Newbies to digital cameras first notice that the moment you press the button is not necessarily the precise moment that the camera takes the picture. “But my old film camera took the picture straight away!” you cry. True. But with a film camera, in the millisecond that you pressed the shutter button the direct mechanical linkage to the shutter fired it — and the picture before your lens was captured. And, oddly, the cheaper the film camera, the more immediate the capture.
With digital cameras the reverse is true: the cheaper digicams may take a second or a little less to capture that magic moment; the more expensive cameras like DSLRs possess almost no shutter lag.
A series of events takes place: first up, the auto focus has to determine and confirm sharp focus; the metering system settles on an appropriate exposure; and finally, the image file is written to the camera’s internal memory or loaded memory card.
How do you lessen shutter lag?
After you’ve composed the picture in the viewfinder, partly depress the shutter button — this will preset the focus point. Then, depress the shutter fully to capture the image. What can also help is to load a faster memory card with a quicker write time.