POSSIBLE MOLD INSIDE CAMERA LENS

Sounds like fungus/mold. Send it in to Canon or reputable repair shop. It will only get worse.

The lens is a manual focus lens. It doesn't matter which mode you have the camera in, you'll still have to focus it yourself.

For Nikon AF and manual focus SLRs. The compatible T Mount System makes it possible to use most any single lens reflex camera in combination with various front camera attachments such as telescopes, mirror lenses and slide duplicators. The T Mount is a metal connector that screws onto the compatible front attachment and allows this combination to be coupled to the SLR camera lens mount.

Check you manual, but it should be no problem- Sony bought Konica Minolta to have the Minolta lens mount (and engineers). Your old lens doesn't have all the internal electronics (and connections) of the new lenses, but every old minolta AF lens i've tried works fine with alpha

The Nikon D40 requires the use of AF-S/AF-I lenses. Here is a chart of lens compatibility for Nikon SLRs:

Nikonian.org

Depending on how new your Minolta SLR film camera was, the lens may or may not work on a Minolta Digital SLR. In many cases, a lens with the correct mount (in this case, a Minolta mount) can be used on the same brand of camera in the digital format.

One thing you should know is that DSLR sensors are, generally speaking, smaller than the size of a 35mm film negative. Long story short, that means that your lens will have a magnification factor on the DSLR. Usually, it is in the range of 150%, so a 70-300 lens from a film camera would cover 105 to 450 on a Digital SLR.

To be sure about the mount, you'll need to seek advice specific to Minoltas -- probably best to take your lens to a local camera shop and see for sure if it fits and what features will work (aperature, auto-focus, etc) and which won't work on the DSLR.

Your Minolta QTsi Maxxum takes a Konika Minolta AF lens. These lenses work on these Konika Minolta DSLR cameras:
DYNAX 5D / Maxxum 5D
DYNAX 7D / Maxxum 7D

Hello
The Minolta AF lens will fit and work on most of the Minolta AF bodies (it will depend on exactly what lens it is as to the compatibility), you will also find that it will fit and work with the new range of Sony
digital SLR camera bodies.

The Quantaray lenses are a little bit more difficult as Quantaray make lenses for several different types of camera body, it should mention on the lens what make the lens mount is for. If you post further information about the lenses it might help.

That info can be found right here on Fixya

Usually mounts are unique to a camera manufacturer. There are exceptions. Sony has the Alpha; lenses for the Konica-Minolta are the same mount. Your AF (autofocus) lens will work on it. You might also consider picking up a Konica Minolta 5D or 7D.....they're no longer made and hence are cheaply had.

The MD and Rokkor lenses won't work on the Sony Alpha.
THIS IS A CHEAP LENS (<$50 VALUE) SO I WOULDN'T LET IT DRIVE YOUR DECISIONS!!