zastavkin писал(а):
В чем причина фронт-бэк фокуса?
Это проблема объектива, камеры, или системы камера-объектив?
Возможен любой из вариантов.
Недавно копировал материалы из сети по этой тематике- кому надо могу на мыло скинуть.
Кусочек из:
"Вот выдержка из документа от Canon для проф. фотографов, работающих с цифровыми единичками, под названием
GETTING THE MOST
FROM YOUR EOS-1
CLASS DIGITAL SLR
TIPS AND TECHNIQUES:
CAMERA HANDLING
& MAXIMUM IMAGE
QUALITY
Testing Your Own Cameras & Lenses
Although photographers in the field cannot duplicate the testing capabilities of a Canon
Factory Service Center, it is certainly possible to test cameras and lenses at home or in a
studio to check their performance. The following procedure may help you determine
whether your camera equipment is in need of calibration.
1. Perform your focusing test at a reasonable light level (office lighting or brighter) to
ensure optimum results.
2. Place the camera on a sturdy tripod and use a remote switch when firing the shutter.
For maximum quality, consider the use of mirror lock. (C.Fn 12 on EOS-1 class Digital
SLRs.) If you are using an IS Lens, turn off the Image Stabilizer.
3. Select a focusing target with adequate detail from center to edge. A newspaper page
is a good choice.
4. Make sure that the target is totally flat and as parallel as possible to the camera.
5. Set the camera to One-Shot AF and manually select the center focusing point.
6. Compose the picture so that the test target fills the frame from edge to edge.
7. For each of your lenses, make one exposure at the maximum aperture of the lens and
another at f/8, varying the shutter speed if necessary to adjust the exposure level as
indicated by the histogram on the camera’s LCD monitor.
Evaluation Method A: Use EOS Capture or RemoteCapture software to analyze your
images as soon as they have been transferred to your computer. RemoteCapture has a
100% magnification viewing option. (If you are using EOS Capture, you can use EOS
Viewer Utility or Digital Photo Professional to enlarge the images.)
Evaluation Method B: Open the images in your computer and make two copies of them:
one “as is” and another with a liberal amount of unsharp mask applied. Here are some
recommended settings: Amount, 300%; Radius, 0.3 pixels; Threshold 0 pixels.
Make letter-size prints on a high-quality inkjet printer using photo paper and photo ink.
Compare the results. If the camera has a consistent focusing problem with several
different lenses, then it’s reasonable to assume the camera needs an adjustment. If you
are getting sharp results from most lenses but not all, then it’s reasonable to assume
that the lens in question may need an adjustment."
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