GigaPan EPIC Pro - Manual (Page 23)

GigaPan Pro User Guide 20
Auto Focus
There are situations when auto focus is a better choice, than manual focus for increasing
the sharpness of a panorama. One example is a crowd of people or a building that are
at an angle and span a large distance. You will not be able to increase the depth of field
to cover the entire distance, especially if you are using a longer focal length. You can use
autofocus to shift the center of focus closer or farther for each position in the panorama
if you have a suitable situation for autofocus. There are advantages and difficulties with
each method depending upon the particular situation. The ‘Shutter length’ setting in the
‘Expert options’ and using a faster lens with a minimum aperture value such as f/2.8 versus
f/5.6 are two ways to make autofocus work better. Another important hardware consider-
ation is the autofocus system of the particular camera body that you are using.
Potential subject problems
Multiple objects at different distances - may need to reduce focus points used or tempo-
rarily switch to manual focus for that region of the panorama.
Areas devoid of discernable features - need to use manual focus for entire or part of pan-
orama. There needs to be discernable features where the camera body focus points are
located.
Moving objects - May need to repeat particular photograph or pause panorama
Enough light - May need to use better equipment such as a faster lens such as f/2.8 versus
f5.6. May need to use manual focus
Important auto focus camera settings include:
1.
A faster lens with a lower minimum aperture value such as f2.8 versus f5.6. The
aperture value is inversely proportional to the diaphragm diameter. A wider opening
allows more light to hit the autofocus sensor.
2. A focus policy where a photograph is taken only if good focus is achieved versus a
release policy where the photograph will be taken regardless of whether good focus
has been achieved. Increase the ‘Shutter Length’ setting to increase the amount of
time that the focus signal is asserted.
3. The auto focus mode such as single servo, continuous servo, or mixed.
4. The focus points that are selected.
With Canon DSLR cameras the auto focus mode is tied to the release or focus policy. Nikon
cameras have a default release priority or focus priority which may be changed using the
camera menu system.
You can use a combination of auto focus and manual focus in difficult lighting situations,
such as blue sky, smooth water, or bright lights.