Well, of course you can put the cartridge in the camera first. That means that now you got to pull out film and fiddle it into the take-up spool. Well, since the film is somewhat stiff, and you already set a constraint, things are more complicated from here on, in particular since now the perforations have to be matched to the film sprocket. This way, and this is what you can see on those videos, people make sure that all is fine by cranking some frames just to watch the film exposing and winding on the take-up spool.
No, I am not going to shoot a video, not yet...
However, here is how I load a film (assuming the usage of a camera in which the film cartridge goes into the left hand side).
- hold the (open) camera in the right hand
- pull out the cartridge axle
- press the film rewind button for a free-wheeling sprocket
- hold the film cartridge in the left hand between palm and middle finger, ring finger and pinky
- hold the film leader with thumb and index finger
- now you have all the dexterity to smoothly insert the film into the take-up spool's retaining mechanism
- with the thumb of the right hand, hold the film in the take-up spool's retaining mechanism
- gently pull the film across the sprocket (it will self align, since it is free) and across the exposure chamber, using your left thumb as a brake
- gently slide the cartridge into it's place
- now, hold the camera with your left hand, the thumb still resting on the film, this will ensure no unwanted movement
- with the right hand, gently push in the cartridge axis
- with the right hand, very gently (!) crank the film "back", i.e. into the cartridge, in order to straighten out the film - if the film does not slip out of the take-up retention mechanism all is fine
- now close the camera
- crank forward 1 frame (which will be partially exposed during the loading) and observe if the backwinding crank moves correctly and the rewind button pops out
It also is the most economical method, usually it get's me about 40 full-frames and 81 half-frames from 1 shop-bought cartridge. (With the BelOMO Agat 18k this method will result in 82 half-frames).
I already mentioned one less common camera, the Agat 18k. There are other cameras (in my collections) such as the Argus C3, which may require either taken 'em up-side down of reversing the hands. I tend to just use the other hand...
Just remember, the cartridge goes in last!
PS: Wow, I found 1 video explaining film loading the correct way:
Congrats to expert village!
PPS: Unbelievable... the same channel: