N3T20 T-Adapter
The N3T20 and the larger N3T30 t-adaptors are designed to correct a couple of different issues. The first is to allow the user to align the centre of the entry pupil along the horizontal axis for cameras with ‘off centre’ tripod mounts.
Most DSLR cameras have the tripod mount point directly inline with the centre of the lens, however some compact and bridge cameras have it offset to one side which would prevent the correct alignment of the entrance pupil. By using the t-adaptor you can easily correct for these circumstances. The second use is give more ‘front to back’ offset by effectively extending the length of the arm on the NN3. This is imperative for a camera/lens combination if the lens is longer than ‘normal’ (some wide and most zoom lenses) and where for once, the small size of the NN3 actually doesn’t work in its favour.
Photo by Rosauro Ona
In my setup with a Canon 20D and 17-40L lens, due to the end of the Canon lens being quite wide and standing taller than the camera itself (forcing the camera to point upwards slightly) it was impossible to get the correct alignment without using the t-adaptor. It was used to increase the distance between the camera base and the arm of NN3 giving ample clearance for the end of the lens. This setup allowed me to attain the required perfect horizontal alignment. See picture below
Tadaptor utilised to give clearance for the wide 17-40L lens
It is also possible to use the NN3 with quick release brackets, although this is an optional extra it will obviously make both setup and break down easier and even quicker.