Pentax 100mm f/2.8 WR
SMC Pentax 100mm f/2.8 D FA WR (35mm and APC-S coverage, 49mm filters, 11.865 oz./336.3g, 1:1 macro, 1'/0.3m close focus, about $550). enlarge. I got mine at B&H; I'd also get it at Adorama or at Amazon.
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This SMC Pentax 100mm f/2.8 D FA WR is the world's smallest and lightest 100mm macro lens, and it also has superb optics as we expect in any 100mm macro lens.
It makes a great general-purpose telephoto and can focus close enough to fill the frame with something smaller than a postage stamp.
You may grab the ring at any time for instant manual-focus override. Pentax calls this "Quick Shift."
Formats & Compatibility
This 100/2.8 D FA WR lens is optimized for full-frame, and of course works great on all Pentax digital SLRs.
It mounts, meters, manually focuses and shoots on Pentax's classic 35mm cameras, but since it has no aperture ring, it always meters and shoots at f/22 on my K1000. Viewing and focussing is wide open, but you have to imagine that it's always set to f/22.
Pentax calls this the SMC PENTAX 100mm f/2.8 D FA WR.
SMC means Super Multi Coating; all Pentax lenses have been SMC since the 1970s.
D means it works on Pentax digital cameras.
FA means it covers full frame.
WR means weather resistant.
9 elements in 8 groups.
The rear groups are fixed, while the front section extends to focus more closely.
Multicoated, branded as both "Super Multi Coating" (SMC).
Pentax EF 100mm f/2.8 D FA WR at f/22.
8 rounded blades.
Stops down to f/32.
There is no mechanical or electronic meter compensation as focussed more closely; the effective aperture becomes much smaller as focussed more closely.
Focal Length top
On Pentax digital cameras it will see angles-of-view similar to what a 150mm lens would see on a 35mm camera.
Angle of View
16º diagonal on Pentax digital.
24.5º diagonal full-frame.
Close Focus top
1 foot (0.3m) from the image plane.
Maximum Reproduction Ratio top
1:1 (1.0x) at close-focus distance.
Hard Infinity Focus Stop? top
You have to let the AF system focus for you at infinity.
Focus Scale top
Depth-of-Field Scale top
Infra-Red Focus Index top
Filter Thread top
Pentax 100mm f/2.8 D FA WR with hood at 1:1.
The plastic bayonet hood is included.
The lens extends at 1:1, so that the hood doesn't do much. This is good, because otherwise the hood would block the light on your subject.
Pentax 100mm f/2.8 D FA WR with caps and reversed hood.
Nice 49mm front cap.
Cheap push-on rear cap, not the usual Pentax bayonet rear cap.
S80-120 case, Pentax 100mm f/2.8 D FA WR.
The case is a padded nylon pouch, which is perfect for throwing in a backpack, trunk or glovebox.
Pentax specifies 2.5" (63.5mm) diameter by 3.2" (81.3mm) long.
11.865 oz. (336.3 g) actual measured weight.
Pentax specifies 12 oz. (340 g).
Pentax Model Number top
Price, USA top
2015 July: $550.
Box, Pentax 100mm f/2.8 D FA WR.
SMC Pentax 100mm f/2.8 D FA WR. enlarge.
The Pentax 100mm f/2.8 D FA WR is sharp, small, inexpensive, handles very well and is reasonably well made.
Autofocus is via 1980s technology: a motor in the body connected via a screw coupling.
AF is pretty fast as mechanically-autofocussed 100mm lenses go. It may be noisier than Canon and Nikon's electronic-autofocussing lenses, but at least it's about as fast.
Just grab the ring at any time the camera isn't trying to autofocus.
The ring turns during autofocus; keep your fingers away until it stops.
Manual focus is easy; just turn the ring.
Bokeh, the quality of out-of-focus areas as opposed to the degree of defocus, is good and neutral.
Focus breathing (the image changing size as focused) is mostly of interest to cinematographers who don't want the image changing size ("breathing") as the lens is focused among different subjects.
The image from the Pentax 100mm f/2.8 D FA WR gets larger as focused more closely.
The Pentax 100mm f/2.8 D FA WR has no visible or measurable distortion, even uncorrected.
This is superb, and as we expect for a macro lens.
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Pentax EF 100mm f/2.8 D FA WR at 1:1.
This little lens handles great, except for the focus ring turning by itself during autofocus. As soon as autofocus stops, you can grab the ring for instant manual focus.
There's no outside mounting index dot; you have to squint and look for the red dot hidden on the mount. It's obvious here in this close-up and well-lit studio shot, but usually invisible in the field.
There's no visible falloff, even at f/2.8, on APS-C digital. This is excellent.
The plastic 49mm filter threads are big enough that quite a few stacked filters won't cause any vignetting on full-frame or digital.
There is no need for expensive "thin" filters.
There are no visible lateral color fringes at 24MP, but there is some minor purple fringing visible on Pentax K3 II.
This is excellent performance, as expected for a macro lens.
It does have spherochromatism, which is a different aberration.
It gets to life-size at the sensor.
Since an APS-C sensor is 16 x 24mm, your close-ups can fill the screen with something as small as 16 x 24mm or 0.6 x 0.9:"
Of course it's super-sharp. Sharpness in macro shots depends much more on your technique than the lens.
Pentax EF 100mm f/2.8 D FA WR. bigger.
The Pentax 100mm f/2.8 IS is reasonably well made with metal on the outside with engraved markings, and a plastic front barrel and filter thread.
Engraved into the focus ring.
Engraved into anodized aluminum.
I see what looks like mostly metal.
Moisture seal at mount
Mostly engraved and filled with paint.
Engraved into focus ring and filled with white paint.
Noises When Shaken
Image sharpness depends more on you than your lens, and lens sharpness doesn't mean much to good photographers. It's the least skilled hobbyists who waste the most time blaming fuzzy pictures on their lenses, while real shooters know that few photos ever use all the sharpness of which their lenses are capable due to subject motion and the fact that real subjects are rarely perfectly flat.
The Pentax 100 D FA WR is super-sharp at every aperture, as most macro lenses have been for many decades.
It's sharp way past the corners on digital because this is a full-frame lens.
Of course all lenses get much softer at f/22 and f/32 due to diffraction, and usually f/22 to f/32 is where we shoot them for serious macro shots of 3D objects just to get any depth-of-field! That's why for real macro shots, lens quality doesn't matter much.
Spherochromatism, misnamed "color bokeh" by laymen, is when out-of-focus highlights take on color fringes at full aperture.
Spherochromatism is a completely different aberration from lateral color fringes.
I see moderate spherochromatism; background highlights will have slight green fringes and foreground highlights will have magenta fringes. If anything it helps bokeh for outdoor portraits, but you will see it if you're shooting at larger apertures.
This is a great little lens for any Pentax. It's small, sharp, fast, light and tough.
It offers essentially perfect optical performance and is the world's smallest and lightest 100mm macro lens.
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06 July 2015