The other thing to note with the difference btw the f/4 and f/2.8 in this situation is that the 2.8 version comes with a tripod collar, the 4 doesn't(and needs to be purchased separately if needed.

if you do any non handheld shooting with such a lens(which I do mostly) .. the tripod collar issue can be a big deal.

The difference in weight between the two types of lenses is only in the 700gr region .. but remember this is for the bare f/4 lens .. minus the tripod collar.

So the extra weight of that plus the nearly $200 extra cost should be factored into the equation if the lenses are to be equally considered.

Also note the tripod collar design of the 2.8 lens is also quite nice in that the square foot end of the contraption is removed(and hence easier to store if not needed) .. where the entire tripod collar of the f/4 lens needs to be removed if not required(or in the way).


Just some more info to consider if this sort of thing is important to you.