Question on Lens and aperature.

I have a question for you guys that I tried searching for on google and couldn't find the answer.

a 50mm 1.2L, 50mm 1.4, and 50mm 1.8... If we put all these the apertures for these lens at 2.8. would the bokeh and quality be the same, on the SAME camera used for this? I'm not sure if this is a bad question. But thanks in advance.

Not necessarily. The quality of the out of focus areas in an image is dependent on the aperture shape. Cheaper lenses often have less blades in their aperture diaphragm, which makes them creating a hole that's further from circular than what more expensive lenses can accomplish.

A circular aperture gives a more "smooth" impression in the out of focus areas.

No, they are not the same. Bokeh depends on the optical formula as well as the aperture design, and those lenses have three different optical formulas and three different aperture designs. There's a comparison in this review:

http://www.the-digital-picture.com ….2-L-USM-Lens-Review.aspx

Thanks for the reply guys... Makes a lot more sense reading that post from you acornsarebitter.