Doug Kerr
Well-known member
Canon notes that the newly-announced EOS 1D X body provides "electronic first curtain" operation, not previously available in the "!" series.
I believe this mode is used as part of one or more of the "silent" shooting modes of, for example, my EOS 40D.
As I understand it, in this mode, the optical (physical) shutter is opened before the shot is commenced and, in effect, the CMOS sensor is "reset" to establish the beginning of exposure.
The exposure is, I believe, ended with the closing of the second curtain of the optical shutter.
Now, the second curtain takes a substantial period to close, "wiping" across the frame as it does so.
Since we want a consistent exposure time across the frame, I assume that in electronic first curtain operation, the reset of the CMOS (or at least the "release" of the reset) must also move progressively across the frame, with a time profile intended to mimic the travel of the second curtain.
Do we know if this is so? And if not, then how is consistent exposure time across the frame accomplished?
Thanks.
Best regards,
Doug
I believe this mode is used as part of one or more of the "silent" shooting modes of, for example, my EOS 40D.
As I understand it, in this mode, the optical (physical) shutter is opened before the shot is commenced and, in effect, the CMOS sensor is "reset" to establish the beginning of exposure.
The exposure is, I believe, ended with the closing of the second curtain of the optical shutter.
Now, the second curtain takes a substantial period to close, "wiping" across the frame as it does so.
Since we want a consistent exposure time across the frame, I assume that in electronic first curtain operation, the reset of the CMOS (or at least the "release" of the reset) must also move progressively across the frame, with a time profile intended to mimic the travel of the second curtain.
Do we know if this is so? And if not, then how is consistent exposure time across the frame accomplished?
Thanks.
Best regards,
Doug