What would be the use cases for 100/1.4 @f1.4 vs say a f2.8 like the current RF100 macro?
For portraiture, wouldn't keeping both eyes in focus be a problem @f1.4?
Planetary images perhaps?
For telephoto/wildlife, wouldn't you be too close?
Others?
People don’t just photograph headshots for driver’s licenses where everything is close and everything needs to be in focus.
Even when shooting models or fashion, you can photograph the entire person from a bit further away, keep the whole head in focus, and get a different perspective due to compression, as opposed to shooting it with a 35mm or 50mm lens.
If you’re interested, I’ve personally shot a lot of stuff with a 135mm at f/1.8. Just a couple of examples: focusing on an isolated head in a crowd at a concert; a shot of a frontman on stage; a model in the sea at dusk (again a whole-body shot); a model swimming at dusk with city lights in the background; a silhouette of an ibex after sunset; a fashion model—whole body shot (with plenty of space to spare in the frame)—surrounded some architectural elements.
An athlete on a bike surrounded by spectators; an athlete (climber) hanging on a ledge at dusk; a side silhouette of an athlete jumping with a bike after sunset.
Then there are shots where I was focusing on different parts of instruments or tools for commercial work. Shooting people in laboratories—focusing on one person working with a machine and blurring the surroundings. I've done full body shots ( sometimes with loads of space left and right of the subject for some environment) of ballerinas and dancers, when it was convinient to blur out some of the ambient (you still get a pretty good idea where the person is) and keeping the focus on the model ...
Just last week I photographed a model that was standing on the inside of a hotel bar next to an open window. We were shooting at dusk, the lights were on inside, I had some light setup outside. I was shooting outside from the terrace, keeping the whole window frame and curtains in the picture, bluring it a bit and bluring the lights and stuff in the back of the room even more. And since the distance from the camera to the the model was cca 6-8 meters and the model was facing me, I can assure you that both eyes came out sharp in final images ;-)
There are so many examples where you either want things out of focus, or you simply don’t need everything to be in focus, but still need to open up the aperture to gather more light. I mean… I’m honestly surprised that you don’t realize— or perhaps just lack the imagination to see— that there are all sorts of images that can be taken with focal lengths over 50mm and at lower f-stops.