switching to slo-mo in mid shot

[woods01]

On my camera there is a slow motion button
which is made to be pressed while shooting
at a standard frame rate. (my camera has 9,
18 and 24 fps). I think the slo-mo speed
is 54 since that seems to be the standard
on other cameras.

My question is if I switch from 18 fps to
slow motion how should I set my exposure?

I am thinking of leaving it on auto although
my experience is the auto setting is one stop
off when I shoot tri-x. The shot involves a
baseball player 18fps as he steps up to the
plate. 54 when he raises the bat and prepares to swing then back to 18 for the actual swing.

[mcarter4121]

Shoot him different times at bat and combine in post. Change camera angles between shots. Use one setting for each shot. Or, adjust the asa setting to compensate for the difference in the light meter.

[Matt Pacini]

What camera do you have?
There is no standard slo-mo speed.
Many cameras are different.
I think you will only be able to do this using auto-metering on a S8 camera.
Many cameras have a "under or over" exposure feature, meaning, you can still have your camera set to auto, but you can set the camera to over or underexpose.

Matt Pacini

[dr.sanchez]

I've done this very trick. On my Nizo, which has a 54 fps button, I tried this with a tennis player--switching to slo mo mid-serve. It came out OK in the autoexposure mode with Plus X (asa 50?) film. I did notice a slight change in exposure though, with the slomo part slightly under-exposed, which is what you might expect with such a fast shutter speed.

It's a pretty cool effect, though.

[woods01]

I've got a Bell & Howell MS 45. Sadly I don't have
a manual so I have no information on the the frame
rate for the slow motion button. I guess it is
either 36 or 54 fps. I am sure the button is made
to be used in mid shot because its positioned on
the camera in a handy spot that can be easily
found on the fly. Where as rates for 9, 18 & 24
fps are on a seperate switch. I'll have to try
it in auto and see how it works out. It would be
a cool effect to add to my bag of tricks if it
exposes o.k.

[mcarter4121]

My Sankyo 660 caught a crow taking off by switching from 18 to 36fps and worked perfectly. Just do it.