sunnym1

<p>I like to photograph flowers outdoors. But lack techniques and practices. Please give me any tips of get a black background when photograph flowers without the help of the black card or other assistant tools.</p>

<p>Thanks to all! I am a beginner and eagerly want a comprehensive understanding of the guide number.<br>

"With a zoom head the GN changes slightly as the coverage angle of the flash changes - but probably not as much as is stated in the flash maker's manual". My <a href="http://www.amazon.com/dp/B00MIG3ON4">hot-shoe mounted flash</a> does have a zoom head (24mm-105mm). The flash manual has a guide number chart for ISO 100. By setting flash to 24mm zoom, 1/1 power, GN is 28 meters. By setting flash to 28mm zoom, 1/1 power, GN is 30 meters. If I set flash to 85mm zoom, the same 1/1 power, how can I calculate the guide number?<br>

<br />If set the flash to 105mm zoom, ISO 100, GN is 56 meters. Then setting the flash to ISO 200, keeping the same 105mm zoom, GN will be 78.4 meters which is 1.4 times as big as ISO 100. Right?<br>

"Anything over 36 (in metres @ 100 ISO) is almost certainly pure fantasy." Real?</p>

 

<p>Somebody told me that all of the ISO, f-number of aperture and focal length of the lens can affect the guide number of a flash. However he didn't tell me how. Anybody can help me? Thanks a lot!</p>

<p>Thanks guys! I would like hear your thought and suggestions.</p>

<p>I have bought a hotshoe speedlight recently. I think its max. guide number is not as real as marked. Is there an easy way to figure out the real GN?</p>

<p>Need an external wireless flash for portraits working with my Canon EOS 7D, prefer third party flash(less expensive with good performance), any suggestion will be helpful.<br /></p>

<p>Very lovely! Nigel Turner shot a successful photography, amazing geyser in winter.</p>