FOCUS
ACCURACY TEST RESULTS
By Francis Poon (
The
test results are part of my AF accuracy test work began since the early
February of 2003. This time I also used a big cross AF target which is perpendicular
to the camera and compared it to the basic 2mm wide vertical straight line used
in the beginning. I find out that the perpendicular big cross AF target gives
the camera a better AF accuracy, though not too much.
A meeting of AF testing - the ruler is in the middle, the AF target is at the
right side
If
you want to know more about the methodology, please go to: http://www.hkdotnet.com/FrancisPhotographyChannel/AF_Test/index.htm
to have an idea first.
The
test results are limited to my existing camera lenses and body, so they are
only for reference and not conclusive. I’ll carry on to test more lenses in the
future whenever I buy lenses and bodies or borrow them from my friends.
My own experience of the pros and cons of Nikon AF system:
1. Quite
accurate and consistent with different lenses
2. Quite fast for F100 in normal light, still good in low light environment.
3. A bit noisy for AF and AFD lenses.
4. Tracking fast moving objects is difficult with AF and AFD lenses, better
with AFS lenses.
5. Limited AFS and VR lenses range.
My own
experience of the pros and cons of Canon AF system:
1. Not quite consistent with different lenses, not as accurate as Nikon for
still objects.
2.
Quite fast for EOS 1V in normal light but slow down significantly in low light
environment.
3.
Tracking fast moving objects is easy with USM lenses.
4. Wide
range of USM and IS lenses.
In my observation, the AF algorithm of Nikon and Canon are not quite the same,
this may influence their AF accuracy in still objects and in tracking moving
objects.
The above are my own findings only, don't take my words and do you own
test and conclusion.
Here is a link http://www.anestoday.com/epson2200/D100vs10D.htm
to another photographer who own both D100 and 10D, he did a good comparison
test between them including AF and noise test, in the AF test he used one of
the AF test chart I developed, unfortunately I changed my website domain name
from www.hkdotcom.net to www.hkdotnet.com recently, so the URL
provided in his webpage become invalid.
Camera:
EOS 1V #202942
Lens:
EF 70-200mm f2.8L USM #053425
|
Focal Length |
Focus Distance |
Aperture |
DOF |
Vertical Line AF target |
Perpendicular Big cross
AF Target |
MF Error (with 2x eyepiece
magnifier) |
||||
|
AF error |
AF error |
AF error |
AF error |
AF error |
AF error |
|||||
|
Lens not calibrated |
||||||||||
|
70mm |
1.6m |
F2.8 |
-45mm +48mm |
+55mm* |
+10mm |
+30mm |
|
|
|
0 |
|
100mm |
1.6 m |
F2.8 |
-22mm +22mm |
+20mm |
+10mm |
+20mm |
|
|
|
+10mm |
|
135mm |
1.6 m |
F2.8 |
-12mm +12mm |
+15mm* |
+10mm |
+10mm |
|
|
|
+10mm |
|
200mm |
1.6 m |
F2.8 |
-5mm +5mm |
+4mm |
+6mm* |
+6mm* |
|
|
|
+5mm |
|
After Calibration with EOS 1V by Canon Service |
||||||||||
|
70mm |
2.1 m |
F2.8 |
-77mm +84mm |
+30mm |
+30mm |
+45mm |
+20mm |
+10mm |
+40mm |
|
|
100mm |
2.1 m |
F2.8 |
-38mm +40mm |
+25mm |
-5mm |
+25mm |
+5mm |
-5mm |
+5mm |
|
|
135mm |
2.1 m |
F2.8 |
-21mm +21mm |
+9mm |
0 |
+9mm |
0 |
-8mm |
+5mm |
|
|
200mm |
2.1 m |
F2.8 |
-9mm +9mm |
0 |
0 |
+2mm |
0 |
0 |
0 |
|
Camera: EOS 1V #202942
Lens:
EF17-40mm f4L USM #147610
|
Focal Length |
Focus Distance |
Aperture |
DOF |
Vertical Line AF Target |
Perpendicular Big Cross
AF Target |
MF Error (with 2x eyepiece
magnifier) |
||||
|
AF error |
AF error |
AF error |
AF error |
AF error |
AF error |
|||||
|
17mm |
0.5m |
F4 |
-84mm+125mm |
-20mm |
-15mm |
|
|
|
|
|
|
40mm |
0.5m |
F4 |
-17mm +18mm |
0 |
0 |
|
|
|
|
|
Camera: EOS 1V #202942
Lens:
EF100mm f2.8 macro USM #85000550
|
Focal Length |
Focus Distance |
Aperture |
DOF |
Vertical Line AF Target |
Perpendicular Big Cross
AF Target |
MF Error (with 2x eyepiece
magnifier) |
||||
|
AF error |
AF error |
AF error |
AF error |
AF error |
AF error |
|||||
|
100mm |
1m |
F2.8 |
-7.5mm+7.6mm |
+3mm |
+5mm |
|
|
|
|
|
Camera: 10D #0630301898
Lens:
EF 70-200mm f2.8L USM #053425
|
Focal Length |
Focus Distance |
Aperture |
DOF (CoC=0.019mm) |
Vertical Line AF Target |
Perpendicular Big Cross
AF Target |
MF Error (with 2x eyepiece
magnifier) |
||||
|
AF error |
AF error |
AF error |
AF error |
AF error |
AF error |
|||||
|
Lens not calibrated |
||||||||||
|
70mm |
2m |
F2.8 |
-40mm +43mm |
+46mm* |
+48mm* |
|
|
|
|
|
|
100mm |
2m |
F2.8 |
-19mm +21mm |
+5mm |
+16mm |
|
|
|
|
|
|
135mm |
2m |
F2.8 |
-10mm +12mm |
0 |
+16mm* |
|
|
|
|
|
|
200mm |
2m |
F2.8 |
-4mm +6mm |
+9mm* |
+8mm* |
|
|
|
|
|
Camera:
10D #0630301898
Lens:
EF 28-70 f2.8L USM #141706
|
Focal Length |
Focus Distance |
Aperture |
DOF |
Vertical Line AF Target | ||