How to set the GN of S&S Ys-27dx?
- Thread starter travelem
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gert7to3
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The guide number (GN) is simply a means of indicating the maximum amount of power that the strobe can produce. Its primary use is now a means of comparison among strobes. There are formulas using GN's to determine exposure based on distance to subject. Remember that underwater GN's are 1/2 to 1/3 of the land based values. Also be aware that the distance figure could be either feet or meters. Just be aware of this if you want to make calculations.
Guide number - Wikipedia, the free encyclopedia
For an illustration of the control location, find the product page for the YS 27 at:
Sea & Sea USA - Underwater Photography Cameras & Video
There is a dial on the lower back right side of the strobe. There will be no set level for this control, though you are correct in noting that is is mostly distance sensitive.. You will most likely take a picture, check exposure, then correct and reshoot for the subject if necessary. Remember that a light colored subject on a light colored background will need much less exposure than a dark subject/dark background. The histogram function on your camera might help determine proper exposure.
Use your manual exposure mode if available. Set ISO from 100 to 200; set your aperture high ƒ5.6-ƒ 8.0. Without your strobe on, take a couple of photos of the general water scape at your depth. Adjust your shutter speed to obtain a pleasing background color (faster is darker/more underexposed). Finally use your strobe control to get the right exposure for your subject.
We'll see how many corrections I get.
Guide number - Wikipedia, the free encyclopedia
For an illustration of the control location, find the product page for the YS 27 at:
Sea & Sea USA - Underwater Photography Cameras & Video
There is a dial on the lower back right side of the strobe. There will be no set level for this control, though you are correct in noting that is is mostly distance sensitive.. You will most likely take a picture, check exposure, then correct and reshoot for the subject if necessary. Remember that a light colored subject on a light colored background will need much less exposure than a dark subject/dark background. The histogram function on your camera might help determine proper exposure.
Use your manual exposure mode if available. Set ISO from 100 to 200; set your aperture high ƒ5.6-ƒ 8.0. Without your strobe on, take a couple of photos of the general water scape at your depth. Adjust your shutter speed to obtain a pleasing background color (faster is darker/more underexposed). Finally use your strobe control to get the right exposure for your subject.
We'll see how many corrections I get.
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