In accordance to the manual, it is recommended to turn the lens image-stabilizer "off" when employing a tripod. ...
The manual is in fact not telling the whole story, see here;
https://photography-on-the.net …d.php?t=86975#post1066324
In particular these parts;
1st Gen IS lenses had to have the IS manually turned off when mounted on a tripod or solid arrangement, as the IS could introduce image anomalies and otherwise unwanted behavior if left on while tripod mounted.
The current 2nd and 3rd generation of IS only adds one set of features in addition to those already found in 1st gen multi mode IS. That feature is Tripod detection and tripod vibration mode.
Canon states this; "the IS mechanism automatically goes into a special mode which is designed to detect and correct for mirror slap and shutter movement at slow shutter speeds" )
SuperTelephoto lenses with 2nd / 3rd Gen IS also detect tripod mounting. Rather than disable the IS, 2nd and 3rd gen Superteles will use IS to counter subtle vibrations that are present and magnified by super teles even when on a tripod. This includes mirror slap vibration.
IE: In some cases it is preferable to leave IS engaged even when mounted to a tripod.
With a super tele, that added IS can make or break an image if the shutter speed aren't high enough, and always helps.
I never turn off the IS on my 500mm for that reason.
The 300mm f/2.8 L IS was the first in the Canon line up to have this 2nd gen tripod mode. It then went into all subsequent Super teles,. which now includes every Canon IS lens longer than 300mm.
The only "white" IS lens that does not have this mode is the older 300mm f/4L IS, which retains 1st Generation IS.
