-
-
:::
Note: all full size images come straight from the camera (large
jpg-compression set at ‘fine’). Crops are 100% crops from original jpg’s without any post-processing and saved with the highest jpg
sampling.
::: Starting
with a coupe of snapshots a full aperture. The first has highlighted
AF sensors. It feels like the AF snaps into focus and the color
rendering is natural. At f2.8 makes it a rather ‘bokeh’ lens that
separates the subject from the rest with a nice blurry background.
::: Click on the image to see the full
size image straight from the camera. A word of caution. This is a 2 MB sized
picture and it will take a while to load !
::: The EXIF file containing all the data
of the shot is still in the image.
::: Click
on the dog to see the 100% crop of the eye. I found this
surprisingly sharp, considering it was taken with Canon 10D body and
with a zoomlens set at f2.8 ! Imagine if it was taken with a Canon
1DS MkII
::: Both shots let me believe the lens is
very suitable for portrait photography as it nicely renders a blurry
background due to the large aperture opening when setting the lens
at 2.8. Stopping down the aperture will increase the sharpness even
more and increases the depth of field. Shooting at 2.8 at close
range requires a absolutely perfect autofocus system as the margin
of error is very limited because of the shallow depth of field.
::: Next
a set of pictures is to check the sharpness of the lens at 300mm
(the most important end for us aircraft photographers) with
different aperture settings. The shots are taken from a distance of
approximately 100 meters. The church tower offers a complex and a
difficult high contrast subject to test the abilities of the lens.
Each crop shows the center or lower left corner of the image. Both
center and corner images shows that the sharpness at f2.8 is good and even excellent when using apertures f4 and f5.8 (and
higher). A pleasant surprise was the sharpness in the corners even
at f2.8 ! But note that one must take into consideration that this test
was not performed with a full frame sensor camera. Also tests at 120
and 200mm shows this lens was very sharp at all apertures. Also I
could hardly find any CA in the image. High contrast subjects, like
the church bell mechanism on the picture, are always prone to CA
especially when photographed at large aperture openings.
-
- 300mm @ f2.8 ISO100
- center
|
-
- 300mm @ f4.0 ISO100
- center
|
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- 300mm @ f5.6 ISO100
- center
|
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- 300mm @ f2.8 ISO100
- corner
|
-
- 300mm @ f4.0 ISO100
- corner
|
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- 300mm @ f5.6 ISO100
- corner
|
::: As
I was currently not in the position to shoot any high speed
aircraft, I decided to try something else to test the auto-focus.
Standing near a road I shot several cars moving towards me at
70-80km/h. By shooting cars towards you, the focusing system has to
work hard to keep the closing subject in focus. Although aircraft
are flying much faster, the test I performed is rather demanding for
the focusing system. Most of the time we shoot aircraft flying from
left to right or vice versa at a long distance. Therefore the
relative changes in distance between the consecutive shots are not
that big. Having done this test several times, it turned out that a
number of first shot in a sequence were not as sharp as the rest. I
think this has to do with the AF of the (not so fast) 10D camera I
use or, more likely, due to the panning technique I use. As the lens
is very heavy it is hard to hand hold it steady at a fixed point. It
is easier to follow the subject and move your upper body along the
path of the subject. Physical training of the left arm is needed
here… Now back to the test. I tried to keep the license plate of the
vehicles in the center of the viewfinder. Turning the AF system of
the camera to A1 Focus, I was able to shoot 5 to 7 sharp images in a
row.
-
- Click on each thumbnail to
view a 100% unedited crop of the license plate.
- Shots taken with 300mm @ f2.8
ISO100
-
-
:::
Further testing revealed some oddities of the
lens. At first I noticed the differences in closest focus
distances at 120mm and 300mm. At 300mm you could focus from
about 2.5 meter, but at 120mm this was as short as 1.5 meter.
More strangely was the fact that when you focused with 120mm
and than zoomed in to 300mm (or the other way around) you have
to re-focus again ! Although it is not a problem, it is rather
different from other optics, you have to take this into
account when you zoom (release and press halfway again).
Conclusions:
:::
Compared to the Canon 300mm/f2.8 IS, again which I only used for
only one
day and only on a D30 body, it looks like it is almost a sharp and only
a little slower in focus speed. The build quality of the Canon is
probably just a fraction better. Not that the Sigma is a badly
build, not at all ! The white vs black finish is a personal
preference, so I won’t comment on that. The lenshood on Canon is
definitely better. When fitted with the big TS-41 tripod collar, the
Sigma is perfectly balanced and easy to hold in a (supported) cradle
grip. A big plus for the Canon is the IS, although one could argue
the effectiveness of it when tracking highspeed jets. If Sigma would
address the zoom/focusing issue and add the IS, or OS (Optical Stabilization) as they call it, to the
lens it would be a killer. On the other end it would add extra
weight to the already heavy lens. It would also increase the now
very competitive price. With a price of less than half of that of
the Canon, it beats the Canon in the 120-299mm range but it just loses the game at 300mm.
:::
Compared to the Canon 300mm/4 IS, it has more
or less the same performance. As I was VERY happy with the sharpness
and focusing of this smaller prime lens, I must admit this is the
best value-for-money prime on the market today. With Sigma’s big
zoom being equally sharp and a more responsive, it offers the flexibility of a zoom but at twice the price.
The Canon however is far more easier to handle due to its compact
size and weight.
::: Compared to the Canon
100-400mm/f4.5-5.6 IS the Sigma wins easily in both sharpness
and focus speed. The Canon starts having a aperture of f5.6 at
approximately 280mm compared to the 2.8 for the whole range on the
Sigma. The push-pull mechanism of the Canon is less precise than the
turning ring of the Sigma. It is also a huge (!) dust pump. Having
used the 100-400 for two month, I had to clean the sensor several
times due to dust problems. Actually when zooming with the Canon (on
a 10D body with grip) I could really FEEL (!) the airflow going in
or out the body at the external power adaptor opening (located near
your right hand pinky when holding the camera). The Sigma has both
internal focusing and zooming. This means the lens will not change
in length and no air is displaced outside the lens tube. As the
Canon will clearly have the advantage by having a range up to 400mm,
although it is getting very soft compared near the end of its range.
On the other hand the Sigma is quite a bit more expensive and
heavier.
:::
The major drawback of the Sigma is its weight. With 2600 grams it
requires a well trained left arm to hold it steady. It is difficult
to hold it stationary at a fixed subject. Panning a moving target
requires some getting used to, but it is easier than holding it
steady. I will have to try a monopod someday. You need to carry this
combo (like al other heavy lenses) by the tripod collar and not at
the camera body. On the magnesium alloy body of a 10D/20D or 1D-version it
will not cause problems. I would not recommend to mount it on a, -no
offence-, plastic 300D/350D body as the center of gravity will shift
forward to much. Also flexing of the plastic body could cause
problems. Also the zoom-and-refocus requirement can cause problems
if you forget the way this lens works (parfocal).
:::
Personally, being on a limited budget the Canon EF 300mm/f2.8 IS is,
despite of its qualities, totally out of the question. I also could-
and would not spend the money on a new Sigma EX 120-300mm/f.2.8. But
with a used –like-new- example I couldn’t be more happier ! (unless
Sigma would make 1 kg lighter...)
Update
(1) (August 2005):
:::
At the last moment I was able to spent a half hour at Twenthe AB and
shot a few landing jets.
