Despite being a fixed focal-length (prime) lens Tokina’s 100mm macro appears to have two grip-rings on its barrel.
Tokina AT-X Pro D 100mm f/2.8 Macro
Despite being a fixed focal-length (prime) lens Tokina‘s 100mm macro appears to have two grip-rings on its barrel. The forward ring is used for manual focusing but the rear ring is nothing more than a stylistic trick of the eye. The change from AF to manual is effected by pulling the focusing backwards and the focus limiter is controlled via a quarter-twist knob.
Being a D-series lens, Tokina’s 100mm is suitable for use on both full-frame and APS-C camera bodies. This versatility is common amongst 100mm macro lenses but it is worth restating given the competitively low price that is attached to Tokina’s lens. Non-macro MTF testing revealed a traditional profile with a slight but tolerable weakness at f/2.8, and highly commendable results from f/5.6 to f/11. Even at f/4 and f/16, resolution remained above the critical 0.25 cycles-per-pixel level. In common with other 100mm macro lenses, improvised macro-MTF testing returned similar results at a lower level.
In theory, apertures can be selected down to f/32 but tests show that lens resolution drops off significantly from f/22. This also applies to other 90-105mm macro lenses and the temptation to set very small apertures should be resisted. The problem is that depth-of-field is so small at 1:1 that tiny apertures often seem essential. An alternative solution is to move back slightly and sacrifice image size to gain more depth-of-field.
Automatic focusing, using a Canon 40D body, is quick and reliable but rather noisy; manual focusing, which requires about 240 degrees of rotation to traverse the full range, is silky smooth. The focus ring doesn’t rotate when AF mode is selected but if the reversible lens-hood is stowed care must be taken not to obstruct its forwards and backwards movement. The simplest answer is not to store the hood on the lens.
Overall, Canon and Nikon users would do well to consider this lens as an alternative to their own manufacturers’ 100mm macros.
These are both reasonable all-round curves but there is some weakness wide-open.