AF100 Zooming Image Gets Darker ? ?

[Erik Naso]

As you zoom in your going to loose light. Even ENG lenses act like that.

Blog https://www.eriknaso.com
My Vimeo Page https://vimeo.com/user626030
Follow me on Twitter @ErikNaso

[Noah Kadner]

Also if it’s not a fixed focal length zoom it will change f-stop as you zoom through if you’re wide open. i.e. don’t be surprised…

Noah

Call Box Training.
Featuring the Panasonic GH2 and Panasonic AC160/130.

[Matthew Sonnenfeld]

That lens specifically is a f3.5-f5.6. I.E., as you zoon from 18mm to 55mm the aperture closes from an f3.5 at the wide end, to a f5.6 at the long end. This is roughly a stop and a half of light loss.

While it is happening on your Nikon as well, you notice is more on your AF100 because sensors are more sensitive to varying stops than your eye is. As in, your eye has such great dynamic range that a stop and a half of light loss doesn’t really matter to it, but to a sensor with roughly 11 stops of dynamic range (being generous), a stop and a half is a BIG difference. That’s why you see it in the EVF and on the LCD of your AF100, but not through the optical pentaprism of your Nikon.

Blackmagic Cinema Camera, RED Scarlet-X, Panasonic HPX170, Canon 7D
2011 Macbook Pro 17″, 2.3 Ghz Quad Core, 16GB RAM
AJA IoXT
Adobe Production Premium CS6, Avid Symphony 6, Final Cut Pro Studio 3
The College of William and Mary

[Henry Panniell]

Are you saying I have to stop asking for my money back ! ! ! – Seriouly . . . Thanks everyone for the replies and explanation. Sound correct to !

Thanks – God Bless

Henry

[Allan Klingler]

I have observed the same phenomenon with my AG-AF100A, it can be an abrupt change in the darkness level. The same can happen with abrupt scenery pans.

———
Professional videography since 1996
https://www.tetonvideo.com