My rule of thumb... Use the lens hood. You will never know the difference between a silver-nose and a black-nose, which all a bunch of baloney anyway.

Use a lens hood on a 75-150 and you will have a new love. Oh yeah, the lens hood on the 75-150 is built-in. So use it.

I think the 135/3.5 also has a built-in hood.

Although there are times when you want flare, then you can leave the hood off.