Test if the back focus is properly adjusted – Nikon Image Converter User Manual

Page 27

Advertising
background image

27

If the image does not appear as sharp as expected, there is a back focus adjustment on the relay.
But before we change the setting of the back focus it is important to realize that the image
photographed by the camera is generated on the focus screen inside the Mini35. This focus screen
lowers the contrast of the image somewhat in a way similar to the effect of a low contrast filter. This
is desirable since it removes some of the electronic detail artifact typical in a DV image, even
though at a quick glance the image may appear less sharp than the one recorded by the unfiltered
original lens.

Test if the back focus is properly adjusted
Place the camera with the Mini35Digital image converter mounted with a 35mm lens, in front of a

high quality test definition chart, such as the Putora 7A9 chart. The iris on the relay should be fully
open. The film lens should be focused by eye to the point of best resolution (highest number of
circles visible on the Putora chart). Without changing anything else, close the iris of the relay a
couple of stops. The resolution should not visibly increase. If it does, the back focus of the relay
needs to be adjusted. Follow the steps below to adjust the relay back focus.

S
O
N
Y

Advertising