Some of the modern 1.5v batteries are, LR-50...PX-1A...A1PX.
Please note: 1.5 volt batteries will not provide accurate metering.
You may find more answers and solutions in the following links.

Small Battery Company-UK:
http://www.smallbattery.company.org....50_adapter.htm

KEH Camera, Battery Blog:
http://www.kehblog.com/2011/09/battery-guide.html

Hope this helps,
Marc