Nikon introduced the D750, the first full-frame DSLR to feature a tilting LCD and built-in Wi-Fi, in September 2014. In this in-depth review Shun Cheung discusses the ins and outs of this new offering...
What's so exciting about an f/1.2 lens? In medium light, the lens can
produce an extremely shallow depth of field, throwing any background
distractions out of focus. In low light, the lens supports reasonable
motion-stopping shutter speeds without forcing the photographer to
choose a high noise ISO 1600 or ISO 3200.
The lens was redesigned early in 2006 and now carries a "II"
designation. The earlier version of the lens was a very high quality
optic, but the new version, at a slightly increased price, offers
improved autofocus speed and transmits focus distance information to
the camera, increasing the accuracy of flash exposure.
What kind of photographer earns enough money taking pictures of people
to recoup the cost of this lens? A wedding photographer. Here's how
to use the Canon 85/1.2L at a wedding:
if the weather is sunny, have an assistant hold a diffuser cloth
in a frame between the sun and the subject
have a second assistant hold a reflector underneath the subject to
remove any shadows underneath the eyes
set the aperture somewhere between f/1.4 and f/2.0 for enough
depth of field to cover minor focusing errors or subject movement
focus on the subject's eyes; viewers will accept the rest of the
image rendered slightly soft
Magnification and Depth of Field
How close does the Canon 85/1.2L lens focus? Can you take a picture
tightly cropped around a friend's head? You might need to bang your
friend's head against the studio wall, then wait a few hours until it
swells up to the size of a prize-winning watermelon. Maximum image
magnification is 0.11X. On a full-frame camera, this is good for a
head-and-shoulders photo, but not sufficient for a head-only picture
(comparison: the 70-200/2.8L lens focuses down to a magnification of
0.17X). For studio portraiture, you might find it convenient to work
with the EF 12 II extension tube. You'll lose the ability to focus at
infinity with this tube attached, but maximum magnification is
increased to 0.25X.
How about depth of field? At the five foot distance that would be
typical for an upper body portrait, the depth of field at f/1.2 is
only about one inch, i.e., at typical enlargement sizes and viewing
distances, objects between 1/2" behind the subject's eyes to 1/2"
ahead of the subject's eyes will be acceptably sharp. You'd better
hope that the subject doesn't move, which unfortunately is the surest
way to get terrible photos. As soon as the average person is forced
to freeze, he or she takes on a strained expression.
What does this mean as a practical matter? Consider the 100 percent
crop (below) from an EOS 1Ds Mark III 21 megapixel image, taken at
f/1.2. The eyebrow is in sharp focus. The eye is soft. The full
size image is at the lower left hand corner of the matrix below.
At f/2.0, the depth of field expands to roughly 3/4" on either side of
the focus plane. At f/2.8, the depth of field is 1" on either side.
Even at f/8, the depth of field is only about 3" on either side. Note
that these numbers are for a full-frame body; see "Depth of Field and the Small-Sensor
Digital Cameras" to understand how the numbers change with a
Digital Rebel or similar camera.
In order to facilitate viewing, single lens reflex cameras keep the
lens wide open until an instant before exposure. The brightness of
the viewfinder does not depend on the aperture that you've set for the
photo; the brightness of the viewfinder is determined by the maximum
aperture of the lens. Mounting an f/1.2 prime lens instead of a
typical f/2.8 professional zoom will send six times as much light to
the viewfinder, yielding roughly an apparent doubling of brightness.
The shallow depth of field at f/1.2 also helps a photographer evaluate
focus. Subjects will snap in and out of focus more dramatically than
with a slower lens. The autofocus system also has an easier time
working, especially on dimly lit scenes.
Image stabilization as close as the nearest tripod...
Canon doesn't put sensor-based image stabilization in its bodies and
they didn't put an optical image stabilizer in this lens. The f/1.2
aperture helps by enabling the photographer to select higher shutter
speeds, but to minimize camera shake you'll find yourself leaning up
against door frames or using electronic flash. If you can't find a
door frame, remember that you need a shutter speed of 1/80th of a
second or less to freeze typical camera shake at typical
The lack of image stabilization makes this lens more of a
portrait/blurred background champ than a low-light-without-tripod
The Canon 85/1.2L incorporates a ring-type ultrasonic motor, for
instant autofocus and the option of touching up the focus manually
even in autofocus mode. The lens lacks internal focus so the front
element moves forward and back slightly as the focus is adjusted.
However, the front element does not rotate as you focus, making it
easy to use this lens with polarizing filters.
The Canon 85/1.2L has the kind of rugged mechanical construction that
you would expect given the heavy chunks of glass inside. The lens
lacks the rubber gasket around the all-metal mount that is typical of
other L-series lenses, such as the 70-200/2.8 and 16-35/2.8. Do not
expect better resistance to rain than you would get with an 85/1.8 or
other non-L lens.
The lens barrel incorporates 8 elements of glass in 7 groups. One of
those 8 glass elements is aspherical.
The diaphragm is an 8-blade design for nearly circular appearance in
out-of-focus highlights. Filter size is 72mm and the clip-on
ES-79 II hood is included.
The penalty for all of this quality is a shoulder-crushing weight of
1025g, more than 2 lbs. and twice as much as a Canon Digital
As digital camera bodies add more pixels, one wonders whether or not
lens resolution will be the limit on image quality. At right is a
studio test with the 85/1.2L at f/8, the aperture that produced the
highest quality results on Canon's modulation transfer function graph
(see link below). The body was the
Canon EOS 1Ds Mark III, (compare prices) (review) set to "ISO L" (50) because we
could not dial down the studio strobes sufficiently to use the native
ISO 100 setting. The subject is Elsa Dorfman, Boston's
best-known portrait photographer, with her 20x24" Polaroid camera.
Below is a crop from the original 21 megapixel image. The cropped
image is presented at 100 percent, i.e., each pixel in the image below
is one pixel from the camera. The crop image was filtered with
Unsharp Mask at the following settings: 75 percent, 1 pixel radius, 0
threshold. It was then saved in .png format.
What's the limiting part of the imaging system here, the camera body
or the 85/1.2L lens? Look at the lack of contrast and the softness of
the "Fuji Photo Optical" lettering around the lens. These are not
distortions that you would expect from the CMOS sensor in the 1Ds Mark
III. These are typical problems that one expects at the resolution
limit of a lens.
If your wallet and shoulder can't support the price and weight of the
85/1.2L lens, consider the Canon EF 85mm f/1.8 USM, (compare prices) (review). You lose
one f-stop of speed, which means that you will need twice as much
light, but the 85/1.8 is an excellent lens and balances better on the
lighter digital bodies, such as the Rebel series.
Nikon produces a very high quality 85/1.4 that is in between the Canon
85/1.2 and 85/1.8 in price and weight. There was a Pentax 85/1.4 lens, but it has been
discontinued. Sony offers a relatively new 85/1.4 lens for their
digital bodies. The Canon EOS lens mount is a bit larger than
competitive lens mounts, which is why Canon has been able to produce
crazy fast lenses such as the 50/1.0 and the 85/1.2.
How well does it work with the Digital Rebel?
This is an EF lens, illuminating an image circle large enough to cover
a 24x36mm piece of film or the sensor in Canon's more expensive
"full-frame" digital SLRs. The lens will work fine on a
small-sensor body, but you will be carrying around ridiculously more
glass than you need. On the plus side, the equivalent focal length
will be closer to 130mm, which provides more telephoto compression of
features and a greater working distance from the subject.
Would a 50/1.4 and a Digital Rebel work just as well?
Given that (1) a 50mm lens on a small sensor body gives the same
perspective as a 75mm lens on a full-frame body, (2) a 75mm lens and
an 85mm lens are awfully close in perspective, (3) an f1.4 lens is
just as useful as an f/1.2 lens 95 percent of the time because it is
so seldom that one wants to take pictures at f/1.2, and (4) a 50/1.4
and Digital Rebel body cost less than the 85/1.2L, ... why wouldn't a
Digital Rebel and Canon 50/1.4 lens work just as well as an 85/1.2L
lens on a full frame body?
For taking pictures in available light, the 50/1.4 and Digital
Rebel would work reasonably well, with the caveat that a small sensor
body will nearly always have more noise at high ISOs than a full-frame
body. Where the 50/1.4 on a small sensor body is not equivalent to an
85mm lens used at f/1.4 on a full frame body is in depth of field.
The 85mm lens at f/1.4 and 5' has a depth of field only +/- 0.5
inches. The 50mm lens at f/1.4 and 5' has a depth of field of +/- 1.5
inches. The dreamy look of the portrait may well be gone.
Where to Buy (or maybe rent?)
We're impatient, so we buy
everything from amazon.com, (compare prices). If you
have a specific short-term project that calls for a very fast 85mm
lens and you didn't grow up on a money farm, consider renting from
your local professional camera dealer. One of the great things about
the Canon system is its popularity with professional photographers,
which enables big city camera stores to run a rental business in the