T********r
发帖数: 6210 | 1 其实对比一下阳光就知道闪光灯有多强了，举几个例子吧。
Danny以前有阵子喜欢搞人造太阳，就是那种有巨大蓄电池驱动的闪光灯，比一般家用
的580ex/sb900之流功率大很多，就这样还是不能盖过户外的太阳光。
户外的阳光照在身上是什么感觉？闪光灯闪在身上是什么感觉？
闪光灯晚上在室内能把屋子照亮到什么程度？太阳能把周围世界照亮到什么程度？我在
室内用430ex II闪光灯bounce拍照，一般的参数是1/2功率输出，ISO 400，f/5.6，1/
125s，距离比较近的时候勉强曝光充分。对比一下阳光16的参数是ISO 400，f/5.6，1/
4000s。也就是说白天太阳的光强比闪光灯bounce强了5档，32倍！
闪光灯的持续时间是1/5000s - 0.002s，就算是0.01s吧，和连续的太阳光对比，照在
同样单位面积上的能量总共差别有多大，不需要我细说了吧。
http://www.pbase.com/jakobe/flash_burst | l*******y
发帖数: 4006 | | l*******y
发帖数: 4006 | | l*****s
发帖数: 1754 | 4 I am using 580 EX II. At full power, i can use 1/200s, f/8, iso100 if I
place light fairly close. I have to bump iso to 200, if I place light maybe
4 feet away. So the flash is f8 at 1/200s, iso200
For sunny 16 rule, the sun is f/16 at 1/200s, iso200. It is only 2 stops
difference. If you gang 2x flash together, it will be only 1 stop difference
. But remember, this is under direct sunlight. If it is in shade, the
ambient light is easily 3 stops darker, so the flash is actually more
powerful. | l*****s
发帖数: 1754 | 5 Attached is a f/8, 1/200s, iso200 photo, with one 580 ex2, in 50' softbox. | t**i
发帖数: 387 | 6 这个是室外太阳下照的?完全overpower sun啊.
【在 l*****s 的大作中提到】
: Attached is a f/8, 1/200s, iso200 photo, with one 580 ex2, in 50' softbox.
| l*****s
发帖数: 1754 | 7 this is indoor, i am trying to figure out exactly how much power the flash
have. in spec, it says guide number 190'. I have a hard time understanding
what it means. It should mean at f/8, I can put light about 24' away at iso
100. But I don't think I can. | l*******y
发帖数: 4006 | 8 这个我不信呵呵
【在 t**i 的大作中提到】
: 这个是室外太阳下照的?完全overpower sun啊.
| T********r
发帖数: 6210 | 9 距离和使用方式是有影响的。凑到眼皮底下直射有可能强于阳光，但是一来谁会这样拍
娃？二来这样拍出来的也不好看。三来，闪光灯的burst时间太短，能传到眼睛里的能
量有限。在家里拍娃，通常要么bounce ceiling，要么透过伞或者softbox，距离至少
一两米远吧。按照liubros的做法，比阳光还是差远了。
【在 l*******y 的大作中提到】
: http://photo101.zjphoto.org/classroom/5yd70.htm
: 2支580ex略强于阳光， 有图
| T********r
发帖数: 6210 | 10 找naturescape的原文的时候看到了这篇文章：
http://blog.xuite.net/csh_alan/x/49712039-%E7%9B%B8%E6%A9%9F%E9
1/
【在 T********r 的大作中提到】
: 其实对比一下阳光就知道闪光灯有多强了，举几个例子吧。
: Danny以前有阵子喜欢搞人造太阳，就是那种有巨大蓄电池驱动的闪光灯，比一般家用
: 的580ex/sb900之流功率大很多，就这样还是不能盖过户外的太阳光。
: 户外的阳光照在身上是什么感觉？闪光灯闪在身上是什么感觉？
: 闪光灯晚上在室内能把屋子照亮到什么程度？太阳能把周围世界照亮到什么程度？我在
: 室内用430ex II闪光灯bounce拍照，一般的参数是1/2功率输出，ISO 400，f/5.6，1/
: 125s，距离比较近的时候勉强曝光充分。对比一下阳光16的参数是ISO 400，f/5.6，1/
: 4000s。也就是说白天太阳的光强比闪光灯bounce强了5档，32倍！
: 闪光灯的持续时间是1/5000s - 0.002s，就算是0.01s吧，和连续的太阳光对比，照在
: 同样单位面积上的能量总共差别有多大，不需要我细说了吧。
| | | l*****s
发帖数: 1754 | 11 I am going to use this
and 3 flash and see if I can overpower sunlight | e********b
发帖数: 223 | 12 yes or no, depends on how close to the subject
【在 l*****s 的大作中提到】
: I am going to use this
: and 3 flash and see if I can overpower sunlight
| t**i
发帖数: 387 | 13 those guide numbers are generally given at maximum zoom position, when you
zoom out you will lose some light, also when you put modifiers (softbox/
umbrella) in front of flash, it loses power further more.
My SB-900 gives me f/8 at 15ft (ISO:100, zoom position:50mm), which gives GN
of 120ft. According the Nikon's manual GN at these settings should be 150ft
. So they are pretty close. I think 580EXII are more powerful than SB-900.
iso
【在 l*****s 的大作中提到】
: this is indoor, i am trying to figure out exactly how much power the flash
: have. in spec, it says guide number 190'. I have a hard time understanding
: what it means. It should mean at f/8, I can put light about 24' away at iso
: 100. But I don't think I can.
| O*******d
发帖数: 20343 | 14 阳光在海平面的能量密度大约每平方米1000瓦。 闪光灯在千分之一秒里，如果输出一
焦耳能量，分布在一平方米的面积上，才能有太阳光的能量密度。 即使达到这个能量密
度，这个只相当于太阳光千分之一秒的曝光量。 | O*******d
发帖数: 20343 | 15 很多交流电闪光灯，输出都是50-100焦耳，甚至有几百焦耳的。 可以达到太阳光的强
度。 | O*******d
发帖数: 20343 | 16 我发现闪光灯标记输出能量，用watt-second，而不是用焦耳。 瓦特就是焦耳除以秒，
瓦特秒就是焦耳除以秒再乘以秒。 多次一举。 | l*****s
发帖数: 1754 | 17 I went back to test my flash power tonight, and to my surprise, f/13 at full
power. But the light is only 2 feets away. So, potentially two of these can
overpower the sun.
GN
150ft
【在 t**i 的大作中提到】
: those guide numbers are generally given at maximum zoom position, when you
: zoom out you will lose some light, also when you put modifiers (softbox/
: umbrella) in front of flash, it loses power further more.
: My SB-900 gives me f/8 at 15ft (ISO:100, zoom position:50mm), which gives GN
: of 120ft. According the Nikon's manual GN at these settings should be 150ft
: . So they are pretty close. I think 580EXII are more powerful than SB-900.
:
: iso
| T********r
发帖数: 6210 | 18 你这个后期刻意调暗了么？白天阳光下拍出来可没这么暗。
full
can
【在 l*****s 的大作中提到】
: I went back to test my flash power tonight, and to my surprise, f/13 at full
: power. But the light is only 2 feets away. So, potentially two of these can
: overpower the sun.
:
: GN
: 150ft
| l*****s
发帖数: 1754 | 19 Ok, here is the real test.
10am, direct sunlight,
1. no flash, 1/200s, f/11, iso100, which is exactly what sunny 16 rule said.
2. stop down 1 stop aperture, f/16, looks like underexposed.
3. 580EX II at max power, max zoom, about 2 feet away, f/22, which is 2
stops abov sunlight, but looks overexposed.
4.pull flash back further, about 4 feet away, exposure looks correct.
5.adding a 2nd 580EX II, pull flash even further out, well, f/22 is the
minimum I can use, I should have use iso50 for more test, but I forget.
6. 7. shows the location of light.
So, looks like one 580 EX II can potentially over power sunlight at fairly
close, two 580 EX II will do it for sure.
【在 T********r 的大作中提到】
: 你这个后期刻意调暗了么？白天阳光下拍出来可没这么暗。
:
: full
: can
| l*****s
发帖数: 1754 | 20
said.
【在 l*****s 的大作中提到】
: Ok, here is the real test.
: 10am, direct sunlight,
: 1. no flash, 1/200s, f/11, iso100, which is exactly what sunny 16 rule said.
: 2. stop down 1 stop aperture, f/16, looks like underexposed.
: 3. 580EX II at max power, max zoom, about 2 feet away, f/22, which is 2
: stops abov sunlight, but looks overexposed.
: 4.pull flash back further, about 4 feet away, exposure looks correct.
: 5.adding a 2nd 580EX II, pull flash even further out, well, f/22 is the
: minimum I can use, I should have use iso50 for more test, but I forget.
: 6. 7. shows the location of light.
| | | T********r
发帖数: 6210 | 21 1. shot at 10:43AM
3. shot at 10:47AM
Looks like they were at the almost the same time under the same condition.
Q1: Is the subject still under sunlight for the 3rd shot?
Q2: Is this a typical setting to shoot photos at your home?
Q3: Is two 580ex full power direct towards a baby a typical setting for a
regular joe?
I told my typical setting at home earlier, 430ex II, half of full power
output, bounce to ceiling. I see no impact to my children whatsoever in this
setting.
said.
【在 l*****s 的大作中提到】
: Ok, here is the real test.
: 10am, direct sunlight,
: 1. no flash, 1/200s, f/11, iso100, which is exactly what sunny 16 rule said.
: 2. stop down 1 stop aperture, f/16, looks like underexposed.
: 3. 580EX II at max power, max zoom, about 2 feet away, f/22, which is 2
: stops abov sunlight, but looks overexposed.
: 4.pull flash back further, about 4 feet away, exposure looks correct.
: 5.adding a 2nd 580EX II, pull flash even further out, well, f/22 is the
: minimum I can use, I should have use iso50 for more test, but I forget.
: 6. 7. shows the location of light.
| l*****s
发帖数: 1754 | 22 Q1, the sunlight is the same. You can tell from the same ambient light at 2
and 3. The difference between 1 and 3 is f11 vs f16.
Q2, this is not typical setting. F16 is not the best aperture, the best is
f5.6-f8, depending on lens. So I normally use 1/4 -1/2 power for key light
Q3, I don't need so much power for indoor shoot. If it is a full body, I
might use 2 flash, 1 high 1 low at the same spot, but just for light spread,
not power. And my kids are old enough where I don't worry about flash being
too strong. And they are not looking into flash anyway. Light will be
coming from side and above.
1. shot at 10:43AM3. shot at 10:47AMLooks like they were at the almost the
same time und........
【在 T********r 的大作中提到】
: 1. shot at 10:43AM
: 3. shot at 10:47AM
: Looks like they were at the almost the same time under the same condition.
: Q1: Is the subject still under sunlight for the 3rd shot?
: Q2: Is this a typical setting to shoot photos at your home?
: Q3: Is two 580ex full power direct towards a baby a typical setting for a
: regular joe?
: I told my typical setting at home earlier, 430ex II, half of full power
: output, bounce to ceiling. I see no impact to my children whatsoever in this
: setting.
| T********r
发帖数: 6210 | 23 picture 1: sunny 16。
picture 4: sunlight + 580ex II full power at 4 feet, f/22, correct exposure.
this tells us that 580ex II is about 3 times of sunlight in this setting
because the sunlight is about 1/4 at this setting.
4 feet is about 1.2m. So at a distance of about 2m from 580ex II max output,
the flash light is about the same as sunlight.
And if flash is through a white umbrella, the light is reduce by about half.
So if the flash is about 6 feet (1.5m) away from the subject and is behind
an umbrella, flash light is about the same as sunlight on the subject.
Again, this is 580ex II at max output.
2
spread,
being
【在 l*****s 的大作中提到】
: Q1, the sunlight is the same. You can tell from the same ambient light at 2
: and 3. The difference between 1 and 3 is f11 vs f16.
: Q2, this is not typical setting. F16 is not the best aperture, the best is
: f5.6-f8, depending on lens. So I normally use 1/4 -1/2 power for key light
: Q3, I don't need so much power for indoor shoot. If it is a full body, I
: might use 2 flash, 1 high 1 low at the same spot, but just for light spread,
: not power. And my kids are old enough where I don't worry about flash being
: too strong. And they are not looking into flash anyway. Light will be
: coming from side and above.
:
| l*****s
发帖数: 1754 | 24 i think the main application for over powering sunlight, is to make sky/
water extra blue. you don't have to over power sunlight in most cases, but
the ability to do so, will have some use. it is like a different bullet. it
is good to have it, and knowing how to use it. | l*****s
发帖数: 1754 | 25 or to get more detail/color out of sunset cloud. | t**i
发帖数: 387 | 26 The most effective yet little known way to overpower sunlight is for those
who has old camera with electronic shutter (such as Nikon's D40, D70, not
sure about Canon). With a SB-900 (similar power to 580EXII) you can
overpower sunny 16 by 3-stop from 8 ft away.
said.
【在 l*****s 的大作中提到】
: Ok, here is the real test.
: 10am, direct sunlight,
: 1. no flash, 1/200s, f/11, iso100, which is exactly what sunny 16 rule said.
: 2. stop down 1 stop aperture, f/16, looks like underexposed.
: 3. 580EX II at max power, max zoom, about 2 feet away, f/22, which is 2
: stops abov sunlight, but looks overexposed.
: 4.pull flash back further, about 4 feet away, exposure looks correct.
: 5.adding a 2nd 580EX II, pull flash even further out, well, f/22 is the
: minimum I can use, I should have use iso50 for more test, but I forget.
: 6. 7. shows the location of light.
|
|
