to check if you need to get the dremel out, attach the lens to the adaptor, and put the adaptor on the camera but don't fasten it all the way closed (i.e. it doesn't click into place.) Support the lens in place, and do a test fire of the shutter. If it works, then just take a little off the adaptor tang where it's marked blue and in the green circle. Obviously, it's also essential to get the adaptor scrupilously clean afterwards - especially if you're going to use it on the digital as well - don't want swarf in your sensor - or indeed anywhere else. I used a spray can of electrical contact cleaner to ensure that nothing untoward was left behind after working on it.