M42 lens - how to handle f/stop if there is no M/A switch?

[aniramca]

My M42 to Nikon lens adapter came the same time with my M645 lens adapter. Using the M645 lens on a DSLR was quite delightful. Those lenses came to life after a pause of over 30 years. After I completed testing on the M645 lenses, I am now just starting to check the M42 lens. The adapter that I got is without corrective lens. I have 4 different lenses to try on : SMC Takumar 35mm, Soligor 80-200mm, Fujinon EBC 50mm (from Fujica ST801) and Jena 50mm (from Praktica LTL).
My first impression, especially in comparison to the Fotodiox M645 lens adapter is generally that my M42 lens adapter does not fit very snuggly into my DSLR. I felt uncomfortable with a very tiny "movement" between the lens and the camera. It is not like the M645 adapter, in which there is a spring loaded device to keep the adapter fit nicely with the camera.
My second observation is as follows, and perhaps someone can provide advice on how to overcome the problem:
1. SMC 35mm and Soligor zoom lens - they have both a switch to change from Manual (M) to Automatic (A). This works OK. I tried some photos with the SMC and I am generally happy with it. I did not try my Soligor yet, as it is rather heavy and lengthty and therefore I do not want to stress the connection to my DSLR.
2. The Fujinon lens does not have the M and A switch. To change aperture manually, the pin on the back has to be pushed in.
3. The Jena lens also does not have the M and A switch, but there is a lever next to the aperture ring (which was used to check depth of field), and when this lever is pressed, the aperture diapraghm closes to the required f/stop.

My question is how to handle with cases no. 2 and 3 above?
Secondly, does a brand of M42 lens adapter have a better fit than another? anyone who uses M42 lens adapter has similar experience that it does not fit snuggly?
Thanks for the suggestion.

[sichko]

[sichko]