I’ve now taken two shots at home with and without the convertor.
My room without a convertor, shot with a CoolPix 5700 at 8.9mm/F2.8, exposure time 1/47 s:
My room with the convertor, shot with a CoolPix 5700 at 8.9mm/F2.8, exposure time 1/25 s:
As you see the automatix matrix exposure tries to ligthen the image with the convertor because of the big black border. At the moment there is no reason for me to take some shots at high resolution as I don’t have an adapter to use with the convertor. And also with the coolpic the convertor’s back lens bumps into my cpx front lens :(