Question on RTI and Cave (Dark environments)

[dempseyg]

I am considering using RTI in a research project this summer.  The location is a natural limestone cave 37m long and about 6.1m in height and c.2m wide.  There is a man made entrance to the cave in the form of a Souterrain (drystone lined tunnel)  there is a small amount of natural light in this section at the opening where I hope to record some carvings. 

 

Within the cave there are some carvings in the rock face which I also hope to record.  Using flash photography within the cave produces mixed results in images, and due to the small width can cause the carvings to be covered by flash photography.  I am wondering if the flash element of RTI could be replaced by a stationary light source which could be rotated around the camera? 

 

Any advice or suggestions on previous work would be appreciated

 

Gary.

[cdschroer]

He have shot quite a bit of rock art and also in some caves.  I'm not sure what problem you are having use flash units in that environment.  For RTi it is critical that everything be totally locked down in manual mode, the camera, the autofocus on the lens, and the flash unit (if you are using flash)  Flashes should be in manual mode, with a wide spread (on the Canon speedlites  that is 24mm)  If you are getting too much light for the situation then turn down the power on the flash unit.

 

To answer the actual question about using other kinds of lights besides flash units, technically the software for RTI does not care what type of light was used as long as you can move the light into the needed positions, and it is even across the surface you are shooting from the required stand-off. 

 

I encourage you to thoroughly read the Guide to Highlight Image Capture version 2 which has a lot of information about setups, illumination choices, etc.  You should watch the videos found on that page as well.

 

The most difficult issue we have found in cave environmnts is the cramped spaces requiring some modifiation to the lens choice and the light distance and how big of an area we can image.  There are trade-offs for these things (like most things in life)

 

Carla