the only time i noticed any lag was when i was shooting from a train trying to time the shot through a break in the trees. but then again, that perceived lag might have just been my reflexes being too slow.
other than that, no noticeable lag with either LCD or EVF and with or without auto-preview. i don't sense my E-M5 to be slower than my D7000 either. having said that, there is a lag for sure, as all cameras have, but not to the degree being described here.
this info might be useful:
Olympus OM-D E-M5 Camera Performance - Initial Test
note the "Prefocused" lag of 0.056s which is fast and compares well with 0.053s for the D7000 and is faster than the 0.072s of the GX1.
and just for fun, try this:
Human Benchmark - Reaction Time Test
i was pretty much on the par with the average at 0.22s, and the one time i got 0.13s was when i was using my jedi premonition skills
so reaction time is nearly 4x longer than shutter lag. technicalities aside, this means one is unlikely to perceive shutter lag unless shooting something really fast, or is moving really fast (like i was on the train).
this leaves some possible scenarios for the perceived lag: A) reflex- you clicked the shutter later than you think you did or B) the perceived lag includes AF lag and not just shutter lag or C) your camera does indeed need servicing
expounding on the possibilities for B:
B1 - you half-pressed but the AF didn't actually engage. hence at full press the total lag is AF lock + shutter lag
B2 - you half-pressed, the AF engaged but wasn't locked yet (no beep or green dot) when you did full press. hence total lag either included remainder of AF time to achieve lock, or the camera restarted on the AF before firing
B3 - you half-pressed, achieved AF-lock, but unknowingly lifted your finger (or eased off the pressing). hence camera again did the whole AF lock sequence before firing
note that all the other shutter response times (from the link earlier) involving AF (straightaway full press, no half-press) are longer (~1/4 to 1/5 s), and this i think is noticeable. also consider that AF speed is dependent on the lens and lighting (eg. shooting children indoors, AF is slower due to less light).
so, to test and isolate whether your perceived shutter lag is actually involving AF, please try the following:
- set camera to shutter release priority
- enable audio beep on AF lock or just make sure the green AF dot is on (and stays on) when you full press
- shoot something moving. nothing too fast and preferably something that stays in the frame while you AF-lock eg. a pendulum, or the second hand of an analog clock
and to test whether it's your shutter button that's faulty/sluggish, set the camera to manual AF, focus, then use the touchscreen to trigger.
good luck!
