Conclusions

From these tests, one can conclude that the lag time, between firing the shutter and capturing the image, is variable according to what camera and lens is being used, the aperture selected, the focal length of the lens, the focus distance and any adjustments in focus. Whilst under test conditions it is possible to somewhat predict might happen at a given aperture, with a given lens, at a certain focal length and focus distance, the huge number of variations and combinations of these parameters made it impossible to come up with a general rule to allow one to predict the lag under normal shooting conditions. It is unclear what is happening to cause this extra delay after a focus adjustment, but the audible noise that can be heard from the lenses give some clue that there is some extra mechanical activity taking place before exposure at the time the lag is greatest. Whether or not this lag variation can be resolved for the affected lenses, in this case the 35mm, 56mm and 60mm, through a firmware update is not clear. The internal design may actually make it necessary to have such variable delays. However, it seems possible that there may in fact be some way to improve the performance, eliminating the extra delay, by not reacting to the focus adjustments, since these adjustments do not seem necessary in the 18mm and 18-55mm lenses…..

Source: www.dpreview.com

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