Cinematography, Lighting, and Composition - Frame-by-Frame Stop Motion: The Guide to Non-Traditional Animation Techniques - page 67

There is another reason why exposure fluctuation occurs: Most digital still
cameras have automated lenses that often come with the camera. When
an iris is set on a camera, in manual or automatic mode, the iris shuts down
to that f-stop when the shutter exposes then opens back up so the viewer
can see through the viewfinder. The open iris allows more light in for better
viewing. If an animator is shooting hundreds of frames, there can be a slight
variation in the iris aperture when it shuts down and opens up over those
numerous frames, and that can account for the slightly varying exposures.
There are a couple of solutions to this issue. One is to use manual lenses that
lack the capability to open and close for viewing every frame. They stay in
their set position all the time. Another solution, which I do not recommend,
is filing down the pin in the lens that triggers this action in an automatic lens.
Some camera operators use tape to hold down the pin on the back of the lens
that engages these automatic functions. These are not elegant solutions but
are practiced in the field. One advantage to using a Canon camera with Nikon
lenses is that the adaptor that allows the Nikon lens to work with the Canon
camera depresses that control pin, eliminating any unwanted functions.
Finally, postproduction solutions can help reduce this fluttering. We get into
this last option later in the topic.
Fig 5.2 Drawing of an open and
a semi-closed iris.
There is always a preference for “prime” lenses, which are single focal range
lenses. They have less glass in the lens, theoretically making for sharper images
with less distortion. Zoom lenses, which often come with new cameras, are
quite well made these days. Their image quality is excellent. They also have a
larger set of options for focal range for the price of the matching prime lenses.
Having a set of prime lenses, including 18 mm, 24 mm, 35 mm, 55 mm, 85 mm,
and 105 mm/macro, gives you everything you need for making a successful
film, but if you cannot afford them, a zoom that ranges from 18 mm to 135 mm
should work quite well. If you buy a certain brand of lens and decide to use
another brand of camera, there are lens adapters so you can mix and match.
Many professionals, these days, use Canon cameras and Nikon lenses, but
other combinations work as well. Canon, Nikon, and Carl Zeiss are considered
excellent brands for lenses, but as usual, there are many more.