Zeiss 28mm 2.8 ZM Biogon Review

The Zeiss 28mm ZM Biogon is a Zeiss’s answer to the m-mount 28mm lens. Its reputation precedes it as an excellent piece of glass, but however objectively good it is, that’s not the sum total of what I’m interested in. What I’m also interested in discovering is just how much of the character I see and love in my 50mm Sonnar can be found in other Zeiss M lenses…

A bit of background first…

After buying and reviewing a 50mm ZM Sonnar I became a little obsessed by the idea that maybe Zeiss lenses are just the lenses I need to shoot for every focal length. The Sonnar has a series of attributes that add up to something that feels as close to perfection as I can imagine from a lens – and that’s despite some small reservations about the lack of a proper focusing tab. Whenever I shoot it, almost regardless of the subject I am happy with the outcome. Me and that lens are just a good fit.

As you can probably imagine, this instils a bit of favour in my mind for Zeiss as a brand. With this favour sometimes comes the aforementioned idea that maybe I should just be shooting Zeiss lenses across all the focal lengths I shoot. The problem is, this isn’t entirely practical. I already have a Leica 90mm Elmarit-M that I am very happy with, not to mention the closest equivalent Zeiss lens (the 85mm f/2 Sonnar) is rare as hens teeth. Additionally to this, I’ve recently bought my dream 28mm lens: the Minolta G-Rokkor 28mm f/3.5. So what the hell am I doing with this Zeiss 28mm ZM Biogon?

A lens on loan

Earlier on this year I visited the Zeiss stand at the Photography Show. Whilst there I spotted a chap called Alexander who I’d met at the show the year before. In the year since that meeting, Alex had helped in my decision to buy the 50mm Sonnar by providing various bit of useful info via email, he’d also answered a few random queries I’d had, and one way or another been quite a helpful guy. As such, when I saw him on the Zeiss stand I thought I’d say hi. We chatted briefly, I asked about borrowing lenses, he then introduced me to a member of the team at Zeiss UK who had in turn said I was welcome to borrow gear for review. At the time I had a Leica 28mm elmarit-M and through this idea that maybe I should be shooting all Zeiss, I was very keen to compare the Biogon to it – a loan of the lens would give me the perfect opportunity to do so.

As such, straight after the show I got in touch with my new contact at Zeiss to ask for a loan of the Biogon. Unfortunately they didn’t have a 28mm in their possession that I could borrow – there was a review/show copy about somewhere within the company, but it wasn’t to hand. The chap I spoke to told me he’d get back in touch when it resurfaced.

I took this as a bit of a sign that I shouldn’t be fretting about Zeiss lenses being perfect for me. I had my Sonnar 50mm which I am happy with, my 90mm elmarit-M that I’m also happy with… And as I explain in this post, I then went on to sell the 28mm elmarit-M to buy the aforementioned dream Minolta lens. I had hoped the Minolta would become my perfect 28mm and I could put this all-Zeiss idea behind me.

Of course, Sod’s law being what it is, when I then got back in touch with Zeiss to ask about something completely different, the response I got included the line: “By the way, I have the 28mm ZM Biogon here now if you would still like to borrow it?” So here it is in my possession – only for a few weeks, and so soon after me buying the Minolta – it couldn’t feel anything more like a cat amongst the pigeons. The question is, does it reignite that desire for an all Zeiss lens line up…?

Technical waffle

Through the process of reviewing the Zeiss ZM Sonnar and Jupiter 3+ I learned a little bit about different approaches to lens design in the 1930’s. Applying this bit of a basic understanding of optical design to looking at Zeiss’s ZM lens line up – on paper at least – I initially came to the conclusion that it’s a bit of a fools errand to chase the idea that the 28mm ZM Biogon will perfectly harmonise with the 50mm ZM Sonnar.

There is a disparity between these lenses that is probably most easily understood by taking a look at the background of the lenses optical designs. The Sonnar is closely related to a very early asymmetrical lens design. The Biogon on the other hand is an almost symmetrical design. Whilst I am by no means an expert on these things, one thing I have learned is that all lens designs are about a balance of gains verses compromises. As I understand it, the early goals of symmetrical lens design were based around the idea of producing images that are well corrected for distortions, flatness of field and colour aberrations. The symmetry in the lens design is what helps cancel these issues out. Asymmetrical designs were better for flare resistance and contrast as they had less glass surfaces internally that would cause the internal reflections that cause these issues.

This idea I had that there would be disparity was further confirmed by Zeiss themselves talking on their website of their Biogon lenses as being the ideal partners to their 50mm Plannar. They make no mention that I’ve spotted of how the Biogon relates to the Sonnar. In fact when reading about these lenses generally – both in terms of what Zeiss say, and the wider reports about them online – to a great extent, the Sonnar seems to stand alone within the Zeiss M line up as lens with a strong character, a character that is touted as “classic”. The rest of the ZM lens lineup are largely Biogons, Distagons and the Planar which are all touted as a lenses that have high objective qualities. All this adds up to the idea that the Sonnar will have a very different look and feel to its results when compared to its brand peers. But then, as I’m finding myself learn more about these different lens configurations – as well as discovering the impact they have – I’m also discovering just how much other factors in a lens’s design play.

As an example, I recently borrowed a Jupiter-3+ from Lomography. Naively I suppose, I’d half expected it to be more similar to the Zeiss 50mm ZM Sonnar. After all they are both Sonnar lenses, and in fact the Jupiter is a direct copy of an earlier Zeiss Sonnar design. What I actually discovered was just how different they are. When using the lenses side by side I found myself really realising just how modern the ZM Sonnar is, as by comparison, the Jupiter more often gave me positively “vintage” (for want of a better word) results. The two lenses did share common attributes; they both suffer focus shift, have similar bokeh, and good contrast. But at the same time, the ZM is even more contrasty and takes photos with a greater sense of 3D pop more readily and reliably. It also has significantly greater control over flare, and has warmer, more rich, more contrasty colours.

As mentioned good flare control and contrast are – at least on paper – traits traditionally associated with Sonnar lenses. Yet what I had found was that the ZM Sonnar excelled in these areas and the Jupiter didn’t quite as much. So what else separates these lenses? Well, apart from slight differences in lens design, the greatest factors that separate them is their different glass and lens coatings.

Zeiss lens coating

One of the things that all Zeiss ZM lenses share is of course Zeiss’s choice of glass and lens coatings. Lens coatings might seem like a small thing – after all physically they are very small things – but the more I read about coatings, the more I realise the extent of the impact they have.

The purpose of lens coatings is to increase transmission of light through the elements of glass within a lens, or in other words they decreases the reflection of light between the elements. The result of this is images that suffer less with flare and gain an increase in contrast. Both flare and contrast have a number of meanings in lenses (some of which I go into here). contrast is an especially difficult subject, as when the word is used, it could be in reference to micro or lens contrast, colour contrast, or indeed overall contrast in results. What’s interesting about lens coatings is that they seem to have a profound affect on all of these things.

This is surly at least partly evident in the fact that the modern symmetrical lens designs – in the case of the Zeiss ZM line up; the Biogon and Plannar – don’t by reputation fall short in terms of contrast and flare control etc. It is therefore quite safe to say that whilst the lens designs themselves bring some separation to the look and feel of the results of Zeiss’ lenses, this separation is likely vastly reduced by the common use of lens coatings across the range of ZM lenses.

Uniformity in the ZM lineup

Ok, so all of the above is definitely Hamish-stream-of-conscious-waffle (patent pending). But, the point of explaining it to give a bit of background, and hopefully demonstrate where I am on the learning curve with all this stuff. It also hopefully explains a bit about my thought processes both for and against the idea of going all Zeiss. It is this potential for uniformity between lenses that makes me wonder that if I like the Zeiss ZM Sonnar so much, will I get equal (or near equal) enjoyment out of the rest of the range of Zeiss ZM lenses? And indeed – somewhat tangentially – should I be aiming to bring more Zeiss lenses into my professional digital career, but more on that particular point in a later post…

The Zeiss 28mm ZM Biogon review

What’s most interesting about the Zeiss 28mm ZM Biogon is that reading one review to the next, really there is no agreement in terms of just how good it is. Some say it resolves better than Leica’s Elmarit-M, some say it doesn’t. Some even say it’s not far off as good as the Summicron! Impossible, how could anything be as good as a Summicron?! (that’s me being facetious, in case you hadn’t gathered).

What I find interesting about this lack of agreement, is that actually what I think it translates into is an entirely pointless argument. If no agreement can be found between people who nitpick about the quality of a lens, then the chances are, it’s too good to worry about just how good it actually is.

Of course, the limitation of the reviews I have read seems to be around the format the lens is shot on. Most seem to be either film or digital, rarely both, and I haven’t found that much info from people using this lens on the likes of the Sony full frame digital cameras.

Whilst I don’t want to focus too much on the area of shooting the Zeiss 28mm ZM Biogon digitally, I was struck by just how problematic shooting the 28mm ZM Biogon on my A7rii was compared to film. As such I thought I’d split this review into two parts for two objective factors that seemed most strongly impacted by shooting this lens on a full frame non-Leica digital camera: Sharpness and vignetting.

Sharpness and vignetting

Shooting film, I have noticed very little in the way of discernible fall of toward the edges of the frame, either in terms of light or sharpness. In fact, my experience when shooting film has been entirely positive. To my eye I can’t really detect any noticeable decrease in sharpness at into the corners, even at wider apertures. Not only this, but vignetting isn’t particularly evident in most circumstances. In fact the only shots I noticed it where in a series I shot in Worcester’s library.

Of course, I’ve done no technical tests. I’ve just taken photos, but in doing so, I’ve had repeatedly good results… At least I have when I’ve been shooting film. When shooting digital, it’s a very different story. Unfortunately for the Zeiss 28mm ZM Biogon, it’s, well, a Biogon. Biogon lenses aren’t ideal – in terms of their lens design – for shooting with digital cameras. The reason for this is that the rear elements of the lens project so far into the body of the camera that the angle of light leaving the lens and hitting the outer areas of the sensor is too oblique. The result of this is potential for softening, darkening and in worst cases colour shifting of the image.

In the early days of Leica digital cameras, Leica combatted this problem by using a smaller sensor – in fact from what I’ve read, in the beginning, they pretty much ruled out full frame sensors altogether. The Leica M8 was Leica’s first digital rangefinder camera, and has a 1.3x crop sensor. This alleviated the edge issues simply by not having the extent of outer edges of the sensor to be effected by the problem. This wasn’t the only measure taken. Thin upper layers of the sensor and offset micro-lenses also helped solve the problems, at least to some extent. Of course as technology advanced, these latter solutions went some way to solve these sorts of issues even with full frame sensors. In fact from what I’ve read, on the full frame digital Leicas, the 28mm ZM Biogon is perfect at all apertures, right into the corners.

On the Leica M8

Unfortunately I don’t (yet) have a full frame Leica to test this. I do have a Leica M8 though, and though there is some more obvious but still very slight vignetting, I can confirm it is not just sharp, but very sharp, even at wide apertures, right into the corners.

On the Sony A7rii

Sadly, the same can’t be said for the Sony cameras I’ve shot it on. At wider apertures there is quite pronounced vignetting, and some very obvious smearing into the corners (sorry about the awful photo, I took it just to make the point).

Quite simply, Sony cameras are just not designed to be used with lenses like this. It’s not the fault of the lens as such, nor specifically the camera. It’s a combination of the two pieces of equipment that causes the issue. Fortunately, if you do have some desire to shoot the 28mm ZM Biogon on a Sony, it is still very possible to get good results that are sharp into the corners. You just have to stop down a fair amount.

Further objective optical qualities

These issues with vignetting and sharpness with the Sony cameras aside, as you might expect, the Zeiss 28mm ZM Biogon is a very good lens indeed. To start with, there are no discernible distortions in any of the photos I have taken with this lens. I’m pretty certain that I read somewhere that it’s large size compared to the Elmarit-M is due to greater attempts to reduce any chance of distortion.

Since I can’t see any distortions in either lens, it’s hard to comment on just how much more successful the 28mm ZM Biogon is in this regard. Suffice to say though, it’s certainly not something I’d worry about in the process of choosing this lens. Additionally to this lack of distortion, I’ve only seen the slightest sporadic signs of chromatic aberrations.

Contrast, 3D pop and colour

What’s been really pleasing for me is finding all the contrast colour and pop in my results. The Zeiss 28mm ZM Biogon is contrasty in all senses of the word. As mentioned, detail is resolved well, but add to this the high lens contrast I’d hoped to find and the result is images that contain the a sense of depth and three dimensionality that I love in my Sonnar.

The colours I seem to get when shooting the Biogon are equally as wonderful as the Sonnar’s too. There’s a richness and warmth that I really find very pleasing.

The lens contrast works wonders in black & white photography too. I love these shots of Norah – the contrast works wonders to really bring out her big round eyes!

Flare & light

Flare is very far from being an issue with the Zeiss 28mm ZM Biogon too. Even experimenting with it, pointing it towards the sun, shooting with the sun just out of frame, all that sort of thing, I’ve not managed to get it to flare in any meaningful or repeatable way. I regard the Sonnar as pretty much immune from flare. This lens is even more immune! Very impressive, at least objectively speaking.

What the Biogon perhaps lacks slightly over the Sonnar is a touch of magic in the way it renders light. You’ll have to read this part of my Sonnar review to see what I’m talking about. This isn’t a shortcoming of the Biogon, far from it. Most would this an an objective improvement over the Sonnar. For me, it just makes it feel more clinical in its rendering. Though really, this is a very personal matter of taste, and comes down to little more than me being very picky.

Bokeh

I nearly forgot to write about Bokeh, it’s slightly redundant a subject with a lens of this sort of focal length… though only slightly. With the close focusing of the Zeiss 28mm ZM Biogon being 0.5m (something I’ll come to in a mo), bokeh can well be a factor. Unfortunately, this is perhaps the most obvious way in which it departs from the Sonnar’s near perfection. Have a look at the flowers in the background of this image and you’ll see some wiry nonsense going on. Does this matter? Probably not, no – it certainly doesn’t bother me.

Gelling with the Sonnar

Though I’ve only really mentioned it in terms of the way it renders light, I think clinical is probably a good word to describe the Zeiss 28mm ZM Biogon when speaking relative to the Sonnar. That being said – to me at least – it feels less clinical than the Leica Elmarit-M. It might just be because I feel at home with the colour and contrast, but one way or another I’ve felt completely happy with the results I’ve had out of this lens. It has a character that I feel like I recognise, and that’s despite strong differences like the way it renders out of focus compared to the Sonnar I am so familiar with.

I started down this road with what were perhaps naive technical founded misgivings about how well it would gel with the Sonnar. As it turns out, largely speaking, I feel like I’ve been proved wrong; the Zeiss 28mm ZM Biogon sits very well next to the 50mm Sonnar in my opinion.

Handling

Ok, so all this is sounding pretty good… A little too good for a man who’s just forked out a fortune for a Minolta lens after ruling out this Zeiss. As you can probably imagine, as the process of me finding out how much I like the optical qualities of the Zeiss 28mm ZM Biogon unfolded, I started internally debating the reason I didn’t pursue just buying this lens in the first place. Track back again to my Elmarit-M review and you’ll read about how buying it made me realise that – at least in terms of handling – I could do better than my Voigtlander Color-Skopar. It was this combined with the thread mount and smaller size that encouraged the eventual purchase of the Minolta G-Rokkor.

On paper, the Zeiss doesn’t work for me. It’s so big that it blocks the corner of the frame in the viewfinder of the camera. It doesn’t have a proper focusing tab, instead having the same pointless little nub that the ZM Sonnar has. To top it off, it’s not thread mount – which for someone who prefers shooting 28mm on a little Barnack Leica is a little frustrating. These justifications initially became my safety net for this experience. However much I enjoyed the results from Zeiss 28mm ZM Biogon lens, I felt I could fall back on them as reasons to stick with the lenses I have.

The problem is, as I’ve been using the Zeiss 28mm ZM Biogon, I’ve realised how meaningless they are. I’m so well used to the pointless focusing nub from using the Sonnar, that it doesn’t bother me. I’ve only noticed the lens in the viewfinder a couple of times, and not really been too phased by it when I have. And, the preference for a Barnack is meaningless when I’m carrying this lens as a second to the Sonnar with one of my M cameras.

Build quality

The only other possibility for finding flaw with the Zeiss 28mm ZM Biogon is its build quality. Unfortunately for me, the build quality is also (obviously) excellent. Zeiss lenses – whatever anyone says – are pretty much as well build as Leica lenses in my opinion. The only thing that separates them is focusing smoothness. This lens, just like the Sonnar, has the problem of the focusing being stiffer in colder environments if left not used for a bit. This isn’t something Leica lenses suffer with in my experience, though, I’m not really bothered by it. It also has perfectly clicky 1/3rd aperture settings, and no unnecessary play in anything. Like the baby’s porridge, it’s just right!

The Zeiss’s trump card – 0.5m focusing

Just to rub salt in the wound it brings something else to the table too! What I’ve found surprisingly favourable with the Zeiss 28mm ZM Biogon is its 0.5m close focusing. I genuinely didn’t think this feature would do much for me. On paper I found the idea that the rangefinder patch would just stop moving below 0.7m (ish) to be a bit odd. What I’ve found in use, is that I’m so used to the close focus limitations that I rarely get closer than 0.7 meters anyway. As such, I rarely notice the limitation of the RF focusing mechanism with the camera to my eye. In theory this means that I gain nothing from the 0.5m close focus – in practice it makes a big difference.

As it turns out, I’m not too bad at judging distance at these close ranges. I find 50cm quite easy to guess within probably 10-15cm. The depth of field of a 28mm lens, even at f/2.8 is about 5cm. Obviously this is smaller than what I’d guess is my room for error, but what I’ve found is that I am quite often close enough that – for my enjoyment at least – focus is close enough to give an acceptable photo.

If I stop down to f/8, I’ve got 15cm of depth of field to play with, and that really is enough to ensure I get an in focus shot every time. What I love about this is that it solves probably the only thing I miss from the days of shooting an SLR. With 28mm lenses, sometimes it’s nice to be able to shoot those close up dynamic portraits. I especially enjoy taking photos of my kids like this. The Zeiss 28mm ZM Biogon allows this style of shooting quite readily. Admittedly focusing is not always perfect, but really the sort of angles I’ve been shooting from, even with an SLR I might not have used the viewfinder to focus anyway.

It’s in the name – Biogon

What’s really interesting about me finding this feature of the lens enjoyable, is that it corresponded almost to the day with me discovering what the word Biogon means. I found a fascinating article by H. H. Nasse that turned out very useful in the process of writing this post. As interesting as the rest of the article was, what had me hooked was contained within the first few paragraphs. Quite early on in the article it talks about the etymology of the word Biogon – with ‘gon’ being of Greek origin meaning angle, and bio meaning dynamic. Biogon therefore translates into ‘dynamic angle’ – which is exactly what I’ve found it more capable of than any other M mount 28mm lens.

Skip to the end (My Conclusion)

As I am sure I’ve made very clear, I really like the Zeiss 28mm ZM Biogon. In fact, I don’t just really like it – it has become in my opinion the best 28mm lens I’ve shot on a Leica M-mount camera. Of course, it’s not the 28mm lens I own – I borrowed it, and soon it needs to go back to Zeiss.

This will leave me back where I was with my Minolta G-Rokkor and Voigtlander Color-Skopar. The Rokkor was the lens I bought instead buying the Zeiss. Of course, the reasons I bought it to improve upon the Color-Skoper still remain valid, not only this, but since I sold my Minolta TC-1, I have craved owning the Minolta lens again. As such, the minolta isn’t likely to be going anywhere soon! So where does this leave me? Well, the one thing I have is time; I have no need to make a decision instantly, but my gut feeling is that I might end up owning more than one 28mm lens!

Of course multiple lenses of the same focal length isn’t everyone’s ideal answer to this question. If your reading this post looking for a recommendation, it’d definitely be the Zeiss I’d point you in the direction of. In total, I’ve tried five 28mm lenses for my Leica mount cameras. The Voigtlander 28mm f/1.9, and f/3.5, the Minolta G-Rokkor and the Leica Elmarit-M have all given me great results. Ultimately though, of all of these experiences, only the Zeiss has so far given me something close to the magic I’ve learned I love in the results from the Zeiss 50mm ZM Sonnar.

For me, borrowing this lens was a bit of an experiment. I wanted to find out if what I loved about the Sonnar were traits only found in it, or if they were traits found more commonly in Zeiss ZM lenses. Zeiss lenses have their fans, and almost all of them talk about the same series of attributes: Zeiss colours, Zeiss contrast and Zeiss 3D pop. Not only have I found myself in agreement with the idea that these traits are indeed common to these lenses, I’ve also found myself completely sucked in by them. By shooting with this lens, what I have found is that I am not just a ZM Sonnar fan, I’m a Zeiss ZM lens fan.

Fanboyism aside though, there’s more to this recommendation than just my personal preference. In the 28mm ZM Biogon these Zeiss traits are combined with a near flawless build and a 0.5m close focus that – provided you have a good sense of distance – can really bring something a little more than you’d normally expect from a rangefinder lens. The handling and size are issues, but in the same way as I forgive the nub on the Sonnar for what else that lens brings me, I forgive these issues in this lens too. Shooting with other 28mm lenses recently, I’ve been getting distracted by issues derived from size, weight and handling – in fact these are quite often issues that bother me with photography equipment in general. The fact that none of these issues have got in the way of this experience – to me at least – says something very positive about this lens! As such, its fair to say that the Zeiss 28mm ZM Biogon get my unreserved recommendation!

Thanks for the loan Zeiss…

Cheers for reading,

Hamish

More of my photos taken with this lens can be found here

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