Setting aperture on Nikon D lenses?
I want to know what will happen if I set focal length 70mm and aperture 3.3 on a Nikkor 35-70mm f3.3-4.5 lens. Second question is how to set aperture on a D lens while using a digital camera.
Your aperture will be f4.5 - zooming changes the focal length and thus the ratio between that and the diameter of the aperture - lenses with a constant aperture are more complicated to make and more expensive.
Most of the time, in using a D lens with a DSLR, you lock the aperture ring on the minimum position and use the camera body controls to adjust aperture - your manual will be more specific.
D lenses don't autofocus with Nikon's D3000/D5000 series, but they will meter.
If you attempt to set the aperture on a D lens connected to a Nikon camera, and the camera is not in Manual mode, you will get a " F - - " error; which means "hey, you attempted to set the aperture".
If in Manual mode, you will not get an error, and the camera will behave normally, and other than you will being responsible to set the proper shutter speed and ISO, the camera will take photos.
However, you can electronically set the aperture of a D lens even in manual mode, so there's really no reason to adjust the aperture ring on the lens.
In normal operation, using DSLRs (and even late model SLRs) always put the aperture ring into the Lock position; which is essentially the smallest aperture (f/22, f/32, etc). This allows the camera to electronically control the aperture (in any mode, including manual).
D lenses having settable apertures were originally made for those that have early model SLRs that could not electronically set the aperture. So this backwards compatibility of older lenses was the reason for the aperture ring. Nikon has always supported the customer in this fashion, and consequently, the latest model DSLR can still use 99% of the lenses made by Nikon in the last 50 years.
Since the situation of using early model SLRs is rare these days, Nikon has removed the aperture ring in the G lenses.
About the only reason these days to manually change the aperture on a D lens, using the lens aperture ring is if you have inexpensive macro rings, or are using a bellows for macro use, etc. And there's no electrical contact between the lens and camera. In that case, you put the camera into manual mode, and you can change the aperture on the lens as needed.