After reading the manual and the Morris Mk 4 User Guide I am slowly starting to get a handle on the settings. However, I am unclear on the relationship between ISO Auto and the other settings (Safety Shift, Av, Tv, M and so on). I have searched several sources and have not been able to find an authoritative source. I have experimented with the settings but am not able find the rule that describes what should happen.
Can anyone provide definitive information or point me to authoritative sources that will answer the following questions. Background:
C. Fn 1-8 Safety Shift settings
0 Disable
1 Enable (Tv/Av) Yes
2 Enable (ISO speed)
"Enable ISO speed safety shift works in the Program mode, shutter-priority mode, and aperture-priority modes. When the subject’s brightness changes erratically and the correct auto exposure cannot be obtained, the camera will change the ISO speed automatically to obtain a correct exposure."
Disable Safety Shift.
Q1. C Fn. 1-8: 0; Tv, Auto ISO. What ISO is picked by the camera if metered aperture is within its limits? I.e., what is the relationship between aperture and ISO?
Q2. C Fn. 1-8: 0; Tv, Auto ISO. What ISO is picked by the camera if the metered aperture is at its minimum or maximum? I.e., what is the relationship between aperture and ISO?
Q3. What is the relationship between C Fn. 1-8: 2 (Safety Shift ISO speed enabled) and Auto ISO?
Q4. With Manual Shooting Mode and Auto ISO the ISO level with be set according to the metering. How does one achieve exposure change as measured by metering other than by turning off Auto ISO and adjusting exposure manually?
Q5. What is the relationship between Auto ISO and C Fn. 1-8: 2?
Thank you for a concise and informative explanation. It appears that Tv, C Fn. 1-8: 1, and Auto ISO (coupled with exposure compensation) could be a useful combination. What I would really like is M, Auto ISO, and exposure compensation. I could then set the shutter/aperture settings I want and let the ISO follow and change the effective exposure. As it is now, one would need to turn off Auto ISO and manually change it.
Where I live the days are now short and cloudy, which is why I bought the ID-V to begin with. The light is changing constantly, usually for the worse. I find auto iso very helpful when I don't have much time to shoot, adjust and shoot again. Our birds just don't hang around for that long. I use it in Tv, with the maximum exposure I can work with, and my normal EC. The camera does not raise the ISO until the maximum aperture is reached. Friday I shot a Northern Shrike on a dark day as the sun was going down. During my 30 second opportunity the ID-IV took the ISO to 2500 with very acceptable results. It would have taken a lot of trial and error before I would have st the ISO that high, and the opportunity would have been lost.
Last edited by Hal Everett; 11-23-2010 at 11:22 PM.
I am headed to Bosque del Apache National Wildlife Refuge and then to White Sands. I have been experimenting in preparation for the trip. I find that I am using two different approaches. (1) Tv with Auto ISO and (2) Manual with Auto ISO to get a quick metering and then setting the ISO. If I am not concerned with depth of field, my shutter speeds tend to be fast, especially with the large lens.
Canon 1D MK 4 Auto ISO Operation
Reply With Quote
