I was casually looking around to see if there was any news about a new 50 with IS since the 85 came out, and found this thread. It's been interesting to read because, as someone noted, the participants seem to mostly be enthusiasts and not professionals, and the analyses regarding why Canon would or wouldn't want to bother updating a 50 are from that perspective - and you can't argue with (most of) the arguments here, which basically sum up to "I can do everything I could possibly need to do with what's currently available so I don't see why Canon would bother".
So I thought I'd chime in with the perspective of someone who uses this focal length professionally. The main thing my partner and I do is weddings, family and baby/child portraits, and things like that (we do also do corporate type stuff, where our equipment needs are a bit different). I do video - and we both shoot with 5d4s (we can share equipment and there's a more-or-less consistent look between the photos and the video for a wedding, for example, though our approach and style is different).
Now, you may be thinking, 50mm is not really a great portrait focal length on a FF body, and isn't wide enough for events. Well, my partner carries two cameras on a harness, the second with a 24 1.4 L - and I use the 35 f/2 IS for wider shots; anything wider than that I typically do with the 24 TS-E II on a tripod. 50mm is certainly a compromise, but a very good one - the problem with shooting with an 85 is that in a wedding, that actually gets you too close most of the time. During the ceremony and speeches etc. she uses a 70-200 2.8 IS - an 85 doesn't get you close enough in that case. The rest of the time, the best moments often happen in very tight quarters with the bride and groom and 85 just doesn't work. So the 50 1.2 saves the day - you get the shallow depth of field that clients love (and you don't actually have to shoot at 1.2 on a FF body to get it) and you can zoom with your feet even in tight quarters to get the framing you want. Likewise for family and kid portraits, it's great because it can be very difficult to track fidgety kids with an 85 or longer length, and with younger kids you need to be close to them to get their attention and to get them to engage with the camera (though she does use the 70-200 for these too occasionally depending on the situation).
So, it's actually the perfect focal length for that stuff. But, I also actually prefer it for a lot of other kinds of photography too, and plan to get the 50 TS-E for my other stuff including architecture and landscapes. I have the 24 II and the original 90 TS-E lenses; I find myself stitching together 90mm TS-E shots to get essentially a 50mm perspective - the increased resolution from stitching is not really worth it for what I do (I will probably sell the 90 because it's an awkward length for me, and eventually get the new 50 and 135 TS-Es). For me, the 50mm perspective is how I see things most of the time and is just ideal for my style of photography.
So that said, for video I primarily use the 35 f/2 IS - and I don't like it (though it's actually perfect for corporate type stuff I do as well where shallow DOF style is less important). I mean the lens is great, honestly, I just don't like how it looks for video You can get shallow depth of field with close-ups on a FF body, but for the most part the way it renders on video is just not my favorite - though it is not actually soft, for my purposes it appears "not crisp" in 1080p video compared to shooting with a shallower DOF (sharpness at this resolution being more about perception than technical specs). I vastly prefer using 50mm. I use the 1.4 for video because it's much lighter than the 1.2, and because we have two copies of it that weren't getting used since she got the 1.2 - and because I'm waiting for an IS version.
Here's what's key here - IS is a godsend for Canon video (even with a tripod, truthfully) since we don't get in-body stabilization (the stabilization in the 6D II is not good for professional results, at least for my style - it's digital processing, which I can do better in post if that's what I wanted, which I do do although as little as possible because it usually looks weird). If you haven't tried it, try a short clip with any recent-model IS lens you have - even a telephoto. It's amazing. I use a shoulder rig because the 35 is not the only lens I use but with modern IS, hand-held is legitimately just as good as a shoulder rig - and that's why I want a 50 with IS. I want to ditch the shoulder rig and instead have two bodies on a harness, one with a 50 IS and one with the 35 IS (with the 85 IS in a belt pouch for certain shots that I currently use the 85 1.8 for).
A 50 IS would be a game-changer for video. I shoot at or near wide-open most of the time (using ND filters outside) to get a "cinematic" shallow-depth-of-field look because that's what I like, and what clients like.
I would gladly pay $1600 for a 50 1.4 with IS, just like the 85. I would also gladly pay *significantly* more for an updated 50 1.2 with IS, no hesitation. I am far from the only one, too, although I will concede that most people doing this kind of low-level professional video are more than happy with their zoom lenses with IS (or their Sony or Panasonic cameras with in-body IS). I aim for something aesthetically far better than that - people like me buy these lenses to shoot wide-open with, and I care more about that (and IS) than the "versatility" of a zoom, or even of absolute technical sharpness (same thinking as e.g. Leica users - and e.g. I also shoot medium-format film wide-open with large-aperture lenses). Canon is *so* close to letting me realize that in really an amazingly easy way compared to what would have been required just a few years ago, and a 50 with IS would take me almost all the way there.
