PhilipBloom.net has an extensive shootout between “three of the most popular ‘affordable’ 35mm Depth of Field adaptors”.

What I wanted to do with this shootout is give people information that I was not able to get when I wanted to buy an adaptor. There are many people with these adaptors, but very few people have been able to get their hands on more than one at a time. I now have used four of them and I want to give people information on my experiences. Ask people on the forums which adaptor is best and you can’t get a proper answer for the above reasons. Each person loves their own adaptor, like each person loves their Z1 or HVX or JVC 100 etc…

In your quest for greatest image quality you should definitely be looking into adapters like these. They’re definitely on my list, it’s just that some other things are in the way right now. This roundup should be helpful for anyone who has to make the decision a little sooner than I.