Given the astronomical prices
charged by the top-tier camera companies (i.e., Canon and Nikon) for
their long telephoto lenses, it’s not surprising that many people end
up buying third-party lenses, even when they’re using Canon or Nikon
cameras. The pertinent questions are, of course, how much more
affordable these third-party lenses are, and also how well they stack
up to the Big Dogs in terms
of image quality.
Table 3.6.1, below, surveys the
birding-lens price landscape as of mid-2009. Prices were taken
from Amazon, so these are “street” prices, not MSRP’s (Manufacturer’s Suggested Retail Price),
which are always inflated for camera products. Keep in mind that
many of these third-party lenses might not have any type of image
stabilization, and in some cases there may be an IS version and a
non-IS version both available from the same company. When several
versions were found to be available, the cheaper model was used for
pricing. Also, 400mm f/2.8
lenses were omitted, since they’re too heavy for hand-held work and are
not the best option for high-powered tripod work (and they’re both
expensive and currently only available from the two top-tier companies).
At the 400mm level, the
third-party lenses are clearly much cheaper than the Canon/Nikon
lenses, both for prime and for zoom lenses. In the field, I
rarely ever see third-party 400mm zooms in use for birding, though; in
the vast majority of cases, birders using a 400mm zoom were using a
Canon or (more rarely) a Nikon. The Sigma 500mm zooms are quite
popular, however, since they’re very cheap compared to a 500mm prime,
and are lighter and more compact, making them hand-holdable (unlike the
Canon/Nikon 500mm lenses). Above 400mm, the third-party primes
become much more comparable to the name brands in price (rendering them
less attractive), and above 500mm even the zooms become outrageously
expensive (e.g., the Sigma 300-800mm zoom). Note that the table
above doesn’t include the ultra-cheap 500mm mirror lenses (which run
about $150) nor the small-aperture (e.g., f/16), manual-focus,
super-telephotos (e.g., 1000mm, give or take) that can be had for a few
hundred dollars and are reputed to be optically horrendous.
3.6.1: Typical street prices for birding lenses, mid-2009.
“#-NNN” denotes a
zoom. Zooms with no aperture given are
typically f/5.6 or f/6.3 at their highest magnification.
*The Sigma 500mm prime is actually f/4.5.
To address the
question of relative optical quality between the top-tier and
third-party lenses, we’ll consider a particular pair of highly popular
birding lenses in great detail. From this very specific example
we’ll then try to (cautiously) draw some very general conclusions about
what may be expected of third-party “glass”. When considering a
particular lens, it’s advisable to try to find a similar comparison to
the one below, for the particular lens under consideration and a
comparable name-brand lens, to see what you might be giving up by going
with the third-party lens.
The two lenses we’ll consider in detail here are the
Canon EF 600mm f/4 L IS
USM, and the Sigma 800mm
f/5.6 EX DG
APO HSM. (We’ll dissect those lengthy names in just a
moment). Since these two lenses have different focal lengths and
different apertures, we’ll make it a fairer fight by putting a 1.4×
teleconverter (the Canon EF 1.4× Extender II) on the Canon, giving
an effective focal length of 840mm and an effective aperture of f/5.6. Now
we’re effectively comparing two lenses of the same
aperture (f/5.6) and nearly
the same focal length (840mm versus
800mm). Since the Canon has a slight advantage in focal length
(by 40mm), we’ll move the Canon lens back a few feet from the subject
during imaging tests, so that both lenses will produce approximately
the same magnification. Note that the Canon is actually somewhat
handicapped by this comparison, since the use of a teleconverter can be
expected to reduce image quality. Keep that in mind when we
compare the resulting images: if the Canon, with TC, turns out to be as
good as the Sigma (with no TC), then that would suggest that the
underlying optics are better in the Canon, since with no TC the images
should be even sharper still.
In terms of the detailed specs for these lenses, the
EF in the Canon
name just refers to the lens mount, which is the same
for the Sigma lens (this Sigma lens is available in Canon, Nikon,
Sigma, and other mounts). The L
is just Canon’s
designation for its most elite lens line (it apparently stands for “Luxury”). The IS is of
course Image Stabilization,
which we covered in the
previous section, and the USM
stands for Ultrasonic Motor,
that the focusing element is moved via subsonic vibrations rather than
mechanical gears, making it both fast and quiet.
The Sigma’s acronyms are as follows. The EX is
a product-line designation, much like Canon’s L, and probably stands for Excellence or some
similar platitude. The DG means
it was redesigned
for use with digital cameras
(Sigma’s product literature is a bit vague on
this point, but refers to additional lens coatings that are somehow
more suitable for use with digital sensors). The APO of course stands for Apochromatic, as we discussed in
the previous section, and the HSM
is Sigma’s version of Canon’s USM.
For the first test, we’ll compare the two lenses by
photographing a US $20 bill affixed to a door at the end of a
hallway. For this test the lenses were mounted on the same camera
(a Canon EOS 1D Mark III), on
the same tripod, with all the same camera
settings. All images were shot at f/8, without mirror lock-up (MLU—see section 6.11),
image stabilization on
the Canon lens turned off.
The result is shown below, with
the Canon image shown on the left and the Sigma image on the right.
Comparing color, contrast, and sharpness between a
Canon 600mm lens with 1.4× TC attached
(left image) and a
Sigma 800mm prime lens (right), using identical camera settings.
The Canon photo was taken a few feet further away.
There are several things that can
be concluded from the figure above. First, the image on the right
appears darker, or more saturated, than the image on the left. As
further comparisons could show, the Sigma lens in fact has a bit
of a yellowish cast that it imparts to all photos taken through it,
possibly due to one of the antireflective coatings applied to the lens
by Sigma. I consider this to be a very, very minor issue, since
it’s often not noticeable (except in direct comparisons like this one),
and can be corrected easily in post-processing.
Second, the Canon image has more constrast than the
Sigma image. Notice how the blacks in the Canon image look black,
while the same regions in the Sigma image look brown instead.
This is particularly apparent in Andrew Jackson’s coat, and in the word
“SERIES” on the lower right corner of the
image (this becomes clearer
in the next figure, below). As a result,
fine details such as those in the former president’s hair or facial
lines, or in the eagle emblem near the lower right corner, seem sharper
at this crop level in the Canon image than in the Sigma. Look
also at the letters T and U along the rightmost edge of the two
images. They stand out much more noticeably in the Canon
image. Looking up then at the U and the “RESE” above that, the
Canon image seems to have greater definition, due to the increased
In order to compare true sharpness, we need to zoom
in to the pixel level, as is done below. The Canon image is again
on the left, while the Sigma image is on the right. (You can
again see the deeper yellow saturation in the Sigma image).
Magnified view of the images shown above.
Left: Canon 600mm + 1.4× TC.
Right: Sigma 800mm.
Notice the fine hexagonal patterning discernible in the
Canon image, which is nearly obliterated in the Sigma.
Note first that the black again seems blacker in the Canon image than in
the Sigma, while the light colors are lighter, indicating greater
contrast. Comparing the “SERIES 2006” lettering and the eagle
emblem, you can see that both lenses do appear to have been focused
properly for these images. But in the Canon image you can see
that the paper has a fine hexagonal pattern embedded in it. (Look
just above and slightly left of the eagle emblem). Seeing this
hexagonal pattern in the Sigma image requires more effort, and perhaps
even some imagination. To be completely fair, this level of
detail might, conceivably, be brought out in the Sigma image by first
correcting the color and contrast issues.
What’s most impressive, however, is the fact that
the Canon setup involves the use of a teleconverter, whereas the Sigma
setup for this experiment didn’t. As discussed in section 3.4,
all teleconverters degrade image quality—even $400 ones like the Canon
1.4× Extender II used in this
comparison. The fact that the Canon lens with a teleconverter
attached was able to out-resolve the Sigma lens with no teleconverter
attached (while, nevertheless, achieving equivalent magnifications)
strongly suggests that the native optical quality of the Canon lens is
strictly greater than that of the Sigma.
But photos of $20 bills aren’t photos of birds, and
what really matters is how well a lens performs in the field. In
the figure below are shown a pair of female Northern Cardinals (Cardinalis cardinalis). The
left image was again taken with the Canon 600mm f/4 lens + 1.4× TC (effective: 840mm f/5.6), while the right image was
taken with the Sigma 800mm f/5.6
prime lens. (For all of the bird photos in the remainder of this
section, the Canon image was taken with a 1D Mark III, 10MP camera,
while the Sigma image was taken approximately a year prior with a Canon
30D, 8MP camera).
3.6.3: Female Northern Cardinal (Cardinalis cardinalis).
Left: Canon 600mm + 1.4× TC.
Right: Sigma 800mm.
The background of the Canon image has been smoothed.
Flash was used for both photos.
Based on the images above, it’s
difficult to conclude that either lens is superior to the other.
Certainly, they both provide a copious amount of feather detail, which
was accentuated in both photos by the use of flash. Note that the
background in the image on the left has been artificially blurred in
post-process, so that comparisons of lens Bokeh (see section 3.7) can’t be
fairly made based on this pair of images. But so far the Sigma
seems to be as good as the Canon.
3.6.4: Prairie Warbler (Dendroica discolor). Left:
A second pair of bird images is shown below, with
again Canon on the left and Sigma on the right. The Canon image
was taken with fill flash, making unbiased comparison a bit more
difficult, but surely the two lenses have performed comparably in these
two situations as well. Postprocessing was done using two
different programs (Photoshop for the Canon, and OS/X Preview for the
Sigma), and the Sigma bird is larger, so it’s not unlikely that the
Sigma image would look every bit as good as the Canon with proper fill
flash, better sharpening in post-process, and an equivalent cropping to
make the bird the same size as in the Canon image. So again it’s
hard to conclude with any confidence that the Canon is optically
out-performing the Sigma.
Canon 600mm + 1.4× TC.
Right: Sigma 800mm f/5.6.
Flash was used for the Canon photo, but not the Sigma.
A final pair of
images is given below, in which it can be seen that the Sigma (on the
right) appears to resolve at least as much detail as the Canon (on the
left), and in this case may show greater contrast, due perhaps to the
particulars of the lighting situation (or perhaps to individual
variations in these birds’ plumages). In any case, it’s once
again hard to conclude that the Canon image is any sharper than the
Sigma, and in some parts of the bird’s plumage the Sigma actually
appears sharper than the Canon (though differences in depth-of-field
could account for this, since the photos were not taken at the same
distance or with the same camera settings).
Dark-eyed Junco (Junco hyemalis).
Left: Canon 600mm + 1.4× TC.
Right: Sigma 800mm.
Flash was used for both photos.
To summarize these three, highly
ad hoc comparisons, I’d cautiously suggest that the Sigma 800mm lens is
providing bird images with roughly the same amount of detail as the
Canon 600mm lens + 1.4× TC combination. That says
something good about both lenses: for the Sigma, it says that the 800mm
prime is a very good birding lens, while for the Canon it says that the
600mm + 1.4× TC combination is a good birding “lens” and that Canon’s own 800mm prime
lens should be even better,
since it provides 800mm of focal length without the need for any
teleconverter. Were we to compare equal focal lengths (without
the use of teleconverters), I’d predict that the various Canon (or
Nikon) lenses would prove optically superior to their Sigma
counterparts, but that the Sigma lenses would prove “good enough” for
The 800mm f/5.6 is one of Sigma’s
most prestigious (and expensive) lenses, so generalizations from the
comparison above need to be very cautious. Certainly, the 800mm
f/5.6 Sigma lenses—both the prime and zoom versions—are becoming
increasingly popular among birders, as are the two current Sigma 500mm
zooms. It’s likely that many birders would be very satisfied with
either of these two Sigma lenses, and as Sigma continues to improve its
lens line, Canon and Nikon may at some point start to notice a
significant loss of market share in the long telephoto segment.
In summary, it appears that at least one third-party
company—Sigma in particular—has the capability of producing lenses with
optical quality rivaling that of Canon and Nikon. Sigma lenses do
seem to have a better reputation than those of the other third-party
manufacturers, so if you’re thinking of going third-party, I’d
recommend sticking with Sigma if possible. Be sure to check all
the designations of the lens you’re considering: the Sigma lens
considered above was an EX DG APO HSM, and was purchased in early
2007. Recent Sigma models having all of these designations might
compare as favorably as the model considered above to the brand-name
lenses. As always, it’s best to do your homework by searching on
the internet for actual comparisons of the lens under consideration (or
for sample bird photos taken with that lens, at photo-hosting sites
such as Flickr), and to buy
from a merchant with a long return period (like Amazon, which typically offers
30-days, or Adorama/B&H which typically offer 14
days) and to test the lens thoroughly yourself during the return
period. Keep your receipt, and if possible avoid filling out the
warranty card until after the return period has elapsed.