P8
Film and Digital
--
Angle of View and Focal Length
Film : 300mm
Digital : 200mm
Digital : 50mm
Film : 78mm
Digital : 18mm
Film : 28mm
*Film = 35mm format.
Telephoto
7˚59'
Standard
31˚11'
Wide 75˚33'
*Digital = Digital cameras with smaller-size imagers.
P7
Designed to fit smaller-size image sensors
in order to reduce its diameter
General
Image sensor
*When pictures taken with a
Di-II lens mounted on a 35mm
film camera or digital SLRs
with image sensor larger than
24mm x 16mm, image corners
become dark
( ie., vignetting
becomes noticeable).
Image circle
for Di II lenses
Vignetting when used
with a 35mm format camera
35mm Film
When designing a lens having a short focal length range (when designing a
wideangle lens), the diameter of the lens inevitably becomes large. However, in
designing the 18-200mm Di II lens, Tamron has successfully solved this problem
by using an image circle designed to match that of general image sensor (smaller-
size image sensor), achieving almost the same compactness as the 28-300mm
lens (A061), which offers the same angles of view produced in 35mm film format.
36mm
24mm
about 23.2mm
about 15.5mm
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