As monochrome said, auto-ISO is not part of the program curve. ISO ramping affects the current EV (shifts it up or down), but does not determine the combination of shutter speed and aperture used to satisfy that EV. That is a property of the program curve settable via the menu system (user manual p46). There is an option for High Speed Priority settable in the menus.
If you want to see the program curve at work, turn off auto-ISO.
Originally posted by monochrome Try Slow ISO and/or Portrait or Action P for chasing children
Yes, that should do it, despite sounding sort of counter-intuitive. The system is designed to ratchet ISO down if possible for highest image quality. Setting ISO to "Slow" will dampen the tendency to do so. ("Slow" refers to sensitivity to change, not subject activity level.)
As far as suggestions to address a need for high shutter speed with exposure automation, the question comes up every once in awhile on this site and usually in regards to people wanting to photograph dogs playing and/or fast children. Here are the points:
- It is not possible to set a range of minimum/maximum shutter speed for modes where shutter speed is adjusted by the camera
- Likewise, it is not possible to coerce the camera to do so with any consistent predictability using some exposure automation hack
- Listed below are strategies to attempt the point above:
- Set the program line to Hi-Speed Priority such that a higher shutter speed will be set along with wider lens apertures. This will affect P and Sv modes and cases where green button action is to return to the program line.
- Use a fixed high ISO -or- set both maximum and minimum ISO to values high enough that auto-ISO will coerce higher shutter speed in P, Sv, Av, or green button operation
- As an alternative to automating shutter speed (the sketchy stuff in the list above), any of the list below is a sure solution:
- Tv mode, setting the shutter speed appropriate for your needs
- TAv mode setting both shutter speed and aperture (ISO will vary between max/min set for auto-ISO)
- Manual mode setting shutter and aperture according current ISO. This approach is very old school, but works amazingly well. Do your settings and shoot freely until either the light and/or your subject changes (think in terms of the light striking the subject, not the light reflecting from it).
Good luck and have fun chasing those kids!
Steve