Sharpness has been for quite some time the Holy Grail of digital-age photographers. In the film era, film was what gave your pictures definition, providing your lens could exceed the film’s performance. Print and slides were the common way to view the result of one’s efforts, and only a small minority of photographers bothered to check for sharpness by poring over large prints with a magnifying glass.
The digital age changed all that. Because the computer monitor is the common way to view pictures, and software puts 100% magnification of any part of any picture only a click away. Furthermore, the gradual increase in pixel count has made the magnification factor increase, because a given number of pixels, as defined by 100% magnification for a given screen size represents full-screen viewing of an ever smaller percentage of a total image.
This has shown that not that many images are actually sharp enough to be beyond reproach if viewed under such conditions. For example, owners of a Nikon D800E, with its humongous pixel count might well find that either their lenses or their shooting technique, which they thought delivered sharp images, were no longer “good enough”. Any resemblance in this description to anyone posting on this blog would be pure coincidence….:-)
But, outstanding though it is, the D800E is not the most demanding camera for lens sharpness, at least outside the corner area. Because the NEX 7, with its 24 Mp APS-C sensor, has greater pixel density than the FF Nikon at 38MP.
So I thought it would be interesting to conduct a simple, brief, real-world sharpness test of 3 very highly regarded lenses on a NEX 7
1. Like with Like
The first test pits the Zeiss Contax G 45 f:2.0 against the Leica 50 Summilux f:1.4. Both are rangefinder lenses, each produced by one of the leading masters of photo-optical design, rivals Zeiss and Leica, and both held in the highest regard as very high performance classics. The question of relative performance is IMHO very appropriate, because the lenses are so comparable. Both small rangefinders, almost the same focal length, both usable in manual focus on the NEX (except for those who already know that this month there should be the release of a new electronic adapter that delivers autofocus for Contax G lenses on NEX cameras, and later, another one for Fuji). But a minor difference is that the Summilux costs about the same as 10 Contaxes. So finding out if the sweetheart of a few years ago can still repel the onslaught of the Leica champ is not exactly moot.
Here are two pictures, left strictly unprocessed from RAW except to up the exposure, chosen as f:5.6. Not strictly identical because the framing is not perfect, and the lighting conditions changed somewhat, but, as you will see when I post the crops, that doesn’t prevent the different in sharpness from showing through -or not!
See the difference in the foliage? Now, before you start to shout “foul!” for my trying to disparage your beloved Contax G 45, the wonderful lens that turns out to be less sharp, this difference does not show up just because the G45 happens to be lacking depth of field. It is slightly shorter in FL than the Lux 50, so it has more DOF, and both were focused on the same point, the front of the small building. Oh, yeah, I haven’t shown you the whole pics. I might as well, so that you can see that both lenses actually draw quite differently. One with substantially more contrast than the other. And, remember, the shooting conditions were not strictly identical, and the pictures are shown without any processing.
Now, just because I am a nice guy, I showed the full pics in the same order as the crops. The one that has more contrast is the G 45. To be totally honest, I was shocked at how much better the Lux is because of the iconic reputation of the Contax. Now you will ask, if I was so sure I had a stellar 45mm f:2.0, why spend ten times the money to get a 50mm lens? Just because focusing the Leica is a dream , whereas focusing the adapter ring on the G is, at best, an acquired taste? Fact is, I was so in love with the Elmar 24 (still am, too), that the thought of acquiring something just as good only longer and much faster was too hard to resist, and I bought it without comparing it to the G 45. I should add, I had no idea how the shootout would turn out, and whether I would end up being the proud owner of the most overpriced 50mm. But, as it happened, not. For sharpness is not the only area where the Lux outshines the 45 IMHO. Look at the colours on the house. And, in other shots, bokeh too. And, of course, it is one stop faster…
2. Leica with Leica
Now I just know that there will be some of you saying that I was just making a case to justify forking out the considerable price of the Lux, at the expense of the G45. As it happens, I intended to make this a 3-way comparison, with another iconic lens of approximately the same focal length, the Leica R 60 Makro Elmarit. Another fully manual lens, designed in the 70s, my copy being well-worn. Not a true macro lens, because it only goes to 2:1 without the bellows. And, being a DSLR lens it is quite a bit larger and heavier than the rangefinder duo we matched above.
Now you will ask, how can one compare a lens designed for close-up, the makro, to another with another one that shines at infinity and can’t get closer than 70cm because of its original rangefinder limitations? Though readers of DearSusan’s will know that this limitation is now in fact over for the owners of a Hawk’s helicoid adapter, with which MFD becomes much shorter, around 40cm.
Well, one of the reasons the Elmarit is held in such high regard is that, not only does it shine at close range, but it is also excellent at infinity. But first, at close range, around 50cm, at f:4.0. The pictures are unprocessed from RAW, sharply cropped, but not 100%. Maybe 60%.
As you can see, the Lux is not that happy close up, clearly not optimized for such close range. The Elmarit image is much more three-dimentional, less flat, with a richer, more subtle colour palette. “Ouch” blurts the Lux, “you’re hurting me!” Now let’s see how they are doing at infinity. The scene is more than 10m away, aperture is f:5.6. Very high contrast, a good test for CA. Again, a very significant crop, but not quite 100%.
This time the pictures are shown in reverse order from the previous test, but the results remain the same. The Elmarit holds more detail, the picture is more three-dimentional. More surprinsingly, the Lux shows more CA as well. Obviously, the penalty for the Lux’s speed is there to be seen, and the Elmarit is simply better corrected, as befits a macro lens. This helps put paid to a myth that “faster lenses are intrinsically better”, they aren’t. A case in point would be the Leica Lux 21 f:1.4, generally not considered as good as the much slower Super Elmar 21 f:3.4 for stopped-down landscape.
So, where does that leave us, keeping in mind the not insignificant fact that you can get some 5 or 6 used Elmarits for the price of one new Summilux? Obviously, the Elmarit offers stunning value for money, a quasi-universal lens of the highest order. Is it perfect? No, because it is relatively slow, relatively heavy, relatively old. Interestingly, while I was palying with thjese three lenses, my friend Boris was testing the all-new Leica 50mm Summicron AA, a shockingly expensive lens at some 6000+€ that has fantastic MTF curves. He found it to be mind-blowingly good at f:2.0, meaning wide open, but stopped down he considered it to be equivalent to the Lux, with pros and cons on either side, which meant that spending so much money for so little improvement is questionable in his mind. At the time of writing, he hadn’t made up his mind on which lens he would keep.
In conclusion, while the Lux bests it, the G 45 is still a fantastic performer considering how little it costs. That it has delivered so many fabulous shots over the years remains just as valid today, and, if I didn’t have the Lux, I would be more than happy with its output. Also, this very brief comparison is centered on sharpness, by far not the only criterion for lens performance, and ont the most important in my mind. Colours, contrast and drawing style matter more for yours truly. But first and foremost, let’s remember that looking for nits to pick at 100% magnification is not what image-making is all about. Ansel Adams didn’t have today’s equipment, neither did Cartier-Bresson. Let’s spend as much time improving our skills as we do picking the best equipment!
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