[Gimp-user] Add frozen object from short exposure frame to long exposure frame

[mikej411 <forums gimpusers com>]

Hello, I'm not sure if I am posting this on the forum, or if these are support
messages? If I am not posting this in the correct area, please feel free to move
this for me, or let me know what area I should post if to...

I am going on a trip to the Yucatan in May and want to take good pictures inside
some of the Cenotes (sinkoles that expose groundwater underneath). Some of these
cenotes are underground with not much light (Beams of light from the sun come
through from the holes at the top of the cave, and some stationary artificial
lighting is provided from the people who work at these caves as well).

So my plan is to use my Rokinon 12mm f2.0 with my Sony A6000 on a tripod and set
it to max aperture and long exposure, with maybe ISO of about 400 to 800. Do
those settings sound about right to get some good low-lit cave pictures? Would
there be any reason to lower the aperture? Keep in mind, I do not plan on going
any further and setting up external light sources, etc. The cave should be lit
enough to be able to grab a decent picture with long exposure.

Anyway, the more important question or concern I have comes into play when I
want to get some action shots or get a person into that long exposure photo,
i.e. freeze the person when jumping into the water (in the air mid-jump). I
think the only way to do that is with a computer program using layers or masks,
correct? I don’t want to purchase anything, and I think this can be accomplished
with GIMP on my Macbook pro.

Last night, I tried masking myself out of a picture (or whatever the term is),
but it was very hard to do in terms of being precise. I tried to fiddle around
with the lasso and the different detections (color/shape/contrast), to no avail.
Maybe part of that was because I was on a small laptop without using a mouse.
But I think most of it was because I am an extreme beginner and this is my first
time playing around with phot editing tools.

Can someone please point me to some detailed Gimp tutorial videos either showing
how to accomplish exactly what I want from start to finish (Add the frozen
person from the short exposure frame to the long exposure frame), or if you
don’t know of a video that explains all of that, then maybe some tutorials on
something similar, like how to precisely mask out people.





-- 
mikej411 (via www.gimpusers.com/forums)