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Pentax SMC DA 17 70mm F4 AL IF SDM Review | 54 Data compared

Avg. price in UK: ~£480
Avg. price in US: ~$600
Lens mount: Pentax K
Maximum focal length: 70 mm
Maximum aperture (telephoto end): 4
Optical image stabilization: no
Maximum angle of view: 79 °

Pentax SMC DA 17 70mm F4 AL IF SDM review. Compare 54 technical specifications and user reviews to see how it ranks among camera lenses and if it is worth buying.

6.4

Good

6.5

Good

6.0

Good

7.1
Low-light photography
Score components:
70.0%
9.7
Maximum aperture (telephoto end)
30.0%
1.0
Optical image stabilization
5.0
Travel
Score components:
30.0%
8.6
Lens length
25.0%
7.8
Lens diameter
25.0%
1.0
Weather sealing (splashproof)
20.0%
1.0
Optical image stabilization

Best prices in UK

Best rankings

#368 in Best Wide Angle Lenses
#828 in Best Camera Lenses

Verdict

The Pentax SMC DA 17-70mm f/4 AL [IF] SDM is a versatile APS-C standard zoom lens featuring a constant f/4 maximum aperture and a 17-element, 12-group optical design with two aspherical elements to reduce aberrations. Its key characteristics include a 4.1x zoom ratio (26–107mm equivalent), a minimum focusing distance of 0.28m providing a high 0.31x magnification ratio, and an ultrasonic SDM motor for quiet, smooth autofocus. Main pros include its constant aperture throughout the zoom range, internal focusing (IF) with a non-rotating front element, a Quick-Shift manual focus override, and Super Protect (SP) coating to repel water and dust. However, some users note cons such as soft corner resolution at the 17mm and 70mm ends, occasional autofocus hunting in low light, and reports of SDM motor reliability issues over time.

Technical Specifications of Pentax SMC DA 17 70mm F4 AL IF SDM

Overall score

6.4

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Popularity

What it is: An indicator based on the number of reviews received by the camera lens.

When it matters: When you want to see which camera lenses attract the most buyer attention and review activity.

Mount & Format

1.0

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Lens type

What it is: The optical category that indicates whether the lens is a prime, zoom, macro, fisheye, or another design.

When it matters: When you are choosing between a prime, zoom, macro, or specialty lens for the kind of subjects you shoot.

Importance: LOW

zoom

Lens mount

What it is: The mechanical and electronic interface that determines which cameras the lens can be attached to.

When it matters: When camera compatibility and access to the right lens ecosystem are central to your buying decision.

Importance: LOW

Pentax K

Sensor format coverage

What it is: The largest sensor size the lens is designed to cover without severe vignetting.

When it matters: When you need the lens to fully cover your camera sensor without heavy corner darkening.

Importance: LOW

APS-C

Filter thread size

What it is: The diameter of the front filter thread used for screw-in filters and compatible accessories.

When it matters: When you plan to use screw-in filters such as polarizers, ND filters, or protective glass.

Importance: LOW

67 mm

Teleconverter compatibility

What it is: Whether the lens can be used with compatible teleconverters to extend focal length.

When it matters: When you want to extend reach for wildlife or sports without changing to a different long lens.

Importance: HIGH

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Optics & Aperture

6.6

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Minimum focal length

What it is: The shortest focal length the lens can provide, which determines its widest framing.

When it matters: When wide framing matters for landscapes, interiors, architecture, or travel shots.

Importance: LOW

17 mm

Maximum focal length

What it is: The longest focal length the lens can reach, which determines its telephoto reach.

When it matters: When you need more reach for wildlife, sports, stage events, or distant details.

Importance: LOW

70 mm

Optical zoom

What it is: The ratio between the longest and shortest focal lengths available in the lens zoom range.

When it matters: When you want one lens to cover a broader range of compositions without swapping glass.

Importance: LOW

4.1x

Maximum angle of view

What it is: The widest scene the lens can capture at its shortest focal length.

When it matters: When you need to fit more of a room, skyline, or landscape into the frame.

Importance: LOW

79 °

Minimum angle of view

What it is: The narrowest scene the lens captures at its longest focal length.

When it matters: When you want tighter framing on faraway subjects without moving closer.

Importance: LOW

23 °

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Focus & Controls

6.3

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Focus motor

What it is: The autofocus drive system responsible for moving lens elements into focus.

When it matters: When fast, quiet autofocus matters for video, wildlife, street shots, or moving subjects.

Importance: LOW

SDM

Minimum focus distance

What it is: The shortest distance at which the lens can focus on a subject.

When it matters: When you like shooting details, food, flowers, or products from a very short distance.

Importance: MEDIUM

Maximum reproduction ratio

What it is: The highest magnification the lens can achieve when focusing at its closest distance.

When it matters: When close-up magnification matters for macro work, textures, or small product details.

Importance: MEDIUM

Full-time manual focus

What it is: The ability to adjust focus manually without leaving autofocus mode.

When it matters: When you want to fine-tune focus instantly without switching out of autofocus.

Importance: HIGH

Internal focusing

What it is: A focusing design in which internal elements move while the outer barrel length stays unchanged.

When it matters: When you use polarizers, gimbals, or close-up setups that benefit from a lens that does not extend while focusing.

Importance: HIGH

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Stabilization

4.2

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Optical image stabilization

What it is: A hardware system that shifts optical elements to counteract camera shake and reduce blur.

When it matters: When you want steadier handheld shots and less blur, especially in low light or at longer focal lengths.

Importance: HIGH

Stabilization effectiveness (CIPA stops)

What it is: The rated stabilizer benefit, measured in stops, under CIPA testing standards.

When it matters: When you are comparing stabilized lenses and want to know how much handheld shutter-speed advantage they offer.

Importance: HIGH

?

Build & Handling

7.0

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Weight

What it is: The total mass of the lens, affecting portability and handling balance on the camera body.

When it matters: When you carry a lens all day for travel, hiking, or event coverage and want to keep your kit manageable.

Importance: HIGH

Lens length

What it is: The physical length of the lens body from mount to front edge.

When it matters: When bag space, balance, or front clearance matters in a compact travel or video setup.

Importance: HIGH

Lens diameter

What it is: The widest outer diameter of the lens barrel.

When it matters: When grip comfort, filter size, or fit inside a tight camera bag matters to you.

Importance: MEDIUM

Weather sealing (splashproof)

What it is: Protective sealing intended to resist splashes, dust, and light environmental exposure.

When it matters: When you often shoot outdoors in light rain, dust, or changing conditions.

Importance: HIGH

Metal mount

What it is: A lens mount made of metal rather than plastic for greater durability at the camera connection point.

When it matters: When durability matters because you change lenses often or use heavier gear for work.

Importance: HIGH

?

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Lab Scores

9.0

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DxOMark overall score

What it is: The combined DxOMark lens rating based on lab-tested optical performance.

When it matters: When you want a quick lab-based summary of overall optical performance before comparing lenses in detail.

Importance: HIGH

?

DxOMark sharpness score

What it is: The DxOMark subscore that reflects how much detail the lens can resolve across the frame.

When it matters: When fine detail matters for landscapes, product work, or high-resolution cameras.

Importance: HIGH

?

DxOMark transmission

What it is: The measured light transmission of the lens, expressed as T-stop rather than nominal f-number.

When it matters: When real light loss matters for exposure consistency in studio, cinema, or mixed-lens shoots.

Importance: MEDIUM

?

DxOMark distortion

What it is: The DxOMark metric that measures how much the lens bends straight lines away from their true shape.

When it matters: When straight lines matter in architecture, interiors, copy work, or product photography.

Importance: MEDIUM

?

DxOMark vignetting

What it is: The DxOMark measurement of corner darkening relative to the center of the image.

When it matters: When even corner brightness matters for skies, studio backdrops, or clean product shots.

Importance: MEDIUM

?

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Pentax SMC DA 17 70mm F4 AL IF SDM vs the average camera lens

Why is Pentax SMC DA 17 70mm F4 AL IF SDM better than the average camera lens?

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Has fluorine coating
Pentax SMC DA 17 70mm F4 AL IF SDM has a fluorine coating, the average camera lens does not. 25.5% of camera lenses use a fluorine coating.
What it is: A protective coating on exposed elements that repels water, oil, and dirt for easier cleaning.
When it matters: When you shoot in rain, sea spray, or dusty places and want easier front-element cleaning.
Importance: HIGH
Pentax SMC DA 17 70mm F4 AL IF SDM has a fluorine coating, the average camera lens does not. 25.5% of camera lenses use a fluorine coating.
Has focus distance scale
Pentax SMC DA 17 70mm F4 AL IF SDM has a focus distance scale, the average camera lens does not. 48.6% of camera lenses include a focus distance scale.
What it is: A marked scale that shows the approximate focus distance set on the lens.
When it matters: When you pre-focus manually for street, zone focusing, or repeatable tripod setups.
Importance: MEDIUM
Pentax SMC DA 17 70mm F4 AL IF SDM has a focus distance scale, the average camera lens does not. 48.6% of camera lenses include a focus distance scale.
0.12 x higher maximum reproduction ratio
Pentax SMC DA 17 70mm F4 AL IF SDM has a higher maximum reproduction ratio than the average camera lens (0.3x vs 0.192x). The average lens has a maximum reproduction ratio of 0.192x.
What it is: The highest magnification the lens can achieve when focusing at its closest distance.
When it matters: When close-up magnification matters for macro work, textures, or small product details.
Importance: MEDIUM
Pentax SMC DA 17 70mm F4 AL IF SDM has a higher maximum reproduction ratio than the average camera lens (0.3x vs 0.192x). The average lens has a maximum reproduction ratio of 0.192x.0.31 x vs 0.192 x
Has focus distance scale
Pentax SMC DA 17 70mm F4 AL IF SDM has a focus distance scale, the average camera lens does not. 48.6% of camera lenses include a focus distance scale.
0.12 x higher maximum reproduction ratio
Pentax SMC DA 17 70mm F4 AL IF SDM has a higher maximum reproduction ratio than the average camera lens (0.3x vs 0.192x). The average lens has a maximum reproduction ratio of 0.192x.
Has fluorine coating
Pentax SMC DA 17 70mm F4 AL IF SDM has a fluorine coating, the average camera lens does not. 25.5% of camera lenses use a fluorine coating.

Focus & Controls

Build & Handling

Why is Pentax SMC DA 17 70mm F4 AL IF SDM worse than the average camera lens?

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No rounded blades
Pentax SMC DA 17 70mm F4 AL IF SDM does not use rounded aperture blades, the average camera lens does. 88.8% of camera lenses use rounded aperture blades.
1.2 higher f-number at telephoto end
Pentax SMC DA 17 70mm F4 AL IF SDM has a dimmer maximum telephoto aperture than the average camera lens (f/4 vs f/2.8). The average lens has a maximum telephoto aperture of f/2.8.
2 fewer aperture blades
Pentax SMC DA 17 70mm F4 AL IF SDM has fewer aperture blades than the average camera lens (7 vs 9). The average lens has 9 aperture blades.
1 fewer low-dispersion elements
Pentax SMC DA 17 70mm F4 AL IF SDM has fewer low-dispersion elements than the average camera lens (1 vs 2). The average lens has 2 low-dispersion elements.
Not weather-sealed
Pentax SMC DA 17 70mm F4 AL IF SDM does not support weather sealing, the average camera lens does. 50.3% of camera lenses support weather sealing.
Older release date
Pentax SMC DA 17 70mm F4 AL IF SDM was released earlier than the average camera lens.
Not weather-sealed
Pentax SMC DA 17 70mm F4 AL IF SDM does not support weather sealing, the average camera lens does. 50.3% of camera lenses support weather sealing.
What it is: Protective sealing intended to resist splashes, dust, and light environmental exposure.
When it matters: When you often shoot outdoors in light rain, dust, or changing conditions.
Importance: HIGH
Pentax SMC DA 17 70mm F4 AL IF SDM does not support weather sealing, the average camera lens does. 50.3% of camera lenses support weather sealing.
No rounded blades
Pentax SMC DA 17 70mm F4 AL IF SDM does not use rounded aperture blades, the average camera lens does. 88.8% of camera lenses use rounded aperture blades.
What it is: A blade design that keeps the aperture opening more circular for smoother out-of-focus highlights.
When it matters: When you care about smoother bokeh and rounder highlight shapes in blurred backgrounds.
Importance: HIGH
Pentax SMC DA 17 70mm F4 AL IF SDM does not use rounded aperture blades, the average camera lens does. 88.8% of camera lenses use rounded aperture blades.
1.2 higher f-number at telephoto end
Pentax SMC DA 17 70mm F4 AL IF SDM has a dimmer maximum telephoto aperture than the average camera lens (f/4 vs f/2.8). The average lens has a maximum telephoto aperture of f/2.8.
What it is: The widest aperture available at the long end of the zoom range, affecting light intake and background blur.
When it matters: When you shoot at the long end in low light or want stronger background blur for portraits and sports.
Importance: HIGH
Pentax SMC DA 17 70mm F4 AL IF SDM has a dimmer maximum telephoto aperture than the average camera lens (f/4 vs f/2.8). The average lens has a maximum telephoto aperture of f/2.8.4 vs 2.8
2 fewer aperture blades
Pentax SMC DA 17 70mm F4 AL IF SDM has fewer aperture blades than the average camera lens (7 vs 9). The average lens has 9 aperture blades.
What it is: The number of diaphragm blades that shape the aperture opening and influence blur rendering.
When it matters: When the look of out-of-focus highlights matters in portraits, close-ups, or cinematic video.
Importance: HIGH
Pentax SMC DA 17 70mm F4 AL IF SDM has fewer aperture blades than the average camera lens (7 vs 9). The average lens has 9 aperture blades.7 vs 9
Older release date
Pentax SMC DA 17 70mm F4 AL IF SDM was released earlier than the average camera lens.
What it is: The date when the lens model was first officially introduced.
When it matters: When you prefer a newer optical design with more modern autofocus, coatings, or stabilization features.
Importance: LOW
Pentax SMC DA 17 70mm F4 AL IF SDM was released earlier than the average camera lens.2008 vs 2016
1 fewer low-dispersion elements
Pentax SMC DA 17 70mm F4 AL IF SDM has fewer low-dispersion elements than the average camera lens (1 vs 2). The average lens has 2 low-dispersion elements.
What it is: Optical elements designed to reduce color fringing by controlling how different wavelengths focus.
When it matters: When you want cleaner edges and less color fringing in high-contrast scenes.
Importance: MEDIUM
Pentax SMC DA 17 70mm F4 AL IF SDM has fewer low-dispersion elements than the average camera lens (1 vs 2). The average lens has 2 low-dispersion elements.1 vs 2
35.3% lower user score
Pentax SMC DA 17 70mm F4 AL IF SDM has a lower user score than the average camera lens (5.98 vs 8.091).
What it is: A rating that combines user reviews and the total number of reviews received by the camera lens.
When it matters: When real-world owner satisfaction and review volume matter to your decision.
Pentax SMC DA 17 70mm F4 AL IF SDM has a lower user score than the average camera lens (5.98 vs 8.091).5.98 vs 8.09
6.8% worse value for money
Pentax SMC DA 17 70mm F4 AL IF SDM has a worse value-for-money score than the average camera lens (6.88 vs 7.346).
What it is: An indicator that combines the camera lens's overall rating with its cost.
When it matters: When you want to know how much overall quality you get for the price.
Pentax SMC DA 17 70mm F4 AL IF SDM has a worse value-for-money score than the average camera lens (6.88 vs 7.346).6.88 vs 7.35

Optics & Aperture

Build & Handling

Graphic comparison of Pentax SMC DA 17 70mm F4 AL IF SDM and

Attribute category

Attribute

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Third-party reviews

United Kingdom

United States

(Reviews last updated: July 2026)

What customers like about Pentax SMC DA 17 70mm F4 AL IF SDM?

Versatile focal range for general-purpose shooting and portraits
Constant f/4 maximum aperture across the entire zoom range
Fast, quiet, and smooth SDM autofocus system
Very high build quality with a solid, rock-solid feel
Excellent central sharpness, especially when stopped down slightly
High magnification ratio (0.31x) for close-up photography
Quick-Shift Focus system allows instant manual overrides

What customers dislike about Pentax SMC DA 17 70mm F4 AL IF SDM?

Soft corner/edge performance at certain focal lengths and wide apertures
Noticeable chromatic aberration (fringing) at frame edges
History of reported SDM autofocus motor failures
Heavier and bulkier than some similar standard zoom lenses
External zoom design is harder to seal against dust/moisture compared to internal designs
Narrow manual focus ring that some users find too loose or easy to accidentally shift

Expert reviews

photozone.de

16/12/2008

Summary of the review

Pentax SMC DA 17-70mm f/4 ALGo to product viewer dialog for this item. [IF] SDM - Review / Test Report

The Pentax SMC DA 17-70mm f/4 AL [IF] SDM review on Photozone highlights this standard zoom lens as a highly attractive "sweet spot" option for APS-C format shooters, offering a versatile full-frame equivalent focal range of 25.5–105mm. On the positive side, the lens boasts exceptionally high build quality with tight tolerances, smooth zoom and focus rings, and an internal focusing mechanism that leaves the front element stationary. It features a unique Super Protect (SP) coating to repel environmental dust, water, and grease, alongside a near-silent Supersonic Dynamic Motor (SDM) that enables very fast autofocus speeds due to a notably short focus path. It also provides an instant manual focus override via its Quick-Shift system during Single-Shot AF. However, the review details a few notable drawbacks regarding its design and functionality. A major con stemming from its ultra-short focus path is that manual focusing is extremely difficult, as tiny physical adjustments to the focus ring cause massive, disruptive shifts in focus. Additionally, unlike some of its predecessors, it drops the old mechanical AF drive screw entirely, meaning it lacks autofocus support...

imaging-resource.com

17/08/2009

Summary of the review

Pentax 17-70mm f/4 AL IF SDM SMC DA - Imaging Resource

The Pentax 17-70mm f/4 AL IF SDM SMC DA is a solid upgrade to standard kit lenses, offering a versatile 26-105mm equivalent field of view and a constant f/4 maximum aperture. On the positive side, the lens delivers exceptional center sharpness even when shot wide open, achieving its "tack-sharp" peak performance at 50mm and f/8. Additionally, corner shading (vignetting) is minimal and practically negligible at most settings, while the lens-driven Supersonic Drive Motor (SDM) ensures autofocus operation is incredibly fast, snappy, and nearly silent. However, the lens has several notable drawbacks outside of its optimal focal ranges. Chromatic aberration is a significant issue, exhibiting noticeable purple fringing in high-contrast corners at focal lengths wider than 35mm and when stopping down at the 70mm telephoto end. Geometric distortion is also ever-present, cycling from heavy barrel distortion at wide angles to a messy blend of pincushion and barrel distortion by 33mm. Finally, while the build quality is physically robust, manual focus users will struggle due to an extremely narrow quarter-inch focusing ring and a very short 25-degree focus throw that makes precise...

ephotozine.com

05/01/2016

Summary of the review

SMC Pentax-DA 17-70mm f/4 ED IF SDM Lens Review

The SMC Pentax-DA 17-70mm f/4 ED IF SDM lens, reviewed by ePHOTOzine, offers a versatile 4.1x zoom range with excellent handling, a firm zoom mechanism, and very good central sharpness that peaks at f/5.6. While the lens is noted for its ability to produce good images in the center, edge performance remains only fair, and it produces severe chromatic aberration with, at times, over 2 pixels of edge fringing.

pentaxforums.com

25/04/2026

Summary of the review

SMC Pentax-DA 17-70mm F4 AL [IF] SDM Reviews

The SMC Pentax-DA 17-70mm F4 AL [IF] SDM is regarded on Pentax Forums as a versatile, high-performing walkaround zoom lens for APS-C cameras, featuring excellent sharpness across most of the range, strong contrast, and a useful 0.28-meter minimum focus distance. While praised for its image quality, the lens is plagued by common SDM autofocus motor failures that can disable AF entirely, alongside soft performance at 70mm and limited weather-sealing. For detailed user experiences, visit Pentax Forums.

dxomark.fr

Janvier 2008

Summary of the review

Pentax smc DA 17-70mm F4 AL (IF) SDM - DXOMARK

The Pentax smc DA 17-70mm F4 AL (IF) SDM is an APS-C standard zoom lens launched in January 2008 with an initial indicative price of $480 USD. It features a constant f/4 maximum aperture across its entire 17-70mm focal range, which translates to a highly versatile 35mm equivalent field of view of roughly 26-107mm. Built with 12 groups and 17 lens elements, the lens utilizes a 67mm filter diameter and a Pentax KAF mount (specifically KAF3). For focusing, it is equipped with an internal SDM ultrasonic autofocus motor and features a 7-blade non-circular diaphragm barrel layout. Physically, it measures 93.5mm in length and weighs 485 grams, presenting a relatively substantial but solid build profile for a walkaround zoom lens. Expert and user reviews highlight a distinct balance of performance strengths and structural compromises for this optic. On the pros side, the lens delivers excellent sharpness and contrast in the center of the frame, especially when stopped down slightly to f/5.6 or f/8, alongside highly controlled chromatic aberration and low vignetting for its class. The constant f/4 aperture and versatile 4.1x...

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