A true macro lens for Pentax DSLRs cameras, which can also be used as a relatively fast, normal prime lens.The SMC Pentax DA 35mm f/2.8 Limited macro lens provides excellent image quality and versatility for its price. Designed for the current crop of Pentax DSLR cameras, its effective focal length is equivalent to 52.5mm in the 35mm format. Consequently, as well as being good for close-ups, it's also usable as a general-purpose prime lens since it has roughly the same field of view as the human eye. . . [more]
The SMC Pentax DA 35mm f/2.8 Limited macro lens provides excellent image quality and versatility for its price. Designed for the current crop of Pentax DSLR cameras, its effective focal length is equivalent to 52.5mm in the 35mm format. Consequently, as well as being good for close-ups, it's also usable as a general-purpose prime lens since it has roughly the same field of view as the human eye.
As the first true macro lens carrying the Limited brand, this lens is a landmark product. Lenses with this nomenclature are assembled by hand and, therefore, produced in limited numbers. And the build quality of this lens is superb.
Build and Ergonomics
The lens barrel, hood and cap of this lens are made from high-grade aluminium, which is both relatively lightweight and very robust. One innovative feature of this lens is the built-in lens hood that pulls out from the front of the lens barrel, adding approximately 20 mm to its overall length. The illustrations below show the lens with the hood retracted and extended.
The Pentax SMC DA 35mm f/2.8 Limited macro lens with the built-in lens hood retracted and extended. (Source: Pentax.)
The optical design of this lens is straightforward, with nine elements in eight groups. A proprietary SP (Super Protect) coating that repels dust, water and grease has been applied to the front element making it easier to keep clean.
A flock-lined aluminium cap fits over the lens hood, protecting the front element, which is slightly recessed into the lens barrel. The inner side of the barrel slopes in towards the front element in a tight series of matte black rings.
The lens barrel itself is in three parts. The outer barrel is fixed to the lens mount and ends at the cut-out for the distance scale, behind which is a depth-of-field scale that covers apertures between f/11 and f/22.
A green anodised ring runs around the outer barrel just behind the depth-of-field scale but plays no part in the operation of the lens. The inner barrel contains the optical elements.
The distance scale is engraved in metres and feet on the middle barrel, which also carries the focusing ring. The focusing ring is approximately 10 mm wide and has twin, ribbed grip rings that are secure and comfortable to hold. The front element does not rotate during focusing but the inner barrel extends by about 26 mm when you move from infinity focus to the closest focusing distance (0.139 metres).
Autofocusing is driven by a slotted drive screw mechanism controlled by the camera. We found it relatively fast but not exactly quiet on the K-7 camera body used for our tests.
The main weakness in this lens is in its focusing system - and it's a result of combining extreme close focusing with infinity focus capabilities. To cover this range, the focusing ring must be turned through approximately 140 degrees.
Pentax has included a Quick-Shift mechanism that allows manual focusing before or after autofocusing. But it's only usable in AF.S (single-shot) mode. We found it took a little more than two seconds for the lens to go from the infinity setting to the closest focus using the test camera's AF system.
This can have some practical consequences. Frequently, when you try to shift between macro and normal shooting, the AF system will hunt wildly and may fail to find focus. Unfortunately, there's no focus limiter to constrain how much the lens elements can be moved.
You can get around this to some degree by using the Quick-Shift mechanism to focus the lens manually, leaving the AF system to provide precise focusing. Another option is to use manual focus and shift the camera until the subject is sharp. But this isn't easy if the camera is hand-held or the subject is moving - even quite slowly.
On the whole, we think most potential purchasers will be able to live with this issue, given the other advantages this lens provides. Once you know what to expect, it is easy to minimise hunting and manual focusing with this lens is relatively easy at close distances.
Imatest showed the review lens capable of high resolution, particularly in the centre of the field of view, although resolution at the widest apertures was disappointing. Edge softening was found throughout its aperture range but was greatest at wider apertures.
Diffraction kicked in at around f/8, after which there was a sharp drop in resolution. The highest resolution was obtained at f/5, as shown in the graph of our Imatest tests below.
Lateral chromatic aberration remained mainly within the 'low' band, drifting into the 'moderate' band at aperture settings of f/8 and smaller. In the graph of our Imatest test results below, the red line marks the upper edge of the 'negligible' CA band, while the green line represents the lower edge of the 'moderate' band.
Coloured fringing was visible in some shots taken with smaller apertures but not detected within the macro focusing range. Distortion was also minimal and barely visible in test shots. The review lens also showed minimal vignetting at f/2.8.
Flare and backlighting were handled extremely well. We found no evidence of veiling flare in test shots, even when the light source was within the frame. Flare-related artefacts due to internal reflections of the aperture diaphragm were also relatively rare.
Bokeh was variable. At close-up and macro distances, it was generally smooth and attractive. However, with subjects further than about 1.5 metres from the camera it could be a little choppy.
The overall strength of this lens is for close-up shots. However, it can be used for portraiture, particularly if you move in close to the subject and isolate the subject from the background. But it's not a good lens for shooting landscapes.
Buy this lens if:
- You require a true macro lens that can also be used on Pentax DLSR cameras for normal photography.
- You require superior build quality and imaging performance at an affordable price.
- You enjoy contre-jour photography.
Don't buy this lens if:
- You need a lens for landscape photography.
(based on JPEG files from the Pentax K-7 DSLR)
Vignetting at f/2.8.
Rectilinear distortion; ISO 100, 1/1000 second at f/3.5.
Close (non-macro range) focusing; ISO 400, 1/100 second at f/11.
1:1 reproduction ratio; ISO 800, 1/200 second at f/11.
Backlit subject (non-macro range); ISO 200, 1/250 second at f/8.
Crop from the above image, enlarged to 100% to show coloured fringing.
Flare resistance at 1:1 reproduction ratio; ISO 100, 1/640 second at f/8.
Backlit subject; ISO 100, 1/400 second at f/9.
Very shallow depth-of-field at f/2.8; ISO 400, 1/200 second.
The same subject photographed at f/8; ISO 800, 1/50 second.
1:1 reproduction ratio; ISO 800, 1/400 second at f/2.8.
ISO 100, 1/40 second at f/2.8.
ISO 100, 1/15 second at f/2.8.
ISO 800, 1/400 second at f/5.
ISO 800, 1/13 second at f/5.6.
Edge softening; ISO 800, 1/800 second at f/5.
Picture angle: 44 degrees
Minimum aperture: f/22
Lens construction: 9 elements in 8 groups
Lens mounts: Pentax KAF
Diaphragm Blades: 9
Focus drive: Slotted drive screw mechanism
Minimum focus: 139 mm
Maximum magnification: 1:1
Filter size: 49 mm
Dimensions (Diameter x L):
Weight: 215 grams
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Rating (out of 10):
- Build: 9.5
- Handling: 8.5
- Image quality: 8.5
- Versatility: 8.8
- OVERALL: 9.0