EF Mount Lenses, Other Lenses | Sigma 50/50e specification

You will also have more things to set on the ﬂash (ISO, aperture, zoom) and on the camera you will have to manually set the lens aperture to what the ﬂash says, and you will have to make sure that your shutter doesn't exceed 1/125 second. Still, with all that, auto ﬂash is a bargain if power and versatility are the main considerations. But if speed & ease of use are a priority get an EX series Speedlite.

The most important consideration with non-dedicated ﬂash units is the sync volt- age. You must test this with a good volt meter (at least 20,000 ohms per volt). With the ﬂash charged up & ready to ﬁre, lay one lead across the contact at the side of the ﬂash foot and the other on the center pin. Canon says it has to be 6 volts or less, although up to 10 volts is probably close enough. Some ﬂash units like the older models of the Vivitar 283 have more than a 200 volt sync trigger. These can fry your camera in one pop, and accumulated use of even a 20 volt sync could damage your camera.

The most complete information about Canon ﬂash technology, metering and theory can be found at: http://teladesign.com/photo/eos-ﬂash/

6 Lenses

6.1 EF Mount Lenses

All lenses that are designed for EOS cameras have an EF mount on them. They all should work with the Elan II/IIe. Some older third party lenses are known to cause the camera to temporarily lock up due to an incompatibility problem that is discussed below. All Canon EF mount lenses will work ﬁne. The better grade of Canon USM lenses (28-105 USM, etc.) use a ring type AF motor that allows Full Time Manual (FTM) focusing without selecting MF on the lens switch. FTM allows you to auto focus and then quickly touch up your focus manually. Used with custom function #4 to move the AF start to the AE Lock button, these lenses will change the way you take pictures. Or at least the way you focus. Before you buy one of Canon's cheaper lenses try one of the better versions. Be warned that cheaper USM lenses (28-90 USM, 75-300 USM) will not allow FTM.

In my opinion there are no good reasons to buy a cheap third party lens with any Canon EOS camera. There are too many incompatibility problems and they are no better than Canon lenses of equal price. However there are quite a number of better third party lenses that can save you money over Canon's good but pricey selection of better lenses. Keep in mind that you get what you pay for. At least sometimes you do.

6.2 Other Lenses

In addition you can use any T mount lens with a T mount adapter ring. T mounts are frequently used for cheap mirror lenses that have nearly worthless image quality. But the T-Mount is also used for macro bellows, attaching the camera to a microscope or telescope as well as some worthwhile older lenses.

You can also use any M42 screw mount lens with a M42 to Screw mount adapter. Very decent, low cost ﬁsheye lenses are often found in M42 mount. These lenses were