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SMC Pentax-DA 17-70mm F4 AL [IF] SDM Review RSS Feed

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

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55 303,976 Sun July 21, 2019
Recommended By Average Price Average User Rating
75% of reviewers $460.93 7.59
SMC Pentax-DA 17-70mm F4 AL [IF] SDM

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

This wide-angle to normal zoom incorporates the new Pentax KAF3 mount, which uses SDM focusing technology but has no mechanical focusing shaft. Thus, it can only autofocus on Pentax digital SLRs that support SDM, including the K100D Super, K200D, K10D, K20D, and later models. On older cameras you must focus manually.

SMC Pentax-DA 17-70mm F4 AL [IF] SDM
©, sharable with attribution
Image Format
Lens Mount
Pentax K
Aperture Ring
Automatic, 7 blades
17 elements, 12 groups
Mount Variant
Check camera compatibility
Max. Aperture
Min. Aperture
AF (in-lens motor)
Min. Focus
28 cm
Max. Magnification
Filter Size
67 mm
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 79-23 ° / 70-19 °
PH-RBM 67 mm
Lens Cap
Weather Sealing
Other Features
Diam x Length
75 x 93.5 mm (3 x 3.7 in.)
485 g (17.1 oz.)
Production Years
2008 to 2020
$499 USD current price
Engraved Name
smc PENTAX-DA 1:4 17-70mm AL [IF] SDM
Product Code
User reviews
In-depth review
Unofficial Full-Frame Compatibility Tests by Pentax Forums
☆☆☆ No coverage at any setting
Show details
Lens mount has a rubber gasket, though the lens is not otherwise weather sealed.
Two aspherical elements.
No autofocus on older bodies (*istD series, K100D, K110D, and film).

Supersonic AutofocusQuick ShiftInternal FocusingAutomatic ApertureAPS-C Digital OnlyDiscontinued
Purchase: Buy the SMC Pentax-DA 17-70mm F4 AL [IF] SDM
In-Depth Review: Read our SMC Pentax-DA 17-70mm F4 AL [IF] SDM in-depth review!
Sample Photos: View Sample Photos
Price History:

Add Review of SMC Pentax-DA 17-70mm F4 AL [IF] SDM Buy the SMC Pentax-DA 17-70mm F4 AL [IF] SDM
Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-15 of 55
New Member

Registered: April, 2015
Posts: 11

1 user found this helpful
Review Date: July 21, 2019 Not Recommended | Price: $291.00 | Rating: 4 

Pros: Silent AF.
Cons: Not sharp enough. Sigma 17-70mm f/2.8-4.5 is far better.
Sharpness: 4    Aberrations: 8    Bokeh: 8    Autofocus: 10    Handling: 9    Value: 1    New or Used: New    Camera Used: K-30   

Sigma 17-70mm f/2.8-4.5 is far better.

Registered: April, 2016
Location: Tirana
Posts: 769

2 users found this helpful
Review Date: November 30, 2018 Recommended | Rating: 9 

Pros: sharp, contrasty, colorful
Cons: AF over 50mm, focus ring range is too small
Sharpness: 9    Aberrations: 9    Bokeh: 9    Autofocus: 7    Handling: 9    Value: 7    New or Used: Used    Camera Used: k-30   

I got this lens on a bargain, about 60 euros, from somebody that dindnt know(obviously) what it was worth. ever since i bought it, i have never put the kit 18-55 wr back on the camera, except for when its rainy, too bad this lens doesnt come with WR. I am fairly satisfied with the autofocus from 17-50mm and from 50-70mm it is a fingers crossed situation. what it catches the focus it does so precisely, but when it doesnt it just wont lock on it. you can try and get it yourself by using the focus ring but since the travel of the ring is only about 60 degrees you have to be precise to the 10th of the millimeter. Other than this this is the best rendering all purpose zoom i have had to date. Image quality feels professional. and the range is very useful. That 1 mm on the wide range is quite relevant differently from assumptions, and the 70mm is very good for portraits...when the focus does lock in, that is. Flare and CA on the optimal side.
Junior Member

Registered: February, 2012
Location: Belluno, Italy
Posts: 34
Review Date: January 22, 2017 Recommended | Price: $400.00 | Rating: 9 

Pros: Focal range, autofocus, sharpness
Cons: some flare
Sharpness: 9    Aberrations: 7    Bokeh: 7    Autofocus: 9    Handling: 9    Value: 9    New or Used: Used    Camera Used: K-5   

I have taken any kind of photo with this lens and it's always a great result! The AF is really fast, good and silent... Maybe a lucky piece
Senior Member

Registered: February, 2015
Posts: 175

3 users found this helpful
Review Date: January 14, 2017 Recommended | Price: $250.00 | Rating: 8 

Pros: sharpness, colour rendition, contrast, large aperture at 70
Cons: focus ring too loose
Sharpness: 9    Aberrations: 9    Bokeh: 9    Autofocus: 6    Handling: 7    Value: 8    New or Used: Used    Camera Used: K3 and K30   

I bought this lens in 2014, second hand from my son who had bought it bundled with K5 in 2011.
I never had trouble with the SDM.

IMO, the lens is sharp at all focal lengths but, wide open at f4, in the 50-70mm range, the depth of field is shallow and the AF needs some training, as the focus ring is too loose and any shake of the camera once focus is locked can move the focus.
Once you are used to it, you just be careful and then it is OK.

The AF is silent, fast and, on K3, doesnt hunt, even in very dim light. On K30, as the focus point are much wider and the AF software is less efficient, it may hunt in very dim light or when the camera doesnt know what to focus on (= busy background, interfering grass or twigs, or very low contrast target). I noticed the same difference in AF performance on most lenses.

The overall IQ, even fully open, is excellent for a zoom lens as regards sharpness, contrast, distorsion and colours.

F4 at the long end already allows some subject isolation, with a nice bokeh.

The 17-70 is a big lens, with much glass. Thus, when I need to go light and/or a more polyvalent lens with a longer focal range, when traveling for instance, I will use the DA 18-135, which is much more compact and lighter, is WR and has better AF performance.

I choose the 17-70 for landscapes and urban scenes when I know I wont need long telephoto, size and weight is not a problem, and I will have time to care about the AF. Also when looking for better IQ when shooting in low light, as the lens is good fully open, whereas my DA 18-135, though only 0,5 stop slower at the long end, needs to be stopped down to deliver a comparable IQ.

Of course the IQ of my primes is much better; DA21, DA35 macro, DA40 and DA70 are sharper; DA15 is wider and has an outstanding contrast and flare resistance, like DA21 and DA40; DA 35 macro, DA35 f2.4, DA40 XS and DA70, and even the fim era FA50 f1.7 are obviously sharper and brighter but the 17-70 delivers a very nice IQ with the convenience of a zoom.

Edit 18/11/2019:

  1. the main quality of this lens is the way it handles contrast and microcontrast: when compared to the lighter, more compact and more convenient DA18-135. DA 17-70 rendition is closer to what my DA limited prime lenses deliver. And of course DA17-70 is obviously sharper across the frame at the long end than the 18-135 at the same focal length.
  2. the main IQ issue with this lens is the loose focus ring and its very short travel, coupled with the Quickshift continuous manual focus override.
  3. but IMO the main limitation is its size and weight
New Member

Registered: January, 2012
Location: Budapest
Posts: 13

1 user found this helpful
Review Date: September 12, 2016 Not Recommended | Rating: 7 

Pros: Optically the best Pentax standard zoom for my taste
Cons: SDM; AF. wobbling at open zoom
Sharpness: 10    Aberrations: 10    Bokeh: 9    Autofocus: 2    Handling: 4    Value: 7    New or Used: Used    Camera Used: K-5   

This is optically the best Pentax standard zoom I have ever seen.
Because of the underdsized SDM and poor AF I do not recommend.

It would have sense to update this lens with WR and DC motor. This would be my choice and I would highly recommend it after that. Unlike the excellent 16-85 this is parfocal, having distance scale and constant F4 aperture (I need three of them). So I can imagine easily both in the Pentax line up in spite of the similar zoom range. (((Now my standard zoom is still the 16-45.)))

RICOH please make this one for me:
SMC Pentax-DA 17-70mm F4 AL [IF] DC WR
Forum Member

Registered: January, 2014
Location: Bydgoszcz
Posts: 98

1 user found this helpful
Review Date: October 6, 2015 Not Recommended | Price: $600.00 | Rating: 5 

Pros: great contrast and color rendition
Cons: autofocus
Sharpness: 7    Aberrations: 3    Bokeh: 6    Autofocus: 1    Handling: 5    Value: 5    New or Used: New    Camera Used: K-3   

The color rendition and contrast of the lens is very good. Also the the range of having a zoom with 17 and 70 at the end is perfect for walk around zoom. Anyway the auto focus (SDM) is a horror. Mine lens is from early productions. Auto focus worked good for 2 years then it started to have a problems, specially focusing at the end of the zoom range. Then it stopped working at all. I sent it to pentax service and they decided to replace the sdm motor inside. After a year the problem came again and now I use the lenses manually, without autofocus. I gave the lens to non pentax service just to see what might be the problem with the sdm motor drive and I received an answer that the whole drive is too small for this big lens to move it properly.

Here are some shots I did with this lens. [url=""]
Senior Member

Registered: May, 2011
Location: Hanoi
Posts: 213
Review Date: August 27, 2015 Recommended | Price: $400.00 | Rating: N/A 

Pros: warm color
Cons: autofocus, non WR
Sharpness: 8    Aberrations: 8    Bokeh: 8    Autofocus: 7    Handling: 9    Value: 9    New or Used: Used    Camera Used: Pentax K10D   

The speed of autofocus is really the matter, sometimes you would be disapointed while hunting action appears.

celebration, on Flickr
New Member

Registered: March, 2015
Posts: 5

1 user found this helpful
Review Date: August 18, 2015 Recommended | Price: $300.00 | Rating: 9 

Pros: Image quality
Cons: AF above 50 mm
Sharpness: 10    Aberrations: 9    Bokeh: 9    Autofocus: 7    Handling: 8    Value: 9    New or Used: Used    Camera Used: Pentax k-30   

In my eyes the primary competitor of this lens in the Pentax line-up is the 18-135. I had a 18-135 at the time I bought the 17-70 second hand. It was the reviews and user opinions which made me decide to give the 17-70 a try. Indeed the 17-70 turned out to be a much better performer IQ-wise. I really like the uniformly solid resolution of this lens. Pictures taken with the 18-135 often seem rude and unprofessional when compared to the 17-70. The price is the narrower focal range. Unfortunately, I can confirm the AF problems at the long end (above about 50 mm). If the camera finds focus, the image is not blurred, but often the AF is just walking up and down and finally gives it up. Altogether I find it a good choice if you want a standard zoom with professionally looking image quality.

Here is a selection of pictures I took with this lens.

Registered: February, 2015
Posts: 11,789
Review Date: April 6, 2015 Not Recommended | Price: $450.00 | Rating: 8 

Pros: Fcoal range, color saturation, sharpness, f4, fast silent AF
Cons: Blurred images due to AF accuracy between 50mm and 70mm
Sharpness: 9    Aberrations: 7    Bokeh: 9    Autofocus: 7    Handling: 9    Value: 8    New or Used: New    Camera Used: K200D,K-5,K-3   

This lens deserve to be praised, BUT, the corrupted AF above 50mm is not acceptable. I missed memorable shots with this lens, the shots look like blurred worse than it it were taken with low quality point and shot camera. Other than that, this lens is convenient, the AF is decently fast and very silent, and the lens is capable of delivering good quality photographs.

- focal range
- f4 constant
- image quality, contrast
- silent focusing
- 67mm thread

- Lens/hood wobble
- Missed AF above 50mm

Would I recommend this lens? If you know how to repair the AF issue yourself, yes, and you can find cheap second hand DA17-70. Otherwise, I'd not recommend using the DA17-70 from 50mm to 70mm and in this case, there are other 16/17/&8-50 alternative from Pentax and third parties.
Forum Member

Registered: October, 2014
Posts: 85

1 user found this helpful
Review Date: November 18, 2014 Not Recommended | Price: $350.00 | Rating: 6 

Pros: very good sharpness, constant maximum aperture F/4, wide focal lengths range
Cons: SDM problems
Sharpness: 9    Aberrations: 7    Bokeh: 6    Autofocus: 3    Handling: 7    Value: 3    New or Used: New    Camera Used: Pentax K-5 IIs   

The smc Pentax-DA 17-70mm F/4 AL IF SDM is a compromise model which does not make much of an impression. Certainly the manufacturer tried to develop a convenient lens with a fairly wide range of focal lengths and a constant maximum relative aperture F/4 and substantially very good sharpness. But in reality the lens is not sharp enough near the 70mm, has SDM motor problem which affects the accuracy of autofocus and the bokeh is neutral and leaves something more to desire.

If the Pentax 18-55 kit lens became a limitation for you and you would like to purchase a pro lens, it makes sense to buy the smc Pentax-DA* 16-50mm F/2.8 ED AL [IF] SDM and not to make compromises. Believe me it's wise to purchase a high quality pro lens and enjoy all the benefits of such lens (outstanding image quality, excellent build quality, dustproof and water resistant body, ultrasonic motor) than to buy a budget lens which you will be soon trying to sell on a secondary market.

My review of my copy of the lens with shots at different focal lengths and apertures:
Site Supporter

Registered: February, 2010
Location: Northern Michigan
Posts: 5,992

5 users found this helpful
Review Date: May 5, 2014 Recommended | Price: $365.00 | Rating: 9 

Pros: Loads of microcontrast, fairly sharp, decent color rendition
Cons: SDM and other AF related horrors
Sharpness: 9    Aberrations: 9    Bokeh: 8    Autofocus: 5    Handling: 8    Value: 7    New or Used: Used    Camera Used: Pentax K-5iis   

Optically, this is a very good standard zoom lens. For mid-aperture shooting, perhaps only the DA* 16-50 can beat it. The lens is fairly sharp and impressively contrasty. Color rendition is good, but not quite at the level of limited or star glass, or of the DA 12-24 and DA 10-17. It's color rendering is a tad on the warm side, closer to Pentax telephoto glass (like the DFA 100 macro and DA* 300) than Pentax wide angle glass.

It's very hard to make a zoom lens with a range as long as 17mm to 70mm consistently good, edge to edge, at all focal lengths. Pentax came close to achieving that standard in the DA 17-70. It's very good edge to edge throughout most of it's range. But it does give up some resolution at the long end. I haven't tested the lens extensively to discover exactly where resolution begins to tail off. It still seems pretty good at 50mm, and maybe at 60mm as well. But at 70mm it's not as good, particularly at longer distances, regardless of whether one stops down or not.

The main problem with the lens, and probably the reason why it's generally rating is, compared to other, optically inferior standard zoom lenses, is because of the SDM horrors associated with it, along with other AF issues that have plagued the lens. I've used two copies the lens. The first copy manifested extremely serious AF issues, resulting from the inability of the lens to report to the camera the correct focal length. Regardless of which focal length was actually used, the lens recorded the focal length as 43mm. This essentially incapacitated the AF at most focal lengths. The SDM worked worked in the sense that it was not the source of the problem; but the lens, confused because of the misreported focal length, floundered like a beached whale, moving with little purpose and even less efficacy. The replacement version, however, has worked without a flaw. It will be interesting to discover how long the SDM horror functions before its inevitably decline and death.

Some samples of the lens, sans recorded focal length:


Registered: November, 2012
Location: Newark, Delaware
Posts: 1,034
Review Date: November 12, 2013 Not Recommended | Price: $450.00 | Rating: 4 

Pros: Versatility, sharp for a zoom, build quality
Cons: erratic autofocus, large & heavy
Sharpness: 9    Aberrations: 8    Bokeh: 8    Autofocus: 1    Handling: 7    Value: 8    New or Used: New    Camera Used: K10D and K5   

If this lens were 17 to 50, I would probably give it a 9. The issue I have with this lens is autofocus of distant images from 50 to 70 mm. I don't know why this is but on both my K10D and K5 I have the same issue with this lens. Zoom wider than 50mm and the autofocus is perfect, quick and accurate but above 50 mm on a distant subject, it sometimes just cannot get a fix on a subject near infinity and just does not autofocus reliably. Close in subjects autofocus fine from 17 mm right up to 70 mm. This is where this lens shines, close up pictures look almost as good as what I get with 15 mm and 40 mm limiteds. If anyone has any suggestions how to get around this, it would be appreciated. I have noticed one other quirk with the SDM in this lens is it does not like to sit around too long without being used. If I do not use it for 1 or 2 months or longer I find I will have to manual focus a picture of two before the SDM gets going, then it is fine. Overall a good to very good lens when I need a quiet versatile lens. Like many other users, it has some SDM usability issues but still after 4 years never needed a repair. EDIT: SDM motor dead this lens is now a paperweight and has been replaced with the 16-85
Veteran Member

Registered: August, 2010
Location: Houston, Texas
Posts: 824
Review Date: October 5, 2013 Recommended | Price: $330.00 | Rating: 9 

Pros: Colors!, Sharp, Great range, Constant aperture
Cons: Harder to focus manually, Fails to lock focus infrequently
Sharpness: 9    Aberrations: 10    Bokeh: 8    Autofocus: 7    Handling: 9    Value: 9    New or Used: New    Camera Used: K100d Super   

I bought the lens used from another forum member here and used it on a K100d Super until very recently when I bought a K-5. The lens SDM worked well on the camera, as advertised. Before this lens, I used the 18-55 II, which is quite good, but this one is well worth the extra cost. The sharpness is better across a broader range, but the most noticeable change is the rich, vibrant colors. The colors are richer with this lens than they were with a circ polarizer on the II. The f/4 aperture has been sufficient for most situations and I have appreciated that it is a constant aperture, something that I have not liked in my other lenses. So I have been very happy with my purchase and it has lived up to my expectations.

If there is a characteristic that is "different" than expected, it is the lens will sometimes fail to lock focus in some circumstances. I cannot pinpoint the scene or lighting conditions, or the lens settings when it does this, and it is not frequent, but it does occur. While this has not bothered me much at all, I wonder if this is the same phenomena that has infuriated other reviewers. Aside from this oddity, the lens is a really good unit.

I regret that I don't experience with other lenses except for the 18-55 II for comparing to this lens. I would love to compare this lens to all the other usual cast of characters when the "which standard zoom" question arises.
New Member

Registered: December, 2012
Posts: 1
Review Date: May 14, 2013 Recommended | Price: $500.00 | Rating: 8 

Pros: sharp, picture quality, constant aperture
Cons: loose front lens. I sometimes get worried about it. low luminosity
Sharpness: 9    Aberrations: 8    Bokeh: 8    Autofocus: 9    Handling: 7    Value: 8    New or Used: Used    Camera Used: K-7, K-5II   

Three months have been using this lens. First to K-7, now with the K-5. Somewhat surprising is the amount of criticism about the autofocus. My copy everything works fine. Focuses very quickly and accurately. Bought a used lens, which has already been 4 years. And not at all disappointed with the quality of the picture ... Perhaps this is an exception
Senior Member

Registered: August, 2009
Location: Broomfield, Colorado
Posts: 152
Review Date: January 30, 2013 Recommended | Price: $380.00 | Rating: 6 

Pros: overall sharpness, versatile zoom range
Cons: AF motor(SDM) failed, focus ring slips using in MF
Sharpness: 8    Aberrations: 8    Bokeh: 7    Autofocus: 1    Handling: 6    Value: 5    New or Used: Used    Camera Used: K20D   

Purchased used in like new condition back in 2009.
Lens has versatile zoom range and excellent overall sharp image quality.
SDM motor failed after about 1 1/2 years of use.

Auto focus (AF) uses an "SDM only" motor. Since mine failed, it is only usable as a manual focus (MF) lens. SDM Repair cost is excessive (>$200) and not covered via warranty after 1 year,

Using MF on a K20D provides focus confirmation with the AF point lighting up. Also, rotating the focus ring to the clockwise limit stops at infinity, and it really is "infinity" (doesn't overshoot and start blurring like some lenses). This makes it easy for shooting subjects beyond about 20 feet away.
MF mode is only tolerably acceptable due to having to constantly readjust the slipping focus ring. The focus ring doesn't have much resistance so it typically needs repeated adjusting after every few shots.
Also, the focus ring doesn't have a long rotational throw so it's easy to go past where you're wanting to focus, requiring you to rotate focus very slowly and sometimes backtrack.

I would have rated the AF higher and the overall value better if it wasn't for the cheap, failure prone SDM motor for the auto focus. This is an extremely annoying and nearly unsettling flaw of this lens, especially when you compare to other camera brands with AF motors "built into the lens only" that last way longer than 1 1/2 years. Pentax dropped the ball on this one, big time!

To be fair, Pentax claims to have finally resolved the AF failure problems due to the SDM motor, which also inadvertently admits there was a problem beyond the statistical assembly and cumulative tolerance errors for which a warranty is supposed to cover!!! So in theory, recently manufactured or repaired lenses are supposed to last longer without SDM failure. That said, I can only make my recommendation for this lens based on my experience with what I'll call the "older version SDM motor" if you can buy it at the right price since the optical quality of this lens is great in spite of the flawed SDM only motor for the auto focus.
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