bad contact?

[Migs]

Hi, my Kenko Extension tube set arrived yesterday and I tried with my sigma 105mm macro with no problems......then this morning I tried to use my nifty fifty with it............"no focus" "the camera switches on, but only the small screen on the top..the back screen doesn't work at all" (EOS 40D)
I then put another Canon Lens on and it all came back.....Any Ideas?
Maybe the contacts on the lens?
Anyway, thanks you all

 

[Janice]

Does the nifty fifty work ok without the extension tubes?

 

[Migs]

When I get home I will try again......I had to leave to work this morning.....
I think it will work with the lens only......I'll get back to you Janice.....thanks