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Built quality and autofocus
When you take the 85mm f/1.2, you are
looking at 1 kg of metal and
glass. It is surprisingly similar to the
discontinued 50mm f/1.0, but the autofocus
is a little better, even though it is not
super fast; other than that, the copy I
tried had a strong backfocus (that is not a
problem with recent cameras, you can easily
correct it). The focus of the 85mm is a bit
different from usual; even the manual focus
is performed by the AF motor; when the
camera is turned off, you can't focus, even
if MF. Not a problem anyway!
The 85mm f/1.8, in comparison, is much
lighter and it has a less professional built
quality, but surprisingly it has a faster
AF! The 85mm f/1.8 USM has the true
ultrasonic motor, while the big 85 f/1.2 has
a much slower AF (I thought that it had
micro-USM, but it seems that it actually has
ring-type USM...it is surprising, because
all other lenses with ring-USM have a
faster, more silent AF, without extending
elements).
The
85mm f/1.2 is more than twice as heavy as
the 85mm f/1.8; it has
the rock solid built quality of the best L
lenses. The huge front element is
impressive; you can protect it with the
large lens hood, that Canon kindly includes
in the $1950 price of this lens :-)
The Sigma 85mm f/1.4 is still a mystery
since at the time of this review (April
2010) it is not yet available. I'll try to
test it when it reaches the market; if image
quality is good, it may be a very
interesting alternative to the 85mm f/1.2.
The 85mm f/1.2 in
the field
There are some things you won't know by
just reading the specifications: for
example, Canon does not tell you that you
will never see the f/1.2 depth of field in
viewfinder. This is true for every super
bright lens: in the viewfinder you see the
depth of field of the lens at about f/4 or
so. You can stop down more by using the DOF
preview button, but you can never see the
true f/1.2 depth of field into viewfinder.
This is a big problem for the 85mm f/1.2,
because it has paper thin depth of field,
and even a minimal focus error gives a
completely out of focus image. But when you
look into viewfinder, you will always see
more DOF than reality: what you can do? You
can either pray&hope, or you can use AF (but
it may not be accurate), or you can use live
view. From my experience, live view is by
far the best option: in LV you see the
actual f/1.2 depth of field, and you can
make a very precise manual focus using the
10x magnification.
Is the depth of field of f/1.2 actually
usable? Surprisingly, yes. If you are extra
careful, you may even manage to take a good
portrait, with both eyes and the lips in
focus - but it is not easy, many times you
will end up with one eye in focus and the
other one out of focus. For a photo of an
entire person, a car, or something like
that, the depth of field is enough, if you
focus carefully and if your subject is
parallel to you.
The 85mm 1.2 is a lens for creativity. It
always gives very smooth backgrounds; it
allows to make amazing effects of selective
depth of field.
Background blur and
depth of field
Is there a big
difference between the background blur
of f/1.2 (as the canon 85 1.2), a f/1.4
(as Sigma 85 1.4) and f/1.8 (as Canon 85
1.8)? This is the same subject
photographed at the three apertures.
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Background
blur
at f/1.2 |
Background
blur
at f/1.4 |
Background
blur
at f/1.8 |
While there is not an
huge difference between f/1.2 and f/1.4,
the difference between f/1.2 and f/1.8
is clearly visible.
Image quality
(in comparison with Canon 85 mm f/1.8)
I have tested the lenses on my Canon
1DsIII (21 megapixel, fullframe). The lenses
were mounted on tripod; I have used mirror
lock up and self timer. The following images
are 100% crop from the unprocessed RAW file.
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