New to Z mount Wide Angle Question

[Scubalens]

Sorry for what I am sure is a stupid question and I know I have much reading to do to learn this new camera. However need help for this question out of the box. I went through the transition from Film to Digital DX 15 years ago, but now just received my first Z mount camera (Z8) returning to Fullframe. I ordered the FTZII converter and the Nikkor 8-15mm to replace the 10.5 dx used on my D300. If I zoom out more than 12mm the frame is not filled and just a small circular image at 8mm, I popped on my 24-80 lenses also with converter and at 24mm the corners are very slightly rounded off. I thought the camera might be on DX mode but when I found the setting in Menu it appears to be FX 36x24. Any help is appreciated.

 

[Barmaglot]

This is by design. At 8mm, this lens is what is called a circular fisheye, projecting a full 180 degree hemisphere onto a circle on the film/sensor, surrounded by black. Some people like this look, many don't. If you don't want it, and would like the ability to zoom in for a tighter shot, you can add a Kenko Teleplus HD Pro teleconverter, either the 1.4x version that will give you approximately 11-15mm accessible zoom range, or the 2x, which will turn the lens into a 16-30mm fisheye. Both will lose some resolution and light.

 

[jezscuba]

Sounds like you've got quite the setup there! I'm not super familiar with the Z8, but from what I understand, the circular image at 8mm is normal for that lens. Have you tried playing around with different focal lengths to see where the sweet spot is for your underwater shots?