutely essential prior to your astrophoto shoot. Vignetting quickly dissipates at f/4 and I have been shooting at this aperture when taking long exposures with my Astro Tracker. This also produces a bit of a diffusion spike on brighter magnitude stars, if you like that sort of thing.

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    Replies
    1. Hi,

      Chris or anybody, could you help me ? I have problem with my samyang 14 with infinity focus. Lens has the best infinity focus at the end of adjustment range, it is exactly on infinity mark. But also on that setting my stars are blured on f/2.8. It looks well on f/5.6. Is something wrong with my Samyang ? What can I do to fix it ? Check out that 100% crop of stars, it is the same part of the sky ! http://goo.gl/IeS6gb

      Are your stars look the same as in my photo on f/2.8 ?

      Delete
  11. Hi Royce,

    First let me say great photographs and I really liked the article on the Rokinon 14mm. I just got mine about a week and a half ago, and have not had much of a chance to use it yet, as we have had snow, rain, and bad weather in general. I did get a chance to take it out yesterday and do some test shots with it, as I wanted to make sure I had a good copy of the lens, after reading the reviews and comments on this lens from people saying they had to return it 2 and 3 times before they got a good lens. My version is for a Nikon (I use a D800), and it has the focus confirm chip in it. I guess one question would be, is the recommended focus point you mention for infinity strictly for night photography and astro photography, or general use at infinity during the day? I made notes on the infinity focus marks you provided in the article, and when I took my first photo I was surprised to find that on subjects that were between 100-200 feet away, the lens was pretty much at the infinity mark on the lens barrel. I moved the mark to where you illustrated in the photo above, and now the scene was out of focus. I was quite surprised with the sharpness of the photos I did take. On one photo of a building, I did see some minor moustache distortion, but it was not terrible at all. Is it possible the difference people have been seeing is related to the different lens manufacturers, and versions for different make cameras. Also, does the Canon version have the focus confirm chip, or just the Nikon version? And I think there is a version for Nikon without the focus confirm chip. So far, with very minimal usage, I am impressed with the lens, and I plan on keeping it. I did do a few shots inside the day I received it, and the was some pronounced distortion shooting close-up wide open on both vertical and horizontal lines. You could see significant distortion on paneling, shelves, doors and windows. But for landscapes, night and astro photography, this lens is awesome from what I have seen when that is what it is used for.

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