Samyang Reflex f/6.3 300mm ED UMC CS

      Photo Review 8.8

      In summary

       The Samyang Reflex f/6.3 300mm ED UMC CS represents excellent value for money for any photographer who wants a super-telephoto lens for a very affordable price.

      Provided you are prepared to work with its limitations (particularly manual focusing and the fixed aperture), this lens will be easy to carry and a great companion for sports and wildlife photography as well as being usable for candid portraits.



      Full review

      Samyang is one of the few manufacturers to produce reflex mirror lenses and its portfolio includes 300mm, 500mm and 800mm focal lengths with various brand names (Samyang, Rokinon, Bower, Vivitar) for most interchangeable-lens cameras. We received the Samyang-branded M4/3 version of the Reflex f/6.3 300mm ED UMC CS model, which is also available for Canon EOS-M, Sony E and Fujifilm X camera systems. It is offered in black or black and silver.


      Angled view of the Samyang Reflex f/6.3 300mm ED UMC CS lens, black version without lens hood, showing the donut-shaped front element. (Source: Samyang.)

      About Catadioptric Lenses
       Catadioptric ‘mirror’ lenses have been around for most of the last third of the 20th century, with Canon, Minolta and Nikon offering several designs with focal lengths from 250mm to 1000mm.   These lenses tend to polarise photographers: some love them while others refuse to use them.

      Although Canon and Nikon stopped making mirror lenses a decade or more ago,  Sony continued production until quite recently. Its 500mm mirror lens was based on a Minolta design (and is, therefore, suitable for Alpha mount cameras) and has the distinction of being the only mirror lens with autofocusing.

      Most mirror lenses use the Cassegrain design, which combines a primary concave mirror, which is located at the mount end of the lens barrel, with a secondary convex mirror, which reflects the light back from inside the front element to the image sensor. A diagram illustrating the design is shown below.


      An example of the catadioptric lens design. (Source: Created by Paul Chin and accessed via Wikipedia –

      This design ‘folds’ the light path, enabling lenses to be made much shorter and considerably lighter in weight than regular refractive lens designs with the same focal length. It has some additional advantages:  chromatic aberration, a major problem with long refractive lenses, and  off-axis aberration, a major problem with reflective telescopes, are almost completely eliminated.

      But mirror lenses have several drawbacks. The convex secondary mirror occludes the centre of the field of view, reducing the amount of light that enters the lens and  preventing the use of an adjustable  iris diaphragm. When over-exposure could occur because you can’t set a fast enough shutter speed, you can’t stop down but must add neutral density (ND) filters, usually to the rear of the lens.

      Almost all mirror lenses must also be focused manually, which is relatively easy when these lenses are used on a modern camera with an adjustable EVF that can deliver a bright, clearly-resolved image. But focusing can be difficult in dim lighting on cameras with optical viewfinders.

      Most mirror lenses suffer from slight vignetting. It’s easily correctable with modern editing software. Rectilinear distortion is seldom an issue with these lenses.

      The final drawback is primarily aesthetic and relates to the characteristic doughnut-shape bokeh in bright, defocused areas of the image. This results from the ring-shaped entrance pupil of the lens design.

      The donuts needn’t be obvious and, unless there are bright highlights in the subject that are very out-of-focus, you’re unlikely to see them. Examples of shots with ring-shaped highlights in various sizes are included in the sample images below.

      Design, Build and Ergonomics
       The optical design of the Samyang 300mm f/6.3 lens comprises nine lens elements arranged in nine groups, including one ED element to optimise image contrast and suppress chromatic aberration. UMC (Ultra Multi Coat) coatings suppress surface reflections, reducing lens flare and ghosting while also optimising overall contrast.

      Build quality appears to be very good for the asking price. The lens barrel seems to be mainly made from lightweight aluminium and there’s a solid, chromed mounting plate.


      The Samyang Reflex f/6.3 300mm ED UMC CS lens, shown with the supplied lens hood attached. (Source: Samyang.)

      The cylindrical plastic hood fits solidly onto the bayonet mounting at the front of the lens. It almost doubles the overall length of the lens but can be reversed over the lens barrel for storage.

      The lens has only one control surface: the focusing ring, which makes up the entire outer barrel. It’s about 58 mm wide, with a 30mm wide ridged, rubber grip band that starts about 12 mm back. Behind this band the lens is stamped with distance markings in metres and feet from 0.9 metres (~3 feet) to infinity.

      The focusing ring turns very smoothly, covering about 165 degrees as the range is spanned. The outer barrel moves outwards by about 12 mm as the lens comes close to its minimum focus.

      You can only focus manually with this lens but, on the Olympus OM-D E-M5 we used for our tests, the bright EVF made the process relatively easy. The fixed aperture setting presented few problems on the E-M5; in the A shooting mode, the camera adjusts the shutter speed to suit the detected light levels. With the M shooting mode, you simply adjust the shutter speed setting until the viewfinder image has the right brightness.

      The lack of electronic contacts means this lens can’t communicate with the camera body so no metadata relating to the lens is recorded in image files and we were unable to take advantage of the camera’s built-in focus magnification aid. But we could take advantage of body-integrated stabilisation, which is really useful for such a long focal length.

      Despite its long focal length (equivalent to 600mm in 35mm format), you can shoot hand-held with this lens on the E-M5, thanks to the camera’s built-in stabilisation. It wouldn’t be quite so easy with a Panasonic M4/3 camera, which lacks integrated stabilisation. The lens itself is light enough (315 grams) to be simply attached to a camera that is tripod-mounted. No special collar is required.

       We were unable to run our normal Imatest tests with this lens as we don’t have enough space in our testing set-up. Consequently, all assessments are based upon subjective observations.

      Although it is possible to obtain sharp images with mirror lenses, that’s not the main reason for buying them. These lenses reflect the imaging light twice on its way to the sensor and both sharpness and contrast are inevitably reduced a little. Colour rendition will also be slightly subdued.

      Traditional refractive lenses with similar focal lengths should deliver sharper results.  But they will also be significantly larger and heavier and much more expensive.

      These issues aside, the review lens delivered some very sharp images with plenty of contrast and good colour reproduction in our practical tests. Backlighting was handled remarkably well and we had no instances of flare of ghosting in test shots.
       Overall image quality from this lens should be good enough to suit most situations in which this lens is likely to be used and sharpness and contrast can be tweaked in post-capture editing. Colour rendition is another easily correctable parameter.

      The slight vignetting caused by the lens design was only noticeable when subjects were photographed against a plain background, such as a blue sky or uninterrupted area of flat water. It was easily corrected with editing software.
       The minimum focusing distance of around one metre makes this lens usable for close-ups and the combination of the fixed, f/6.3 aperture and 600mm equivalent focal length lend themselves to creative close-up shooting. If donut-shaped highlights appeal, this lens will deliver in most situations, although unless backgrounds contain a fair bit of contrast, the donuts may not be really obvious.

       The Samyang Reflex f/6.3 300mm ED UMC CS represents excellent value for money for any photographer who wants a super-telephoto lens for a very affordable price.

      Provided you are prepared to work with its limitations (particularly manual focusing and the fixed aperture), this lens will be easy to carry and a great companion for sports and wildlife photography as well as being usable for candid portraits.

      Buyers of this lens will need to be cautious on hot days when atmospheric disturbances caused by heat rising from sun-drenched surfaces will degrade image quality. All long lenses will be equally vulnerable to these conditions.




       Picture angle: 4.2 degrees (on M4/3 camera)
       Minimum aperture: n.a.
       Lens construction: 9 elements in 9 groups (including one ED lens element)
       Lens mounts: Canon M, Sony E, Fujifilm X, M4/3
       Focus drive: Manual focus only
       Minimum focus: 90 cm
       Filter size:   25.5mm  (rear mounted)
       Dimensions (Diameter x L): 72.6 x 64.5 mm
       Weight:  311 grams
       Standard Accessories: Front and end caps plus cylindrical lens hood and soft carrying pouch





       Vignetting, JPEG original.


      Vignetting, converted ORF.RAW file.


      ISO 200, 1/400 second at f/6.3.


      ISO 200, 1/1000 second at f/6.3.


      ISO 200, 1/640 second at f/6.3.


      ISO 200, 1/640 second at f/6.3.


      ISO 200, 1/500 second at f/6.3.


      Strong backlighting; ISO 200, 1/4000 second at f/6.3.


      Candid portrait; ISO 200, 1/800 second at f/6.3.


      Hand-held close-up at closest focus; ISO 400, 1/500 second at f/6.3.


      Hand-held close-up; ISO 200, 1/640 second at f/6.3.


      Hand-held close-up; ISO 400, 1/400 second at f/6.3.


      RRP: AU$449; US$309


      • Build: 8.8
      • Handling: 8.5
      • Image quality: 8.3
      • Versatility: 8.3