Sigma 105mm f/2.8 EX DG Macro (Nikon F)

Sharpness is the whole pitch here, and Sigma delivered it. Wide open at f/2.8 the 105mm EX DG Macro already resolves fine detail across the center, and by f/5.6 to f/8 it is biting edge to edge on a full 35mm frame. People bought this lens to put a dewdrop or an insect eye under the loupe and find that the grain of the film gave out before the lens did. That reputation held up against Nikon's own 105mm Micro and Tamron's 90mm, which were the two lenses anyone cross-shopped against it.

The EX badge was Sigma's pro tier in this era. DG marked it as optimized for digital bodies, with coatings tuned to cut reflections bouncing off a sensor stack, which on film just means clean corners and well controlled vignetting. This is not the later internal-focus OS HSM version, so the barrel actually extends as you rack toward 1:1, growing noticeably longer at life size before it pulls back in for distant subjects. Working distance at full magnification is still generous for a 105, which is why bug shooters and product people preferred it over a 50 or 60mm macro that makes you crowd the subject and cast your own shadow.

Bokeh is the honest weakness. It is a macro lens first, optimized for flat-field sharpness, so the out-of-focus rendering is competent rather than beautiful. Specular highlights render cleanly enough but without much character, and at portrait distances the background blur is smooth but a little clinical next to a dedicated 105mm portrait optic. It works fine as a short telephoto for headshots, and plenty of shooters used it that way, but nobody confuses its drawing with a Sonnar.

Flare control is good, contrast is high, and the rendering leans neutral and modern, which is exactly what you want when you are documenting an object and need the color to be true rather than flattering. Field curvature is well corrected, an asset for copy work and flat-art reproduction. The minimum aperture goes all the way to f/45, which sounds useful for depth at 1:1 but in practice softens everything to mush from diffraction. f/11 to f/16 is the real working range for macro.

Here is the metering note that matters for a 1:1 macro on a film body. As you focus closer and the barrel racks out, the effective optical length grows and the light reaching the film drops, sometimes by two full stops at life size. Your handheld meter and the lens markings know nothing about that loss. Feed the magnification into Zone Light Meter and it computes the bellows (extension) factor for you, so the reading you act on is the real one at the film plane instead of the open-aperture fiction.

Today these turn up cheap on the used market, often under a hundred and fifty dollars in Nikon F mount, and they remain one of the best value-per-dollar macro lenses you can put on a film SLR. The trade is build and bokeh, not sharpness. If you want one lens for close-up work that occasionally moonlights as a portrait tele, it still earns the bag space.