I have a Nikon D-40 and D-90 with a wide assortment of prime lenses. I like fast primes for low light photography.

Some of my lenses are sufficiently old that they do not auto focus at all. Others do, but some Nikon bodies don't have an AF motor, they just rely on the silent wave.

The problem is, I can't seem to find a way to have the AF assist light (on the camera, or on a flash) come on when manually focusing, or when the camera detects that auto focus is not possible. I have gone though every setting that I can find and have yielded nothing.

Is this just not possible, or am I missing something obvious?

I have a Nikon D-40 and D-90 with a wide assortment of prime lenses. I like fast primes for low light photography.

Some of my lenses are sufficiently old that they do not auto focus at all. Others do, but some Nikon bodies don't have an AF motor, they just rely on the silent wave.

The problem is, I can't seem to find a way to have the AF assist light (on the camera, or on a flash) come on when manually focusing, or when the camera detects that auto focus is not possible. I have gone though every setting that I can find and have yielded nothing.

Is this just not possible, or am I missing something obvious? In certain settings, its just impossible to get a good focus without that. I don't hit the same problem with most film cameras (or anything else with brighter view finders) nearly as much.