Underwater Camera Assistant

[LimHKim]

Greetings.....

 

Recently, I was on a shoot that requires underwater camera assistant. Being a clapper/loader in the job, I volunteered for the sake of experiencing and of course I am a diver as well. We were shooting in a man-made pool size of 20ft X 20ft X 6ft height. There was only 1 talent swimming and the camera was locked off at the bottom of the pool.

 

#1 Basically, what is the job descriptions of u/w camera assistant ? Is focusing part of the job ?

 

#2 As objects are magnified 25% in underwater, how to actually do the focusing ?

 

Hoping someone out there can provide me some infomations.

 

Thanks

[Delorme Jean-Marie]

hi

yes, the main part of a camera assistant is to do the focus.

u/w is a bit tricky because the water act as a lens.

to be 100% sure of your focus you'll have to do prior specific camera test.

1) leak test of the housing it looks stupid but i had a leak once on the pendant destryoing all the electronic.(in egypt red sea !!!!)

2) re-write the marks with eye focus on an illuminated chart (full aperture) in a water pipe, for every lens!!!!

3)shoot in a close distance the chart, with a tape mesurment and compare the eye focus and the negative

then you'll know where your focus is.

it may change a bit with the salt density but you shoot in a pool

if you shoot in video, focus with the video feed back and stay dry

have fun

[LimHKim]

Thanks.....

 

 

By conducting a leak test doesn't mean that there will be 100% leak proof during the shoot. There were once I heard the water leaks into the housing was due to mis-handling of the O-ring. O-ring has to really really taken care of and a slight twisted will jepordise the entire shoot. Silicon gel should always come as part of the equipment list.

 

I was told by my senior that 1'0" on land = 0'9" underwater, I guess it's 25% of magnifying. The confusion starts here. What you see underwater and what the camera sees aren't both the same, 25% of magnifying. ? How could it possibly be when the eyes see of the distance of 10 feet and the focus on the camera is put at 9 feet distance ?

 

:blink:

[Delorme Jean-Marie]

an eye chek is thrue the eye piece or video filming the ground glass and what is on the ground glass (if adjusted properly) is what is on the film.

the difference is between mesurment and eye chek

and ALWAYS do your eye chek at full aperture

by

[Laurent Andrieux]

Sorry since I'm packing for moving house I can't check but I remember from school that water has a refraction indice of 1.33 but I guess it depends on the nature of the water, its components etc... I would try to figure out the factor with a long focal length and trust my eye since the ground glass was checked before...