Teleconverter and Nikkor Reflex 500mm

[treeve]

I have a Nikon F2, with 50mm Nikkor,
together with a Nikkor Reflex 500mm.

[Also a Sigma 70-300mm zoom; it did not have meter
coupling so I have added a coupler (borrowed from
the 28mm lens) to work with the F2.]

In between the lens and the camera body, I can fit the
Vivitar Automatic Teleconverter 2X-3.

There is no metering for the 500mm reflex which is f8,
but it is simple enough to use in conjunction with the
Weston meter.
The question is, when using the teleconverter, what
will be the relevant f stop to be used for metering?

[Canis Vulpes]

I assume your TC is a 2X from part number 2X-3 in which case your effective aperture will be f16 after loosing two stops in the TC.

[treeve]

Thanks Steve,
it is a long time (50 years) since I last did optical calcs.
Looks like I'll need a long exposure and/or fast film. May be
useful on the odd occasion to have a 1000mm equivalent lens.