I am still relatively new in the usage of the Canon lens 135 F2 L. When I first try my hand on it, I am rather shock to see my picture - Blur and not sharp. Kind
of disappointed with the 135 F2 after hearing all the good stuff of the lens. At one stage I even thought of sending the 135mm for calibration
But after a while and looking at my own short coming.. I realised that i have been using tamron 17 - 50mm lens non VC and EF 85mm 1.8 on my 40D ( no problem with it) and to change to a slightly heavier lens and longer prime, I find it a challenge - less hand holdable.
Before, I use 1/60, 1/100, 1/125 shutter speed for my 135mm but now I try to use at least 1/160 and 1/200 shutter speed for my pic using 135mm on my Canon 40D. The result is much better and Im still trying to steady my hand to reduce the camera shake. At times, I will increase my iso to 200 or 800 depending on the situation.
I m not sure if it is true if I used a FF camera like 5D, it will be better to improve the hand holdable of the 135mm F2. It seem to me that on the FF camera, 135mm is easier to use compare to a crop camera like 40D.
After overcoming the initial usage of the 135mm lens, I really appreciate the power of this lens - Sharp and really give a 3D kind of effect on the portrait. Amazing and wonderful lens!
Just sharing my little experience with the Canon 135mm F2. Thks.