Canon Model 7S - Manual (Page 74)

and outer shell slots should be superimposed.
Turn the inner shell counter-clockwise until it
clicks into a locked position.
6. When the film magazine is properly loaded
and locked, draw out the film and trim it, as
illustrated.
• This procedure must be done in a dark
room or under safe lighting conditions.
• Keep the magazine in its case when loaded.
• Keep the magazine clean.
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