Tuesday, June 04, 2013

Tandoori Lens Summit Part Three: Images from MFT Sensor

grid of crops from 6 lenses

Introduction


In Part One of our Tandoori Lens Summit I set the scene and wrote a bit about food. In Part Two I outlined our lens choice, testing method, processing, and motivation. Now let's look at some images. Remember that we shot on two platforms, the APS-C sensor of the Pentax K-5 and the MFT sensor of the Olympus E-PL2. It is the second set under consideration here, because they turned out to be more consistent and easier to (minimally) process.

In fact, let me say more. Metering with the Pentax "green button" is a terrible process, ergonomically broken and inaccurate. We wasted a lot of time shooting on the K-5 only to have the Olympus make a fair comparison possible. Pentax, uncripple the K-mount! OK, rant over.

On the plus side, the Olympus platform allowed us to include in the comparison a native lens for MFT mount. Around these parts we like apples and oranges.

I can't upload every image at full-size, so decided to share the f/2 shots, since that's the widest aperture that all the test lenses can manage. You can click through each shot to get to full-size images on Flickr. These are JPG saved at quality 90.

A more comprehensive look how these lenses performed, across a representative range of apertures, is visible in the grid at the top of this article. This comprises 400x400 pixel crops from the focus area of each image. Yes, it's pixel peeping time!

Now follows our own personal evaluation of these photos. You may have different conclusions or opinions - we welcome comments!

The owner of this blog, Robin Parmar, is joined in this discussion by Robbie Corrigan, whose work you can see here. Let the lens summit begin!


Lens Discussion


K = SMC Pentax 50mm 1:1.2

SMC Pentax 50mm 1:1.2

A = SMC Pentax-A 50mm 1:1.2

SMC Pentax-A 50mm 1:1.2

Let's start with the Pentax lenses. The manual "K" and auto-aperture "A" versions of the 50mm f/1.2 are supposed to have the same optics. The glass is 7 elements in 6 groups with close focus at 45cm and a 52mm filter. Both are 49mm long and similar in weight, 385g for the K and 385g for the A. They are hefty lenses with a tank-like build. Focus is nice and smooth. The only difference besides the aperture control is that the aperture blade count went up from 8 to 9 on the A.

Robbie: I've had the pleasure of using both these lenses for a fair amount of time. As you know, I once had this K as a loaner from you, then I bought it from you, and finally bartered it back trying to persuade you to be my wedding photographer! The A is the third sample I've had; the previous two did not match up or better this particular K.

I would describe them both as mini 85s. They feel like good solid pieces of metal and glass and on a K-5 balance nicely, as if designed for the camera. Or perhaps the camera was designed with these in mind. A K-5 mounted with an A or K 50 f/1.2 does have a purposeful look to it. Focusing feel on both is firmer than, say, a Super Takumar 50 f/1.4 -- which is a silkiness benchmark. Both have been outfitted with Nikon HN-3 hoods which as luck would have it is an excellent fit for this lens in that it is relatively deep, does not vignette (even on a 135 sensor) and the bottom of the hood is only a millimetre shy of the bottom of a K-5.

Robin: The images from the A looks slightly better than the K across the board, in colour saturation, detail, clarity, and contrast. But the difference is ever-so-slight. Just on this evidence I wouldn't want to categorically state that one lens model is better than the other, as it's likely just variation between the two samples we happen to have. Except that this does confirm what I had previously read from other tests, some of which are more scientific than this one!

Robbie: Looking at the two examples, the A just edges it, being a tiny bit sharper, tiny bit better in contrast. It is indeed down to a variation of lens samples. A good K will show up a so-so A -- these both happen to be good K's and A's. Usage-wise, there is no comparison; the A comprehensively out-guns the K with the auto aperture which keeps the viewfinder nice and bright and allows 1/3 stop granularity instead of the 1/2 stop intervals on the K. Set your ISO, dial in shutter and aperture on the fly, and you're in manual photography heaven.

Robin: That's true on a Pentax, for which they are made. Mounted on an MFT camera, that difference is a wash. Both lenses get metered automatically and accurately. But you must rely on the aperture dial for control over f-stop. I notice from the images that both lenses benefit from stopping down to f/1.4 from wide open. It makes you wonder if one shouldn't save money and bulk and simply buy an f/1.4 in the first place! Pentax makes lots of good fast fifties. The answer, of course, is that some people like the soft look a very wide aperture brings.

Robbie: Hmm, f/1.2 is doable, perfectly doable but you have to be really careful with distance to subject, subject type... and no coffee! Contrast and saturation can be recovered with PP and sharpness as well to a lesser degree. It is very plain to see that both begin to recover contrast, sharpness, and pure bite with each step down on the aperture. Each full stop is very different to the stop before. You would find it very difficult to find another 50 that has such a broad range of talents. You want tiny DOF? Check. 3D look? Check. Silky smooth bokeh? Check. Good sharpness stopped down (at least as good as f/1.4 or f/1.7 variants)? Check. All you have to give up is autofocus!

Robin: And coffee. Remember that you also have to give up the coffee.


C = Cosina 55mm 1:1.2 MC

Cosina 55mm 1:1.2 MC

The Cosina 55mm 1:1.2 MC is a lens made by Tomioka, also marketed under their own name plus a host of others: Yashica (Yashinon), Ricoh (Rikenon), Revue (Revuenon), Chinar (Chinon), and even Vivitar Series 1 (for serial numbers beginning with "84"). Yet it's not an easy lens to find, and will sell now for much more than the initial cheap "clone lens" price. This Cosina version is in K-mount. Like the Pentax K and A, it's a 7 elements in 6 group design. It weighs 325g, has 60cm close focus, a 58mm filter, and 9 blades. It requires an after-market hood.

Robin: Bringing the Cosina into the equation I find the K is slightly preferable wide open. But could this be that the slightly longer focal length of the Cosina (55mm versus 50mm) is throwing detail more out of focus? At f/2 lens C appears to have more contrast and detail than K or A. By f/4 you wouldn't really be telling these three f/1.2 lenses apart, except the stronger colours of A still win me over.

Robbie: I was very interested in the Cosina having never used one before. Build is 6/10 compared to the Pentax variants 8/10. Focusing was smooth but not as precise. It does not impress when compared to the other two. Built to a different budget and price and it shows and feels it. I suppose at this stage I should submit to being a lens snob -- can't help it, won't change. I adore precise, finely-engineered optics that reward in a tactile sense. While I would respect this lens if I had not experienced the other two, I would not love it. And what were Cosina thinking with only allowing full stop aperture changes? I was stunned when I discovered this.

Robin: I have to agree on the build thing. As far as image quality goes, all three f/1.2 lenses are in the same ballpark and will produce the look people want from a super-fast lens. But it does seem that the more you spend the better image you get.

Robbie: It puts up a good fight to the other two at f/1.2. I'm wondering if it is down to the extra 5mm in reach but it does go softer faster than the Pentax variants in the immediate OOF area. It also exhibits a ghosting effect in higher contrast areas which is not showing on the others. Coating perhaps?

Robin: Yes, there is really no beating the Pentax coatings. They are being continuously improved but were remarkable even back in film days.

Robbie: I agree with you on the cost analysis. Cosina is half the price of an A, with the K somewhere in between. I think the Cosina is actually very good value if we carry on the analogy from Part One. It is not that far off the Pentax lenses in IQ, giving 90% of the flavour for 50% of the price of the pedigrees. Would I buy one? Nope, I have a good A so I'm sorted!


L = Pentax SMC-FA 43mm f/1.9 Limited

(Note that this lens does not have a manual aperture stop for f/2. Unlike the others presented here, this photo was taken wide open at f/1.9.)

Pentax SMC-FA 43mm f/1.9 Limited

The Pentax 43mm f/1.9 FA Limited is part of a triumvirate of lenses built by Pentax with exceptional attention to optics and physical detail. It is also the only lens in Pentax history to have been made for Leica M mount. The focal length was chosen to be the perfect normal on full-frame (135). The optics has 7 elements in 6 groups, a Double-Gauss design with an extra element before the rear glass. It has a 45cm minimum focus distance, a 49mm filter, and 8 aperture blades. It is only 27mm long and 155g in weight, and comes with a dedicated screw-on hood plus push-on felt-lined cap. Very nice!

Robbie: The FA 43 Limited. I'm going to admit straight away that I adore this little lens. If Pentax ever comes out with a 135 digital camera, this will be without doubt the first lens I'll put on it. On the forums there have been battles raging to and fro about this versus the DA 40. But for me this is the ultimate wolf in sheep's clothing. We both have one; we both adore them; we both have shots that have been taken with this lens that have wowed us. My biggest problem with this lens is that it is so unassuming. I'll throw on the A50 or FA77 or FA31 because they are more fashionable and forget that I have the 43. Then I remember it, put it on, and it just delivers.

Robin: Looking at the images, the L is sharper and clearer than any of the three f/1.2 lenses, and this is true starting wide open at f/1.9. Wow! Though I love this lens I wouldn't have quite expected that. Well, OK, maybe I would! I have shot thousands of great images with this lens. Plus I know that it's extraordinarily sharp wide open in the centre of the frame. From f/2.8 to f/5.6 it's the sharpest Pentax lens ever tested by Photozone.

Robbie: Surprised? Not in the slightest. It takes on any normal 50 and with a completely insouciant manner slaps them silly. As you've said quite eloquently, it has it all: sharpness, contrast, bite, a lifelike rendering that has bags of character. Colours are returned with extra deepness and tone. This lens is not about charts or comparisons even though it does well here. It is a reportage lens, 7 to 15 feet is its element.

Robin: Yeah, sharpness is not everything. I know from experience that the FA43 renders volume second-to-none. This enables it to produce that special "pop" when all the planets align just right. Compared to the lenses we've looked at so far, this one is tiny and furthermore supports auto-focus. However, this inevitably means that the manual focus feeling is compromised. It simply doesn't have the nice firm friction of a Pentax Takumar or K lens, a Zeiss, or a Leica.

Robbie: Focusing as you say is not as silky as a Takumar, K or even the A. Only the lightest touch is needed but you feel a certain roughness due to the AF mechanism.

Robin: Is auto-focus the biggest evil inflicted on photographers? All our lenses are now designed for motors, not human hands.


Z = Carl Zeiss Makro-Planar 50mm F2 T* ZK

Carl Zeiss Makro-Planar 50mm F2 T* ZK

Zeiss discontinued support for the K-mount, so the ZK version of the Carl Zeiss Makro-Planar 50mm F2 T* we are testing here is no longer available except on the second-hand market. It has a 6 elements in 8 group design with 9 aperture blades and a 67mm filter. The Makro-Planar is not a true macro, attaining 1:2 magnification at its 24cm minimum focus distance. It's a huge lens for a normal prime. The 65mm length is extended by an extra 32mm at full magnification. And it weighs 530g. The hood is small but sufficient since the front element is deeply recessed. The ZK version has auto-aperture but otherwise no coupling to the camera. It is, of course, manual focus only.

Robin: It has to be said that the image from Z trumps the Pentax offerings overall. There is more clarity and saturation, even in the out-of-focus regions. You can clearly see that the highlights in the OOF have distinct shapes. Yet this does not detract from the bokeh, which is appealing. Though this is subjective, of course, as some might prefer the more smeared look of, say, the Cosina, for its "artistic" effect. I do not.

Robbie: I was expecting this result, to be honest. The f/1.2s are all well and good, but this is not a fast fifty but an uber fifty! What I like about this lens is the smooth, oh so smooth transition to OOF. Sharpness is there are you'd expect, nay demand from an optic of this calibre. I know from experience that the distance we were set from the subject is in the optimised area for this lens.

Robin: That's a good point to emphasise. Some of these lenses might perform differently at longer distances. But it's a preference of mine to have close focusing lenses, since I like a lot of magnification. I'm a detail-oriented person. That's also consistent with the fact that all my lenses have a narrower field of view mounted on MFT sensors... and I don't mind.

Stopped down, Z gains definition and a bolder look. I have to point out the possibility that this is down to subtle light changes over the course of our session. But that's just me waffling, since we really saw no such thing!

Robbie: With each stop it gets sharper, deeper, revealing more and more... but you know what? The FA 43 is not that far behind and on some of the shots at the same aperture is showing just as much if not a little bit more in the OOF area.

Robin: Yeah. I think I swung to the Zeiss camp a little easily since I have fond memories of using their lenses on the Contax system. And I am over-familiar with the Pentax Limited series, so I see change as good. Your viewpoint is more fair.


O = Olympus M.Zuiko 45mm 1:1.8

Olympus M.Zuiko 45mm 1:1.8

The Olympus M.Zuiko 45mm 1:1.8 MSC is a native Micro-Four-Thirds lens, so it was made to cover a much smaller image circle than the others we've looked at. It has 9 lenses in 8 groups with 2 of these being special E-HR. This is somehow not the same as Extra Dispersion. Oh how marketing departments confuse! The 7 blades form a circular diaphragm. Though 37mm in length it weighs only 116g, being constructed with plastic compounds (though the mount is metal). It has a 37mm filter and an "optional" hood. The MSC designates silent auto-focus operation, especially for video. Manual focus is "by wire" as there is no direct coupling to the helicoid.

Robin: I was ready to declare Z the winner in our little shoot-out, but then I looked at O. The comparison is made difficult given the focal length difference. The 45mm puts more into focus than 50mm and so the image is going to look better at first glance. Even despite this, I see significantly more micro-contrast with the Olympus, showing detail that Z simply doesn't render. The colours and bokeh are very similar, I must say.

Robbie: Hmm, here I'm going to disagree with you. From f/1.8 to f/2.8 the Olympus is amazing; after that it tails off in my opinion. Colours, saturation, sharpness are all there which is astounding really but then again is it? This is a 45mm behaving as a 90mm, tuned no doubt to the MFT sensor. I'm wondering if it is another example of lens and sensor tuning that makes the sum better than the component parts. Remember the Photo.Net article "An Optical Paragon"? Perhaps this is another example.

Robin: I doubt it really. I don't think for the accessible price that Olympus would go to that design extreme. I am not even sure what it would mean to tune optics to a sensor. Especially as sensors have been improved in different generations of their cameras. They'd be chasing a moving target. And I must point out that all the lenses are operating with half the field of view on this sensor. The baseline is the same for all, so it's still a fair comparison.


Some Conclusions


Robin: In terms of the image the Pentax FA Limited, Zeiss, and Olympus may be the winners, but how can one possibly choose between these in a practical sense? The Zeiss Makro-Planar is a 530g chunk of metal that grows to 10cm long. The Olympus M.Zuiko is a featherweight 116g and only 3.7cm long -- though a lens hood adds more. The Zeiss is built like a tank with great manual focus but no auto. The Olympus has a cheesy plastic feel but auto-focus works silently and instantaneously. Then you have to consider that the Olympus is a fraction of the price.

Somewhere between is the FA 43 Limited, since it is indeed small, but is well built. It can't possibly achieve the lovely focusing of the Zeiss, and it too is not exactly cheap.

Robbie: The little Olympus. What an awful lightweight horrible little thing that blows us away optically. Carl Zeiss, built and engineered like a Panzer! Which would I choose? I have done already; I have the Zeiss. It can be used on MFT, APS-C and the so-called full frame. And it will deliver on all of these. If only Olympus would throw away the plastic and replace with lightweight alloy, give it some tactility, some sense of pride in its build which optically it deserves.

Robin: Though I own the Olympus 45mm I have never liked using it. Hand feel is so important for me too, as is manual focus. Plus I prefer an aperture dial. The fact it is optically superior is astounding to me, considering how much time it spends in my drawer. I did not expect this result and it will force me to rethink.

Robbie: Cosina is outclassed here optically; the K50 falls by the wayside by virtue of usability. It's a much-of-a-muchness between it and the A optically. Then I would say the Olympus because I think it falls off earlier but it is frankly astounding really. It really does pack a punch pound for pound. Yes the Zeiss wins optically but not by that much over the FA 43 which is a credit to Jun Hirakawa and his design team. Because the 43 Limited has AF and is one-third the size of the Zeiss.

Robin: That for me is the trump card. I moved into Micro Four Thirds to get a smaller system that would enable me to keep shooting all my favourite Pentax glass. Zeiss is simply too big. It's an ancient optical design that they have seen no need to update. And as we can see, there is no need when considering only optics. But Olympus shows us that they can build a tiny modern lens with Zeiss rendering.

Imagine for a moment if Zeiss used some modern tech and shrunk their lenses. Or if Olympus built lenses with aperture rings and manual focus. That would be my heaven.

But until then, I think we are agreed, taking into account image quality, handling, build, form factor, and other practical considerations. On a Pentax camera, the FA 43 Limited is the winner. On a MFT camera, the Olympus 45mm wins. If you really need f/1.2 for some reason, mount the Pentax A 50mm on either system.

OK, now where's that tandoori chicken?

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2 comments:

bryantakespictures said...

Great writeup. Very thorough. I haven't had the Oly 45 for very long, but I'm already being impressed by it's optical quality. Pity about the plastic.

robin said...

Thanks Bryan. I must say that I have found myself using it more after completing this test!

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