What makes a ‘good’ lens? (part II)

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This might seem like a very obvious question, but the moment you try to define a set of criteria to quantify ‘good’, you soon realize there’s quite a lot more to lens performance than immediately meets the eye. So, for those of you without the ability to try a large number of lenses – let alone samples of the same lens – how do you know if the one you’ve got is ‘good’?

Continued from part I.

Today, we start with what is probably the most subjective of all of the pictorial qualities of a lens. Generally speaking, ‘good’ bokeh isn’t distracting. Distractions are caused by areas of an image that unintentionally stand out; in the case of bokeh it takes the form of double images, hard edges to highlights, geometric shapes of highlights, and color fringing. Few lenses are optimized to also deliver neutrality in the out of focus ares – this requires correction for spherochromatism and longitudinal chromatic aberration. The very best lenses have a smooth transition from in-focus to out-of-focus areas with no odd artefacts in the intermediate zone; subjects should be recognizable but not distracting.

Ergonomics, build and ease of use
I think this category is pretty much common sense: are the rings located easily to hand? Do the switches move accidentally? Is it robust, weather-sealed and does the hood stay in place? Do the extensions wobble if it’s a zoom? Is it front-heavy? Bottom line: do you feel comfortable using it, or do you have to consciously change the way you shoot to accommodate the lens? A good example is the Nikon AFS 200/2 VR: optically, it’s one of the greats. Ergonomically, it always throws me off balance: it’s not very large, but very front-heavy, and the hood is far wider than it needs to be – so it can reverse over the stubby tripod foot that usually creates mounting issues with bodies that have a vertical grip because there’s no longer sufficient clearance between that and a large tripod head.

Autofocus performance – speed, accuracy and ability to precisely accommodate small changes in subject distance – is a function of both the lens and the camera’s AF system. Most of this depends on the type of motor used to move the focusing group; ring-type coreless DC motors (USM, HSM, SWM etc) can move quickly and in small increments. Lenses which are body-driven will have some backlash in the gear train that can cause slight focus ‘misses’ that become an issue with small changes in subject distance and fast apertures. In such situations, it’s often better to completely defocus the lens and start again to eliminate slack in the gears/ helicoid.

Manual focus and spacing/ gearing
Here’s another highly subjective quality. Some people prefer tight rings, others loose; regardless, backlash/ slop is not desirable because it makes small changes in focus distance difficult. This is usually the result of a helicoid with tracks that are slightly loose, or multiple helicoids not meshing properly. You also don’t want a lens that doesn’t have sufficient throw across the distance range – it’s difficult to hit a precise difference if only a tiny movement is required to go from infinity to 2m, and fast gearing also tends to increase the impact of backlash since tolerances remain similar, but will have a larger absolute effect.

Lenses that have increasing reliance on electronic components – motors, stabilisation actuators, focus clutches, distance confirmation chips, buttons, etc – both have a greater potential number of failure points, as well as limiting compatibility. Put it this way: you can mechanically adapt a 50-year old lens to a modern mirrorless body, but modern DSLR lenses may not even have aperture control. Though these protocols can be reverse-engineered, they don’t always work very well…

System matching/ performance
Optical formulae are always derived with an ideal back focus distance in mind. Changing this will inevitably change the optical performance of the lens. Beyond this, digital photography has introduced a new complication: the sensor surface is not flat and relatively homogenous at the microscopic level, but rather takes the form of a collection of pits – each of which contains a photosite. This affects both light collection efficiency and introduces potential optical issues due to shading and interference effects with the walls of the pits. Though modern sensor designs now incorporate microlens arrays to increase light collection efficiency – effectively focusing light from the sensor directly onto the center of the photosite – they also add another optical element into the system. Perhaps the most obvious example of this interaction is when you look at the corners of older wide angle lens designs; the output rays are not telecentric – i.e. they subtend from the exit pupil of the lens at an angle – which creates not only vignetting/ shading at the photosite level, but potentially also causes added chromatic aberration and color shifts due to interaction with the microlenses. In effect, each microlens for each individual photosite is another optical relay within the system: it too has to obey the same laws of physics as a complete lens. Although offset microlenses can compensate for this to some degree, modern ‘designed for digital’ lenses almost always perform better as they tend to be telecentric to begin with – thus negating any potential radial effects.

Ergonomic and electronic issues aside, it is also for this reason that dedicated lenses tend to perform better than adapted ones – aside from potential planarity issues leading to decentering and tilting. There are of course exceptions to both rules, but in my experience with dozens of different sensors and hundreds of lenses, this is generally the case.

Caution on using converters, filters and adaptors
Again, though there are always exceptions to this rule, additional optical elements will degrade overall system performance because lenses were not designed for to accommodate them in the first place. It’s why using a teleconverter on a fast wide will produce terrible results compared to a normal prime, and why superteles tend to not exhibit very much degradation with teleconverters. It’s also why cheap filters are a bad idea: the glass may not be perfectly planar, the coatings may be poor and introduce flare/ reduce transmission, and if they break or crack – you’re still going to land up scratching the front element anyway. As for adaptors between systems/ mounts – just bear in mind that you are introducing an additional pair of mount surfaces into the equation, both of which may potentially decenter or tilt the entire optical assembly. It is even more apparent with a high resolution sensor; scientific tests by various other sites such as Lensrentals have found this to be the case, and it matches with my own experience. Never mind the fact that you’re going to at very least lose AF and gain size/ bulk…

A note on built in lenses
Built-in lenses take two general forms: zooms in utility (‘Swiss army knife’) cameras and high quality primes (GR, Coolpix A, X2 etc). There are also some good zooms – the RX10 and X Vario come to mind. The higher end of this spectrum tends to perform very well indeed; the GR’s lens has a bite to it that is matched by few – if any – interchangeable lens solutions of a similar size. This is simply because these lenses are almost always designed to match the sensor; the entire optical system is optimized from the start. Practically, this means a GR may well be a better solution than looking for a good 28mm-equivalent for your APSC or 24MP FX DSLR.

Lastly: there’s always that special ‘something’ – an indefinable quality that makes you simply like the quality or rendering style of the output. Quantitatively, it’s a combination of many of these factors; however, it can be harder to put a finger on. Although a good lens may have high resolution, flat field, no distortion, uniform spectral transmission and low chromatic aberration, you might also like one that has moderate resolution, strong field curvature and warm transmission because it renders skin and portraits beautifully. I find that lenses with a very distinctive ‘signature’ tend to be quite polarizing: either you like the look, or you don’t; if you don’t, there’s not much point in buying one since you can’t do a lot to neutralize it. However, the opposite is also true: a lens that’s completely neutral and ‘transparent’ adds no character of its own: it’s all down to the photographer. Transparent or not, it’s still down to the photographer. MT

A future article will deal with the increasingly important topic of sample variation.


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  1. I’ve just come back to the site after a 5 month hiatus while real life intervened and thoroughly enjoyed catching up on the posts I’ve missed.

    Your comment on the “Special Something” made me stop and think: is this what makes photos (which invariably turn out to have been taken on Leica cameras) stand out? Not the camera body but the lens? Do others get the same reaction to Leica glass? Or is it the photographer’s style, which is brought out by the special type of camera used?

    • I don’t agree with that observation, sorry. I’ve had people mistake my iPhone images for Leica images and vice versa – in the film days, there might have been some logic to it, but post processing is the great equaliser.

      • Interesting, it would be enlightening to compare some without knowing the camera and lens being used.

        • And there the great democratiser of printing comes in. There’s almost no way to tell what’s what in the final output – just good and bad.

  2. Peter Boender says:

    I found that system matching / performance plays a very strange part in the determination of a lens being “good”. For example, I’ve always been an enormous fan of the AF DC-Nikkor 105mm f/2.0D. With it’s sharpness, contrast, acquity and especially it’s bokeh, I felt that “special Nikon optical signature” all over it. But now that I use it on my Nikon D800E, I’m beginning to see some flaws. For instance, I particularly notice some heavy Longitudinal Chromatic Aberrations (LoCAs). Does that make the lens less “good”? In a sense it does, but it also makes me realize that today’s top bodies are very scrutinizing. That requires taking a look at your entire arsenal of tools when changing/upgrading parts of it. The upgrade path is not so simple anymore. I can see why Nikon is advertising the use of it’s gigantic user base of legacy lenses with the Df (and not with the D800 or D800E). That 16mp sensor is very fast and very capable in low light, but maybe not so critical optically. Back to my short tele: I’m now wondering if my system performance with the D800E would benefit from the more modern short tele Nikkors, like the 85mm f/1.4G (big, bulky and expensive) or the 85mm f/1.8G (nicely sized, good balance, best performance/price relation ever, but no nano coating, however will I notice?). For the time being the 105mm will do (especially in B&W), but it remains something to consider.

    BTW, I wish Nikon stuck that 16mp sensor in the D800 body, give it a big buffer, make it do 10fps RAWs and call it the D800S. Would make an excellent action/sports/PJ camera, wouldn’t it? And an excellent companion to the D800(E). No-brainer…

    • Spot on, Peter. The 24/1.4G and 85/1.4G pair I loved on the D700 were pretty poor on the D800E; basically, if a lens works well on the D800E, it’ll be just fine on any of the lesser resolving bodies. And to answer your question, I sold my 85/1.4G for a 85/1.8G because it doesn’t suffer from anywhere near as much CA; it will do, at least until the Otus 85 arrives later this year.

      A D800S as you propose would eat D4 sales…

  3. Brett Patching says:

    Thanks for describing all the aspects of lens performance in clear and simple language Ming! There are some things that I finally understand thanks to these two articles.

  4. Marcelo Vaz says:

    Otus is currently the most acclaimed lens whose focus is manual. Have you tested your nikkor 58mm 1.2 on d800? In terms of resolution it does not fulfill its role better than any other nikon G lens (mainly f2)? I’m interested in a nikon 50mm 1.2 AIS and would like to know if it is a good lens?

    • Yes. The 58/1.2 has nice pictorial results, but needs to be at f2.8 before the centre sharpness matches the Otus, and the edge sharpness never matches at all. LCA and LoCA are on a completely different level, unfortunately. It is on par with the current Nikon G lenses, and I think slightly better than the 58/1.4 G.

      The 50/1.2 and 58/1.2 are NOT the same lens at all. The 58 has an aspherical element, the 50 does not. Performance of the 58 is much better, but then again so is the price…

      • liramusic says:

        Ming, your blog is great! I did not even know what Otus meant. My thoughts are so random but to me it makes me love photography all the more. I see bokeh as a driving force here in these designs and “the cinematic look.” I see that as the direction and also in my small mind where I want to be. The fact that it is expensive is a footnote. I find myself looking at the backgrounds of photos and skipping the subject. I am being cute here, but “that look” as if one is in a darkened theater; the idea of a large or huge lens that takes me visually to a land that looks like a dream. I am a musician, but photography can seem like the coolest art form in the history of the world. Who cares what your eyes see. What does your heart see… These expensive lenses are amazing. It just makes me laugh the way people cut them down. But yes, you have pointed out that no matter what the beauty of its design, it matters if the tool serves my needs. As a photographer, I am trying to extras something and so these are my tools. Do they work for me…

        • liramusic says:

          “to express,” not “to extras.” auto spellcheck gets me every time. Sorry, jim

        • The Otus is a lens (Zeiss ZF.2 1.4/55 Otus APO-Distagon – review here). Possibly the best lens made for a DSLR, bar none.

          But yes: about as useful as a bottle cap unless it works for you 🙂

          • liramusic says:

            Whoa, “I’d like to see the bottle that goes with that cap.” I go to sleep dreaming that I’m on a magic carpet and counting all my bottle caps.

  5. Recently, I got a Coolpix A to complement my DX setup. For me, it’s the DX wide angle that Nikon never made, with a nice sensor to boot. No regrets at all.

    • Yes it is…in fact, you’d probably pay close to the same money if they made an 18mm prime as good. Except here you get the rest of the camera thrown in too…

  6. Tom Liles says:

    Well, that’s the first time I’ve seen a Noct-Nikkor on an F2 Titan called cliche. Iska might be a stern Marxist critic, pre-occupied with structure and not content. You never know.

    Just on AF and the good aspects of AF, as we’ve looked at “good” here, my objectively best lens (on criteria over pts I&II) — the Micro Nikkor 60 ED — definitely loses on AF. I’m not judging unfairly on something inappropriate like its ability to lock quicky on things out in a busy street scene, or on a well defined target in vigorous motion (sports, etc); no, I’m judging it on studio setting AF performance with a static or barely moving subject—it’s really quite surprising how it (or it and the D3) just can’t lock on to an easy target, sometimes. Or how it can completely lose lock and confuse itself with slight subject movements or re confirming a previous lock with a press of AF-ON. Particularly apparent in AF-C: the target can be in focus and a small shift (model shifts body slightly) and whump, it loses the plot completely and takes a close to in-focus image and blurs it utterly. Manually turning the ring back to a closer distance sometimes works; but usually it requires turning the camera off and on again. And since in that situation I’m usually tethered, it’s the minor kerfuffle of stopping and restarting the capture session; but over and above, the person (usually) at the other end of the lens going “wow, he can’t even focus the lens? Ok…”

    I’m not sure it’s something inherent in silent-wave motors (which should be good for incremental changes); doubt it as as other AF-s lenses I own don’t do this; it seems obviously something to do with the macro functionality. And some effect this is having on phase detect, as, as I say, the same situation and a 50G, for example, has no problemo—all other things being equal.
    Maybe a dedicated range switch (as on the side of the Coolpix A or RX1, etc) on the lens would be an idea?

    • I actually think the optical properties of lenses should be evaluated independently of AF, since poor focusing can really make a mess of things. Fortunately we have live view these days.

      The problem with the macro lenses without limiters is that they can throw themselves so far out of focus relative to the target (due to the wide focus distance range available) that you may well land up with phase exceeding 180deg and confusing the AF system. The simple solution is just rack it back to the ballpark manually, and the camera will sort itself out.

    • Barry Reid says:

      In the end I, think, static subjects are often hardest for AF systems to handle. I gave up on AF for a lot of my architectural shots long ago. In recent experience even the Eos 1Dx can fail to consistently achieve satisfactory focus on architecture and architectural details.

    • Peter Boender says:

      [Tangent Mode ON] You were dying to get the kerfuffle in, weren’t you 🙂 Very nice! [Tangent Mode OFF]

      • You need to give him a more challenging word.

      • Tom Liles says:

        Peter> I was. I also got “bagsy” in in pt.I one. They just roll off the keyboard, what can I say 🙂

        Ming> The German word for lollipop is a challenge. Peter knows it; I’ve forgotten it. While I’m on the Germanic words though, lex non-grata around me is Schadenfreude. All good words are “look at me” words, but the sch-word is look at me in such a bad way… Trendy Guardian writers love it—just to give everyone a feel for the cringe factor.

  7. Sorry. For poor formatting whilst editing mobile. I hoped to add that sometimes less-than-ideal may come up better than nothing at all. Or the reverse. Sometimes well worth the added investment, case by case depending on what the objectives are. Preferences on the other hand …. ;b

  8. liramusic says:

    I am in awe of your narrative. Merely one comment that is so obvious, and I would bet that you think respectivly “oh well,” is to be careful of manufacturers’ ads for their own lenses. What I mean is that, manufactures entice and make us feel that all high-end lenses will be part of “ecstatic-lens experience.” Reading their ads, I become light headed and want every single lens they every made (nikon in my case). Up until now, I have chosen gear only via the internet ads and even Amazon comments. I need to be more careful. I live a little bit away from things in a rural area. There is no camera store. So what do I do? I buy expensive gear and hope for the best– until now. Your blog is very, very nice. Thank you.

    • Thank you.

      For the most part, the expensive stuff is good, but it may not be for you. I noticed after the Otus review a lot of people realized that whilst the lens is excellent – it probably wasn’t for them because it doesn’t work for their applications (Frequently requiring AF, for instance). Similarly, if you’re always going to shoot stopped down, I cannot think of any reason to buy say an 85/1.4 G over a 85/1.8 G.

      And beware sample variation…

      • liramusic says:

        Indeed some wish to buy camera gear to be fashionable or to hope to become better. I think that expensive items can be atheistically beautiful to gaze upon. I am not rise at all but I recognize these different ways of seeing things. 🙂

  9. To me the discussion of adapters brings up tradeoffs of being able to invest in a range of glass for all the mounts
    / bodies on hand, vs a less optimal experience with an adapter, vs don’t bother at all with the less desirable combination

  10. Dirk De Paepe says:

    Great two articles, Ming. Again, I learned a few things. Thanks for that.
    A few considerations though. Concerning adapters, you write “Never mind the fact that you’re going to at very least lose AF and gain size/ bulk…” Indeed, AF will be lost, although some adapters, like some of the Metabones, transmit electronic data and keep the AF active – yet it will probably get considerably slower.
    On the other hand, gaining size/bulk is a very relative matter and depends of wherewith one compares. If you compare with the body where the lens was created for, as a matter of fact you will always end up with a lot less size/bulk if you use this lens with an adapter on a mirrorless body, since this body will be much lighter/smaller – otherwise it would be impossible to apply this lens via adapter. And compared with native lenses on the same body, often you’ll still end up with a smaller lens/body combination, although this depends of what specific lens you use. But I think it makes the most sence to compare a certain lens with the different bodies (DSLR versus mirrorless) and in that case, the adapter application with mirrorless body will be the more compact and light one. So in fact you add some bulk with the adapter to save a lot more bulk with the body. Saving total size/bulk – not gaining. It makes no sence to consider only the lens, when talking about size/bulk, it only makes sence to consider the body/lens combination.
    Besides that, indeed one ads a pair of surfaces with the possibilty of planarity issues. I experienced this with some old Jupiter lenses, for which I used cheap adapters. First I thought the lenses were really not that good, when mounted on a FF body, but after reading one of your former articles, I tried other adapters, which improved the situation considerably. So reading your blog proved to yield direct results! 🙂

    • Putting total size and adaptors aside – there are ergonomic issues. Mirrorless bodies handle much better with smaller lenses as they have smaller grips and less area to hold. SLRs can work with both, though I find them better with midsize lenses. Put a large lens on a mirrorless body and the ergonomics are shot; which in turn means reduced stability and compromised images…

      • Dirk De Paepe says:

        Correct. But the Sony A7r offers a solution for bigger lenses: mount the grip. I think I have proven this, by putting a selfie on my flickr page, called “Selfie @ f/1.4 and 1/10sec (36MP file)”. It is shot before a mirror with A7r+Otus, out of hand at a shutter speed of indeed one tenth of a second. I experienced this combination to be exceptionally well balanced and just wanted to prove this by going to the very limit. I posted a full size file with Exif data, so one can check the shutter speed. Looking at 100%, one can see that the focus was correctly placed on the text around the lens and that there was no moving blur. I don’t have to tell you that this is a very delicate operation, with Otus at f/1.4. I chose f/1.4 and a very precise focus point, to make it as difficult and as clear as possible. With less than perfect balance and stability, it would have been plain impossible to realize this. So nobody can claim any longer that Otus + A7r has ergonomics issues. I’d like to see this shot taken at 1/10s with a D800E…
        I think it’s time to get rid of some prejudices about mirrorless – or at least to prove that it’s wrong to generalize, because the A7r is a great tool even with big and heavey lenses.
        BTW, also on tripod, this combination is perfectly balanced, which I show in a picture called “Tripod balance”. The clamping knobs are fully loosened, still the camera doesn’t fall aside. This allows for fast and perfect framing on tripod and great stability, because of perfectly distributed weight. As good as it gets. I guess the D800 with Otus on tripod will be pretty unbalanced, compared to that, falling forward due to the 1kg Otus and the mounting on the tripod with the body screw. I guess stability will not benefit from this uneven weight distrution. Correct?

        • Except once you attach the grip, it’s no longer small anymore. You require the same size of bag to hold it as you would a full DSLR.

          We’ve gone in endless rounds on this topic already after the A7R review. I’m pretty sure we agreed to disagree. If you find something that works for you, good for you – there’s no need to try and convince me of it. I’ve tried it for myself and no, it doesn’t work for me. I find the ergonomics terrible with or without grip, and unpredictability of shutter vibration/ double images rules it out as a professional tool. You may only have one chance to get the shot. I don’t want it to be blurry.

          • Dirk De Paepe says:

            I fully appreciate that, Ming. And I’ve said before: would I have your job, I’d make the same choices as you do for sure. In my case, being able to shoot compact and big whenever I want with one body is a real advantage. And missing a single shot is not a disaster for me. Unlike for you. Absolutely. Having said that, I think Sony will take care of the shutter issue in the (near) future. They had a long way to go and approach step by step, sometimes they take huge steps to even lead the pack in some domains. I will probably buy a new body then, although I’m not bothered with the one I have.

            • I certainly hope so. There’s something to the A7R, but it isn’t a mature product (or one that should have been released, frankly). Given the number of other serious users who’ve found the same problem, I’m surprised – actually no, just disappointed – at Sony’s arrogance and refusal to acknowledge the issue. That doesn’t really bode well for consumer confidence and after sales service. Buying another product to replace one that’s fundamentally flawed in the first place is insanity – for a $2 pen perhaps, but not a $2000+ camera…then again, finances are relative for everybody anyway.

              • Dirk De Paepe says:

                Frankly, I don’t doubt those shutter issues, because so many photographers, that I appreciate a lot, mention it. But I shoot with my A7r like I always did, at all shutter speeds, and some of my pictures are a no-go, but many are – like it has always been in the past, with no better or no worse keepers rate. Are those no-go’s partly because of shutter issues? Possibly. But honestly, I couldn’t tell. When the next generation body is announced, chances are that I’d buy it anyway – that’s what I have been doing four the last forty years. But at this moment I don’t feel the urge that much, because I’m happy with what I have. Still I understand your resentment against Sony, when I hear what you experienced. Personally, I have the best experiences. I had a sensor changed with my NEX-7, without questions, at their suggestion, because of a central blue spot, which afterwards appeared to be due to the (non-Sony) focus convertor. I guess you understand that I have no complains. But I dealed with our local distributor and we’re some 14000km apart. Maybe that makes a difference…
                About flaws, what to think about the first digital Leica Ms, sold three times more? From a company with the greatest legacy?

  11. A very interesting pair of articles. Thank you for taking the time. They help to explain things I regularly experience. I was happy to see you left a blank for that special “something” that refuses to be quantified or otherwise accounted for yet can be very apparent.

  12. Reblogged this on This Got My Attention and commented:
    More great information!

  13. Iskabibble says:

    You know, fewer shots are more of a cliche than the “focus on the lens writing, blur out the camera” shot. Hasn’t this been done about a million times??

  14. Thank you for this informative and thoughtful lens article. I learned a number of things. Your blog is my favorite photography site on the internet.

  15. Ron Scubadiver says:

    There is a lot of interest in manual focus lenses, but the only one I have, a Rokinon 85mm f/1.4, seems to me to be too hard to focus.

    • It’s your focusing screen, not the lens. Modern cameras are simply not set up for manual focus, and the pixel density (and consequent demands on focusing perfection) really don’t help, either.

      • Ron Scubadiver says:

        I agree the focusing screen is a problem. Pre-AF cameras had something in the middle that helped with accurate focus.

        • The micro prism collar and split prism center? The matte portion of the screens was also coarser, which aids focusing but is darker – and not really suitable for f5.6 consumer zooms…

          • Ron Scubadiver says:

            Yeah, that is what they called those things. Anyway, I like the speed of AF. I want to be able to concentrate on composition and don’t have much time with candid and street. If the camera does more of the work, I am better off.

  16. Barry Reid says:

    Lenses are so important, and I agree that sometimes a lens really does just make you go wow. I’ve had a few of those down the years. The most spectacular example being the Canon TS/E 24mm MkII, which was so much better than any other Canon wide it was like a sensor upgrade. Still the best lens I’ve ever used, though there is a new contender – the Sony/Zeiss FE 55mm f1.8. I’ve only had time to shoot a few frames (and mostly on my ‘lowly’ NEX-6) but, like the 24TS/E it seems to have a special clarity, which is more than just it’s high resolution and into colour rendering.

    • The Canon 24 TSE II is better than the Nikon 24PCE, and I’m very jealous of the 17 TSE – though I’m told it isn’t that great optically.

      The FE 55/1.8 is actually pretty good. Not as good as the Otus, but surprisingly not that far off, either.

      • 17 TS-E is excellent optically, not sure what you mean. It is a tad less sharp than the 24 TS-E but being a 17 one would expect that. It is much better than ZE/ZF 18 and has a much wider image circle than normal non T/S lens. The ability to Shift at 17 is huge and makes the lens great for architecture and landscape.
        The new 55/1.8 seems to have strong field curvature which extends backwards on the sides. Otus is very sharp across the whole frame without field curvature. The contrast and clarity of the Otus wide open is unmatched. What you would expect with the huge price difference between the two lenses.

        • It would appear sample variation comes into play again. The single 17 TSE I’ve tried wasn’t that great in the corners – some smearing and CA. It isn’t exactly an easy lens to get hold of, so no opportunity to retest.

          The 55/1.8 does have some field curvature, but it appears to be mostly gone by f4, and it’s not easy to tell apart from the Otus at that point, especially if there are no high contrast areas in frame to provoke CA.

          • Barry Reid says:

            I would concur with Wayne. The 17mm is very good but not up to the 24. Tellingly the while the 24 works well with a 1.4x Extender the 17 doesn’t. It’s also tough to control flare with the 17mm, it really needs to be flagged for almost every shot.

            • Out of curiosity, why would you use the 24 with an extender?

              • Barry Reid says:

                It’s quite a popular combo for architectural shots because 24mm can be a too-wide perspective at times, the 45 TS-E is mediocre, no-one makes a 35mm shift lens or similar any more and the Canon 24 + 1.4 MkIII combo almost certainly outperforms any readily-available-for-adaption 35mm shift lens. It’s possible that the C/Y fit Zeiss 35mm PC Distagon would be better, but that’s quite a scarce lens.

                • That makes sense – us Nikon users have a strong 45 and 85, but the 24 is relatively weak and there’s no 17 at all.

                  • I would love to disagree with you about the a7r, the size and IQ with 55 native prime is something that is truly revolutionary. But, there are sadly a number of unforgivable flaws, auto ISO logic, shutter shock, etc. But, the lack of weather sealing on a weather resistant camera is in my mind the most shocking

  17. Great informative article. I’m not sure if this goes against the spirit here; elsewhere you’ve used the phrase pantheon of (your) legendary lenses — at least I think that was the phrase. Would you be willing here to share that with us here? A list perhaps.

    • It’s all of those that got 10s in the Camerapedia:
      Leica S 120/2.5 APO-Macro-Summarit
      Zeiss ZF.2 1.4/55 Otus APO-Distagon
      Zeiss ZF.2 2/135 APO-Sonnar

      Sitting on the edge are the Nikon AFS 200/2 VR, Zeiss 2/28 Distagon (highly subjective), Olympus 60/2.8 Macro, Olympus 75/1.8, Leica 50/1.4 ASPH-M, Leica 35/1.4 ASPH FLE.

  18. Jeff Schiller says:

    Ming, when you say that a built in prime lens (for example a GR) tends to perform superbly I wonder how much of that is due to a superb lens and/or superb corrections by the camera’s computer. In fact how much of a modern lens’ performance on a digital camera is due to the camera’s computer?

    • Quite possibly a bit of both – but there’s nothing stopping a similar level of correction to be applied to interchangeable lenses – in fact, ACR has a fairly comprehensive database of corrections for most popular lenses. I say use it – if it makes average lenses good, it would make outstanding lenses incredible…

      • Agreed. Over the past decade of rapid upgrades in both camera bodies and the mark II versions of pro lenses, it’s shown me that often a newer camera will bring improved performance to an existing lens OR a new lens version will add noticeable improvements with an existing body. There’s also the possibility with some camera bodies of fine tuning the performance on a lens by lens basis. I’ve never done this myself, but am curious, now that I’m shooting with an Olympus E-M1 for somewhat demanding print sizes, on how this is done well and if it’s something you do yourself. I kind of wish the cameras were smart enough that a user could use a specific chart (like we do with color profile building) that the camera could identify and make suggested tweaks auto-magically for that lens, for each f/stop and for near and far distances. Maybe some already do. In the mean time, I’m becoming more careful to observe the characteristics of each lens and to try and understand their individual qualities and how they behave in various situations so that I can get the best possible results from them. (I treat them like my children: I’ll take them all with me to fun places, but I’ll also schedule time one on one and spend concentrated time with each one individually.)

        • Some things like CA, distortion and certain aberrations can be corrected in software – and almost certainly are already profiled for a lot of cameras (or if not, ACR). But other such as field curvature or simple lack of resolving power cannot be. And for that, you do still need better lenses…

  19. Tell that to Mr. Daido Moriyama.

    An esteem international street photographer.

    A compact camera (Ricoh) was and is still is his tool to extrapolate a realistic world of his surroundings into a non-realistic image.

    His body of work are not post cards nor calendar images.

    I believe you had seen his work.

    Louis de la Torre

    • It’s an artistic interpretation that works synergistically with the correct tool. I’m not sure what your point is here. I’ve owned, use and still use most of the generations of Ricoh GR he uses. And never complained about the results.

  20. Great stuff, as usual! I am very curious to use a nikkor 200mm f/2, seems like the perfect portrait lens, but its leica price isn`t very attractive.

    • There’s also a lot more technology and glass in one of those than a Leica lens…

      • liramusic says:

        I feel a little bit bad when discussions shift to money. I can’t even read most reviews on camera gear because they all end up capitalist-based. It seems fairly clear to me that the 200mm f/2 is a work of art. Yet I think technical discussions are fine. I love this blog. When it comes to money, it swings one of two ways to me. Either the equipment will pay for itself, or you are worth it. I guess that’s my idea about the price of that lens. There are other ways to frame a narrative but I am so thankful here that money is not the main point. I guess my comment is philosophical. Thanks.

        • For some, it is; but what I don’t understand is the people who can (and do) buy Leicas, then complain about $50/100 here and there, or call Nikon glass expensive – 200/2 money certainly does not get you anything similar in Leica territory!


  1. […] Photography News: What makes a ‘good’ lens? (part II) This might seem like a very obvious question, but the moment you try to define a set of criteria to quantify ‘good’, you soon realize there’s quite a lot more to lens performance than immediately meets the eye. So, for those of you without the ability to try a large number of lenses – let alone samples of the same lens – how do you know if the one you’ve got is ‘good’? Continued from part I. Read full story => MingThein […]

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