No.
Bokey does not matter.
We survived for 100 years without being neurotic about the fuzziness of the background, in tiny ways that have no real impact on the quality of the photograph.
Bokeh has a cousin -- fuzzy second eyes, caused by shooting wide open, to get one eye sharp and to make the rest of the picture inspire eye-watering when trying to see it.
It does not matter if the lights on the Christmas tree in the background behind the kid opening her present are a tiny bit more round, or a tiny bit more 8-sided.
What matters is the kid, and the present, and the joy of the holiday.
Bokey is free breadsticks.
You go to the Italian restaurant, and you order the veal and the zookini, and before the meal arrives, the waiter brings a glass with some breadsticks sticking up.
My, that's nice. But it doe not change the taste of the veal or the texture of the vegetables, or whether or not you'll come back to that restaurant.
Imagine two photos. 16 x 20. Framed. Hanging on the wall. Extended family gathered together in the home for New Year's day.
The little girl, opening her gift, is the subject of the photos, taken a week ago, on Christmas day.
One, shot af f1.8 with the one-sharp-eye and the beautiful fuzziness, including the fuzzy stuffed (toy, not real) bear and the fuzzy beautiful hair, and the wonderful round blur of tree lights shot with circular diaphragm blades. Not sure what the colored blobs are - too fuzzy to see they are part of a beautiful tree.
The other one, shot at f5.6, with a five year old lens without bokey-friendly diaphram blades. The girl, and her hair, and Winston (that's the name of the bear, named after a man in a Karsh portrait) are sharp. And you can make out some of the decorations on the tree. The tree is sharp enough that it adds a Christmas spirit to the shot.
Now, sit on a stool, clipboard on your lap.
Count the number of friends and relatives who stop at the fuzzy shot, and at the sharp shot, and count to seconds each stays with the photo.
And count how many times the girl's parents are asked for a copy of the bokey-dokey shot, and how many ask for copies of the "she sure is beautiful, isn't she?" shot.
UNKNOWN: I have no idea about your camera, and other lenses, but in the world of good photos, the 50 STM plus the 10 - 18 STM, which together cost about the same as the 50 f1.4, will give you many more good photos for the same money than you'll get buying the f1.4 based on fuzzy backgrounds.
PHOTOZONE: Notwithstanding any of the above, the f1.8 STM loses Bokeh fringing at a wider aperture than does the 50mm f1.4, according to the Photozone tests.
And to accurately compare bokeh between the two lenses, it would be necessary to make comparisons at a number of apertures, of a number of subjects, with a number of different distances.
Sort of like having salted or unsalted butter, or olive oil -Turkish, Italian, French - to go with the breadsticks.
Anyway, my take on the Photozone tests is that the STM 50 is just as good as the f1.4 in any way that matters, and costs a lot less.
