i never done starstrails with a SLR, only with DSLR.
But, i do know that film exposure at 1/2 sec and more (1s, 5s, 10s, etc ...) require to over-expose the film exponentially.
So, for a Ilford delta 400 iso, if you use your SLR metering, and you have a couple like f8, 10 sec. You will need to expose your film 30sec, to get the right aperture. And the more your SLR ask a lot of second, the more you will have to over-expose.
( see, page 2 ->
http://www.ilfordphoto.com/Webfiles/2010628953322222.pdf
For more information, choose a film, then go on the website of the maker, and go into data sheets, or specifications, and you'll find all those data.
To finish, a release cable is absolutely necessary to get good result.