85mm f1.8 vs 200mm f2.8 bokeh or portriat

Background of my questions:

I have a 6D and intend to buy 70-200 f4L IS or 70-200 f2.8L IS. I mainly take leisure picture when walking around city or nature treks. The f4L is my preference because it is lighter and 6D has very good low light and low ISO performance. However, about 1% of my photo are head shot portriat.

I intend to travel with 2 full frame bodies, 17-40 f4L, 70-200 f4L and 85mm f1.8, somewhat like Karl Grobl's setup. http://karlgrobl.com/blog/advice/equipment/retiring-my-canon-mark-ii/

My question:

In your personally judgement, does the 85mm prime at f1.8 gives better bokeh or portriat than the zoom at 200mm & f2.8?

davidli wrote:

Background of my questions:

I have a 6D and intend to buy 70-200 f4L IS or 70-200 f2.8L IS. I mainly take leisure picture when walking around city or nature treks. The f4L is my preference because it is lighter and 6D has very good low light and low ISO performance. However, about 1% of my photo are head shot portriat.

I intend to travel with 2 full frame bodies, 17-40 f4L, 70-200 f4L and 85mm f1.8, somewhat like Karl Grobl's setup. http://karlgrobl.com/blog/advice/equipment/retiring-my-canon-mark-ii/

My question:

In your personally judgement, does the 85mm prime at f1.8 gives better bokeh or portriat than the zoom at 200mm & f2.8?

They're both excellent. Better? Different is probably a better way to describe them. I haven't used my 85 since I purchased the 70-200f2.8L IS II, 100f2.8L IS Macro and my latest low light lens, the Sigma 35f1.4''A''. You must also remember that while the 85 is a good lens it doesn't have IS or weather sealing like the zoom. Granted the zoom is heavy but you get use to it and 2.8 is great for stopping the action. I recommend you consider the 24-70f2.8L II and the 70-200f2.8L IS II.

One problem is that the 85mm f1.8 wide open will give you more purple fringe in high-contrast areas. It's worst in out of focus areas. This can be corrected to some degree in post processing.

Its not about IQ or bokeh, its about astoundingly different form factor, intimidation factor or walkaround factors.

One is f1.8 at 85 the other is f2.8 70-200...one is light and relatively compact, the other is not.

FYI the Canon 85mm 1.8 will start to have polygonal bokeh when stopped down.  70-200 not so much, but then again it doesn't go to f1.8...so still apples vs orange comparison.

There are more optical corrections built into the 70-200s, compared to the simpler 85...but there may be things about the 85's rendering you like more (i.e. potentially less clinically sharp wide open for sure).  But again f1.8 vs f2.8.  If you want to compare the tele end of the 200mm for bokeh purposes than you are getting more compression, flatter look, and probably only headshot only framing?  f2.8 on 70-200 will still get you plenty thin DOF shots...with probably less CA to boot, the question is just the size and weight and form factor penalties/preferences.

Just a food-for-thought suggestion... what about the 135mm f2L as a compromise between the properties of both of the very different lenses you proposed? It's one of the best lenses I've ever owned - it's incredibly sharp, has immaculate bokeh, great (but not extreme) telephoto compression, short and fast enough to be used indoors for head & shoulders stuff, and long enough to put a good distance between you and a full-length subject outdoors. I *love* it, and have never felt a need for a telephoto zoom.

Thank you for all your replies. They are all helpful opinions.