By: Darwin Wiggett
Sigma 17-50mm f2.8 vs Canon 17-55mm f2.8 and Tamron 17-50mm f2.8
On full frame cameras the 24-70mm
f2.8 lens is the go-to lens for travel, sports, wedding, street, and
landscape photography. On cropped sensor cameras the equivalent focal
length to a 24-70mm is roughly 17-50mm. This latter focal length gives
you wide, normal and telephoto lens perspectives in a relatively small
package that fits on cropped sensor cameras. If you are looking for a
fast all-purpose lens for your Canon camera whether a Rebel, 20D, 30D
40D, 50D, 60D or the 7D, then you have four choices:
Canon EF-S 17-55 f2.8 IS USM- Image Stabilized
- Ultrasonic lens (no focus noise)
- UD glass
- internal focus
- close focus 0.35m
- filter size 77mm
- weight 645g
- cost $1200 CAN
- optical stabilized
- hypersonic motor motor (HSM) – no focus noise
- internal focus
- two low dispersion FLD glass elements
- close-focus 0.28m
- filter size 77mm
- weight 565g
- cost $775 CAN
- vibration compensation
- LD (low dispersion) glass
- internal focus
- close-focus 0.29m
- filter size 72mm
- weight 570g
- cost $579 CAN for the VC version and $450 CAN for the non VC version
A Bit of History
When I picked up my first cropped sensor
Canon camera (a Rebel Xsi) I wanted a light, fast lens for hiking and
backpacking. I tested out the Tamron 17-50mm lens (the f2.8 XR di II LD versionwithout
the vibration compensation feature). I found it to be surprisingly
sharp and I picked up a new one for a sale price of $350 CAN! It was
perfect for landscape photography especially for me because I almost
always use live view and manual focus on the Rebel to make landscape
images. I owned the lens for a year or so and took many landscape photos
with it in all sorts of conditions. It was a super performer for the
price! But… be aware that the Tamron lens is really lacking as an
auto-focus lens. It was painfully slow to focus and was noisy when
focusing. I tried using it with dogs and sports and it was not really
suited for action photography.
©Darwin Wiggett - Tamron 17-50 f2.8 lens
©Darwin Wiggett - Tamron 17-50mm f2.8 lens
And Then…
Sigma sent me their 17-50mm f2.8 lens to
try it. I was incredibly happy with the Tamron in terms of sharpness and
so my first tests were to see if my budget priced Tamron was as sharp
as the more expensive Sigma lens. I did the standard tests in the studio
using a lens chart to check sharpness at all apertures and at various
focal lengths. And then I took the lenses out in the field and
photographed the typical kinds of subjects that I shoot to see how the
lenses performed in terms of contrast (snap) and colour rendition and
also things like flare control and distortion. Rather than bombard you
the reader with tons of detailed comparison shots the conclusion of all
these tests was the same. Both lenses performed the same optically but
with the nod going to the Tamron in the 17-35mm range at f2.8 (better
edge sharpness).
©Darwin Wiggett - Sigma 17-50mm lens at f14
But… the Tamron was terrible auto-focus
performer! I’ve found that using live view at 5x magnification and
manually focusing lenses gives me much sharper images than using
auto-focus even in bright contrasty light. This result is consistent
across cameras I have tried from the Canon 1ds Mark III, Canon Rebel Xsi
and Rebel T2i, Canon 60D, Canon 7D and the Nikon D300s. On workshops
and tours I often illustrate this to participants using their own
cameras. To try it yourself, simply set your camera to aperture priority
and use the smallest number on your aperture dial like f2.8. Use the
center focus point on your camera and let the camera focus on a
contrasty part of the subject. Now go into live view and magnify the
area (e.g. 5x) where the camera auto-focused. Switch your lens to
manual focus and adjust the focus to see if you can get the image
sharper than the auto-focus. Often you can easily improve on the
sharpness. Check out the scene below. I had the Canon Rebel Xsi mounted
on a tripod and the auto-focus was set to ‘one shot’ with the center
focus point selected. I had the aperture set to f2.8 and let the camera
auto-focus. Then I rephotographed the same scene using manual focus in
live view.
The auto-focus test scene
Below are the results of the test using
the Sigma 17-50mm lens at f2.8. The image is magnified to 100% view. The
top photo is auto-focus, the bottom is manual focus in live view.
Sigma 17-50 at f2.8: top=auto-focus, bottom=manual focus in live view
Tamron 17-50 f2.8: top=auto-focus, bottom=manual focus in live view
What can you say? The auto-focus on the
Tamron lens is terrible! It is slow, it searches, it hunts, it creeps,
it’s noisy. I have tested and tried several Tamron lenses (from their
70-200 f2.8 to their 10-24mm lens) and the problem is the same. If, like
me, you mostly use manual focus and a tripod, then the Tamron is easily
the best buy of the group (especially the non VC version of the lens)
and optical performance is really fine. But if you want a sports,
travel, portrait lens where you can rely on auto-focus, then I would
pass on the Tamron. Also note I did not test the vibration compensation
(VC version) of this lens, other reports on the web suggest that
sharpness of the VC version is lower than the non VC version. Test
before buying!
And so, after testing the Sigma 17-50
f2.8 against the Tamron lens, I decided to sell the Tamron and keep the
Sigma. The Sigma was just as good optically (except at f2.8 where edge
sharpness was lower) but it had fast and accurate auto-focus and it had
optical stabilization for hand-held shots.
And So What About the Canon 17-55mm f2.8?
This is Canon’s flagship lens for cropped
sensor cameras and numerous reports state that this lens is super sharp
and an all around great performer but it comes at a high price ($1200
CAN). Is the overall quality and performance of the Canon worth the
extra cost (more than $400) over the Sigma?
I took the two lenses out over a weekend and ran them through a few tests such as:
- Optical performance (sharpness, vignetting, flare etc.)
- Auto-focus tests
- Image stabilization tests
- Close-focus capabilities
Optical Performance
I compared the sharpness of both the
Sigma and the Canon lenses using manual focus in Live View. When
precisely focused I really could not give the nod to one lens over the
other when it came to center sharpness at all focal lengths and
apertures. But at f2.8 in the focal range of 17 to 35mm the Canon had
significantly better edge sharpness than the Sigma.
Edge sharpness at 17mm at f2.8 (Sigma top, Canon bottom)
It’s easy to see here that the Canon lens
is really good wide open even at the edges. The Sigma lens does not
match the edge performance of the Canon until stopped down to f8! After
f8 the two lenses perform equally well.
Another weakness of the Sigma Lens are
fringing artifacts at the edges of the frame when the lens is shot from
17- 35mm in high contrast light. The Canon also suffers these effects
but to a lesser extent.
Edge fringing at f2.8 at 17mm - Canon top, Sigma bottom
The Canon lens appears to be optimized for best performance in the aperture range from f2.8 to f8. Images at f11 are decent but less sharp overall and images at f16 or higher are terrible!
Canon 17-55 at f5.6 (top) and f22 (bottom)
I found that although center sharpness on
the Sigma is as good as the Canon at f2.8 and f4 that overall image
sharpness from edge to edge is best with the Sigma in the f5.6 to f11
range with good performance up to f16. The Sigma is better than the
Canon in the f11 to f16 range and therefore is a better choice for
landscape work requiring large depth-of-field.
Sigma lens at f16 top photo, Canon lens at f16 bottom photo
The Sigma lens also records images with
more contrast and ‘pop’ and with a more accurate colour cast than the
Canon lens which tends to record scenes flat and washed out and cool in
colour tone.
Sigma lens top photo, Canon lens bottom photo
Sigma lens top photo, Canon lens bottom photo
In numerous tests I found this same
difference in contrast and colour between the two lenses. All
comparisons were shot at the same exposures, white balance etc. The
Sigma lens simply had a more pleasing rendition of scenes for my tastes.
As far as flare is concerned it depends.
Sometimes the Sigma gave more flare (e.g. at 17mm) sometimes the Canon
was more prone to flare (e.g. at 28mm).
Auto Focus Tests
I tested both the Sigma and the Canon
lens for accuracy of auto-focus vs manual focus in live view and both
lenses returned similar results. Live view gave slightly better results
for both lenses. Only in dim light did the auto-focus capabilities start
to falter.
With action sequences of people running,
cars on the highway and moving dogs, I saw absolutely no difference in
the ability of the Sigma and Canon lenses to track focus. As well, with
static subjects both lens were zippy and fast to auto-focus and for me
they seemed matched in their abilities.
Image Stabilization Tests
Handheld images using auto-focus and
image stabilization (Canon) and optical stabilization (Sigma) returned
fairly similar results but I got a slightly higher percentage of sharp
shots in the 1/15th to 1/30s range with the Canon lens. So nods in this
department to Canon.
Close-focus Capabilities
The clear winner in this category is the
Sigma lens. Not only does it focus closer (see images below) but when
photographing close subjects (e.g. head and shoulders or closer, the
Sigma is significantly sharper at all apertures than the Canon lens. The
Canon does not seem to like close subjects and optical performance
really suffers. This is not a good lens to use for close-up work!
sigma at closest focus at 50mm
Canon closest focus at 55mm
Sigma close detail sharpness at f8
Canon close detail sharpness at f8
Which lens you choose all depends on your
budget and on your needs. If want the best overall optical performance
for your dollar then the Tamron SP AF17-50 f2.8 Xr Di II is a fantastic buy! Although I did not this test the lens directly against the Canon lens, I
think it is just as sharp at all apertures but it costs almost 1/3rd
the price of the Canon lens! But the Tamron is not a lens to buy if you
rely on auto-focus. This is a good landscape lens when used on a tripod
and focused manually in live view. But do not try action photos with
this lens or you’ll be disappointed.
If you want a lens with good all around performance at the a reasonable price, then the Sigma 17-50mm f2.8 lens
might be the lens for you. The Sigma is as good as the Canon lens in
terms of auto-focus, it’s a sharp as the Canon lens when stopped down to
at least f5.6 and it is a much, much better lens for close-up subjects.
As well the contrast on the Sigma lens is snappy and the colour
rendition is accurate. The Sigma is a better landscape lens than the
Canon because it has better performance in the f11-f16 range which are
apertures often needed for depth-of-field. Also the lens is the lightest
of the bunch. I would recommend this lens for nature and generic
photography.
If you want to photograph people, sports,
or action or hand-held street photography where wide apertures like
f2.8 or f4 are regularly used then the Canon 17-55 f2.8 lens lens is the best choice. It’s sharp edge-to-edge when wide open (with little fringing), has
great image stabilization and zippy auto-focus. The drawbacks are its
heavier weight, poor close-focus performance, flat contrast and cool
colour rendition and large price tag.
In short, none of these lenses are
perfect but some work better for some purposes than others. As always
try before you buy but hopefully this review will help narrow your
choices.
©Darwin Wiggett - Sigma 17-50mm lens at f11
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