Canon Speedlite Transmitter ST-E2 Instruction manual - Page 10

Basic Wireless E-TTI. Autoflash O~eration (5) Taking the picture and flash confirmation When you press the shutter butt o n c o n ~ p l e t e l ya, w i r r l c s s s i g n a l is transmitted to the slave, then the slave fires a preflash and then the main flash when the picture is taken. The subject's flash cxposurc reading is obtained with the preflash and used to set the main flash output. Wireless flash photography is thereby executed with a n optimum flash ou1put. When the correct flash exposure is obtained, the ST-E2's flash confirmation lamp lights for about 3 sec. immediately after the flash fires. If it does not light, the picture might be underexposed. In this case, use a larger aperture or place the slave 28 closer to the subject and repeat steps (2)to ( 5 ) . B With the EOS-3, the modelI,ng' flash can be fired to see the lighting effects before the piclure is taken. See page 32. The slave must be properly positioned to receive the wireless transmission. After the picture is taken. the slave's operation result is displayed on the slave's display panel. If the slave is in t h e SE (Save Energy) mode, pressing the ST-E2's test transmission button will cancel it. When you press t h e shutter button halfway and activate the camera's exposure meter, the ST-E2 cannot be used to cancel the slave's SF: mode or to execute a test transmission. The camera's exposure meter must turn off (viewfinder's exposure setting display t u r n s off) before t h e S E mode can be canceled or a test transmission executed. AF-assist beam Under low-light or low-contrast conditions, t h e ST-E2's AFa s s i s t b e a m is e m i t t e d t o a s s i s t autofocusing. The AF-assist beam is compatible with the EOS-3's Area AF. The AF-assist b e a m ' s effective r a n g e is a b o u t 0.6 m e t e r t o 10 m e t e r s at t h e center a n d 0.6 m e t e r to 5 meters along the periphery. The ST-E2's AF-assist bran> c a n he e m i t t e d only while t h e ST-E:! is attached to the EOS-3. In the case of EOS cameras with a built-in AFassist beam emitter, the beam will be emitted by the camera. The slave's AF-assist beam is not emitted (except when the flash is ready). 44 To prevent overheating, limit t h e n u m b e r of consecutive wireless transmissions to 50. After 50 consecutive wireless transmissions, allow the ST-EP to rest for 10 minutes.