When I had the 85/1.8, I preferred this 135/2L on the 5D for portraits due to its better color and sharpness below f/4. Once I got the legendary 85/1.2L II for portraits, I swapped the 135/2L for the equally-good 200/2.8L II ($625) because it's a focal length I needed more. If you're always going to have the 1.4x TC on the 135/2L (189mm), then you may as well just get the 200/2.8L and avoid any loss in sharpness and focusing reliability.
The 135/2L is an excellent telephoto prime lens for close-ups, candids and sports ($900). f/2 is sharp and comes in handy for low-light action shots. This lens is particularly sharp with my full-frame 5D, which spreads its pixels out over more of the glass (less pixel density at the center). The bokeh at f/2 beats that of the 85/1.8 wide open due to the longer focal length. With the full-frame 5D, one has to get in even closer to fill the frame, thus creating even more bokeh for the same framing and focal length as on a 1.6x crop camera - the 5D needs to be stopped down 1 1/3 stops to achieve the same DOF (e.g., use f/3.5 instead of f/2). Unless you are trying for ultimate bokeh, it's probably best for extreme facial close-ups to stop this lens down to at least f/4 on the 5D. It helps to use a shutter speed of at least 1/200 to avoid blur from camera shake. With a 1.4x extender ($280) one can make this an 189mm f/2.8 without noticeable loss in sharpness, and this is a great focal length for indoor sports. This lens, even with the 1.4x extender, is sharper than the 70-200mm f/2.8L IS zoom, so I sold the zoom and got a 300mm f/4L IS for more reach in outdoor sports with my 5D.
I recommend the The-Digital-Picture.com for comprehensive reviews.
The 135/2L is an excellent telephoto prime lens for close-ups, candids and sports ($900). f/2 is sharp and comes in handy for low-light action shots. This lens is particularly sharp with my full-frame 5D, which spreads its pixels out over more of the glass (less pixel density at the center). The bokeh at f/2 beats that of the 85/1.8 wide open due to the longer focal length. With the full-frame 5D, one has to get in even closer to fill the frame, thus creating even more bokeh for the same framing and focal length as on a 1.6x crop camera - the 5D needs to be stopped down 1 1/3 stops to achieve the same DOF (e.g., use f/3.5 instead of f/2). Unless you are trying for ultimate bokeh, it's probably best for extreme facial close-ups to stop this lens down to at least f/4 on the 5D. It helps to use a shutter speed of at least 1/200 to avoid blur from camera shake. With a 1.4x extender ($280) one can make this an 189mm f/2.8 without noticeable loss in sharpness, and this is a great focal length for indoor sports. This lens, even with the 1.4x extender, is sharper than the 70-200mm f/2.8L IS zoom, so I sold the zoom and got a 300mm f/4L IS for more reach in outdoor sports with my 5D.
I recommend the The-Digital-Picture.com for comprehensive reviews.
