So it’s the Olympus M.Zuiko Digital ED 12-100mm F4.0 IS Pro. But why?
First of all, it’s got excellent reviews. Basically everybody says this lens is insanely sharp across the range, beginning wide open (which, admittedly, is not very wide).
Yes, you can’t have shallow DOF, at least not for typical situations like portraits. On the other hand, I am not as interested in shallow DOF as I was ten years ago. I take most of my images at apertures between 4.0 and 8.0.
Yes, a starting aperture of 4.0 means that I have less light and I will have to compensate with higher ISO. That’s correct, this is not a low light lens. It is stabilized (in-lens stabilization working along with in-body stabilization) to an insane degree, but an f1.2 lens with in-body stabilization will beat it in low light. No comparison.
The real reason is versatility. This is an excellent zoom that makes only one compromise, namely with its starting aperture. If you can’t live with that, that is no lens for you. If you can, this lens may be your best investment ever.
It’s been a year and two months since I bought the lens. I’ve used it on vacations, I’ve experienced its single weakness and I’ve seen its fabulous quality. Normally I couple it with the 7-14/2.8 PRO, and if I think I might have use for something shallower, I can always add the feather-weight that is the 45/1.8 or maybe the 25/1.8, if I feel more like that. Or maybe the manual Mitakon Speedmaster 25/0.95, if I don’t mind the slightly higher weight.
What I get is the convenience to not have to change lenses most of the time. For me it is the perfect vacation lens, at least in cases when I have to haul my equipment all day. Nowadays I only use the three 2.8 zooms, when I mostly drive around by car. For everything else I love this lens.