The Fuji S1 shoots bursts only in jpeg. If you set raw or raw+jpg then the burst mode button does nothing at all. This took me a while to figure out since I had never seen such a behavior before. How wood, as Jar Jar would say.
Meanwhile, the HS50EXR will burst with any combination of file formats and is very fast.
I did a few tests and can say that both cameras are extremely fast on short bursts of around 6 images. But they are quite different on sustained long bursts, with the HS50EXR being faster. The HS50EXR also retains a lot of speed even when shooting raw+jpg. That was a surprise.
Note that I used my best card in both cameras to do these tests, the Sandisk Extreme 16GB 45Mb/s card.
Fine JPEG large size: 32 images in 31 seconds. 1 per second average.
Fine JPEG medium size: 38 images in 30 seconds. 1.27 per second average.
Normal JPEG large size: 32 images in 30 seconds. 1 per second average.
So if you want a slight increase in speed, shoot medium sized images.
Large sized JPEG: 195 images in 107 seconds. 1.82 per second average.
I did not bother shooting long sequences of the others, but I did note that the raw images did not slow down all that much. I believe that this shows clearly that Fuji do engineer the top gun better than the average consumer camera.
S1 Firmware Bug
And since I raised the topic of engineering, I discovered a weird firmware bug in the S1 in bursts of any length – the capture time of the first image and of sporadic images throughout the sequence are incorrect, although the position in the sequence by file name is correct.
This causes the sequence to appear out of order in almost any management application or gallery page where the sort is by capture time. This really had me going until I checked the sort both ways. Here is what that looks like:
The image in the first row that is highlighted is out of order by capture time. When I change the sort order to filename, it moves into second position as shown on the bottom row. Lightroom shifted the highlighting without me realizing it. Sorry about that confusing touch.
Anyway, nasty bug, but not fatal. I.e. so long as one processes the images by file name sort order, one will see the sequence in the correct order. And of course the capture time could be adjusted to make sure that the images always sort correctly.