Yes, the Canon EOS 400D has both EF and EF-S lens mounts. Therefore, the TS-E 90mm WILL fit on the camera because it has an EF lens mount.
Absolutely yes. Canon EOS 450D has the same mount as Canon EOS 400D, wich is EF and EF-S.
Yes. Canon EOS film cameras uses EF-mount lenses. All Canon EOS Digital cameras will also accept EF-mount lenses.
Vivitar makes lenses for several different camera mounts including Canon. A particular lens may fit or not depending on the mount.
Yes, if you purchase the 'EOS' version of this lens (the one intended for Canon) it will fit just like any other 'EOS' lens would. I have the 500D and it fits fine, but a Google search will show others successfully using the Samyang 8mm fisheye with other Canons e.g. 450D.
Yep!
The short answer is: "No" The long answer is: The T70 uses Canon FD mount lenses. FD lenses can only be focused manually. All of the exposure communication connections between the camera and lens are mechanical. An EF lens will not fit onto an FD body. In 1987, Canon introduced EOS cameras that use EF (electro-focus) lenses. All of the exposure and focusing communication connections between the camera and lens are electrical. An FD lens will not fit directly on to any EOS camera. The Rebel XSi camera is a Canon EOS digital camera that can use EF lenses or the smaller EF-S lenses made for APS-C DSLR's. Adaptors are available on a popular internet auction site that will connect an FD lens to an EOS body. The price in 2008 is just under $40, including shipping. Lens functions are manually adjustable only, and are not very convenient when used in this way.
All of canon's EF-mount lenses will fit on all camera bodies in the Canon EOS system. Simply, if the lens says "EF" on it, then it will fit any Canon camera that says "EOS" on it. If it says EF-S on it, it won't fit on a EOS film body or a full-frame digital. EF-S lenses only work on EOS digital SLRs with APS-C sized sensors (Digital Rebel and 10/20/30/40/50D series) If it says FD on it, it won't fit on any EOS body. These are the old manual-focus lenses from the 70's and early 80's.
The Canon 50mm lens is used mainly by the Canon EOS line of Cameras, since they have an EF Mount which is designed to fit this range. They do also fit other Compact SLR cameras however due to the fact their mounting is similar to that used by most cameras.
In short, yes. More specifically, as long your zoom lens is an "EF" mount lens, it will work with all Canon Digital-SLR models from the EOS line. You can determine if a lens is an EF mount from the full name of the lens. The full name of the lens is usually written on the outside of the len itself.
No, not without an adapter. There are adapters avalable that lets you mount FD-lenses on newer Canon EOS cameras with EF-mount
I don't think they will fit any. The lens mount was changed right after the Canon T70. Someone told me they will fit a Nikon so I'm trying to find that out. (They don't fit Nikon cameras.) Canon T70 lenses only fit Canon SLR's (single lens reflex) made between 1964 to 1987. The T70 uses Canon FD mount lenses. FD lenses can only be focused manually. All of the exposure communication connections between the camera and lens are mechanical. An EF lens will not fit onto an FD body. In 1987, Canon introduced EOS cameras that use EF (electro-focus) lenses. All of the exposure and focusing communication connections between the camera and lens are electrical. An FD lens will not fit directly on to any EOS camera. The Rebel XSi camera is a Canon EOS digital camera that can use EF lenses or the smaller EF-S lenses made for APS-C DSLR's. Adaptors are available on a popular internet auction site that will connect an FD lens to an EOS body. The price in 2008 is just under $40, including shipping. Lens functions are manually adjustable only, and are not very convenient when used in this way.