C or T mount

[egproductions]

I am looking into building a 35mm adapter for my video camera. One of the reasons i want to build it myslef is becasue any of the already cheaply build ones usually work with nikon or canon mounts. I want this one to work with my pentax k mount lenses. What mount do i need to hook up the prime lenses to? I have seen epople using c mounts but i have also noticed there are t mounts out there. Whats the diffrence? Whihc one will allow the lense to stop down when i change the aperture on it and not just constantly be open all the way?

[delfino]

Most old style T-mounts are manual type. This means that you will have to view it with the f-stop you currently selected.

So if this is the case, your Pentax K lenses will be stopped down when you view it via the adapter.

Most SLR lenses have spring loaded prong connected to the camera body. The prong in the camera is set so that the f-stop diaphragm in the lens is always open as you mentioned. When you trip the shutter, the camera releases the lens prong and the f-top closes to the preset stop you set i.e. F5.6 or as determine by the built in meter.