In article , (Bob
Monaghan) wrote:

[...]
even more shocking, the value of mirror lockup may surprise many
photographers, including many whose current cameras don't offer this once
common feature, see http://medfmt.8k.com/third/mlu.html chart of Pop tests
telephotos gained circa 100% (135mm) to 170%+ (300mm) when used with MLU
on sturdy tripods at speeds around 1/15th to 1/60th second etc. Yeech! ;-)

Thanks for the pointer to the excellent articles, Bob.

One more thing - I can show how the wrong cable release can lead to camera
shake. My favorite release is the long (about 12") thin type, however I
got a 'deal' on some short, high-tech heavy releases. What a huge mistake.
Sighting down the side of a 500mm lens I could see the lens and camera
move as I depressed the release. Bad! I switched to using the camera's
self-timer and the differences in the negatives were profound.