Konica-Minolta Maxxum 7D AS (Anti Shake) test
by
Alan Browne, Montréal.
2005.05.08
(REV D) minor
update: 2005.10.29 [ typos ]
Introduction
(or skip the blah
blah and go straight to the:
100mm
test table or 200mm test table)
[ Coming at some
time in the near future ... 20 or 28mm ]
The Maxxum 7D is an advanced
6 Megapixel Digital Single Lens Reflex (DSLR) which has in body Anti Shake.
This is to allow handheld shooting at relatively low shutter speeds. The camera
is compatible with the entire range of Minolta A-mount lenses.
Unlike Canon IS (Image Stabilization)
and Nikon VR (Vibration Reduction) which are optical stabilizations incorporated
in about 12 Canon lenses and a half dozen Nikon lenses, the Minolta approach
is to stabilize the image capture in the camera body by moving the sensor in
response to camera shake.
It provides about 2 stops
of stabilization advantage, that is to say, you can shoot handheld at about
4X longer shutter speeds than the usual "rule of thumb" speed of 1/focal_length.
(For example, when using
a 50mm lens, the usual hand held speed for a film camera is 1/60 (nearest).
So AS would permit shooting at 1/12s to 1/15s handheld).
As the Maxxum 7D is a 1.5X
'cropped sensor', the rule-of-thumb speed is the lens FL multiplied by the crop
factor. So, for the 50mm lens, figure it as 75mm. So the slowest speed would
be 1/(75/4) =~ 1/15 to 1/20s.
A little nitpicking point
here. Handheld non-flash photos are not the best at any speed. The "rule
of thumb" for shooting handheld applies to making relatively small prints
like 5" x 7". But 8" x 10" only in the best of circumstances
with higher shutter speeds or flash. As much as possible: use a tripod.
The Canon / Nikon IS/VR
solutions are a little bit better (about 1 stop worth), but only available in
those lenses that are equipped for it. The AS solution works with all Maxxum
lenses (including those from Sigma, Tamron and other 3rd party vendors) except
the 1x-3x macro (for which it would not be of much benefit in most cases).
Test
I shot 6 photos of each
test case of a stop sign at the end of my street. I did not take much care to
be very stable. Why 6 shots? Because a given shot can be 'lucky' or 'unlucky'
so I shot a half dozen at each setting to get a more representative set.
1. All Handheld,
standing, left hand supporting lens and manual focus redone between shots.
2. Lenses:
100mm f/2.8 macro (Maxxum),
effectively a 150mm with the 1.5X crop of the Maxxum 7D. "Rule-of-thumb"
speed is therefore 1/150 (or 1/160 on this camera).
80-200mm f/2.8 G (Maxxum),
effectively at 300mm with the 1.5X crop. "Rule of thumb" speed is
1/300.
3. I did not try particularly
hard to be stable, and I had had a couple cups of strong coffee prior to shooting.
4. In camera JPG's used
here. No post processing (sharpening) applied (some in camera sharpening takes
place).
5. All the test shots, below,
are 100% crops of about 140x220 pixels from images of 3008x2000 pixels (5% in
x dimension) from 24 separate images with the scene 'seen' by the lens at the
top of the table.
6. Shot in manual exposure,
manual focused. The 100mm f/2.8 had no filter. The 80-200 f/2.8 had a B+W UV
filter. Exposure determination was via the monitor/histogram.
TABLE
1: Maxxum 7D and Maxxum 100mm f/2.8 macro |
As seen
by the 7D @ 100mm 
|
| |
No
AS |
With
AS |
With
AS |
No
AS |
| 1/25
s |
1/25
s |
1/40
s |
1/160
s |
| f/22 |
f/22 |
f/16 |
f/8
(thanks
gnupublic and hokafai) |
|
2.7 stops slower than 'rule of thumb' speed
Overcast |
2.7
stops slower than 'rule of thumb' speed
Overcast |
2
Stops slower than 'rule of thumb' speed
Sunny |
'rule
of thumb' speed
Sunny |
1 |
|
|
|
|
2 |
|
|
|
|
3 |
|
|
|
|
4 |
|
|
|
|
5 |
|
|
|
|
6 |
|
|
|
|
|
No
AS |
With
AS |
With
AS |
No
AS |
|
TABLE
2: Maxxum 7D and Maxxum 80-200mm f/2.8
@ 200mm |
As
seen by the 80-200 f/2.8 @ 200mm |
| |
No
AS |
With
AS |
With
AS |
With
AS |
With
AS |
No
AS |
|
1/50
s |
1/50
s |
1/80
s |
1/160
s |
1/300
s |
1/300
s |
| f/13 |
f/13 |
f/10 |
f/7.1 |
f/5 |
f/5 |
|
2.7 stops slower than 'rule of thumb' speed
Sunny |
2.7
stops slower than 'rule of thumb' speed
Sunny |
2
Stops slower than 'rule of thumb' speed
Sunny |
1
Stop slower than 'rule of thumb' speed
Sunny |
'rule
of thumb' speed
Sunny |
'rule
of thumb' speed
Sunny |
1 |
|
|
|
|
|
|
2 |
|
|
|
|
|
|
3 |
|
|
|
|
|
|
4 |
|
|
|
|
|
|
5 |
|
|
|
|
|
|
6 |
|
|
|
|
|
|
|
No
AS |
With
AS |
With
AS |
With
AS |
With
AS |
No
AS |
Finally,
shot on tripod with mirror lockup without AS: (100mm f/2.8)
Conclusion
Konica-Minolta's Anti Shake works well to 2 stops slower than "rule of
thumb" and will improve shots at "rule of thumb speed". In particular
if you take a little care, which I didn't. Not as good as a tripod, of course,
but could help for many marginal situations.
My Maxxum 7D "nits"
page and the Phil Askey Dpreview
of the 7D
© 2005 Alan Browne,
All Right Reserved.
e-meil:
alan dot browne at videotron dot ca
