I have a Canon EOS 100 film camera, and I would like to change to a Canon digital, but I'm concerned that the lenses I have:
will not work on the new digital Canon cameras. [It doesn't matter if all of them work, as long as some do]. Could you please advise me as to what digital Canon cameras will not render the list of lenses above useless, or what adjustments I may have to make to still be able to use those lenses?
Since Canon introduced the EOS system in 1987, all EOS EF mount lenses will work on all EOS EF (full frame, APS-H) or EF-S (APS-C) mount bodies. This means they will be functional in terms of automatic metering and auto focus.
What field of view each lens will yield on a digital body depends on the size of that camera's sensor. For a closer look at that issue please see What is crop factor and how does it relate to focal length?
Any current EOS DSLR you buy today will be able to use the four lenses you list in your question and give performance at least as good as what you were able to get out of them with your EOS 100 film body.
Many of Canon's newer lenses, however, are much improved both in terms of optical performance and in terms of auto focus accuracy and consistency. A lot has been learned since 1991 when your film camera was introduced! So while a newer digital body can use those old lenses to their full potential, the same can not be said about those lenses allowing a newer digital body to reach its own full potential.
Those are all Canon EF mount lenses. They will work with any current Canon DSLR, but are so old you may desire newer versions with newer technology.
As others have pointed out, any EF lens should work on modern EOS digital SLR's. One thing to keep in mind, though, is that they will only look about the same on Full Frame digital SLR's, e.g. 1D, 5D or 6D series, because the sensor in those cameras is similar in size to the size of film exposed in a 35mm film camera. On other cameras, "APS-C" or "crop sensor" cameras, e.g. all the rebels, the sensor is smaller, which is modeled by a "crop factor" of 1.6. This means that in terms of field of view, your 100-300mm lens will appear more like a 160-480mm lens, and your 28-80mm will look more like a 45-130mm. The subject of crop factors is a little more complex than that, but that's the gist. In any case, your lenses will not be useless.
Some of these links may have more useful details on crop factors:
