FD lens mount. Manual focus. Manual metering only, centerweighted metering pattern, match needle metering display, split image microprism focusing screen, dedicated hot shoe, PC sync terminal (X sync only). Shutter speed range: 2 sec to 1/1000 plus B, flash sync at 1/60, self timer. ISO film speed range: 25- 3200, manual film advance and rewind. Removable back, DOF preview. Special Note: The AT-1 is the one camera in the A series line that MUST have a silver-oxide battery; no lithium or alkaline substitutes should be used. Recommended Accessories: Data Back A, Power Winder A. Recommended flash: 199A, 177A, A series.