Canon CHDK - Manual (Page 15)

shutter and minimal ISO when shooting still landscapes) Method - The camera will try to
maintain lowest ISO as long as shutter speed is no-slower than user defined (more below).
Custom
Auto ISO will kick-in whenever ISO HI /Auto ISO is chosen. This allows a quick
manual override by choosing a specific ISO value.
Example: Camera set ISO 100 at 1/8s. Auto ISO configured to ISO50-400 at
1/15s:
Auto ISO will shift to ISO200 to maintain 1/15s shutter speed.
This feature is available in all modes except for Shutter priority (Tv). It is also
disabled in stitch assist to prevent using different settings for each panorama part.
• Enable Custom Auto ISO Enable [•] / Disable [ ]
This is the master switch for this feature.
• Minimal Shutter Speed [Auto 1/8 -etc]
Here you have basically two options:
1) Auto - This is for use when photographing still-life,
landscapes, etc. It will use the factors below to prevent
camera shake, but will assume the subject holds still.
2) Numerical setting - hint to the camera what the optimal
shutter speed is for the subject you are photographing.
The camera will try to use this value or a faster one as much as possible (to prevent blur),
e.g:
1/8s - 1/30s - Slow moving subjects.
1/60s - 1/125s - Kids, Pets, general movement
1/250s - 1/1000s - Sports, Fast action
• User Factor (1/FL/factor)
This setting accounts for the user’s ability to hold the camera steady. It is based on the old
rule that the shutter speed should be no less than 1/focal-length. Start by dividing the
effective focal length of the lens by the actual focal length. The answer is generally
somewhere around 6. Then increase or reduce this amount by a self-assessed value of your
steadiness. If you think your hands are steadier than average then decrease by 20%. If you
think you’re shaky then increase by 20%.
• IS Factor (Tv*factor)
In determining the ISO setting, the effectiveness of the IS system will be taken into account.
Use a setting of 4 if the IS is effective enough to give you a two-stop reduction in shutter
speed. Use a setting of 2 if the IS isn’t very effective, or 8 if the IS is very effective.
• Max ISO HI (x10)
Sets the maximum “HI” ISO that the camera can select.
• Max ISO Auto (x10)
Sets the maximum “Auto” ISO that the camera can select.
• Min ISO (x10)
Sets the minimum “Auto” ISO that the camera can select.
Clear override values@start Enable [•] / Disable [ ]
Extra Photo Operations overrides will be cleared for the next time the camera is started.
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