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SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM Review RSS Feed

SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM

Reviews Views Date of last review
154 530,841 Sat April 9, 2022
Recommended By Average Price Average User Rating
94% of reviewers $794.89 9.03
SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM

SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM
SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM

Like all current DA lenses, the SMC Pentax DA* 50-135mm is designed only for Pentax APS-C DSLR cameras. It was announced in late February, 2007. It auto-focuses with an SDM ultrasonic motor on the K10D (firmware 1.30) and newer cameras. On older cameras the lens will auto-focus with the 'screw drive' mechanism.

SMC Pentax-DA* 50-135mm F2.8 ED [IF]
©, sharable with attribution
Image Format
Lens Mount
Pentax K
Aperture Ring
Automatic, 9 blades
18 elements, 14 groups
Mount Variant
Check camera compatibility
Max. Aperture
Min. Aperture
AF (in-lens motor or screwdrive)
Min. Focus
100 cm
Max. Magnification
Filter Size
67 mm
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 31.5-11.9 ° / 27-10 °
PH-RBK 67 mm
Lens Cap
Weather Sealing
Yes (AW)
Other Features
AF/MF Switch,Internal Zoom
Diam x Length
77 x 136 mm (3 x 5.4 in.)
685 g (24.2 oz.)
w/ Hood: +80g
Production Years
2007 to present (in production)
$1049 USD current price
Engraved Name
smc PENTAX-DA* 1:2.8 50-135mm ED [IF] SDM
Product Code
User reviews
In-depth review
Unofficial Full-Frame Compatibility Tests by Pentax Forums
★☆☆ Usable with reservations at select F-stop/focal length combinations
Show details
Internal zoom.
Three ED elements.

Screwdrive AutofocusSupersonic AutofocusQuick ShiftWeather SealedInternal FocusingInternal ZoomingAutomatic ApertureAPS-C Digital Only
Purchase: Buy the SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM
In-Depth Review: Read our SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM in-depth review!
Sample Photos: View Sample Photos
Price History:

Add Review of SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM Buy the SMC Pentax-DA* 50-135mm F2.8 ED [IF] SDM
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Senior Member

Registered: November, 2017
Location: Sydney, NSW
Posts: 114
Review Date: July 5, 2019 Recommended | Price: $300.00 | Rating: 9 

Pros: all weather, internal zoom, internal focus, parfocal zoom lens
Cons: inconsistent and slow auto-focus
Sharpness: 9    Aberrations: 10    Bokeh: 10    Autofocus: 6    Handling: 10    Value: 9    New or Used: Used    Camera Used: Pentax KP   

I bought this lens secondhand. It is mainly used for landscape as well as indoor/outdoor events. Occasionally, I will use it for portraiture.

Overall, the lens delivers great optical performance. Its sharpness is good wide-open and great from f/3.5 to f/8 throughout the zoom range. I cannot remember any issue with CA using this lens. Further, it produces the smooth and pleasing out of focus area.

In term of lens construction and handling, the lens is well-built. Its zoom ring is in an adequate size for my hand. The focus ring offers a large area to grip on when a manual focus is needed, which requires about 135 degrees of turn to change from its minimum focusing distance at 1m to infinity or vice versa. This long focus throw allows a high degree of accurancy when focus manually. The AF switch on the lens allows catch-in-focus. I have not yet brought the lens through any harsh condition, but it can withstand light rain many times without any issue.

The only problem I find in this lens is its auto-focus. Although silent in sound, its auto-focus is slow and somewhat inconsistent (especially in case of a contrast-based auto-focus in live view). If the lens has not been used for a very long time, it may need a bit of warm-up period, where an auto-focus is slower than usual, before it can operate at the normal speed. Sometimes, auto-focus with this lens does not give an accurate result. Also, the lens may miss the focus from time to time, which is really annoying. When the auto-focus is hit, however, it can deliver great results.

To mitigate the misfocus issue, I would recommend zooming all the way in first in order to acquire focus. Then you may zoom out and compose the image. From my own experience, I believe this lens is a parfocal zoom lens, i.e., the focus distance does not change when the zoom ring is rotated and the focal length is changed.
New Member

Registered: February, 2010
Location: Roma
Posts: 1
Review Date: March 22, 2019 Recommended | Price: $780.00 | Rating: 9 

Pros: Color, sharpness, bokeh
Cons: No FF, SDM life
Sharpness: 10    Aberrations: 9    Bokeh: 9    Autofocus: 8    Handling: 9    Value: 9    New or Used: New    Camera Used: K20D, K3, KS2, K1   

I bought it in Greek new @ less than 800$, it was a great deal !

But...before end the warranty autofous stop operation first time, it was repair in France free of charging, after 5 years broken again and spent around 300€

Great lens for portrait, color and saturation are magic, autofocus is slow but (when is working) is very precise (so in my country is called the Sloth)
I love short tele, so in APS-C for me over 100 mm is too much for portrait, but good to get photo in sports in small field or sometime in landscape where chromatic aberration are well controlled !

For reason eplained above I prefer the FA 77/1.8 Limited to it, but the Sloth is more versatile, aboslute best in CA, wheather sealed well balance when is monted on K3 for example.

I tested with K1, but as you know is useable in FF @ 135 mm over f/8, even do in crop mode for portrait is still valid, is the right range in full frame, it's a shame we don't use it in FF mode, for those reason I decide to sell it.

Best lens for APS-C!
Loyal Site Supporter

Registered: October, 2018
Location: Quebec City, Quebec
Posts: 5,326
Review Date: March 18, 2019 Recommended | Price: $1,000.00 | Rating: 10 

Pros: Very sharp and contrasty, internal focusing.
Cons: None
Sharpness: 10    Aberrations: 9    Bokeh: 9    Autofocus: 10    Handling: 10    Value: 9    New or Used: New    Camera Used: Pentax K5, K3, K3 III   

Batiscan River in the Fall, Notre-Dame-des-Anges

Downtown Montreal at night

Fall foliage, Saint Leonard

Quebec City from the Observatory (above @ 50 mm, below @ 135 mm)

Marina on the Saint Lawrence (below) :

Re-activating the DA* 50-135 mm f/2.8 this morning, ISO 200, 1/13 sec @ f/8 :

50 mm FL

85 mm FL

135 mm FL

The AF sprang back to life immediately, no SDM problem.

Optimum aperture opening for landscape purposes : f/8
Forum Member

Registered: April, 2018
Location: Tartu
Posts: 79

6 users found this helpful
Review Date: December 19, 2018 Recommended | Price: $500.00 | Rating: 9 

Pros: light weight - weathersealed - sharpness - bokeh
Cons: slow AF
Sharpness: 9    Aberrations: 9    Bokeh: 10    Autofocus: 7    Handling: 10    Value: 10    New or Used: Used    Camera Used: K50 & K3 & K1   

Pentax DA*50-135 F2,8

My thoughts after 18months of use.
(not a review, I don't have the necessary know-how and equipment to review a lens.)

Ergonomics and design
  • Very good size and weight. You can definitely carry it around all day, even shoot one handed on the wider end.
  • The weathersealing is tight. It will even survive underwater for some time. (don't ask me, just know it's not completely watertight :P) In rain, no question.
  • The grips are from rubber and real tight. The rubber hasn't slipped once even after I've removed it from the zoom ring various times. (why? Keep reading)
  • The resistance on both the zoom and focusing rings are good. No complaints there.
  • The hood is long and tough. It might seem sometimes it doesn't attach properly, but in real use it has never come loose so no lost points there. I'm actually glad it's big. Makes you feel bigger and helps keep the contrast.
  • This lens has an dedicated MF/AF switch. I don't use it much at all because in addition it has quickshift: you can use manual focus in AF.
  • Mounted on a tripod (a rather cheap one ~50$) it doesn't move in landscape orientation. When I turn my ballhead 90 to the side (portrait orientation) it has a hard time keeping steady and sometimes starts sliding. So a tripod collar would have been nice with this lens :/
  • The housing is made from metal and the paint hasn't started coming off from any parts. My copy is almost 8 years old and it still looks like a mint one from the outside.

  • It's okay. The bokeh is smooth (no onion rings etc) and keeps it's round shape throughout it's apertures.
  • There is some aberration, but very minor and mostly goes unnoticed.
  • Haze is under control when shooting into a bright light source. Don't expect anything exceptional though. You'll still lose a lot of detail in the shadows as with most lenses.
  • Sharpness at f2,8 isn't the best, but from f3,5 it's tack sharp until f11~f13 where it gets soft again.

Compared to Tamron 17-50/f2.8 and Pentax-M 50/1.4 all at f5.6, I'd say the 50-135 takes a close second behind the 50/1.4, but well ahead of the Tamron (which is a very sharp zoom lens).

*When I started photography, I noticed many people telling something like "shoot with a kit lens at f8 and it's as sharp as premium glass wide open". I have to disagree Even though it's a bit hazy at 2,8 there's a lot more fine detail visible. So don't trust that misbelief.

  • It's slow. There's no point in sugarcoating it. Not ideal for close range fast paced action @f2,8.
  • For everything else, it's more than enough. Goes from infinity to close focus in just over a second.
  • Sometimes it feels a bit laggy and has trouble locking focus.
  • More rarely, the lens might start and take the first couple of shots a little out of focus. Usually this issue goes away with a few seconds of focusing(AF).

*People have also pointed out it's not precise. I have to disagree. Having used a K30, K500, K50 and now a K3, the issue lies inherently within Pentax's own AF system. I can never be 100% sure I'll get pixel perfect focus. There's always a small room within which the AF system misses and catches focus and it has done so with all my cameras and different lenses. With fast glass these tiny errors show up more.
**My copy of this lens needed AF microadjustment. More on the older bodies, less on the K3.

Problems and FIXES

Let's start with the big one:

SDM failure

The good news is that in most cases the SDM doesn't die, it simply gets stuck. If you can't fix it via warranty and don't want to convert this lens into a screwdrive one, there is a simple fix available. I've made a separate blog post about it here: LINK

*this happened to me once and I fixed it

focus locks up

Turning the screwdrive screw on the back of your lens should do the trick.

*this happened to me once

Misses focus on some focal length, but not others

This indicates the zoom ring pins are bent or broken. See my link above, I also talked about this in my post. Again, it's an easy fix that doesn't require any mayor lens disassembly.

*never happened to me

Doesn't find any focus at all, only focuses inside a narrow range and doesn't respond to manual focus

I don't know why this happened, but I've read once or twice about it online too so I'm not the only one.
I just took the lens off and afterwards it worked perfectly again.

*this happened to me once

You might think this lens comes with a fair share of potential problems, but I assure you, all of them are rather rare and every lens regardless of manufacturer has problems like that. Newer copies of this lens have a better SDM that doesn't get stuck so easily. After doing a lot of research and meddling with the interior of my lens I'm convinced this lens won't magically break. For everything that happens there's a reason and most of the time the fixes are rather easy.

I recommend this lens. It's probably the best APS-C zoom lens for Pentax.

*I also tested it on the K1. The lenshood produces a good chunk of the vignette. Without the lenshood you can shoot @50mm and do a 1,1~1,2x crop to get rid of the dark edges. 1:1 crop has no vignette. Really, the vignette is not that bad without the hood. Works as a FF lens in the higher mm range. AND it remains sharp. So, no need to sell it just because you upgraded to a K1.

2022 Update
I've been shooting with Sony A7III + Tamron 28-75 & Sigma 85/1.4 for a few years now. At the time the 50-135 was a major jump from my kit lenses. I really loved that lens and I remembered it being good. This lens is at its best as sharp as the Tamron 28-75 RXD. However the AF on Pentax bodies is so bad, you'll mostly not see it unless you like shooting at f8.

Updated scores on the logic: 0 being the worst possible pinhole lens, 10 being something like my Sigma 85/1.4 dg dn:
Sharpness: 7
Aberrations: 7
Bokeh: 7
AF: 4
Handling: 10
Value: 5? Depends on the price.

Registered: July, 2011
Location: Melbourne
Posts: 1,269

2 users found this helpful
Review Date: September 30, 2018 Recommended | Price: $1,150.00 | Rating: 10 

Pros: smooth bokeh in a compact lens
Cons: price

Well I used this lens for the September Single in challenge for the month of September 2018. I started off the month playing with this 50-135 2.8 hoping to finally see why people like it so much. After a month of shooting with it I have gained a respect for it. The photos taken at 2.8 seem to have a special quality about them, the way it handles areas of out of focus is very pleasing with a nice transition from in focus to smooth bokeh. The speed of autofocus and lack of hunting for focus worked well with my style of shooting. The size and balance with the K3 worked well and the lack of bulk made the combination easy to take with me each day. When I examined the photos closely I was unable to fault the sharpness of the lens other than due to using too slow a shutter speed leading to some softness from me rather than the lens. I can now see why it has such a great following. The silent lens focusing worked well for me and compared to the older screw drive mechanism, I found it very effective. The large zoom and focusing rings were easy to use and turn in the "correct" pentax way. Examples taken with this lens can be found in the following album
I highly recommend this classic lens
Senior Member

Registered: January, 2016
Posts: 127

1 user found this helpful
Review Date: August 19, 2018 Recommended | Rating: 9 

Pros: takes photos like a prime
Cons: slow AF
New or Used: Used    Camera Used: K-3   

This lens makes gorgeous pictures. On a crop sensor, it's the coveted 70-200 focal range. I use mine for all my portrait work and the photos are always lovely. But in a quick movement or needed candid sometimes it won't autofocus in time. The AF is just slow. My SDM still works but I still might convert it to screwdrive. I originally wanted it for work where I needed quiet autofocus (weddings and the like) but I end up doing manual focus in those instances anyway, so at least screwdrive would give me some speed. This lens is easy to use, not overly heavy and takes photos like a prime. Even with fears of SDM failure, I recommend.

Veteran Member

Registered: December, 2013
Posts: 796

2 users found this helpful
Review Date: July 23, 2018 Recommended | Price: $610.00 | Rating: 10 

Pros: Sharp, fast, versatile, IQ
Cons: Big, heavy, slow AF
Sharpness: 10    Aberrations: 10    Bokeh: 10    Autofocus: 7    Handling: 9    Value: 8    New or Used: Used    Camera Used: K-30, KP   

This zoom lens excelent IQ. Near to primes. The zoom range is very versatile for portraits and from 70mm the F2.8 aperture gives sufficient background blur. The bokeh is excelent in the full zoom range. The build quality also very good, the zoom and focus rings are smooth, maybe the best I ever used on an AF zoom lens. The hood is bigger than what I would like, but the lens works well without it. In general I like the small primes, but this lens worst it. The AF is the only weak point of this lens, it's slow and occasionally I had acccuracy problems also. Overal this lens is the best zoom I ever used.

Here are some images:
IMG170422_0004 by Benjámin Czétényi, on Flickr

IMG170414_0056 by Benjámin Czétényi, on Flickr

IMG170603_0284 by Benjámin Czétényi, on Flickr

IMG170603_0190 by Benjámin Czétényi, on Flickr

IMG170603_0202 by Benjámin Czétényi, on Flickr

IMG170611_0002 by Benjámin Czétényi, on Flickr

IMG170923_0079 by Benjámin Czétényi, on Flickr

IMG170923_0029 by Benjámin Czétényi, on Flickr
Site Supporter

Registered: October, 2006
Location: North Face of Mount Shasta
Posts: 120
Review Date: March 14, 2018 Recommended | Price: $600.00 | Rating: 10 

Pros: Sharp and Sharper, Internal Focus and Zoom, Build Quality, Good Contrast and Color Rendition
Cons: SDM ... need I say more ...
Sharpness: 10    Aberrations: 9    Bokeh: 8    Autofocus: 7    Handling: 10    Value: 10    New or Used: Used    Camera Used: K3   

Just 2 weeks after purchasing this lens from another PF member, the SDM quit on me. So be it ... the member I purchased it from was a very honest individual about the condition when I purchased it and I had no intention of backing out of the deal.
I eventually converted it to screwdrive and have loved the lens every since. It's one of those lenses that just make you a better photographer and I don't regret my purchase for one moment. This lens is the bomb and one of the best that Pentax has ever produced. I love mine and if you ever have the opportunity to pick one up, whether new or used, do it!!

Forum Member

Registered: December, 2012
Location: Warsaw
Posts: 83

2 users found this helpful
Review Date: November 18, 2017 Recommended | Rating: 9 

Pros: IQ
Cons: SDM failure.

Veteran Member

Registered: April, 2016
Posts: 542

5 users found this helpful
Review Date: January 7, 2017 Recommended | Price: $500.00 | Rating: 10 

Pros: Sharpness wide open, beautiful rendering, smooth bokeh.
Cons: SDM unit prone to failure
Sharpness: 10    Aberrations: 10    Bokeh: 10    Autofocus: 8    Handling: 10    Value: 10    New or Used: Used    Camera Used: Pentax K-3   

This is probably the best APS-C lens that Pentax have ever made. Nothing else comes close in providing the utility or quality that this lens provides. The colour, sharpness and bokeh are amazing. Like one reviewer put it, this lens makes a mediocre snapper look like a great one.

I've had five copies of this lens, all used. Three out of five have had SDM issues but all of these were easily fixed by opening up the lens and massaging the motor. Tutorials can be readily found for this procedure.

The copy that I now use exhibited a squealing motor as well as sluggish response to autofocus so I converted it to screwdrive using my K100d. Again, a procedure that is well documented. Autofocus is now much more responsive.

In all, this is the one lens I'd pick if I could only have one. It's equivalent to 70-200 on full frame so it's really not wide at all, but the images produced are out of this world. Ignore the autofocus issues. Screwdrive is worth the extra tiny bit of noise if your SDM motor dies. This lens is THAT good.
Senior Member

Registered: August, 2011
Location: San Diego
Posts: 221

1 user found this helpful
Review Date: October 15, 2016 Recommended | Price: $999.00 | Rating: 8 

Pros: Great image quality
Cons: Auto Focus (died)
Sharpness: 9    Aberrations: 9    Bokeh: 9    Autofocus: 6    Handling: 8    Value: 8    New or Used: New    Camera Used: K5IIs; K3   

I bought the lens in 2013. I also got a 3 year extended warranty due to all of the reports I read here about the auto-focus failing. With a month to go on the warranty, the auto-focus failed.
New Member

Registered: August, 2010
Location: San Diego, CA, USA
Posts: 11

2 users found this helpful
Review Date: September 7, 2016 Recommended | Price: $965.00 | Rating: 10 

Pros: Sharpness, color
Cons: Heavy
Sharpness: 10    Aberrations: 10    Bokeh: 10    Autofocus: 7    Handling: 9    Value: 9    New or Used: New   

It's been a spectacularly good experience owning this lens over the last 6 years. It never ceases to amaze me. Nothing makes me look like a good photographer more than this lens. Incredibly sharp and the colors never need to be corrected. The 3-D effect is something hard to find in a lens, but this one excels at it. Pixie Dust galore. I can't say enough good things about this lens!
Junior Member

Registered: June, 2010
Location: Massachusetts
Posts: 27

1 user found this helpful
Review Date: July 15, 2016 Not Recommended | Price: $800.00 | Rating: 3 

Pros: Beautiful, clear shots of stationary objects, when it doesn't backfocus
Cons: Not for use with objects or people in motion, especially in unfavorable lighting
Sharpness: 10    Aberrations: 9    Bokeh: 10    Autofocus: 1    Handling: 7    Value: 1    New or Used: New    Camera Used: K-50, K200D   

When it takes focuses, it frequently takes gorgeous shots and, in some lighting situations, it is the only lens I have that will take nice shots. However, that depends greatly on whether it will focus. People talk about sports shooting, as if that's the only type of action which can befuddle a camera. I tried to shoot a talent show tonight with stage lighting. If people weren't moving, it could be coerced into focusing and taking some nice enough shots. But, if anyone in the frame was moving at all, the AF would not work at all. I missed a lot of shots watching the lens hunt. I should have gone to manual much sooner, although, given the lighting, that wasn't easy either. It was very frustrating. In fact, by the end of the night, I was almost ready to throw over Pentax completely. Awful AF is really the only problem with the lens, but, unfortunately, it has the power to render its strengths useless. If you plan to buy this lens, plan on using manual focus a lot.
Update: the SDM motor never worked well and eventually died completely. I had a Forum member fix it by overriding the silent, non-focus system for just $30. At first, it worked fine. Using it to shoot a church service on Sunday, after less than an hour, the AF quick completely. It did come back later, but I expect much more.
Unless you always manually focus or don't mind a lot of frustration, find something else.
Junior Member

Registered: June, 2012
Posts: 47

1 user found this helpful
Review Date: June 28, 2016 Recommended | Price: $400.00 | Rating: 7 

Pros: Good for indoor events
Cons: Stay away from this lens built prior to 2012 SDM failure
Sharpness: 8    Aberrations: 8    Bokeh: 8    Autofocus: 5    Handling: 6    Value: 7    New or Used: Used    Camera Used: K5   

People are selling off DA* lens because of the release of K1. So price dropped quite a bit. But use caution before you buy an used copy. SDM failure rate was high before 2012 redesign. Check the SN and compare with the forum's database to determine the manufacture date.

Otherwise this is a good lens on APS-C for wedding and alike. Not suit for sports because of the slow AF and reach limits.

Also it's quite heavy at 1.5lbs. You don't want to carry it all day unless you have to use it to make money.
Veteran Member

Registered: April, 2012
Posts: 387
Review Date: May 27, 2016 Recommended | Price: $1,200.00 | Rating: 8 

Pros: high quality image and build, constant F4
Cons: Bad autofocus - since the first year, I have to exercise the focus because its very weak when I start shooting, and doesn't get much better after use.
Autofocus: 4    New or Used: New    Camera Used: 5 years   

This is a well built, high quality lens that gives great results. However, its autofocus has been a disappointment. After the first year, the focuser would appear to not work at all initially until I exercised it for a while - i.e. focus far, focus near. Its still working and hits the mark but its quite annoying to have to "warm it up" before using.
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