Originally posted by Swift1 The metering system in most SLRs is set up assuming that your ete will be covering the viewfinder. If you are shooting from a tripod and your eye isn't covering the finder, light entering the viewfinder will drastically change the metering.
That's correct. I find it easier to keep a small piece of black gaffer tape in my bag and lightly cover the viewfinder than to remove the eyecup and use the cover . . . which I probably already lost anyway. I wouldn't think it hard to design an onboard cover of some type rather than a loose one, but apparently it is.