I know there are many great lens for portraits, but due to price and other lens I've decided my next purchase will be either the 24-105L f4 or a 100L f2.8 macro.
I guess the decision will mostly come down to whether I value to versatility of the zoom, or the bonus of macro.
But what I wanted to ask on this site, is will there be much difference in the quality of portrait shots, taken at the same focal length, at say f5.6 and above?
I truely understand where youre coming from.
But before that…you didn't state what camera you're using and what lenses you currently have. That will matter on what lenses you get.
From my point of view, don't worry too much about people saying this lens is not that sharp wide open at F1.2 etc…if budget isn't a problem, i'm sure everyone would get every prime L Canon made…and i'm sure you have a budget, like almost everyone else
Also, it isn't often you're going to shoot wide open for portraits for starters…shooting wide open is more an "art" that will come much later so don't worry too much about wide open and bokeh madness for now.
If you don't already own a good walkabout zoom, then definately the 24-105 will be fantastic for you. You'll use it not only for portraits but also for almost everything else.
If you're using a crop camera, than the 100 becomes 160mm which might be too much for portraits.
True, the 85 f1.8 isn't fantastic at f1.8 but at 5.6 which you are going to use alot in portraits, it's almost identical to the 85L and definately alot better than the 24-105L.
Personally, i shoot 90% portraits and of those portraits, 70% of them are at f4-f5.6 only.
And when i started out, i used the 24-105 all the time on a crop body and it was great.
However, now on a FF, the 24-105 isn't sharp enough at the corners.
I've since switched to the 50 f1.4 and 85 f1.8, yes both NOT the L versions because well, i can't afford both of them. I would like to but i can't and at f.4-5.6, there's really not much improvements between them..and you can grab a used copy of those lenses for much less than 1 L lens.
So yea, for a start, get the 24-105…it'll be a lens for everything until you get more comfortable and know which focal range you want and what lens to get ultimately in the future…but the 24-105 will always be a handy lens to have to whatever reason.