183MC on a Nikon Nikkor Lens

mranch1

Hi, I'd like to attach my 183mc to my 70-200 Nikkor lens. The lens does not have a manual way of setting the f stop. Does anyone know if it's possible to set the f stop somehow? Thanks,

Bob

w7ay

mranch1 Does anyone know if it's possible to set the f stop somehow?

Check out these guys, Bob:

https://astromechanics.org

Chen

enaiman

mranch1 Look at the lens when the camera is powered down or the lens is disconnected. If the aperture is wide open, that's all you need. If it isn't, then you need to look for something else like Chen suggested.

w7ay

mranch1 Does anyone know if it's possible to set the f stop somehow?

Do not use a camera lens at maximum aperture. You will not be happy with the results.

If you don't want to use the iris in the camera to set the aperture (which can produce 8 or 12 diffraction spikes), use a set of what are called "step-down" rings; your local camera store has them, and so does Amazon. Try for at least 1 f-stop below the wide-open f-stop of the lens, while setting the lens itself to be wide open. Camera lenses are designed to work with various focal distances. Astrographs only have to work at one focal distance -- infinity.

Chen

mranch1

Thanks everyone! The aperture is wide open. I'll see if i can find a set of step down rings that go small enough.

Bob

Kevin_A

I just use a plastic wedge I made that holds the metal tab in place and the aperture wide open on my Nikon format lenses. The lenses I use however are best wide open and work great at that setting. Some lenses don’t work well fully open!