I don't know anything about the E-3 or E-5, but if they have the option to use "live view" that should make things a little bit more quiet. What is causing the most noise is the mirror as it flips up and out of the way of the shutter. By using live view, the mirror is flipped up and out of the way before you press the shutter button. You then have to use the LCD screen instead of the view finder to frame and compose your images. Depending on your cameras features, you may also loose the ability to auto focus. Hand holding a DSLR with a long lens may be a challenge when using live view. Live view will also use up your batteries faster.Originally Posted by buglinbilly
I guess the bottom line is, there really isn't a perfect answer for your situation. Photography has always come down to the art if compromise...