5 questions

[zio]

i was wondering if anybody could answer some of these questions that i have. i've got a test tomorrow and need some help with this review.

1. how does a thyristor control get the right exposure automatically?
2. whats the guide number of an electric flash and its purpose?
3. how do you get correct exposure with manual control of a flash?
4. the zone system by ansel adams?
5. how do you know what shutter speed to use with a flash?

i couldnt comprehend the lecture about using a flash

 

[ksmattfish]

1. how does a thyristor control get the right exposure automatically?
2. whats the guide number of an electric flash and its purpose?
3. how do you get correct exposure with manual control of a flash?
4. the zone system by ansel adams?
5. how do you know what shutter speed to use with a flash?

1) I don't know. I'm sure there's a great explanation on the Vivitar websire.

2) The GN is a measure of flash power. GN (in feet/meters) divided by flash to subject distance (in feet/meters) = f/stop.

3) Use the GN (as in question #2) or the flash exposure calculator/chart built into most manual flashes. On modern TTL flashes that have a manual setting, but no calculator or chart, you can do the GN math and write it on a piece of paper and tape it to the back of the flash for quick reference.

4) Although possibly it's most famous author, Ansel Adams was just one of many who worked on developing (no pun intended) the Zone System. The full Zone System is a method of using very precise testing and control of your materials and previsualization to manipulate contrast, tonal range, brightness, etc... to create a print that is as the photographer previsualized, but not necessarily accurate with reality.

5) You need to be at your camera's flash synch speed or slower. Shutter speed controls the amount of exposure for the background and other parts of the image that don't get flashed.

Most of this stuff is in your flash instruction pamphlet. I'm teaching classes again this summer. The first thing I always tell my students is to read thier equipment manuals every once in a while. Lot's of good stuff in there.