M42 adapters on Me Super - metering shift !?

I have just got a Pentax Me Super from ebay and started to try some M42 lenses I got earlier. With M42 to Pentax K adapters, I am able to put old M42 lenses on my Me super. However, there is an annoying problem of metering shift. Based on tests I have done, the problem seems to be from the adapters.

I have two adapters, both are third party. One of them, which has no flange, makes the metering constantly 2 stops under correct exposure, and the othere, which has a flange, makes correct metering. They are tested with the same lens. Therefore, I come to realised that it is the adapters that are really making the problem. I wonder if anyone of you have encountered similar problem. Is this normal? Will a genuine adapter from Pentax solve the problem?

Please help. Many thanks!

Pei

I'll put it another way - the Pentax Adapter K will work fine with no problems whatsoever.

I wouldn't be so sure John, I have an original Asahi Pentax adaptor and consistently have to set +1 stop compensation to get proper exposure with my M42 lenses (film, DL2 and K10D so it's not just the K10D acting up)

I think it's just a hazard of the territory with M42 adaptors in general, the slightest imperfection and they mess up the exposure.

It's annoying but you just have to get used to your adaptor and dial in the compensation. I have the User mode on my K10D set to the correct compensation for my Zeiss Flektogon 35mm M42

I'll rephrase it to I've never had any problems whatsoever!