Length of Actual Exposure Does Not Match Set Exposure

[Hondo]

If I set a capture plan of 600 second subs why does the shutter actually close 2 or 3 seconds before it is supposed to.  This happens with other sub lengths as well and with two different cameras.

 

Scott

[admin]

Good question.

 

Sadly Canon has its own definition of how long 1 second is.  I did extensive tests about 2 years ago and I came to a solid conclusion that 1 second on all Canon DSLR inner timer is not 1 second but rather approximately 0.995 second... so all camera bodies will fire the end bulb sequence about 1 second sooner for every 200 real life seconds... or thereabout.

 

BYE listen to that timer and will end the sequence according to the Canon timer... but the number you see displayed in BYE is the actual *real life* seconds.

 

Hope this makes sense.

 

Guylain

[Hondo]

Thank you Guylain.

[s3igell]

BYE listen to that timer and will end the sequence according to the Canon timer...

 

Is this action a type of Active Polling ??

 

Perhaps that is part of the reason that BYEOS v3 usually keeps 1 core of my i5 Quad Core fully busy when in the "waiting" (not background image / exif handling) portion of an Exposure... 

[admin]

Is this action a type of Active Polling ??

 

No, it's eventing.  The camera fires hundreds of events when connected to the the PC.  Whether you listen to those events or not they are fired.

 

My PC and laptop idles almost when exposing (outside background image / exif handling).

 

I had a user report a similar issue several months ago and he later found it was he antivirus software draining his PC.  Not sure if there is a relationship.

 

Guylain

[admin]

Perhaps that is part of the reason that BYEOS v3 usually keeps 1 core of my i5 Quad Core fully busy when in the "waiting" (not background image / exif handling) portion of an Exposure... 

 

I had 1 other user report this in the past and he traced it down to his anti-virus system.  I not sure it this is related though.  Just a thought.

 

The only other thing I could see would be the spinning progress wheel.  If this is the case v3.1 may do the trick.  In v3.1 I have added a setting to allow the progress wheel blink once every 2 seconds instead of an update every few milliseconds.  This should also minimize battery draining for those that travel light in terms of power source out in the field.

 

Hope this helps,

 

Guylain