Is this lens faulty? SEL1670z (broken aperture?)

Started 11 months ago | Questions thread
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lazerin88 New Member • Posts: 2
Is this lens faulty? SEL1670z (broken aperture?)

I have just received a Sony refurbished Zeiss 16-70mm SEL1670z and tested it on my Sony a5100.

My camera is on the latest firmware v 3.10. The lens is v.01.

It is hard to describe the fault with the lens succinctly, thus I have recorded a video to demonstrate what I mean.

I am not sure exactly what the fault is but essentially the lens doesn't seem to have the correct aperture after repeated zooming or is not exposing correctly.

When I first turn on the camera, it functions correctly. When I adjust the focal length to full tele and back a few times, the image becomes several stops darker. This can be seen with the increasing shutter speed. In the video, you can see that the image starts at 1/60 shutter speed, then by the time I've zoomed in an out a few times, this is now significantly slower.

I am demonstrating this on Program mode first, then auto, then aperture priority mode.

This happens without adjusting any settings. This happens on all the different shooting modes (though I only demonstrated Aperture priority and auto). On shutter priority the image just becomes black and completely under exposed. For what it's worth, the zoom ring seems to stutter at times as well.

The environment lighting does not change in the video.

It seems like the aperture control is broken or lacking behind but I really have no idea. It just doesn't seem right. I don't have this problem on my SEL1650, nor my SEL55210.

The video is too large to upload so here is the shared link:

Would love to hear what your thoughts are? Will be calling Sony in the morning as well.

This question has not been answered yet.
Sony a5100
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