I kept constant scale earlier because it seemed not practical for me to have to look at the scale every time I was looking at the chart. Log scale seems better indeed, so I've changed it.
Thanks! Now, we don't have all the interesting orders overshooting anymore. I personally would love a way to set upper and lower end though -- the range I find most interesting (200~2000) is only one block small now. With the scale lines so dim, it's sometimes hard to make out the larger changes. If I was able to set the top and bottom end of the log scale, it would be even more awesome.
The 0 in the center makes no sense on log scale though, it must be a ±1. Also, I would make the minimum at least 10. Nobody in his right mind cares about an accumulated order change of size 8 BTC or so.
If you have the time, nerve and wish to make it perfect, I recommend the following:
- switch for log/lin scale
- setting for upper limit, including the option "automatic"
- setting for lower limit if log scale is chosen
- default either to linear automatic or linear max 2000 (Not that I care about defaults, but that's what I'd choose.)
I might drop you a BTC if you do that.

Last but not least: Thanks for the zoom! It is
awesome!
Edit: I'm having issues with nonsensical bars appearing. Red up far to the left, and red down far to the right.