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

["Rick Strong" <rnstrong primus ca>]

If I read you right, you will be time exposing the cave overall.
I'd suggest starting with ISO 200 to keep the noise down and the time 
exposure relatively short. Switch "on" long exposure noise reduction if you 
have it on your camera.

Then you want a short-duration shot of someone to:
"freeze the person when jumping into the water (in the air mid-jump). "

Is there water in the cave that they will be jumping into? If so, just 
expose a hand-held flash during the jump during the long exposure. Set it to 
work with your max f-stop, or whatever f-stop you will be using, and at the 
distance the jumper will be from the flash.

Otherwise, I guess you will have to photograph the jumper either in a dark 
swimming pool or at a lake at night, again using flash and a short duration 
speed (1/200/sec, 1/250/sec). You may have front/rear curtain adjustments 
that allow you to show motion trails. See your camera manual.

Good luck,
Rick S.



-----Original Message----- 
From: mikej411
Sent: Friday, February 24, 2017 1:45 PM
To: gimp-user-list gnome org
Cc: notifications gimpusers com
Subject: [Gimp-user] Add frozen object from short exposure frame to long 
exposure frame

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)
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