I have a D800, D4, Nikkor 24-70 2.8 and Nikkor 70-200 2.8. A studio light was pointed at a white background that meters f/8 at 1/250 and ISO400 with a Sekonic L-508. Both bodies were set to manual, ISO400, f/8 and 1/250, and both lenses are set to 70mm. One would reasonably expect the exposures to be identical with both lenses, but the 24-70 comes out slightly more than 1/3 stop underexposed on both bodies. The difference can be seen on the LCD, and it's confirmed by the histograms. Explanation?
Thanks. Now it makes perfectly (?) good sense, and it's easy enough to pick up with the histograms. The 1/3 stop difference between the Nikkor's isn't a big deal, but I imagine it could be much more unpredictable with cheap glass.
It's probably not the glass. Shutter speeds for any camera are never exact. You might pick 1/250 but you may vry well be getting 1/200. There was something published about actual versus selected shutter speeds and ISO settings. Being off by a third stop between cameras is pretty good to me.
