(Disclaimer: I am not Calking. I did not write the post shown below.) - caver3d
Calking (fujirumors.com - October 29, 2013)
And let’s put the whole f1.2 DOF thing to bed too — how many photographs do any of us aspire to shoot where only the tip of someone’s nose in in focus, or one leg on a grasshopper, or one petal on a flower. As a professional photographer commented recently, “You’ll find yourself in trouble more often than not shooting full frame wide open.”
Let me start by saying that I like fast lenses and primes.
My Olympus 35-100F2 and 15F2 and my Panaleica 25F1.4 and Rokinon 85F1.4 are among my favourite lenses, and let's not even get started on how I enjoy my Voigtländer Nokton 17F0.95.
And yes, occasionally I use those to get as shallow DOF as I can get on FT, isolating a subject (or even a part of it, like an extended hand, from the background etc. For my Nokton, I bought a variable ND filter, so I should not pretend that I only bought it for light-gathering : I want to use that lens occasionally also wide open in good light. So shallow DOF was and is an artistic consideration. Let's not kid ourselves and pretend that it isn't ever.
And thus I am fully aware that if shallow DOF was my main concern, I would be better off with FF.
But it is not.
I like those fast lenses mainly because I hate to use flash. For my documentary work, a flash is just a nuisance, ruining the intimate atmosphere of a scene in which I am immersed and in which I try to remain the unnoticed fly on the wall.
So I do almost 99% of my work with available light, even if that available light is very limited. In my images I like to not only USE available light, but also to SHOW the light itself at work, as part of the composition.
Fast lenses are (for at least 95%) about light-gathering for me.
And for those purposes, the somewhat deeper DOF of (µ)FT versus µFF is a blessing, because it allows me to focus manual lenses more easily (handheld in dynamic situations) and because it shows just enough of my subjects in focus (not just the nose but the whole face), even when shot wide open.
Like here (almost completely dark scene, shot at ISO 3200 with F0.95 and 1/15th sec handheld:
Circus backstage scene with Nokton 17.5mm on E-M5