Doug Kerr
Well-known member
The Canon EOS 20D, 30D, 5D, and certain 1-series cameras have a Custom Function (Custom Function 4, "C.Fn-04" or "CF04") that allows customization of the effects of half press of the shutter release button and press of the "*" button on the execution of automatic exposure (AE) and automatic focus (AF) functions. Four settings are available. The entire scheme is complex, with the implications varying with the combination of metering, autofocus, and drive modes in effect.
I have prepared a chart that shows in considerable detail the implication of each of the four settings of CF04. I have just made it available on my technical information site, The Pumpkin, here (click on the title to access the document itself):
http://doug.kerr.home.att.net/pumpkin/index.htm#CF04chart
The chart itself is accompanied by a narrative synopsis of the implications of the four settings and a brief discussion of where and how each might be useful.
Thanks to the many correspondents who have assisted me in refining this chart during its development, and especially to René Damkot for his recent revelation to me of some subtleties I had missed during my testing and analysis.
The chart is wholly based on testing with the EOS 20D. The applicability of the chart to the other models mentioned above has been advised by various colleagues. There could well be subtle differences in the details among those models.
Note that in the "2007 models" of the various Canon EOS dSLRs (40D, 1D Mark III, 1Ds Mark III), there is no direct equivalent to CF04, the various facilities for customization in the relevant areas being done in wholly different ways.
I'm sure I haven't yet discovered or correctly plotted all the mysteries in this area. I would of course be pleased to hear from any one who has any corrections or suggestions.
I have prepared a chart that shows in considerable detail the implication of each of the four settings of CF04. I have just made it available on my technical information site, The Pumpkin, here (click on the title to access the document itself):
http://doug.kerr.home.att.net/pumpkin/index.htm#CF04chart
The chart itself is accompanied by a narrative synopsis of the implications of the four settings and a brief discussion of where and how each might be useful.
Thanks to the many correspondents who have assisted me in refining this chart during its development, and especially to René Damkot for his recent revelation to me of some subtleties I had missed during my testing and analysis.
The chart is wholly based on testing with the EOS 20D. The applicability of the chart to the other models mentioned above has been advised by various colleagues. There could well be subtle differences in the details among those models.
Note that in the "2007 models" of the various Canon EOS dSLRs (40D, 1D Mark III, 1Ds Mark III), there is no direct equivalent to CF04, the various facilities for customization in the relevant areas being done in wholly different ways.
I'm sure I haven't yet discovered or correctly plotted all the mysteries in this area. I would of course be pleased to hear from any one who has any corrections or suggestions.