If you have a smartphone (particularly an Android one) then try a light meter app first.

I use the BeeCam one on my HTC, it's an incident meter and seems pretty effective assuming you know how to use it (you need to make sure that the light level falling on the meter is the same as that falling on the subject). It worked fine in woodland with uneven lighting, both heavy overcast and sunlight (different days).

I've used it with both the Zeiss Ikon and the Bronica ETR now, no exposure problems with either.