I'm using a Nikon D5300 with a Manual Nikkor 28mm F/3.5 lens.
I've been using this set up for years without a problem but recently noticed that when I rotate the camera's aperture ring (physically) it produces no change in aperture in the shots. I've removed the lens and changed the aperture while looking down into it, and the blades are physically moving. However, when I reattach the lens and take a few shots with the camera in Manual (but not hooked up to the laptop), the photos are all the same exposure.
I've tried looking for a setting within the camera that might have been accidentally changed, but can't find anything that works.
I'm not a natural with settings but have done a whole bunch of internet research with no success.
Sorry, didn't see this back when you posted it.
When I used Nikon lenses on a Nikon body, I partly unscrewed the lens so the camera can't open up the lens between exposures. I suggest, since the aperture does stop down on the lens itself when it is not connected, you try that. I did it to avoid flicker, but it should also make the camera unable to change settings on the lens, whatever setting is causing it. With my old manual lenses, there is a spring-loaded lever on the back of the lens, you push it in a circular path and you can see the blades close down. If you don't push it, the blades stay open, whatever aperture you have set. My Nikon body had a bar that would physically push it when the lens was attached, and it would only let it stop down when you press the shutter. Then it opened up again to give you a nice bright view through the viewfinder.
If you stop the lens down to the smallest aperture you want to use, like f-16, press the lens lock release button on the camera and unscrew the lens until the blades close as far as they are going to, and turning a little more does not make them go any further. It should still be held securely. At this point, the camera can't change the aperture, it should stay stopped down to whatever f-stop you set it to on the lens barrel. This will make the live view darker, and you need to adjust the gain in Dragonframe Cinematography window to compensate - I usually have it on +4 which is the highest setting. This only affects the video live view, not the final image.
I don't know what has changed with your camera, but maybe this will work around it. My Nikon D40 was from before they added live view to DSLR cameras, and I moved to a Canon with my Nikon lenses when I upgraded. So I 'm a bit out of date with Nikon cameras. Since I use a lens adapter to fit the Canon mount, I don't need to partly unscrew the lens, as I did when putting it on the Nikon body.
Thanks for your answer. To be honest after switching out my manual lens with my digital kit lens and then back, the problem vanished. I suspect it indeed had something to do with the connection between the lens and the body. If it comes up again I will investigate the points you mention. Good for future reference.