I'm looking for a portrait lens to pair with my 24-70 Mark II on my 6D camera. Unfortunately, I spent too much money on my 24-70 Mark II, and can now only afford a lens in the $7-900 range. I was pretty set on buying a 70-200 f/4IS, but I'm worried about the lack of background blur at f/4. This has me also considering the 100 f/2.8L Macro. I looked over the mtf numbers of both lenses and they are nearly identical, with the 100L being ever so slightly sharper (Not sure why people say that macro lenses are "too sharp" for portraits, because according to the MTF numbers this isn't the case.)
I think overall I'd use this lens 70% for Portraits, 20% for walking around to pair with the 24-70 Mark II, and 10% for food photography. I like that the Macro does 2.8, has Image stabilization, and is black/light. I like that the 70-200 f/4 IS has faster autofocus in case I want to take action pictures of my dog, and obviously goes to 200mm. I think again my main consideration is just portraits and image quality of the portraits. I'm going to be traveling to the US next month to visit aunts, uncles, cousins, nieces, etc. I'd like a lens to take with me to take pictures of them. I know the macro lens does 2.8, but at f/4 would the 100 f/2.8L and 70-200 f/4is produce the exact same image quality for portraits....or would one produce better color, saturation, "pop", etc?