The Pentax 15mm Limited is the reason I bought into the Pentax system. The news surrounding its introduction was my first exposure to the DA Limiteds and I was immediately smitten. The Sony / Minolta gear I was using at the time was fantastic optically, but build quality in the affordable lenses was lacking. At the same time, I was getting into film photography using manual focus lenses forged from a single piece of granite. Why couldn’t I have that kind of build quality and “feel” in a modern lens? Turns out I could.
Pentax truly read my mind when they designed the 15mm. All of the DA Limiteds have a 49mm filter diameter, which places a size constraint on the lens designer. How to keep a 15mm lens this small? Smallish maximum aperture of f/4, screw-drive autofocus and image stabilization in the body of the camera instead of the lens. Those are all acceptable tradeoffs to anyone who’s had the pleasure of using the 15mm. The screw-on lens cap is cool, but you’d have to be crazy not to replace it with a $5 pinch style cap. The lens hood is built-in and collapsible and made of metal and so much fun to fiddle with. Image quality-wise, Pentax seemingly prioritized rendering quality above edge-to-edge sharpness. While nowhere near as soft as the Pentax 50-200, it pays to be careful about what you place at the edges of your frame when shooting at f/4. A bit of corner softness can be seen in this photo, but it’s usually nothing to worry about. Depends on the subject.
How silly of me, I’ve gone this long writing about the Pentax 15mm Limited without mentioning how good it is at shooting into the sun. Example, from Farmington, NM:
And another example from Cannon Beach, OR:
This is the first lens I’d show someone who thinks sharpness or bokeh are the only lens qualities worth paying attention to. All of the Limiteds are accused of having pixie dust in them, but I think the 15mm is the best example of a lens with a “prettiness” to the way it renders that is hard to describe quantitatively.
The DA 15mm Limited is Pentax at their best. It’s not perfect, but that only makes it more appealing.
I’m not a fan of telephoto zooms in general. The good ones are big, heavy, and expensive. The cheap, small, light ones just aren’t very good. In my opinion, Pentax excels when it goes after high optical quality, high build quality, and small size at the cost of weight and sale price. That’s the formula for the Limiteds and the reason I bought a Pentax in the first place.
Even though I rarely enjoy using telephoto zooms, I miss not having one. I live in constant fear that I’ll see a gazelle 100 meters away and I’ll be unable to fill the frame with its face. I had the Tamron 70-300 for A-mount, and I had a lot of fun with it. Probably the best lens of the type for the money. Tamron sells the same lens for K-mount, but I wanted something smaller and weather proofier.
I didn’t feel a need for a K-mount telephoto zoom for a while because I got a manual focus Pentax M 135mm f/3.5 essentially for free. That lens doesn’t have the best reputation among Pentaxians, but I found it to be a gem. Small, fast enough, and pretty good optically. Manual focusing on a DSLR is not my favorite, but I managed some nice shots with the lens and got used to its quality for my telephoto shots. Instead of honing my skills with a quality lens, I decided I had to have a lens with autofocus and weather proofing.
Enter the SMC Pentax blah blah 50-200 blah blah WR. It’s small, light, inexpensive, zoomy, autofocussy and weather proof. It’s also built well for a modern lens. I like everything about it except for the image quality. The image quality isn’t bad at all, but it’s nothing special. Furthermore, with all the convenience features like zoominess and autofocosity, I get lazy and take boring photos. Other photographers most certainly make fantastic photos with this lens, but I struggle with it.
Maybe that says more about me than about the lens.
Let’s get this out of the way first: I know these lenses were designed for different mounts, different formats and even different recording media. Still, it’s not apples to apples; it’s more like apples to pears or peaches to nectarines. The Pentax and Olympus 75-ish mm lenses are the same price, the same-ish focal length, the same maximum aperture, roughly the same size, similar build quality, and oh yeah, they both take pictures when you stick them on a camera and point them at stuff.
The Pentax FA 77mm Limited is one of the best AF lenses ever made and it has a devoted following of Pentaxians who wait year after year for Pentax to release a “full-frame” DSLR to put it on. Some Pentax fans even adapt full-frame Canon DSLR’s just to use this lens. I can’t say I understand the thinking there since Canon sells a silent-focusing 85mm f/1.8 for about half of what Pentax charges for its 77. Perhaps it’s the pixie dust. The Pentax FA Limiteds are built like no other AF lenses. They are compact, metal, and heavy. Even without taking a picture you can tell they are special. That specialness doesn’t stop once you start taking photos. The 77 is sharp from wide open and has beautiful rendering. Stop down a little and you’d be hard-pressed to find a technical flaw. I suppose I should mention that the focusing is slowish and loud, but I don’t care. Try this lens for a day and I guarantee you won’t care either.
I’m renting the Olympus 75mm, so I don’t have very much personal experience with it. It’s very new, but already has an excellent reputation. For micro 4/3, there is no AF competition for this lens. The build quality is better than any other micro 4/3 lens I’ve ever used (I’m guessing that the Voigtländers are built better). However, it’s not as well-built as the Pentax. I’m sure they are both perfectly reliable, but in terms of “feel” it’s not even close. The Pentax wins. Also, how about that size difference? I said they were close, but the Olympus is significantly bigger than the Pentax. One of the huge advantages of micro 4/3 is that the lenses are so much smaller than their APS-C or 35mm equivalents. How is it that the Pentax, which was designed for a 4x larger sensor is so much more compact than the Olympus? Ok, it’s not that much of a mystery: the Olympus has a more complicated modern design and internal, silent focusing.
I haven’t yet had time to take any “real” photos with the Olympus, but I found this comparison too interesting to pass up. I compared the Olympus 75mm on an OM-D and the Pentax 77mm on a K-7. That’s 16MP vs 14MP and 150mm vs 115mm equivalent FOV. I used contrast-detect autofocus for both cameras and took all pictures hand-held because that’s how I take most of my photos in real-life. Here are a few 1:1 comparisons for you to peruse:
The differences are small, but it’s not hard to tell the Olympus is sharper than the Pentax. Surprisingly, they both had about equal purple fringing. The Pentax is known for being pretty bad at fringing and micro 4/3 lenses are software-corrected for fringing. For me, the differences between the lenses come down to issues with their respective formats. DOF control between micro 4/3 and APS-C is essentially the same. Any difference between the two can be easily mitigated. Full-frame does offer more control of DOF but there is not yet a full-frame Pentax DSLR, so the point is moot.
I’ve been shooting exclusively micro 4/3 lately, so going back to the K-7 was interesting. The autofocus speed was about the same between the OM-D and the K-7 with their 75mm-ish lenses attached, but the contrast-detect autofocus of the OM-D was way more accurate and repeatable than the phase-detect system in the K-7. The auto focus design of DSLR’s is inherently dependent on calibration and thus susceptible to front or back focus errors. Contrast detect focusing measures whether the actual image data is in focus. There is a speed advantage to phase-detect sensors, but that gap is closing fast. I had to switch to the glacial live-view contrast detection AF mode on the K-7 to get these samples to focus accurately. It’s not all bad news for the Pentax, though. I’ve yet to use a camera that feels better in hand and has better control placement than the K-7 (and the identical K-5, K-5II etc).
What’s most interesting to me is that the differences between the two just don’t matter much. If the lens is good enough then the variables that pop up when we are out shooting are going to dwarf any tiny differences in image quality between two excellent lenses. I threw in some shots with the Olympus 45mm as well. When you get closer to the subject to match the subject size to the 75mm shot, the DOF is roughly the same. So much unnecessary internet-blood has been spilled by people arguing over differences in DOF between different lenses and formats.
Since this is a “battle” I must now choose a winner… The winner is the Olympus, but I reserve the right to change that verdict after shooting with it in the real world (until I have to ship it back). Don’t throw your Pentax up on ebay just yet, though. The 77/1.8 is still an amazing lens that can be used to produce images with a signature look. The slightly older design of the 77/1.8 means it can’t compete on sharpness with newer lenses, but it has just the right blend of character and technical perfection. In fact, I better stop writing about it now because I might end up changing the verdict.
Update: I removed the 100% crop comparisons with both lenses mounted on the OM-D because I messed up the manual focusing. The full images are still available for comparison, but keep in mind that the focus point is different between the two shots.
Warning! This post contains cliché photos of cats, Christmas tree bokeh, and in some cases…BOTH. Please forgive me.
What I like about Pentax is their utter disregard for following convention. There are certain focal lengths for prime lenses that everyone seemed to agree on: 24, 28, 35, 50, 85, and 135. Lenses bearing those numbers can be found in any manufacturer’s lens collection. Pentax however, went their own way: 15, 23, 31, 43, 77. Their FA (full-frame) Limited lenses (31/1.8, 43/1.8, 77/1.8) are renowned for their compactness, build-quality and image quality. Pentax offers some made-for-digital DA Limited lenses (including the 35/2.8 which I own) which are excellent, but Pentax users seem to have a special place in their hearts for the older FA Limiteds. The FA Limiteds are even rumored to have fairy dust in them which makes your pictures better. Since I knew I’d need the extra speed (f/1.8 vs. f/2.8) for indoor photography during the holidays, I decided to rent the 31mm Limited and find out. When the lens arrived, I was surprised that it wasn’t as compact as I expected and it was fairly heavy, but it oozed quality in a way that few digital goods do these days. As is required of any new lens, I tested it on my cat.
Pentax K-7, 31mm ISO1600 f/2.5 1/30
This bored him. I apologize for the gratuitous Christmas tree bokeh. It’s unnecessary and it won’t happen again.
Pentax K-7, 31mm ISO1600 f/1.8 1/60
Oops, there it is again, I’m sorry. Here’s a close-focus, wide-open aperture shot to show off more of that legendary bokeh. It’s sharper at f/4, but the sharpness here at f/1.8 is more than adequate and far better than my Minolta 50mm at f/1.8.
Pentax K-7, 31mm ISO1600 f/2.0 1/80
Oh man, another cat picture. The combination of moderately wide angle and shallow depth of field that the 31/1.8 provides is just plain fun. A shot like this wouldn’t turn out as well with the 31mm Limited’s competitor, the Sigma 30/1.4. Reportedly, the Sigma is sharp in the center of the frame, but very soft in the corners. However, you could buy three of the Sigmas for the price of one 31mm Limited. Hmmm…
Pentax K-7, 31mm ISO800 f/2.0 1/80
Look! People! The holidays are a great time to take photos of the relatives that you don’t see very often, but it can be hard when those relatives get annoyed by being photographed. But what is it really that annoys people about being photographed? Usually it’s the shutter noise (for DSLR’s) or the flash. The K-7’s quiet shutter and the large aperture of the 31mm Limited solve both of those problems. Also, 31mm isn’t so wide that you get weird distorted body parts.
Pentax K-7, 31mm ISO800 f/2.0 1/80
Here’s another shot of game-playing fun and a bit more Christmas bokeh to clog up the interwebs.
Pentax K-7, 31mm ISO1600 f/2.0 1/60
I took this picture of my grandmother getting dessert ready and it’s probably my favorite photo taken with the 31mm. Mmmmmm, pie.
Pentax K-7, 31mm ISO1600 f/2.8 1/60
I don’t have a point to make with this photo, but I thought the internet could use just one more cat photo.
Well, I hope you’ve enjoyed this collection of Christmas snapshots disguised as a lens review. The Pentax FA Limited 31mm f/1.8 lens was tons of fun to use and I’d love to own one. However, it’s very expensive and it’s not as versatile or as compact as my 35/2.8 macro. The large aperture of the 31/1.8 is nice, but there are more cost-effective options out there. Neither of those should count against the lens and in fact I can’t come up with a single thing to fault the 31mm Limited for. Excellent build-quality; excellent image quality right from f/1.8; compact enough; a little heavy, but not too heavy. The great thing about any of the Pentax Limiteds is that they have that extra something that makes them more fun to use and there just might be some fairy dust in them after all.
Bryan Takes Pictures 