I recently bought the 16E for my Hasselblad 203FE, and used it on the 150 F2.8 for a studio portrait. The film was exposed and developed normally, but afterwards I realized I should have compensated for the extension (it's 16mm i guess). The negative looks about 1/2 a stop underexposed, but might be more.
So the question would be:
Do I need to overexpose 1/2 a stop, or more? Is there a simple calculation for this, and is it the same for all lenses?
Thanks for any reply on beforehand, I'm doing some new portraits soon, and would like the highlighgts where they should be!