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tests done for max flash power -SB900 SB700 yongnuo 560III
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<blockquote data-quote="WayneF" data-source="post: 316324" data-attributes="member: 12496"><p>Don't get that started, but it really does not seem awesome to me. In one way, flash is just a light we add. Yes, if we don't know nuthin', and can only use point&shoot, sure, it all must seem very hard and mysterious. Things happen, and we have no clue why. But if we understand exposure (how and why and when to use ISO, aperture, shutter speed), then daylight and continuous light is not very mysterious at all. Even the reflective meter can be handled if we think about it. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /></p><p></p><p><cynical view> Yes, it does require we think about it a bit (which point&shooters seem unwilling to even attempt to do). It seems right that our grandmothers can use their little cameras by just pushing the button, but avid amateurs and esp pros charging money for their skills, ought to actually acquire a few skills. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /> Adding flash is just one more light. Yes, flash is a little different than continuous, and it really won't ever actually be point&shoot, but its easy to understand how to use it... If we care to try. It seems most won't even try.</p><p></p><p>My point of reference is that this is also true of my own experience. I went very many years, active, buying lots of bulk film, acquired some dark room skills, etc, imagined I knew a lot, but without ever actually knowing anything about the camera or the process. I could parrot back some facts, but it was not working knowledge that I had learned to use. Back then, cameras had no menus, the only controls were shutter speed and fstop, but I really knew nothing about it except how to center the camera meter. I simply was an unthinking novice for very many years. Then one day, I finally started wondering, how does this stuff actually work? And paid more attention and thought a little bit. Then, regarding the basics, it all became easy, the light came on, things changed. With really very little effort. The difference was, there was finally some effort.</p><p></p><p></p><p></p><p>The flash A mode was pretty good stuff, and it can still work well, like it always did, but TTL has become todays option. The main difference is that the flash has a wider light sensor, often around 35mm lens wide, used for any lens in every situation. And the camera TTL does offer more, to meter the same view the lens sees (be it wider or more narrow), and adds features like Spot or Matrix metering, and provides the computer to add features like flash balanced with ambient, etc. </p><p></p><p></p><p></p><p>That's backwards from my expectations, but its always good to know for sure.</p><p></p><p></p><p></p><p>No way to know without knowing the distance you used, comparing it to what the manufacturer says it should do. If you were are at 1 meter, it did not do well, but no way for me to know, you didn't say. Flashes will of course meter at a weaker level if at a greater distance.</p><p></p><p></p><p></p><p>No, it is not wrong at all, just not fully useful. To compare, obviously all flashes have to be at exactly the same distance, but how hard is it to carefully measure and set and tell that distance? Because, if unknown, there is no way to evaluate if it is reasonable result or not. Me, I like to know more details so I can wonder about more things. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /> So you can use any reasonable distance, but I'm suggesting to know that distance, to spend a minute verifying the distance between flash and meter is some specific number (like 2.0 meters). Some specific number adds meaning in regard to flash power.</p><p></p><p>All the flash manuals have a detailed Guide Number chart, typically at the back of the manual. This is how direct flash works.</p><p></p><p>SB-900 says (page F-19) at full power, ISO 100, FX mode, 35mm zoom, the GN is 111.5 (feet) or 34 (meters). I use feet, but I suspect you use meters. Same result, so long as we are consistent. GN in feet is always 3.28 times GN in meters (because that's how many feet in one meter).</p><p> </p><p>That means that proper exposure of direct flash is expected to be:</p><p></p><p>1 meter .... GN 34 / 1 = f/34</p><p>2 meters ... GN 34 / 2 = f/17</p><p>3 meters ... GN 34 / 3 = f/11.3 (BTW, what we round off to call f/11 is actually precisely f/11.3... matters in GN computations).</p><p></p><p>If you're at 2 meters and meter it 1/3 stop off, that's not much surprise, things vary, esp our procedure.</p><p>If you're a full stop off, that is something to wonder about.</p><p>If you don't tell us distance, it's not much to know, and we have no clue what it means.</p><p></p><p>The SB-700, 800, and 900 have the GN mode which uses this chart (and which can be pretty accurate). The hot shoe sees the ISO, aperture, and zoom, and then we can enter the measured subject distance, and the mode will set manual flash power level to deliver the correct exposure for that distance, from this chart. This mode has advantage of being independent of the subjects color (white dress, black dress, etc), which tends to fool TTL metering.</p><p></p><p>Elaborating because I assume you are interested:</p><p></p><p>For example, without taking any picture, just put the SB-900 on the hot shoe (at some ISO, fstop/ zoom - any values, not extremes of anything - just don't change anything).</p><p></p><p>Then in flash GN mode, enter 2 meters or 10 feet, or some distance, or simply just use the distance it already shows.</p><p></p><p>What distance does it show?</p><p></p><p>Then try same everything with the SB-700.</p><p></p><p>What distance does it show?</p><p></p><p></p><p>These two distance numbers show the expected power relationship that Nikon designed into the flashes. They won't be equal numbers for a SB-900 and SB-700.</p><p></p><p>The way it works, if you enter closer distances, it reduces the flash power to be correct for that distance.</p><p>If you enter greater distance number, it increases flash power until it reaches maximum, and won't increase any more.</p><p></p><p>If the distance was reasonable for the scene, and if you did take two pictures here (of the same scene), they should compare well as to proper exposure.</p><p></p><p>Whatever those distance numbers are... multiply the distance by the fstop number, which will be the Guide Number. </p><p> It should approximately match the number in the GN chart for same ISO and zoom values.</p><p></p><p>For example, my SB-800... ISO 100, zoom 35mm, says at maximum distance of 12 feet at f/10, so GN is 12 x 10 = GN 120.</p><p>The chart in the manual says full power at 35mm is GN 125. There is rounding involved, so this is pretty close to actuals, not a concern.</p><p></p><p>Hope that is of any interest.</p></blockquote><p></p>
[QUOTE="WayneF, post: 316324, member: 12496"] Don't get that started, but it really does not seem awesome to me. In one way, flash is just a light we add. Yes, if we don't know nuthin', and can only use point&shoot, sure, it all must seem very hard and mysterious. Things happen, and we have no clue why. But if we understand exposure (how and why and when to use ISO, aperture, shutter speed), then daylight and continuous light is not very mysterious at all. Even the reflective meter can be handled if we think about it. :) <cynical view> Yes, it does require we think about it a bit (which point&shooters seem unwilling to even attempt to do). It seems right that our grandmothers can use their little cameras by just pushing the button, but avid amateurs and esp pros charging money for their skills, ought to actually acquire a few skills. :) Adding flash is just one more light. Yes, flash is a little different than continuous, and it really won't ever actually be point&shoot, but its easy to understand how to use it... If we care to try. It seems most won't even try. My point of reference is that this is also true of my own experience. I went very many years, active, buying lots of bulk film, acquired some dark room skills, etc, imagined I knew a lot, but without ever actually knowing anything about the camera or the process. I could parrot back some facts, but it was not working knowledge that I had learned to use. Back then, cameras had no menus, the only controls were shutter speed and fstop, but I really knew nothing about it except how to center the camera meter. I simply was an unthinking novice for very many years. Then one day, I finally started wondering, how does this stuff actually work? And paid more attention and thought a little bit. Then, regarding the basics, it all became easy, the light came on, things changed. With really very little effort. The difference was, there was finally some effort. The flash A mode was pretty good stuff, and it can still work well, like it always did, but TTL has become todays option. The main difference is that the flash has a wider light sensor, often around 35mm lens wide, used for any lens in every situation. And the camera TTL does offer more, to meter the same view the lens sees (be it wider or more narrow), and adds features like Spot or Matrix metering, and provides the computer to add features like flash balanced with ambient, etc. That's backwards from my expectations, but its always good to know for sure. No way to know without knowing the distance you used, comparing it to what the manufacturer says it should do. If you were are at 1 meter, it did not do well, but no way for me to know, you didn't say. Flashes will of course meter at a weaker level if at a greater distance. No, it is not wrong at all, just not fully useful. To compare, obviously all flashes have to be at exactly the same distance, but how hard is it to carefully measure and set and tell that distance? Because, if unknown, there is no way to evaluate if it is reasonable result or not. Me, I like to know more details so I can wonder about more things. :) So you can use any reasonable distance, but I'm suggesting to know that distance, to spend a minute verifying the distance between flash and meter is some specific number (like 2.0 meters). Some specific number adds meaning in regard to flash power. All the flash manuals have a detailed Guide Number chart, typically at the back of the manual. This is how direct flash works. SB-900 says (page F-19) at full power, ISO 100, FX mode, 35mm zoom, the GN is 111.5 (feet) or 34 (meters). I use feet, but I suspect you use meters. Same result, so long as we are consistent. GN in feet is always 3.28 times GN in meters (because that's how many feet in one meter). That means that proper exposure of direct flash is expected to be: 1 meter .... GN 34 / 1 = f/34 2 meters ... GN 34 / 2 = f/17 3 meters ... GN 34 / 3 = f/11.3 (BTW, what we round off to call f/11 is actually precisely f/11.3... matters in GN computations). If you're at 2 meters and meter it 1/3 stop off, that's not much surprise, things vary, esp our procedure. If you're a full stop off, that is something to wonder about. If you don't tell us distance, it's not much to know, and we have no clue what it means. The SB-700, 800, and 900 have the GN mode which uses this chart (and which can be pretty accurate). The hot shoe sees the ISO, aperture, and zoom, and then we can enter the measured subject distance, and the mode will set manual flash power level to deliver the correct exposure for that distance, from this chart. This mode has advantage of being independent of the subjects color (white dress, black dress, etc), which tends to fool TTL metering. Elaborating because I assume you are interested: For example, without taking any picture, just put the SB-900 on the hot shoe (at some ISO, fstop/ zoom - any values, not extremes of anything - just don't change anything). Then in flash GN mode, enter 2 meters or 10 feet, or some distance, or simply just use the distance it already shows. What distance does it show? Then try same everything with the SB-700. What distance does it show? These two distance numbers show the expected power relationship that Nikon designed into the flashes. They won't be equal numbers for a SB-900 and SB-700. The way it works, if you enter closer distances, it reduces the flash power to be correct for that distance. If you enter greater distance number, it increases flash power until it reaches maximum, and won't increase any more. If the distance was reasonable for the scene, and if you did take two pictures here (of the same scene), they should compare well as to proper exposure. Whatever those distance numbers are... multiply the distance by the fstop number, which will be the Guide Number. It should approximately match the number in the GN chart for same ISO and zoom values. For example, my SB-800... ISO 100, zoom 35mm, says at maximum distance of 12 feet at f/10, so GN is 12 x 10 = GN 120. The chart in the manual says full power at 35mm is GN 125. There is rounding involved, so this is pretty close to actuals, not a concern. Hope that is of any interest. [/QUOTE]
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tests done for max flash power -SB900 SB700 yongnuo 560III
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