I'm interested in finding out how the inbuilt metering (histogram) of a DSLR measures up with an old school Flash Meter setting.
Like I've said, the histogram is a poor tool for determining correct exposure as the shape of the histogram is linked to the type of scene you are shooting. Take a look at my avatar. The histogram for that photo will be skewed to the left. A naive interpretation of that histogram would suggest that the photo is underexposed. However, I've exposed for the face and this has been correctly exposed. Now take a look at Citruspers' avatar and you'll get the opposite problem, the histogram will be skewed to the right indicating that it's over exposed.
A lot of photographers who follow the Strobist's blog (http://www.strobist.com
) will likely use the "blinkies" approach mentioned by citruspers. This is also know as chimping, so you'll know what to Google for if you want an elaboration on this technique
The main advantage of this approach is that you don't need a light meter. What you do need is a lot of practice so that you don't spend ages chimping to get the correct exposure.
If you want consistency in your photos, there is no avoiding manual. Manual flash and manual exposure. Most of the time, you don't really need such consistency and whatever variations in exposure can be corrected in post processing.