This weekend I did a little bit of a Zuikofest 100mm shootout. My storied
100/2.8 against this new king of the hill 100/2. To quote one of my favorite
lines: "Veddy interesting!"
Let's get two things out of the way first.
1. My 100/2.8 is an unusual one that has sometimes exhibited characteristics
not found in other samples. Some people feel that I've made some unfounded
claims, but I continue to stand by my claims and other people, who have
experienced this specific lens, tend to agree.
2. The 100/2 is sharp enough WIDE-OPEN that it exceeds the resolving ability
of either of my digital cameras. I don't know just how sharp it really is.
But it definitely sharp enough that it's pretty much maxing out whatever
film I normally use in my OM bodies.
Oh, and one more thing. If you don't agree with me on my testing procedures
or conclusions, I welcome a competing test. Don't just believe what I write,
prove it yourself.
To eliminate as much human factor as possible, I use live-view with the
magnifier on the DMC-L1 to attain critical focus. I do a rock back and forth
and adjust for the mid-point. Even at that, I discovered a very slight
variance between shots. Or have I? Here is where things get a little
interesting. When shot at exactly the same apertures, and carefully
selecting the same focus point, the 100/2.8 always seems to have a touch
more DoF on the near-side. At this time, I'm calling this a human error, yet
time and again, when focused in exactly the same manner on exactly the same
point, the 100/2.8 is sharper closer in. I've even focused the lenses
stopped down and the same thing occurs. Before letting this go, totally,
what I'm wondering is whether or not the rate of defocus either side of the
plane of focus is assymitrical between the two lenses.
So, that is where the second test came in, I did do a "bokeh/dof" test using
the ultimate calibration and test tool--a farm implemement. That's right. A
haybale conveyer. Again, the focus was ever so slightly off. In this case I
focused almost exactly at 2 meters distance. The 100/2.8's plane of focus
was probably 3mm closer. But, the bokeh expansion in the 100/2.8 is slightly
more constrained than the 100/2 and has a tighter gradient. So, the rate of
expansion is not the same between the lenses on the near side. On the far
side, however, the rate of expansion is nearly identical, but the 100/2.8
has a harsher bokeh. For instance, the wire fence in the background, even
though out of focus, had more distinct edges than the 100/2.
OK, what about sharpness at normal apertures of F5.6 or F8? It was pretty
much a dead heat. Both lenses exceeded the ability of the sensor to capture
any further detail. I'll call this a "good 'nuff" result. Again, this was
through maximum detail extraction (complete with converter artifacts) of a
DMC-L1 raw file which is similar to that of an E-3 raw file. Either way, it
just confirms what I already knew--the 100/2.8 smokes most of the films I
use anyway. The 100/2 is just more of the same in that regard.
However, this is only part of the story. What about F2 to F4? Obviously, the
100/2 is better at F2 than the 100/2.8. Let's just say that it's good enough
to be almost creepy sharp. A head-shot portrait last week was so sharp
(where it was sharp) that I couldn't bear to zoom in too closely for too
long. The intimacy was disquieting. At F2.8, the 100/2 is sharper and
contrastier. At F4, the two lenses become almost identical, except the bokeh
is a little harsh in the 100/2.8. F5.6 to F8, the lenses are essentially
identical. I'm finding no significant difference other than what has already
been noted. If you could restrict usage between F4 and F8, there is no
reason to select the 100/2 over the 100/2.8. I'm happy with either. Outside
of that narrow range, the nod is definitely given to the 100/2.
Both lenses have a strong green/magenta color shift for front/rear blurred
edges. In overlapping apertures, I think the 100/2.8 has more of it, though.
Still not bad, but it is obvious that the 100/2 has a touch more correction.
Stopped down to smallest aperture, I find less diffraction blurring with the
100/2. In fact, stopped down, the 100/2 remains so much constrastier that
there is an implied sharpness to the image which far exceeds the 100/2.
For close-up work, things do switch around a little. When at 1:2 to 1:4
image magnification, I like the 100/2.8 a little more. Any specular
highlights which are within the 2X working distance seem to be a bit
hard-edged with the 100/2, but have a nice penumbra with the 100/2.8. The
100/2 is a little sharper, but I can tell that the highly corrected optics
are not optimized for this close of a range and you end up fighting those
optics.
Flare. The 100/2.8 is definitely more susceptable to an overall veiling
flare, but the 100/2 will get wierd streaks and hotspots of flare in a
manner I haven't been able to figure out the causation of yet. More research
to follow.
What about full-frame? I've tested both lenses on an OM body with Ektar 100.
I'm going to call it a wash at the smaller apertures, but the 100/2 is more
flat-fielded across the entire image. The 100/2.8 has a touch of vignetting
at F2.8, but the 100/2 is about as flat across the entire image as I've ever
seen. No exacting tests yet, but even wide-open the 100/2 does not produce
any noticable vignetting. I'm comfortable extrapolating corner information
from either lens based on the trending seen on the crop-sensor camera. These
two lenses are very well behaved, but the 100/2 is definitely more better
behaved.
So, tests aside, what do I think of the 100/2 as compared to the 100/2.8?
This is a fascinating question for sure. The fact is, I like BOTH of them.
They may share the same focal length, but the lenses do render the scenes
differently. The 100/2 doesn't appear to have the "red spread" of the
100/2.8. I think that "red spread" is what makes the 100/2.8 such an amazing
portrait lens. Each lens is unique, yet obviously from the same family. The
100/2 has no "sweet spot". It's good at every setting and is definitaly
biased towards wide-open. The 100/2.8, at F4 and F5.6 is incredible for
portraiture and has a bit more "glow". OK, maybe a lot more "glow",
(whatever "glow" is). I' survived for 25 years shooting this 100/2.8 and it
has earned more money than all the rest of the lenses combined, so it does
extremely well. The 100/2 had a very high bar to jump over.
Comparing the 100/2 to the 35-80 is a fascinating experiment. I've only
began that slippery slide. Those two lenses are so completely different, yet
both exceptionally good. The 100/2 has the bokeh/dof advantage, but the
35-80 seems to have the 3D advantage. More to come there.
Pictures? Well, yes. I'll be posting pictures at some point, but not until I
have done a few more tests that try to figure out some oddities first.
The funnest part of the 100/2 is handing an OM with 100/2 to another
photographer. Without exception, they smile, laugh, exclaim praise, then
furrow their eyebrows as they contemplate the equipment they currently have
and wonder what lens in their mount they can buy to duplicate it.
Is the 100/2 an expensive lens? Let's say it runs around $1000 USD. So, yes,
for a used lens in a discontinued lens mount, it is expensive. But when you
figure what $1000 buys you these days in brand new lenses, I'd say that the
lens is a bargain if it provides the usefulness of which you seek. If narrow
DoF is your game, combined with ultimate sharpness, I can't think of another
$1000 lens that comes close.
AG
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