I did a quick search of Chopin images and came up with quite a few different croppings of what appears to be the same image, and the photo you're showing can be explained as the most extreme crop of all, of the same image. The more you crop into the image, the softer and less sharp the image will be. There are other possible explanations too--someone attempted to make a copy of the original image and didn't properly focus the copy camera? Could be. At any rate, I don't believe it is a different image from the same shoot, or a new, heretofore unknown image.
Sorry but I don't think this explains it at all. There is a CLEAR difference between these two photos.
The head seems to be slightly angled differently and look at the mouth. It's a dead giveaway.
You may be on to something with the mouth, as there is an unexplained shadow coming up from the left side of his mouth (his left). But there are still other explanations for that one detail--perhaps were looking at a photo made from a copy neg--which I believe to be the case--and a bit of dark fuzz or something, or anything dropped onto the photo being copied, or there was damage to the copy neg during development or subsequent handling. There are any number of other things that might give rise to this detail.
As to the angle of his head, I'm not quite sure what you're seeing, unless it's maybe that his head in the shot that is cropped at mid-chest, is canted just so slightly clockwise (clockwise to the viewer). I'd have to get a square out to see if that is really happening. But anyway, if it's from a copy neg--again, as I suspect it is--it would have been very easy to cause the change in angle by slightly turning the picture being copied. Such a turning could have even happened by accident.
As to what someone above referred to as "wear marks" along the edges, there are numerous causes for these, all supporting the idea that the image is from a copy neg. The lines along the right and left side are very typical of marks left by abrasion, or touching, or the masking of a 4X5 film holder, no matter what type of film is being used. But the marks along the bottom? I'll go even further. It looks like the kind of imperfect development one gets using Poloroid type 55 positive/negative film when the film is either old or cold. Also, the horizontal lines across the top look very much like the lines left by a Poloroid 4X5 holder when the Poloroid type 55 film isn't pulled out evenly and quickly. I've seen it a hundred times. The usual tell tale signature of Poloroid type 55 that fine art photographers love to include--the little mesh holes across the top edge--was probably cropped off, as intended by the Poloroid Corporation.
Style is another reason I believe this is from a copy neg. The style of cropping in the 1830s and 40s was often full body, or from the waist or mid-torso up. The very tight head shot came into its own quite a bit later. Also, think about what the photographer would have had to go through in Chopin's time to produce such a tight head shot. He would have had to laboriously frame the tight head shot, using a very cumbersome and heavy wooden tripod, and then attempt to force focus his camera when his bellows simply wouldn't allow for it, and then wasting an expensive piece of photographic material on a picture he knew would not be in the style of his times, nor would it be, could it be, sharp--I'll admit, this last objection would be a possible explanation for why it is so very soft in focus.
For all of these reasons, I believe this photo is from a rather inept copy neg made on Poloroid type 55 positive/negative film. It would have been sometime after, say, 1975, as this film was introduced about that time or later. All sans photoshop.