June 10, 2014

Samyang / Walimex 14mm (Nikon mount)

You do not encounter every day a good quality ultra-wide lens which doesn’t cost you an arm and a leg. The Samyang 14mm is one of them: quite luminous (maximum aperture is f2.8), it covers the full-frame format (so it can be used on old Nikon SLRs with AI/AIS mount) and has a good reputation too, at least according to a few reviews.
Just to remove any doubt, this is not a fish-eye!  In spite of its very short focal length, this is a rectilinear lens, i.e. projection is rigorously perspective (straight lines are preserved). Maybe the term “rigorous” is a bit excessive, because this lens is affected by some moustache distortion. However, you will notice it only in particular situations and it can be easily corrected in post-production. The angle of view is 110°, much less than the 180° of a fish-eye (which can never be covered by a perspective-projection lens).
It’s a manual focus lens, that means that you have to adjust the focus by rotating the focusing ring on the lens.  Focus range is from 28cm to infinite. Unfortunately, no indication of the depth of field is provided on the focus scale.
It has a real aperture ring, but it is only used with old manual cameras. On DSLRs you control the aperture only through the camera controls.
The Samyang 14mm is also marketed under a few different brands: Walimex, Rokinon, Vivitar, etc.. In all these cases it should be exactly the same lens, so it's better to choice the cheaper one (my 14mm, for instance, is a Walimex).
On manual Nikon SLRs it works like any other AI/AIS lens.
It works great on a DSLR too. Latest versions have a chip which communicates to the camera the EXIF data.
When this lens is mounted on a DSLR, the aperture ring shall be set to its smallest aperture (f16). Not doing so, an error (fEE) is raised and the camera is totally unusable, even in manual mode.
Nikon D5100 + Walimex14mm

On DX format the focal length is equivalent to a 21mm, still a rather wide lens, in spite of the crop factor.

Nikon D5100 + Walimex 14mm, RAW file processed in Lightroom
When this lens was launched on the market, there was no way to mount filters, owing to the big protruding front lens. For polarizers this was not a real issue. In fact, a real polarizer would be virtually useless with such a wide field of view. It is preferable to emulate it in post production.
On the other hand, if you shoot b&w film (like I do) the impossibility to mount filters is very annoying, especially in those situations where you need an orange or red filter to make skies look a bit darker and dramatic.
So I found a DIY solution, building a special filter holder with black opaque Perspex. I also  used transparent coloured Perspex for making my contrast filters.

The total cost of materials was about 10 euros. The result was a bit cumbersome, but it worked!

However, for some corollary of the Murphy’s law, as soon as I completed my DIY work a real filter holder was announced on the market. It was also given for free to anybody who did purchase a 14mm Samyang (this reminded to me mine was a Walimex).
The filter holder is named SFH-14 and can mount up to two filters at the same time. Three special filters for this holder are manufactured by Cokin: a ND8 filter, a half grey filter, a half blue filter.
Being rather cheap, I ordered it. However, the only solution for red/orange filters was still the Perspex, very cheap indeed (and very effective too).
(The picture of the official holder is coming soon!)
While my DIY was a bit loose, I found the commercial holder very tight. So tight that I had to work very hard to remove the holder from the lens! I quickly fixed this problem by smoothing the plastic notches which hook the holder to the lens.
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A few references:
  • the review of Samyang 14mm on DxO
  • la official page of Samyang 14mm
  • the Samyang filter holder SFH-14

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