Wide Open: Pentax 31 Limited & Leica 35 Summilux ASPH

I have been testing out the Pentax K7 for a few weeks now and today I received a couple of nice lenses to use while I finish up with the camera, woo hoo! Finally happy to get some decent glass with a camera when testing it!  These lenses get super high raves from those in the Pentax community and the owners swear by them. The Pentax Limited FA 31 1.8 is one of these lenses. Many (in the Pentax community) say this is one of the best lenses ever made. A bold statement indeed! Since I happen to have a Leica 35 Summilux ASPH on hand I decided to do a “just for fun” comparison.

I was testing out the 31 on the Pentax K7 today, mainly shooting wide open at 1.8. Just for fun I was snapping right along next to it with my M9 and 35 Lux ASPH, also wide open! After looking at the images on my ImacI figured that some of you may like to see the results. I really just want to show how each lens renders. It’s not about showing crops but more about the “feel” of each lens. I can state right now that the 35 Lux is leagues sharper at 1.4 then the Pentax at 1.8 but what about the color and bokeh? The Leica 35 Summilux is a $4500 lens so I would not expect the Pentax to beat it, but how close can it come for 1/4 the price?

The Pentax K7 is not a full frame camera but the FA 31 Limited lens is meant for full frame and it is beautifully made. It is a VERY nice looking and feeling lens. I will have much more from it in my K7 review (hopefully this weekend). For now, here are some comparisons.

To see the differences clearly you can click each image for a large 1800 pixel wide version.

I shot this with both lenses wide open. The Pentax at 1.8 and the Leica at 1.4. If you view the larger version you can easily see how much sharper the Lux is over the Pentax, which I find soft when shot wide open. Some will say the Pentax version is OOF but nope. Not only did I AF this shot, I also manual focused when I saw how soft it was and I shot this 4 times, each with the same result.

Again, both wide open. I was wanting to see the Bokeh of each lens. The Lux is MUCH sharper here but which do you prefer?

This time the Leica is on the bottom…and these two are straight from camera JPEGS this time.

and one more….

So far I have shot about 50 frames with the Pentax 31 Limited and maybe 15 or so of those have been “real” photos and not  tests. In these side by sides you can see that the Leica is a sharper lens with a more “wow” kind of look. But remember! The Leica is about 4X the cost of the Pentax which comes in at almost $1000. So far, even with it’s softness wide open I really like the Pentax 31 Limited on the K7. It is not in the league of the Leica but there really are not too many that are and for the cost its build, feel and performance is really good. When stopped down to 2.2 it sharpens up nicely. If I owned the K7 or a Pentax Kx, I would probably buy the 31 Limited for myself.

The other Pentax lens I am shooting with is the 77 Limited 1.8 and that lens is REALLY sharp, even wide open. Look for images with both in my Pentax K7 review, which again,  I hope to  have up this weekend. Until then, here is one “real” image from the 31 Limited shot wide open at 1.8 and then converted to B&W using Silver Efex Pro. This is after all what the lens was made for…”real” photos 🙂

Pentax K7 and the FA 31 Limited 1.8 Lens, at 1.8

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  1. The leica is fantastic and quite likely superior to the 31. But I can’t help but think the difference is quite increased by the APSC vs FF aspect

    If you want to check lens performance, now there K1 that is also FF or you could compare APSC crop on the m9. This would focus more on the lens performance than the camera body.

    Sure that if the way to compare is K7 + FA31 or M9 + leica 35 then the latest is better and at time with nother better than K7, it made sense as you couldn’t get FF on Pentax. Now this is different.

  2. One thing has to be taken in consideration here: Leica M9 has FF without Antialiasing filter, while K7 is APS-C sensor camera with relatively strong Antialiasing filter …. no wonder Leica appears visibly sharper….I guess those two lenses can be objectively compared only if you mount them on same camera – possible only at some micro4/3 at the moment….if I am correct…
    anyway thanks for effort…

  3. Steve,
    I must concur with the posters who mention the issue of AF Fine Adjustment on the Pentax DSLR. I use a Pentax K-5 with some very nice Pentax glass (FA43, DA70 Limited, DA16-45), and have gotten very sharp results with all these lenses. HOWEVER, I had to make use of the AFFine Adjustment function on my K-5 (Custom Function 26) before I was assured of good sharpness! Notice I say “Good” rather than “Optimum” sharpness, because I don’t trust my 55 year-old eyes to determine the BEST POSSIBLE Sharpness from my system. Frankly, this is precisley why I am considering a Mirrorless system such as the Fuji X100S or the Olympus OM-D, because a function to adjust Focus is superfluous, because there is no mirror, hence no front/back focus issues! Your image is simply IN focus or it is not. Though my images at totalqualityphoto have been called very sharp by others, since I’m a sharpness fanatic, having used large format systems many yearss back, I simply want to know I’ve reached the “optimum” sharpness and detail rendering possible, and that’s why I’m rethinking my DSLR vs. Mirrorless idea.

  4. Thanks for the comparison. The Leica simply embarrasses the Pentax in this test which I am a little surprised about. I own the 31 and 77 and find the 31 is at least as sharp, probably sharper, than the 77. The 31 photos look softer than I’d have expected given my own copy and experience of it, but the those Leica samples are unbelievably sharp, I don’t think even a correctly focused good copy of the 31 could equal that level of sharpness wide open.

    • twitch, you are not right. The summilux was tested on FF camera, but 31Ltd. It’s clearly seen the key is sensor size in this case.

  5. From the 2nd, 3rd & 4th samples, the FA31 BF slightly. If they were MF, then the viewfinder needed calibration.

  6. It’s the same OLD test! The Pentax was NOT calibrated(what else do you expect?) and after looking again,again,
    I see that there are power lines in the Pentax image. TG for Leica,you don’t need “photoshop”.
    I use Leicas and Pentax. I love lenses that don’t flare. That’s not the case with my Leicas. One can adjust focus on a Japanese Dslr but whadyado on a RF? My shots wide open with a 90mm on M8 were mostly out of focus!
    I know I am not used to RF, using Leicas professionally since 1966. So all the smart mouths, zip it!

  7. I suppose there’s a front or back focus with K-7, as well as shutter-induced blur described by Falk Lumo.
    BTW I envy about your photography skill. There was nothing, but you managed to get appealing shots )

  8. Great job, Steve! It would be totally nice if you post some words how K7 + 31lim compares to M8 + 35cron. I mean everything…your feelings, IQ. Just your thoughts caus you have lots of experience with M8. Thanks!

  9. I purchased the 31mm Ltd some month ago and i am very disappointed. The results are soft and the lens performs worse then a consumer zoomlens. I did run a comparison test between the PENTAX 16 – 45 mm lens and this lens outperformed the 31mm. I did return the 31mm to PENTAX but they rejected my claim. The supplier Konijnenburg was so kind to order a replacement for me.
    I agree that the 77mm is a much better lens and i reserve my judgement on the 31mm untill i have seen the results of the second copy. Furthermore i am disappointed about service of Pentax but impressed with the service of Konijnenburg in The Netherlands.

  10. I know it’s a long time since you posted this comparison, but I came across it through your twitter feed today. I must say it’s a bit disappointing that you didn’t notice the back focus issue before you posted it. It’s also curious that most of your respondents didn’t get it even when Peter G and Rob pointed it out to them.

  11. Mind that there are 2 versions of pentax FA limited 31 and 77 lenses… One with a purple coating which is the latest one (most probably you own that version) and one with a green coating which is the older version. The ones with the green coating are considerably sharper lenses…

  12. IMHO i prefer the look of the Pentax as regards the background(bokeh). i really dislike the aspheric look..How much sharpness is needed?TY for the review. Am a user of Pentax and Leica.

    Side note.Recently purchased a Kodak Digicam 3.2mp.Probably on of Kodak’s 1st easy used, real cheap box.It has simply stunning colors. Yes, some are too magenta(blacks/shadows). The screen no idea of the magic when one downloads. It is similar to Kodachrome.Sharp like you cannot believe.I’ve used a friend’s M8 and it’s so similar in look!

  13. The review of the lenses superb. Lots of hard work. True,maybe not as familiar with DSLR as your Leica M9.The bokeh of the Summilux sucks at maximum aperture..It is a common sight on all aspheric lenses of Leica. I hate it! I’d rather keep my outdated older lenses. I use professionally Leica M’s,Nikon F’s and F3, Pentax’s of many kinds(all cameras are film). The Pentax’s have simply been the best in terms of service. What services required? On the other hand, I know the first name and often names of family members, of the folks, all over the world, who are needed to keep my Leicas going.. The Nikons mainly needing repairs for being thrown, dropped and stoned..

  14. Dear Steve; pease look again at your pictures and see how the plane of sharpness is not identical for the Leica and Penatx versions. This is especially evident for the 2nd and 3rd examples. With the 3rd exapmle the perspective (angle of vision) differs also. Do you really consider images with different plane of sharpness and different angle of vision helpful for comparison purposes?


  15. Steve, I am new to your website, but I gather that you are mainly a Leica M shooter and are not very familiar with modern DSLRs. This explains why you were not aware of the capacity for user adjustment of AF on the K-7. This is a relatively recent feature on DSLRs, so your missing it is certainly understandable. I consider it to be a great advancement, as it allows the end-user to get his/her lenses focusing very precisely without having to send the camera and lenses for service.

    My own K-7 is brand new, and I am loving it as well. Up until a few years ago, my main camera was a Contax G2, so I know the joys of rangefinder shooting (automated variety.)


  16. Steve Huff wrote: “No problem, doesn’t bother me at all. I like to let everyone have their say and voice their own opinions!”

    If this means that you have no bad feelings, and that you will take into account the above accoments, than I am happy for and with you.

    If however it means that you mean to carry on without reconsidering yor testing procedure, that would simply be bad.

    Greetings from Hamburg


  17. Steve, I hope you don’t take all these too seriously, not a good way to welcome you to the Pentax family. Just hope you know that we’re all not like this.

  18. Well, for some reason, the photo did not show up. I will try again. As I understand it, I am supposed t enter the URL where the image resides.


  19. Here is a sample of the what a calibrated Pentax 31/1.8 Ltd on a K-7 can do wide open. It is a photo of some fabric with lots of texture shot at minimum focus distance, f1.8, ISO 200, 1/20sec, handheld. I would say that the Pentax can give the Leica 35/1.4 a good run for its money. Hope that it shows up well, as I have never posted an image to this forum before.



  20. Regarding the importance of focus calibration, I don’t think that Steve is the only one who has failed to take this into account when publishing his tests. I would bet money that none of major photo websites do it either. So when you are pixel peeping at comparisons of Camera A and Camera B on Imaging Resource or dpreview, keep that fact in mind. It is possible that they bracket focus, but I have seen some examples on those sites that are definitely out of focus.

    Undoubtedly, the rangefinder on Steve’s Leica is properly calibrated. It is really a simple matter to calibrate the K-7 using LensAlign, and I would love for Steve to repeat the comparison of the two lenses after doing so or after using any other valid calibration method. My guess is that the 31 Ltd will perform better than before. Overall, I think that Steve’s reviews of the K-7 and the 31 Ltd are useful, because they are written from the point of view of a skilled photographer using the gear in a real world fashion, rather than from that of a techno-geek locked up in a lab. The photos that he publishes are a pleasure to see as well.


  21. 1.) You did not compare lenses but lens + camera combinations.

    2.) I cannot see how you can claim to be able to say anything about the lenses’ (or lens + camera combinations’) sharpness, if you obviously were not evben able to make sure that the FA31/1.8 Ltd. was focused correctly. AF cannot be trusted, and manual focusing without a proper focusing aid is worthless unless you focus the lens several times with a very small focus increment between subsequent shots.

    3.) To test or compare lenses properly is a very demanding task. Better think again before publishing another “test” whose results are simply not true but only misleading.


  22. Of course, Leica 35/1.4 is outstanding, but the system are too different to compare. IMO.
    18 MP FF CCD without AA filter and 14.6 MP APS-C CMOS with АА.
    If Pentax makes FF camera with Kodak sensor without AA filter….:)

  23. I enjoyed your review. Regarding the softness of the Pentax 31 Ltd wide open, unless you took the time to properly calibrate the focusing, it may indeed be out of focus. This is true whether you used manual or autofocus. In the case of the former, what you see through the lens optically is not necessarily what the sensor sees. Steven Tapes discusses this topic at his LensAlign website. My K-7 had severe backfocusing issues straight out of the box, but they corrected nicely with careful AF calibration.

    I am not claiming that the Pentax is as good as the Leica lens, but rather that the testing procedure may not have been optimal.


  24. FA31 has the same sharpness wide-opened as FA77. If you say that FA77 is sharp and FA31 is soft…;) It means his copy of FA31 is not good…100%.

  25. Anyway, FF LEICA WITHOUT AA filter will be ALWAYS sharper than ANY APS-C WITH AA filter. It’s not comparision of lens resolution and sharpness.:)

  26. Not correct comparision.
    M9 has 18 MP FF CCD, K-7 – 14.6 MP APS-C CMOS.
    Leica has no AA filter, K-7 has. If it’s JPEG, I can say that there is difference in JPEG defaults and JPEG engines.

    I don’t see that Leica is MUCH sharper. It’s very good at f1.4 But at f1.8 both lenses are very close.
    As for CA – FA31 has very low CA. What are you talking about?

    APS-C camera + lenses need PP and additional sharp.

  27. Shocking difference. Love the penax, love these tiny sexy limiteds but hey, leica just ate that lovely limited. It would be nice if you’d compare 77mm and another similar leica lens 😉

  28. Wow I can’t believe how sharp the Leica is at wide-open, it’s almost impossibly sharp at f/1.4, even the bokeh is so much silkier than the FA 31, despite some even saying the FA 31 lens has the best bokeh they’ve ever shot with. The FA 31 f/1.8 is known as one of the best when compared to all from Canikon to Olympus, but not in the league as the Leica and nowhere near at all! Now when people say these Leica glass are in a whole ‘nother league, I really understand now; before I just thought that Leica is just for the name and is no different than Canikon, but now this comparison tells a whole different story.

  29. Because of the lack of AA filter in the M9 and the larger sensor, I think the difference between the two lenses is exaggerated. The increased DOF of the M9, for example, is bound to make the bokeh seem smoother on the Summilux, and this with the sharper image from the M9 is key to producing that great image pop. In my use, the photos from the FA31 wide open often need just a touch of sharpening in post to get a similar look.

    This said, I would not be surprised if the FA31 would be bested by the Summilux even under identical conditions. I’m glad the FA31 can even compete on this level.

  30. I think the fact that Steve chose to use the Leica for comparison purposes is a real compliment to the Pentax. There’s no doubt that the Leica is superior.

    Steve, have you compared the Pentax lens to the Panasonic 20mm 1.7? I think my decision for an affordable small body camera (I could care less if it’s micro 4/3 or an slr) might rest on the lens options.

  31. well if I had to make a statement between the two… the pentax captures images, while the Leica captures art. Who would want to even think of capturing the first example as Steve has with most cameras? well any of the pictures…. look at the isolation of the focus point, compare the colour, compare the other attributes that let the eye realize fully what the intention was. I don’t own a Leica, and I’m not going to try and argue, its what you are willing to pay for said tools.
    Yes the last picture is excellent… but if you took the same with the Leica – perfect??

  32. …absolutely agree w/ Matteo…wow!!! It just seems like the curves, graphs and charts take care of themselves when art is born. Nicely done…thanks.

  33. Hey Dan, I will assume that the next version of the K7, wether it be a K8 or K7II WILL have the improved sensor. They would be nuts not to do that but a full frame would be even nicer 🙂 The K7 is almost a perfect DSLR in regards to build, features, quality and price. Only thing holding it back is the high ISO performance.

    I can see myself buying one of these (or its successor) with a mix of DA and FA primes. The size is small, the build it high and it is a system with quality fast primes. Perfect!

    • well, its 7 years down the track, and….. Pentax KP ticks all the boxes you mention. High ISO, no AA filter, and pixelshift for true colour fidelity.

      Im considering a KP and set of LTD primes as a genuine alternative to getting a new digital M. Although its an SLR of course, its kinda similar to an M in many important ways. Weird but true. Closer than an XPro. Philosophically they are very much tuned for careful and deliberate stills shooting, with no compromises made to broader market appeal.

      Would be interested to see what sort of music it played to you, if you could have a decent session with one, from the point of view of an M shooter.

      Would be an interesting comparison for sure.

  34. Steve…I always enjoy your reviews and the information you provide. I am in the same boat with Mr. Cadman. I want the body of the K-7 and the sensor of the K-X. I was originally going to add the E-P2 to my arsenal and still may, but a K-7 paired with a DA limited pancake makes an awfully attractive combination.

  35. Thx for all of the comments guys. I have manually focused the 31 as well as used AF and no matter what the focus point the lens is soft wide open and has a dreamy look to it much like some classic Leica glass. Now the 77 is an AMAZING lens and has superb color, contrast, sharpness etc. The 31 is also nice but the 77 is better. Review should be up Saturday with TONS of images 🙂

    • Where is the 77 review/comparo going up? I am excited to see the results! I like the way you do your reviews, gives me a real feeling of how the glass performs. I am on the fence with getting the FA Limited 77… but the price keeps telling me its not enough IQ or pixie dust to get it.

  36. Steve, I also think the Pentax shot is not precisely focused as the Leica one. After all, FA 31 Limited has been well known for its sharpness right from F/1.8.
    But anyways the 35lux shot is really awesome. It’s worth every penny.

  37. The pentax does well. I like the small build of the pentax lens and I am curious what it can do in Steve hands. Of course its not a leica 35mm lux ASPHalt but it does rather well.

  38. Anti-aliasing filters aside, the Pentax lens + K7 combination has an obvious problem in the comparison pictures; back focus. The plane of sharpness of the Pentax combination is clearly some inches (depending on subject distance of course) or so behind the plane of focus for the M9+summilux. Look at the fence for instance, the fence is pretty sharp to the left on the Pentax, but unsharp with the Lux because the plane of focus on the Leica is closer. On the jpeg-picture of the flowers the pentax plane of focus is also a bit behind, making it impossible for the central flower to “pop”. The lux is clearly much better, less abberations, but not as much as one first would think.

  39. Hi Steve
    The Pentax is nowhere near the Leica in any aspekt. Thats why we in a calm resignation will like to spent that amount of money…..to get those pictures with a little magical vision inside……thats the whole difference….but its the crucial factor….
    Thorkil Brodersen

  40. Hi Steve or anyone else, I am at the end with all my research. I like the body and looks of the K7 plus a lot of other things But keep hearing better things about the KX sensor.The KX seems to perform better in low light and at higher ISO. Low light performance is crucial for me and using flash is not an option.I plan on using an (Older) Pentax SMC 50 mm 1.4 and possibly one or both of the lenses that you’re reviewing. I can’t decide ~Please~ Help ease my decision between the KX and K7.

  41. if i ever got a pentax slr / dslr, i would just get those two limited primes you mentioned, beautiful. Im trying to get rid of my nikon zooms as it is.

  42. WOW, those 35 lux images just jump off the screen. Amazing. It’s really just in a whole other league.

    That said, I think the Pentax set makes a decent showing for $2000 of equipment.

    I think Vlad raises a good point with the FOV, though I’m not sure cropping is the trick. I’d be interested to see it next to a 50mm lens.

  43. The Leica M9 will be always be sharper because of its lacking an AA filter.

    The only SLR that does not have an AA filter would be the new SD 15. There are some folks that convert sigma to canon mount with autofocus intact. It would be cool if we can compare the sigma with zeiss ZE lenses with the M9. Albeit the the pixel difference there will be common ground for comparison.

  44. Vladimir: That’s a statement I’ve never heard before. I know the crop factor gives an extended zoom and greater depth of field but I’ve never heard that APS-C sized sensors are less sharp than FF sensors. I know for a fact that sensors with AA-filters are meant to capture less detail than those without (which is the case here with the K-7 vs M9) but the sensors themselves should be just as sharp.

    Steve: The 31 f/1.8 bokeh looks harsh to me. It seems to look even harsher because of the side by side comparison to the 35 Lux 🙂

    • > That’s a statement I’ve never heard before.
      It works for the equal effective focal ranges. The example: 31mm on K-7 ≈ 46mm. But the real 46mm gives higher magnification than 31mm, so the resolution of the 31mm should be higher to achieve 46mm sharpness on the FF. It looks like Steve tried to get the same frame size for both lenses. But this case is different: it looks like Steve tried to get the same frame size with both lenses. It means he need to step backward with K-7 (remember the 46mm of EFR!). So, in this case 31 which still has lesser magnification than 35mm Summilux should achieve better resolution from the longer distance.
      That is the explanation why the FF cameras gives better shots than APS-C ones: because they are not so exacting with lenses. It also shows why FF cameras will never achieve medium format quality.

    • I am surprised you haven’t heard this before. Of course the limited 31mm has disadvantage in this comparison. Let me give you an example: If you put two identical 35mm lenses on a full frame camera and also an aps frame camera, and shoot at the same distance, you won’t see the same pictures. The FF camera will give you a much wider view. So to get the same angle of view, you need to either crop the picture of the FF camera, or move the FF camera closer to the target and shoot a new picture. After you crop the middle of the FF picture, you will need to amplify it 1.5x to become the same size as the pentex picture. Then your picture becomes less sharp.

  45. Steve-
    Thanks for putting this up. I really like your review style. Due to the crop factor on the Pentax the FOV will, of course, be different between the two lenses. I prefer the way the Summilux renders, but the Pentax seems like a very good value. I mean, the K-X kit is currently under $550 at B&H. Put that image stabilized body together with an f 1.8 and you have a machine that will be great for low light conditions and cost around $1500.

  46. Thanks for the test, really interesting.
    But actually images on the FF M9 will be always sharper just because sensor bigger, you should crop M9 images to APS-C sensor size to compare real sharpness.

    …love your photos,
    and sorry for my English. 🙂

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