In TortoiseSVN, why can't I show the log older than 6 weeks or so?
Ah I worked it out - you have to use the button down the bottom of the log dialog window that says "Show Range" or maybe "Show All". If you click the arrow next to the button you can then specify a date range.
The date filters at the top of the dialog box seem to only filter whatever you are currently looking at.
Refer to the screenshot below,
