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Pentax SMCP-DA* 16-50mm f/2.8 ED AL (IF) SDM user review

Pentax K10D + 16-50 f/2.8 DA*

My friend Stephen loaned me his Pentax SMCP-DA* 16-50mm f/2.8 ED AL (IF) SDM lens so I could put it through its paces and compare it to my kit lens (SMCP-DA 18-55mm f/3.5-5.6 AL). If you don’t know already, Pentax’s DA* (”D-A-star”) line of lenses are their highest quality zooms. They feature very high quality construction, weather sealing, silent ultrasonic focus motors (SDM), and Pentax’s best SMC coatings (SP) to date. Retailing at close to $700 this lens seems like it should be a huge step up from the $99 kit lens.

This isn’t a technical review. If you want MTF and distortion charts go here. Instead, I’m just going to cover my observations during real world everyday use. Keep in mind that I do have a unique perspective here so take my opinions with an appropriate grain of salt. Here are my overall findings. Feel free to read on for a more in-depth look at how I formulated my opinions.


  • Excellent build quality
  • Useful zoom range
  • Silent SDM focus motor
  • Weather seals
  • 9 bladed aperture


  • Very soft around the edges wide open
  • Distracting CAs below f/4
  • Big and heavy
  • Very long for a 50mm lens
  • Pronounced barrel distortion at 16mm
  • Expensive


While I would normally suggest upgrading the standard kit lenses from Canikon, Pentax has done an excellent job with their SMCP-DA 18-55mm f/3.5-5.6 AL and this gussied up DA* lens only helps to prove that point. Had I bought this lens myself I would have sent it back after the first day and put my money to better use. This is a big, heavy and expensive lens that does not prove a significant upgrade to the kit lens in everyday use. Get and/or keep the kit lens and put your money towards a dedicated ultra-wide angle lens and/or some fast primes to compliment the kit lens (some suggestions can be found at the end of this article).


Pentax 16-50 f/2.8 DA* vs. 18-55 f/3.5-5.6 DA kit lens

Purchasing a lens for me encompasses four primary areas of concern: image quality, build quality, handling, and value. There is no standard order of importance here as all of these issues carry different weight depending on the intended application of the lens in question. In this case, the 16-50 seems ideally positioned as an upgrade to the standard kit lens. This makes it an all purpose lens that should perform equally well in all four areas while handily outperforming the kit lens (which is why I am comparing the two here).

100% edge crop

Image Quality

I think the crop above says it all. Shoot this lens at 16mm with anything less than f/4 and the color fringing (chromatic aberrations or “CAs”) and edge softness are quite disappointing. F/8 is required to eliminate the problem altogether from wide shots. The fringing persists all the way up to 50mm but is generally less of a problem at the longer focal lengths due to the shorter depth of field at f/2.8 (CAs get lost in the bokeh). Center sharpness is pretty good wide open (f/2.8) at all focal lengths and becomes tack sharp at f/4 and above. Overall color and contrast are very good (as it is with all Pentax lenses).

My biggest issue here is that the three main advantages this lens should have over the kit lens are sharpness, speed and the wider field of view (FoV). I found myself stopping down to at least f/4 for most of my shots with this lens, only using f/2.8 in extremely low light hand-held situations and when controlling the depth of field (DoF) was critical. The extra 2mm on the wide end (16mm vs. 18mm in the kit lens) are noticeable due to the greater FoV but more notably for the exaggerated barrel distortion. This isn’t a deal breaker for me but is disappointing at this price point.

On the other hand, stopped all the way down to f/22 and opened up wide to 16mm, this lens produces some very nice results for landscape photography. Its nine bladed aperture creates awesome 18 pointed starbursts with very little flare. This is one of the areas where the higher build quality of the DA* really shines (pun intended).

f/8 @ 16mm

That 9 bladed aperture also produces very nice bokeh even when stopped down. The image above was taken at 16mm and f/8 and exhibits very smooth blurring of the background with mostly circular out of focus highlights. This shot also illustrates the 16-50’s macro performance. It’s 0.3m (11.8″) minimum focus distance makes it pretty useful for getting in tight even if the 50mm maximum focal length doesn’t provide a tremendous amount of magnification. Keep in mind that the minimum focus distance of a lens is measured from the sensor (ie: film) plane in the camera body and not from the front of the lens. This means that at 50mm you can get up to about 3-4″ away from the subject with the front glass. This may be useful sometimes and a problem at others. Personally, I like shots like this where you get in close with the wide angle to exaggerate scale and perspective. Meanwhile, the kit lens can focus down to 0.25M (9.8″)…

Build Quality

Not much to say here. This lens is built as well or better than the best lenses from any mainstream manufacturer. One heft and you will not question its price tag. Typical to the DA* line, the 16-50 features gasketed seals to prevent dust and moisture penetration, including a seal at the lens mount to seal it to the camera body. Combined with Pentax’s weather sealing on the K10/20D bodies this makes for a very practical all-weather combination. I’m sure this is a useful upgrade but I have shot in some pretty nasty conditions with my kit lens and have not had any problems with moisture penetration. (I have to wonder if most non-professional photographers would put their cameras through the kind of abuse this level of construction suggets is possible). The zoom and focus rings are well damped and buttery smooth with nicely ribbed rubber rings. There is no slop or wiggle between the various moving parts anywhere throughout the zoom range.


For me this is one of the most conflicting areas for this lens. On one hand Pentax has included some very nice design features that make this lens a worthy step up from the kit lens. On the other hand, the sheer bulk of this lens really gets in the way. Here are a couple of the nicer design features:

lens hood port

The access port on the lens hood is a nice touch common to all Pentax lenses. It allows access to the control ring on rotating filters without removing the lens hood (like polarized, graduated and special effects filters). This is a very user-friendly feature that all lens makers should adopt. After all, you usually find yourself needing to use these types of filters and the lens hood at the same time anyway, right?

SDM focus switch

Another nice feature of this lens is the SDM ultrasonic focus system. This lens focuses absolutely silently. This can be a bit strange at first considering how loud the screw drive focus system is with standard lenses. It’s not noticeably faster or more accurate than the screw drive system (still hunts too much IMO) but its silent operation draws less attention to the fact that you are taking pictures (if only the extra-loud shutter wouldn’t betray us so). The focus ring can be used anytime to fine tune the focus. However, it is not directly coupled to the focus mechanism so it does not stop turning when you reach the either end of the focus range. Pentax has included an AF/MF selector switch on the lens for those times when you want full time manual control. This is a lot easier to use than the switch on the camera body and is a nice touch.

DA* lens cap

Why does Pentax make me spend $700 to get a decent center pinch lens cap?

16-50 DA*, 18-55 DA & 50 mm f/1.7 all @ 50mm

Now for the bad news. This lens is a brick. On my kitchen scale the 16-50 weighs 20oz while the 18-55 kit lens weighs in at 8oz and my old 50mm f/1.7 is only 5 3/4oz. (BTW, the K10D body w/ battery weighs 28oz). I realize that there is a weight penalty to step up to f/2.8 in a zoom but, considering this lens’ lackluster performance at f/2.8, I really have to question the benefit here. I mean, why carry around all this glass if you’re going to be shooting at f/4 anyway?

Mounting this lens to the front of my K10D felt very awkward. The grip on the K10D is a bit shallow and hanging all that weight off the front of the camera made it very difficult to hold securely with one hand. I found myself carrying the camera by the lens and having to use two hands for most of my shots. (Adding a battery grip would help balance the camera and provide better leverage with the heel of your right hand). Don’t get me wrong. I don’t mind a heavy and expensive lens if the performance and application justifies it. (Canon’s EF 70-200mm f/2.8L IS USM is one of my all time favorites). Overall this did not prove to be a very good walking around combination. I find this interesting since this sort of everyday use seems to be the main focus of lenses in this zoom range.

Pentax K10D with 16-50 f/2.8 DA*

Another negative aspect the comparison photo in the section above illustrates is how long this lens is. The 16-50 is at its longest (5 3/8″ to the mount) at 50mm and its shortest (4″) at 16mm (as shown directly above with lens hood). The kit lens is only 3 1/8″ at its longest which is at 55mm and 18mm. As you zoom from 18mm to 55mm the kit lens starts off long then retracts to its shortest length of 2 3/4″ at 35mm then back out to 3 1/8″ at 55mm. This double action means it only has to extend half as much (percentage wise) as the 16-50 does throughout its zoom range. I point this out mainly because 50mm on a 1.5X APS-C sensor is the equivalent of 75mm on a full frame sensor and 35mm film. This puts it right in the sweet spot for close portrait photography. However, when you point this thing at people they tend to back away as if you’ve just aimed a bazooka at them. I imagine it would be fine in studio situations but for candids and street photography the kit lens (or better yet, a 50mm prime) is clearly the better choice.

16-50 DA* vs 18-55 DA

Not to belabor the point too much here, but another aspect that should be considered with respect to lens size is how much space it takes up in your bag. Here you can see the 16-50 f/2.8 DA* and kit lens both suited up for travel with hoods and caps. As you can see, the 16-50 will require a pretty massive hole in your bag (4 1/8″ X 4 7/8″). If you are anything like me you have to consider very carefully what goes in your camera bag. Which brings me to my conclusion…

The advertised advantages of this lens are its wide FoV (16mm), speed (f/2.8), SDM focus motor, build quality, 9 bladed aperture, weather sealing, and sharpness. However, in actual use I don’t find any of these things in combination to be a significant enough improvement over than the kit lens as to justify the price and bulk of the 16-50 f/2.8 DA*. In fact, if this were the kit lens I would be looking to upgrade. If you have $700 burning a hole in your pocket there are a number of better choices out there.

I suggest you look at the Pentax SMCP-DA 12-24mm f/4 ED AL (IF) ($670). It is a re-badge of the stellar Tokina 12-24mm f/4 AT-X 124AF Pro DX ($490) and makes a much more useful ultra-wide angle addition to the kit lens. (It is a bit frustrating that we Pentax users have to pay an extra $200 for the same lens the Canikon folks can get directly from Tokina). It is still pretty heavy (15oz) and will take up just as much room in your bag as the 16-50, but the ultra-wide angle shots you’ll get with this lens will absolutely blow you away. If speed and sharpness are what you are looking for pick up a fast prime or two like the Pentax SMCP-FA 50mm f/1.4 ($200) and/or the Pentax SMCP-DA 35mm f/2.8 Macro Limited ($480). If you really feel a burning need to try out a DA* lens, check out the new Pentax SMCP-DA* 200mm f/2.8 ED (IF) SDM ($890). Its bulk is easily justified by its extra reach and speed (just beware of some nasty purple fringing in high contrast scenes).

Finally, if you are buying a new Pentax body and are looking for an upgraded alternative to the kit lens, don’t. The kit lens is one of the best values available for these cameras. If you are determined, take a look at Sigma’s 18-50mm f/2.8 EX DC Macro ($420). This was the lens I originally bought with my first K10D back in ‘07. It is not nearly as big and heavy as the Pentax 16-50 f/2.8, has almost identical image quality, and adds a very useful macro focus capability across the entire zoom range. I shot several thousand shots with it in 2007 in several parts of the world and can attest to its quality. That being said, I now know that the Pentax 18-55mm kit lens makes better pictures ;-)

Some sample photos taken with this lens during testing.


A number of readers have suggested that Pentax’s $380 SMCP-DA 16-45mm f/4.0 ED AL might be a better upgrade choice over the 16-50mm f/2.8 DA*. I have no experience with this lens so I did not mention it as an alternative. Reading over the test report I can see that at only 12.9oz it is considerably lighter than the 16-50 DA*. Size wise it is slightly smaller than the 16-50 DA* with the added benefit of being at its shortest at 45mm (opposite of the 16-50). Also, it features an 8 bladed diaphragm which should result in decent bokeh and nice starbursts when stopped down. Resolution seems to be very good with distortion and vignetting similar to the 16-50 DA*. The only real noteworthy negative mentioned is heavy CAs at the edges of wide angle shots. If I can get my hands on one of these I will definitely post a similar review and find out if this lens is worthy of consideration.

After writing this review it was brought to my attention that the 16-50mm f/2.8 DA* has suffered from some quality control issues. It is entirely possible that this example is flawed. However, in researching this a bit more I still find a number of reviews pointing to similar image quality problems on lenses that are supposedly in proper working order. Potential QC problems aside, my opinion remains unchanged about this lens.

It’s the lens that matters most

new toy

I have been thinking a lot lately about lenses and I thought I’d share some of my thoughts. I’m planning on doing a more specific lens comparison but I will save that for a later date. For now I just want to talk about my general thoughts about lenses and their applications. Why is this important? Well, as you begin to expand your collection of lenses you will soon learn that what you have really invested in is a lens system and not a camera system. Quality glass (lenses) will last a lifetime and will likely outlast the latest whiz bang technology of the latest DSLR you just bought. Hopefully by sharing my thoughts and experiences some of you will have an easier time of navigating the confusing quagmire that comes along with upgrading your DSLR’s optics and make the most out of your investment.

For this discussion I am going to primarily refer the standard 35mm film focal lengths of lenses. I will add APS-C (1.6X) focal length or 35mm equivalents in brackets [ ] where appropriate. In general, if I say 50mm I mean 50mm focal length on a 35mm film camera or full frame sensor DSLR. The reason I am doing it this way is that the 35mm equivalent focal length of a lens describes its field of view (FoV) more accurately than APS-C (or DX) format measurement does. If any of this is confusing to you I strongly suggest reading the Wikipedia page on the APS-C format before continuing.

What would I buy?

Let’s imagine for a moment that money is no object and I could fill my camera bag with whatever I wished. What would that be? While we’re in dreamland, let’s assume that the camera I’ll be shooting with all this fictional glass is Canon’s awesome new 5D Mark II. Here are the lenses I’d want to have available and why (I’m sure I could find similar choices for Nikon but I know the Canon stuff better):

  • 17-40mm f/4 L wide angle zoom. Why if money is no object would I choose the 17-40 f/4L over the faster 16-35 f/2.8L? Simple, the extra speed the 2.8 provides is not worth the extra weight.  A super wide lens like this is something I’m most likely to carry around with me while traveling and the lighter it is the more likely I’ll take it with me. Also, the idea of wide angle shots is usually to capture as much detail as possible (think streetscape, landscape or 5-year-old birthday party action) so a larger aperture is just going to work against you. I’m sure there are specific situations where the extra speed of the 16-35 f/2.8 would come in handy but for me I’d most likely choose the slower and lighter option here and just dial up the ISO as needed in low light situations. The only caveat here is if I was shooting an APS-C body. Then the 16-35mm [26-56mm] would make a logical upgrade for the standard 18-55 kit lens. See my comments below for APS-C wide angle lens thoughts.
  • 35mm f/1.4 L wide angle prime. I really like having a fast wide angle lens for available light shots of the kids around the house and for other times when a 50mm lens just doesn’t provide quite enough FoV to capture a scene the way I want to. In fact, while a 50mm lens best reproduces the magnification the human eye sees, a 35mm lens better represents the field of view our eyes can see (in focus). Having never owned a fast 35mm I can only guess but I bet it would end up being my standard lens mounted on my camera 90% of the time. Becomes a medium angle lens [56mm] on an APS-C camera.
  • 24-105 f/4 IS L zoom. This is a close call. The 24-70 f/2.8 L is a very tempting choice. I have rented both lenses and they are both superb. The 24-105 f/4 is the one I’d put in my bag though because money is no object here and I’m going to have all these other lenses to choose from. Huh? Well, if I could only have one lens it would be the 24-70 f/2.8 L. Easy. However, if I’m going to be toting around a bag full of glass the 24-105 f/4 just makes more sense. It is lighter (see argument for 17-40 above), has a wider zoom range (better for “walking around”) and has IS. There are times when a slower shutter speed (1/30-1/4 second) is what you need to capture action and IS is the only way to get get these shots w/o the hassle of a tripod. The 24-105 focal range means I would have a stabilized lens that covers all wide to medium telephoto applications. Also an awesome all-purpose [38-168mm] lens on APS-C bodies (though lacking a bit on the wide end).
  • 50mm f/1.4 USM prime. Here I go again cheaping out even though money is no object. Yes, Canon’s 50mm f/1.2L is the Mother of All fiddies. However, from what I can tell it is not that much better than the non-L 50 1.4 but it is that much bigger and heavier (and somewhat slower to focus). I know this whole weight thing is getting long in the tooth, but for the way I shoot it is important. When I travel I typically head out on foot to explore which means I have to carry my gear on my person. After spending an entire days lugging an overloaded camera bag around Hong Kong and Paris I can tell you that less is definitely more. The main problem is that you get to these wonderful places and you are faced with making the choice of picking one or two lenses and hoping for the best- or lugging your entire kit with you. I’ve done both and can say that whatever the choice the weight of what you carry always remains an issue. Studio, sports and landscape “trunk” photographers are the only ones that don’t have issues with how much stuff weighs. As for me, I carry my camera almost everywhere (including on my bike) so I want to find the best balance between size and performance. Here, the 50 1.2 just doesn’t make sense for me. YMMV. See fast prime suggestions for APS-C cameras below.
  • 100mm f/2.8 USM Macro. You can’t beat a dedicated macro lens. I like the 100 f/2.8 on a full frame body as it provides the right mix of magnification and stand-off distance from the subject. I like to shoot most of my macro shots at arm’s length. Canon’s 50mm f/2.5 Macro is OK but I have found that I often have to get too close with the camera to get the magnification I want (often blocking out the available light). Meanwhile, Canon’s 180mm f/3.5 L Macro is an awesome lens but its longer focal length pretty much requires a tripod to get decent results. APS-C photographers should check out Canon’s EF-S 60mm f/2.8 Macro.
  • 70-200 f/2.8 IS L zoom. This is one of photography’s greatest lenses. Perfect for portraiture, sports action, school plays, wildlife, the occasional macro shot, and pulling in details in just about any situation. The f/2.8 version gets the nod over the f/4 version even though it is larger and heavier. You’ll need the speed to catch those low light shots and the shorter DoF will make your subjects pop. My bet is that you’ll rarely shoot this lens at anything other than wide open. Works great on both full frame and APS-C bodies.
  • 400mm f/2.8 IS L super telephoto. Here’s where the “money is no object” part really pays off. I have always wanted a fast super telephoto for getting in tight to stuff you can’t get up close to. I’m thinking sports car racing, school plays, African safaris, and the occasional full moon. Not a lens I would carry around in my bag but definitely one I’d like to have if the situation warranted it. I’d skip the 100-400 f/4.5-5.6 IS L in favor of lens speed and ultimate image quality. Have an APS-C camera? Then your 1.6X crop factor makes this monster a 640mm f/2.8 equivalent for no extra charge ;-)

OK, so back to reality for a second. Most of us are amateurs and can not justify dropping $15K on our camera gear. Therefore, what should you take away from all of this?

  • Buy the best lenses you can afford. It will outlast your camera and you’ll never find yourself second guessing a lens purchase. If you find you don’t use a lens enough to justify keeping it, you’ll also find that pro-quality glass earns top-dollar on the used market. If you are thinking of dropping $180 on a Canon 28mm f/2.8 to get a wide angle prime do yourself a favor and save your pennies until you can step up at least to the $420 28mm f/1.8 USM. What you will gain in ultimate image quality and versatility will pay off many times over in your photographs. That 28 2.8 will end up in a drawer somewhere collecting dust as soon as you realize that its useless below f/4 anyway. Trust me. I know.
  • Do your research. This may directly contradict what I just said as you will find bargains out there. The non-L 50 1.4 I mentioned above is one example. In fact, at only $90 brand new Canon’s 50mm f/1.8 II is probably the best value in lenses anywhere. (Check out’s new review of the Canon EF 50mm f/1.8 II.) That being said, do your research so you know what you are getting. Personally, I would wait and save up for the 50 1.4 just to get the speed and silence of the USM focus motor. Also, the 50 1.4’s 8 bladed diaphragm produces far superior bokeh and starbursts when stopped down than the 50 1.8’s 5 bladed diaphragm. Buy the 50 1.8 II and you’ll be perfectly happy with it until you shoot one of the USM lenses. Then you’ll start beating yourself up. The best places to research are websites that actually test equipment. I prefer,, and because they use standardized testing procedures. There are blogger/photographers (like me) who “test” lenses and write their opinions about them. Take those with a grain of salt but they are usually pretty useful. Be wary of discussion forums and review ratings and the like. These are typically very unreliable sources for quality information.
  • Pick up a fast prime lens. My recommendation is a 50mm equivalent focal length at f/1.8 or faster. If you are shooting an APS-C sensor camera this is going to be tough. Technically you’ll need a 31mm lens to get an equivalent 50mm focal length. Sigma is one of the only lens manufacturers making a lens like this. Their 30mm f/1.4 EX DG HSM looks like it fits the bill perfectly. However, it’s relatively pricey ($500) and tests say it is very soft off center. Pentax’s SMCP-FA 31mm f/1.8 AL Limited is an ideal choice for Pentax shooters but at $800 you’ve got to be mighty deep into Pentax. 35mm focal length lenses are probably your best bet. Unfortunately, truly fast versions are usually pricey and hard to come by (see the $1,200 35mm f/1.4 L above). If you can’t find a 30-35mm f/1.8 or faster lens do what most everyone else does and put your money into a fast 50mm. It’ll end up being a bit long on an APS-C sensor camera [80mm] but at least you can start exploring the Wonderful World of Bokeh and available light photography.
  • Consider an ultra wide angle zoom. I’m not talking fisheye. I am talking at least 15-17mm on the wide end, though. A super wide angle lens opens a whole new world of photography for less money than most lens investments. I’ve already shared my feelings above about Canon’s 17-40 f/4L and 16-35 f/2.8L lenses for full-frame applications. However, neither of these fit the bill for an APS-C body. Look for something around 10mm [16mm] on the wide end. There are a number of choices depending on your camera so do your homework. I hear Canon’s EF-S 10-22 f/3.5-4.5 USM is superb. I’ve owned Sigma’s 10-20 f/4-5.6 EX DC lens and thought it was great.
  • Avoid super zooms. These are the 18-200mm+ do-it-all lenses that are so popular at camera stores and on-line discounters. Sure, the idea of one lens for every situation seems like a good idea, but the reality of making such a lens results in some pretty significant compromises in lens speed, image quality and usability. While prime lenses will always give you the best ultimate image quality they may not be the right choice for every situation. However, you will be much better off if you limit the range of your zooms and follow suggestion number one above. In my experience you can get very decent results from mid-level primes but anything other than top-of-the-line zooms are likely to suffer in more than one area (speed, sharpness, vignetting, chromatic aberrations, etc).
  • Save up for that super telephoto. Don’t waste your money on bargain brand telephoto lenses. There are a lot out there (Phoenix) but most of them aren’t worth the plastic they are made of. If dropping $5K on a lens doesn’t seem like it will ever fit into your plan then…
  • Rent before you buy. So, if you’re following my advice and buying the high dollar glass maybe you should take it for a test drive before you take the plunge. There are a number of camera equipment rental services out there. I have only rented locally while I am traveling so I can’t recommend any of the on-line services, but I hear good things about many of them. Also, renting is a great way to get those awesome once-a-year close-up Christmas school program photos of Jr. from the back row of the gymnasium. No sense putting that $5K lens in the closet until next year, right?

I hope this helps clear up the mystery of lens selection a bit for those of you who are just starting to wade into the hobby. Feel free to post specific questions in the comments or drop me an email. Those of you who are more experienced please take a moment to share your thoughts on the subject as well.


I'm an industrial designer and an avid hobbyist photographer. People are always asking me "how'd you do that?" So, I decided to create this site as a place to share my experiences and insights about photography, the gear and what it all means to me. I'm not sure if this site will make anyone besides myself a better photographer but I figure it's worth a try. Take a look around and let me know what you think. Thanks for stopping by!


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