This is my first chance to use an iPhone with a motion co-processor running iOS 8 (in this case a new iPhone 6 with the barometer built in.)
Go to Health > Health Data > Fitness > Steps > Show All Data
I'm finding that even during continuous periods of walking (hundreds of steps without a break even for a second) the phone is nearly always grouping them into many, many entries but with only a few (it's usually 5) steps at a time.
Is anyone else seeing this? Is it normal? There's been the odd screenshot in the last month or two (from iPhone 5S owners using the iOS8 beta?) showing maybe a few hundred steps and then a few groups of 5, 10, 20 steps – which makes it much easier to read.
The total does seem extremely accurate – I've counted in my head a couple of times as I'm going along, and you can also leave the app running and see it add entries as you're walking along – incredibly it can still count perfectly if you walk but keep your hand really steady...
But I don't understand why the groups are so small?
There don't appear to be any other problems with my phone – the compass and the spirit level seem very precise, as does the GPS. I'm not sure how I'd test the barometer (although flights climbed is about right – outdoors anyway – indoors it logs I've climbed the stairs (2x7) about 50% of the time.)
I've tried with the phone in front and back pockets, I've tried walking faster and slower. The highest number of steps I've had is ~20 a few times when walking around indoors. I did wonder if was something to do with it wanting to group steps according to GPS position. Putting the iPhone into airplane mode doesn't make any difference either.