The above images were created from a variety of sources. Some are from my Sigma SD Quattros using the 21:9 crop available. Some are screen grabs from 4K video shot in 'Cinemascope' format (via the Filmic Pro app.) on my iPhone and some are panoramic stitches, either from multiple images or shot continuously, again on my iPhone. Now in terms of still photography I've always had great success with Panoramic images. However, I'm now shooting video in the same format and have had some difficulty in convincing stock libraries to take them. However, now some do but others can't see beyond the 16:9 format.
These days in terms of stock sales it has to be realised that electronic publishing is more the norm than the exception and wide screen images (and videos) do look good across web pages. And particularly in the UK, these are being used more and more. I was even watching a popular BBC TV programme the other day and realised that it was actually shot in widescreen, with 'letterboxing' top and bottom.
One of the reasons I think it works well is that we see in 'panorama vision' with our eyes. If I hold up fingers on each hand at the limit of my vision, it's almost 180 degrees, so we are all used to 'widescreen'. And as time passes I'm shooting more and more in these wide formats. Not just for commercial reasons either. I'm particularly taken with my Sigmas 21:9 option, which by shooting S-HI jpgs. gives me 30+ MP files of extraordinary quality.
So something different and something I think will be seen more and more.