Aperture behavior on Zoom lenses (24-85mm VR)

Started Jan 28, 2013 | Discussions thread
OP Deleted-pending Senior Member • Posts: 2,665
Re: Aperture behavior on Zoom lenses (24-85mm VR)

kiirokurisu wrote:

Are you setting the aperture to 5.6 before entering live view? Otherwise it would still be at 3.5 when starting to record and close down to 5.6 which would result in the darkening you observe.

If the above is not the case, then my theory would be that the aperture lever position for f/5.6 is different at different zoom settings of the lens. Since the camera can't/won't adjust the aperture during live view, the lever stays in the same position and the effective aperture changes. This is only a theory of course, I don't have any variable-aperture lenses to test it on. You could check if this is happening by looking in the front of the lens during live view zooming in and out and see if you notice the aperture blades moving or not.

Yes I set the aperture as F5.6 and even F8 before entering Live view - however, it is really hard to tell if the aperture blades are moving or not with the lens on, they are located behind a dark plastic circle, with the lens off, the aperture lever goes back fully open. For information, I tried it on my Sigma 10-20mm, Nikon 18-70, 24-85mm VR and 18-300mm VR, they all behave the same. The only one who doesn't close back is the tamron 17-50mm 2.8 VC...

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