 Bernard |
speedlite settings For correct flash exposure do seasoned users actually do the calculations such as: correct flash = distance x apertute divided by ISO factor, or does experiaence make trial and error a faster method of flash exposure adjustment.
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Jon Close |
Can't speak for others, but I use the GN formula just to ball park exposure. Mostly just rely on auto flash exposure from a dedicated speedlight, either TTL (E-TTL for Canon, i-TTL for Nikon, etc.) or the non-TTL auto. Then apply Flash Exposure Compensation to fine-tune exposure (though the programmed exposure usually works for me).
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Bernard |
Thanks Jon very enlightening, I was under the the impression that most experienced users used manual settings most of the time.
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A C |
I've seen pros handle flash in different ways. It depends on what works for you (and on the particular situation). How you want to mix it up with ambient light is a personal preference, so it's gonna vary from photographer to photographer. I love this guy's work: http://planetneil.com/tangents/flash-photography-techniques/ And he shoots Auto with Flash Exposure Compensation.
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Alan N. Marcus |
Hi Bernard, Mr. Close is spot on. If one tests specific situation for best aperture setting, the guide number can be devised by aperture x distance = guide number. Sometimes it is necessary to modify (change exposure) then we apply by multiplication a modifying factor: + 1 stop multiply by 0.7 Example: If guide number for 100 ISO is 120 then for 200 ISO we modify the guide number 120 x 1.4 = 168 etc. Alan Marcus
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Bernard |
Cherylann thanks for the info and link. Alan, I now understand modification of exposure when needed as stated above. also stated above:
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Oliver Anderson |
Bernard, its funny you bring this up because the other night while boozing with another photographer I realized how LAZY I am when it comes to my Speedlights (Canon). He uses 2 580s + 430 and I have strobes so I never really cared to learn how to maximize the Speedlight. I've got a couple 550s so I was reading up on them, I do modify the stops going up 1 or down 1 but these Speedlights are amazing tools and I'm very surprised by what I can do with these little flashes. As powerful a tool as these flashes are I'm surprised at how few people know about shooting with them...E-TTL is the setting of most everyone I know uses.
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A C |
or you could use your flash on camera AND off: http://strobist.blogspot.com/2006/02/welcome-to-strobist.html I use my flash as a strobe from time to time. One of my next purchases will be a set of Pocket Wizards, then I'll use my flash wirelessly and in manual mode even more. k, sorry. I guess this is a bit off topic
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Bernard |
Oliver, cherylann That's very interesting, these speedlite's are very versitalile, I will be puchasing another SB 800, and an infra red remote, I believe it will take me to another level.
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Alan N. Marcus |
How ISO figures in the equation: Guide numbers are published for a specific ISO. Usually based on tests performed using a media positioned at 100 ISO. Read the fine print accompanying your flash unit. If you test yourself, you will also be choosing a specific ISO to work with. Assume in this instance, a published guide number is 160 for 100 ISO media. To figure out what the guide number is for a 200 ISO media, multiply by 1.4 thus: 160 x 1.4 = 224. For 400 ISO we multiply by 1.4 again thus: 224 x 1.4 = 313. I think you get the idea! Please don’t get me wrong, I am an advocate of chip logic and the dedicated flash. Once-upon-a-time we had to place our confidence in solely in guide numbers. Today, chip logic takes the forefront. A modern dedicated flash/camera system uses a sensor to measure, in milliseconds, the intensity of the return (reflection) off the subject. Using this data, chip logic determines the ideal flash duration time based on a pre-selected aperture. This works because the components of exposure are intensity of the illuminating light times time. Stated another way; exposure is the product of light energy accumulated over time (duration). This all happens before you can say “pixie dust”. Anyway, all this black box stuff works like magic and my hats off to the engineers. Alan Marcus
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Bernard |
Well! it's good that I can depend on the logic systems of the speedlite and camera's TTL, and balance TTL mode.I will still study the manual mode formulas, but not with as much urgency. Thanks again.
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