D7000 - Strange behaviour when Movie manual settings is ON

[bernieraffe]

Something a little weird happened today with my D7000, and I eventually discovered it was caused by the Movie manual setting being switched ON. Here's the scenario:-

1. Using a variable aperture lens, say F3.5 to F5.6
2. Set camera to Manual
3. Shutter speed say 50th at F8, ISO 100
4. Auto ISO off.
5. Zoom out on lens to widest setting
6. Go into Live mode.

Now, when I zoom in I can see the aperture start to close down, F8 to F11, then F16 and then F22. When I reset the lens to the wide setting, start recording and then zoom in, the end of the film (where I'd zoomed in), is underexposed.

The problem doesn't occur when the Movie manual setting is OFF and the aperture remains at F8.

Obviously the aperture would change if it was initially set to F3.5, but not at F8! Anyone understand what's happening here?

Cheers,
Bernie

 

[Blackpeppers]

This is caused by the ramping of lens which can't be compensated in LiveView (no control over the aperture).

Check on the internet for more details. You can't do anything, except avoiding zoom when you are in LV or buy a fixed aperture zoom lens.