Reflex 300mm f/6.3 MF Macro £279
Affordable 300mm catadioptric (gla ss and mirror) lens for Micro-Four
First impressions of Tokina’s Reflex 300mm f/6.3 are very good. The lens has a simple design that devotes the majority of its all-metal barrel to a generous manual focusing ring with object distances marked in both metres and feet. There are no other switches or controls of any sort. Focusing is a little stiff, and a more prominent grip would doubtless make rotation easier, but the movement feels very smooth.
Most lenses provide about 90° of rotation on the manual focusing ring but Tokina’s mirror lens requires around three times as much movement to go from infinity to its minimum object distance of 0.8m (at which range it is capable of capturing half-life-size images). The reason for this is a finer thread on the MF ring, which is itself needed because the folded optical path within a mirror lens means that very small movements produce a large change in focus. Even so, focusing is tricky not only because of the responsiveness issue but also because the unusual appearance of out-of-focus areas makes visual assessment harder.
The centre of the front element is obscured by a black disk, which is the external side of an internal mirror that reflects the light inside the lens to achieve a shorter physical length than would otherwise be the case. As a result, out-of-focus «points» have a doughnut shape that echoes the annular appearance of the front element of the lens. Some people like this effect whereas others feel it looks unnatural.
One of the defining characteristics of mirror lenses is their fixed aperture and in the days of film photography the only way to adjust the exposure was by using neutral-density filters. Things are a little easier in the digital age and Tokina’s instruction sheet advises users to set Auto-ISO so that different exposure times can be accommodated using different recording sensitivities.
Nevertheless, MTF testing was confined to a single aperture and was conducted using the minimum ISO setting (200 in this case): the results were disappointing, never exceeding 0.14 cycles-per-pixel. The instruction book also advises disabling MF-Assist. This is a very sensible recommendation because the huge «reach» of this lens means further magnification of the image field renders most subjects unrecognisable.
Some of the 300mm’s images were distinctly soft (partly owing to the difficulty in focusing) and lacking in contrast (a common observation for mirror lenses). Successful use was characterised by static subjects illuminated by bright, non-frontal lighting on a clear day. The absence of in-viewfinder image stabilisation made life especially awkward but activation of AF-with-MF mode at least meant that focusing confirmation was visible in the viewfinder (and also indicated audibly).
Given its sub-0.25-cycles-per-pixel MTF figure and the fact that this result effectively applies right across the aperture range, Tokina’s mirror lens has only achieved an overall score of 11/20 for image quality.
It also lacks image stabilisation and automatic focusing. On the other hand, it has great build quality and an amazing reach that allows it to capture extremely distant objects. Tokina’s Reflex 300mm f/6.3 mirror lens isn’t easy to use but it is still worthy of attention at such an affordable price.