Hasselblad user examines Leica S2 pre-review coverage
Related: digital sensor, field curvature, Leica, Leica M, Leica medium format, medium format, optics
One Hasselblad owner took issue with my S2 pre-review coverage.
I check your blog every day and have enjoyed it over the last few months. I grimaced this morning when I read one of your S2 comments, so I thought I would cough up my hairball as a way to underscore how important it is to maintain your practical approach to equipment evaluations. I noted in your blog from yesterday the following comment regarding the Leica lenses: “ Add in what look to be the worlds’s best medium format lenses, and it could be a winner.” When I read this, my first reaction was: ' what does " best " really mean? ', quickly followed by: ' how would he know? ' High level assessments are tricky, sometimes useful, and always subject to second guessing. Here are some points to consider.
DIGLLOYD: The phrase “look to be” has specific meaning, namely that something has the appearance of an attribute, but some doubt lingers. I chose my words carefully, the goal was to set possible expectations. I haven’t evaluated the equipment yet.
As readers of my reviews know, some of my reviews include an extensive discussion of what “best” means, and how the term can be ambiguous, or mean different things to different people (eg a lens with strong distortion is never “best” to an architectural photographer). I reserve the right to use plain English sometimes, because I can’t always insert 3 pages of didactic discussion.
I shoot my fine art work using a Hasselblad H3D-39 with H series lenses. In my initial testing all 5 of my H series lenses, and in using them in the field for three years now, I have concluded that the optical quality of these lenses are not the limiting factor in the final resolution of the images: the 39mp sensor and operator tradeoffs/errors limit in almost every case I have closely examined. If you have personally used all the medium format platforms in the field, then I would accept your assessment of which lenses are 'best' having experienced all the systems in a real world circumstance. But few of us have the time and resources to try everything, make a living and lead a life. So the easiest way to compare platforms is by examination of comparative data. Comparable MTF charts spring to mind. Also tricky.
DIGLLOYD: “Optical quality” is just as nebulous a concept as “best”. Given the very real problems with medium format system alignment, the “use all platforms” idea is a dubious concept. I’m glad this user finds Hasselblad lenses excellent, and I have no doubt that they are outstanding. My review will assess the performance of the S2 system as a whole; as my discussion already pointed out, the system performance is what matters. But the notion that one has to test every medium format system to be able to render any judgment is absurd. The term “real world” is just as ambiguous as “best”: maybe this reader is always shooting at f/11 or f/16, and thus will see only diffraction-degraded performance! Perhaps f/2.8 is also “real world” for some shooters, as is focus accuracy, and there are likely to be real differences there.
The role of MTF charts in a comprehensive evaluation of a given lens can be debated. Perhaps the mfg's published MTF charts, or actual MTF measurements, may offer some useful data for judging medium format lenses for various platforms; perhaps not.
DIGLLOYD: MTF charts are always a useful starting point, if only to show that field curvature or focus shift might be present. It’s an asymmetric usefulness: a fantastic MTF chart invariably means a great lens in some sense, but the converse is not necessarily the case; a disappointing MTF chart might simply indicate field curvature and focus shift, yet a lens could still be outstanding when applied appropriately (though such a lens is in fact a weak performer with some subject matter). My lengthy simple discussion of MTF addresses these issues. The Leica S lenses MTF charts are fantastic, and that’s a fact. MTF shooting doesn’t show a lot of things, so field proofs are the final word.
With all the post-processing tricks now possible on image contrast control and sharpening, the film-based MTF standard of 50% doesn't mean much anymore, but perhaps a nominal comparison is useful to folks if the MTF charts generated are employing consistent methodologies and accurately represent the performance of actual production units. That's a big if.
DIGLLOYD: The clarity of a top-grade lens always comes through in the image. Heavy post-processing requires time and effort, and can look artificial. A good lens looks real, comes alive. Post-processing does not achieve the same effect with a lesser lens— improved perhaps, but different. But that‘s not MTF per se, many attributes are not measured by MTF. Field evaluation is necessary.
J. Holmes did an great job in throwing an important spotlight on the high sensitivities of lens and sensor alignment to overall system performance, as you pointed out. Hence, I find it hard to get too terribly excited about comparing optical qualities between platforms if the quality levels of the optics exceed the sensor performance by a substantial amount. To wit: in the case of the H series 120mm Macro, I have seen estimates of it being able to suitably perform when paired with sensors up to 120mp, and based on first-hand experience with this remarkable lens I do not doubt this estimate whatsoever.
DIGLLOYD: Yes, Joe Holmes exposé was well done.
Here is “have cake and eat it too”. MTF is questioned, but “estimates of it being able to perform up to 120MP” is somehow unrelated? That’s an MTF question. Furthermore, field curvature and focus shift and diffraction all come into that equation, and all are manifested in an MTF chart. My assessment of the Leica MTF charts for S glass shows that they are as good as I’ve ever seen for medium format, which should mean that field results are outstanding, something that needs to be shown of course.
All that matters to me is that it's a great lens, so my choice of sensor, my choice of mechanical platform and my skill limitations are limiting my images, not the glass.
DIGLLOYD: I’m not sure why it’s important to emphasize the best optics so strongly, then feel satisfied that the rest of the system limits the performance (possibly severely), as I discussed under Sensor Resolution is Only Potential. Modest differences in optics are likely to matter less than whether a camera system that can consistently produce the best possible results from that glass. Focus accuracy comes to mind; even a minor focus error negates differences between the best and the average. But we seem to agree that top-grade lenses at least eliminate the lens as a factor, one less challenge to deal with.
If you want to provide links to back up your assertions of which lens family are "best", blog followers and google cruisers interested in optical components can look at the dimensions and measurements for assessing lens quality for themselves, relieving you of any potential conflict of interests in making such assertions.
DIGLLOYD: I’ll provide those links right after I finish my Meaning of Life book. The phrase “look to be” that I used in context has specific intent, as was the fact that “best” was used as a useful simplification. The idea that the topic must not be discussed from my own perspective, or that everyone out there is capable of or wants to perform their own analysis... still scratching my head there. I’m not sure what “conflict of interest” means here, but it stands bereft of any explanation. This reader should study my Leica M9 review, for it contains numerous criticisms of that system.
But for those shooters who understand that reliable overall system performance is what really matters, it makes more sense to me to identify the limiting factors and weaknesses of a given platform rather than spend time on platform component comparisons that are not interchangeable.
DIGLLOYD: See Sensor Resolution is Only Potential. As well as my various reviews where I elaborate on system performance.
You are a practical guy, and your reviews reflect a practical approach to photography. Let Leica deal with component comparisons if they want to satisfy the curiosities of the pixel peeper segment. The more valuable assessments for most shooters will come from field experiences that generate observations/insights about system performance and system durability.
DIGLLOYD: My reviews have always been primarily about usage in the field. But I always have to start somewhere.
As for “pixel peeping”, it’s a moronic pejorative used to dumb-down a discussion, and to denigrate anyone who thinks that it’s fine to invest $50K for a system (not me!), then blithely assume that the image quality is better than something that costs 1/3 the price. Or that the system is delivering what it’s supposed to. Talk to top pros who shoot advertising or fashion who know that they’ll lose not just that client, but maybe their career if they bomb a job because the equipment was off in some way, something as simple as focus accuracy, let alone other factors. Nor do such pros switch gear without looking very carefully at image quality. That’s the Real World. The most vocal critics of “pixel peeping” are those that rush to buy the next highest resolution digital back, then slyly talk about the improved “performance”.
