I'm not going to say it's a major annoyance: Canon is different, and there were indications of what was coming in terms of oddball controls as early as the T90. But the modus operandi is very fiddly (as with all custom functions). People with big fingers find it impossible to reach inside the trapdoor on the side in a hurry. Like cameras, people are different. I don't have chunky paws so I can easily get in there to change things, but wearing gloves in winter is another thing: I use the tip of a pen to do it! My brother-in-law has such big hands he cannot even grasp the camera! Especially annoying to me and a noteworthy faux pas (covered in depth in the Canon EOS-1-series mir.com.my site that I contributed to) is there is no visual advisory on the displays that MUP is engaged, and legions of photographers pressed this matter on Canon for years. Woe betide you if you get the itch for a spontaneous from-the-hip shot and discover that faithful Brutus is in MUP and the choice moment has long gone.