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Old Dec 5, 2005, 11:07 PM   #1
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Hi Experts,

I've bought my Canon 20D and a Speedlite 580EX for a while but faced difficulties in controlling these two equipment when shooting with flash on. That is when I install the 580EX on my 20D, what I can do is to set back to shooting mode Full Auto or P. However, the results were out of my expection as all the shots seemed under-exposed. I was advised by someone to try to use the 580EX with my 20d shooting mode set to M. But when I tried M, the exposure metering scale in the view finder dropped to -2 stops. So I got to push it to ward to 0 and all the shot were terribly over-exposed. Did I do anything wrong?

I would much appreciate your advising how to use the 20D with a 580EX on optimally since I am going to shoot a wedding for my sister in law.

Another question is how to check when is enough to compensate the flash by looking at the LCD of the camera. You see, all I want is what I shoot goes perfect (lighting/exposure not under or over) without having to be adjusting in PS or other software later.

Any great tipsin setting up the 580EXwill be great and when and howwe should set the flash catlight panel, wide panel of the flash, bounce angle, etc. and how we use camera setting to Av or Tv with the flash on and for what purpose other than M mode or other full auto and P mode.

What is the difference between flash and non-flash lighting in studio? Which oneis better?

Thanks a lot for your advice on these silly questions.

Regards,

Quan








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Old Dec 8, 2005, 8:20 PM   #2
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Hello All,

It seems none of you can answer these questions. Anyway, I post this to another forum for help.

Rgds,

Quan




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Old Dec 14, 2005, 2:06 PM   #3
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Quan Tran wrote:
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I was advised by someone to try to use the 580EX with my 20d shooting mode set to M. But when I tried M, the exposure metering scale in the view finder dropped to -2 stops. So I got to push it to ward to 0 and all the shot were terribly over-exposed. Did I do anything wrong?
The best way to use the Canon flash system is on M !!!
-> the camera is on manual (M) i.e. you can both control the shutter and aperture this way, but the flash remains on automatic. What you are observing on the exposure metering scale is the ambient light that the camera is metering (Do not push it toward 0!)
When you take the picture with the existing camera settings the flash will expose the image correctly :idea:
(regardless of the exposure scale in the viewfinder!)

If you compensate the exposure by moving the scale toward 0, the ambient light is properly exposed, but when the flash fire it will put additional light on the suject hence you get overexposure.
To compensate for the flash you can adjust the adjust the +/- scale on the 580EX (flash exposure compensation) and not the camera...



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Another question is how to check when is enough to compensate the flash by looking at the LCD of the camera. You see, all I want is what I shoot goes perfect (lighting/exposure not under or over) without having to be adjusting in PS or other software later.
The easiest way is to meter off a "Grey Card" in the approximate distance of your subject: i.e. press the AEL (*) lock button for the camera to pre-flash and make an initial metering. Now while holding the (*) button down, press the shutter release the exposure is locked in the camera memory even if you recompose...



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What is the difference between flash and non-flash lighting in studio? Which one is better?
Studio lighting is all about mastering (i.e. control) of light - You can do it two ways:
1. Halogen or 'hot' light (warm tone)
2. Flash (whiter shade)

My guest is VN is hot so you'll be hotter with halogen lamps in a small studio. Flash also is easier to attach to other accessories since they don't tend to catch fire, but cost more... :-)
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Old Dec 16, 2005, 3:52 AM   #4
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Hi NHL,

Thank you very very much for your helpful advice. I'm now OK with my 20D and the 580EX in manual mode (the camera only no the flash). You know, while waiting for the advice from the forum and I googled again and there was one thread advising the 20D with 580EX in M exactly like what you say.

Thanks again and regards,

Quan








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Old Dec 18, 2005, 8:18 PM   #5
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Hey Quan - Here isa copy of a post I wrote for a similar thread:

When using flash, use P or M. When using P, the camera exposes automatically for the flash. Meaning, your subject or foreground will be properly exposed, while your background may not get any "flash" at all, and therefore be very dark. This is the easy, less attractive method to usng flash.

A better method is to use flash in M mode, and think of it this way. There are 2 exposures in the one shot: The flash automatically properly exposes the subject, and this is mostly independent of the shutterspeed/aperture you choose. Then for the background, set the manual exposure settings to expose the background. You can point the camera towards the background, get a reading by half-depressing the shutter, and set the aperture/shutter speed accordingly. A good place to start would be to set the exposure at -1EV. This will give you some background, but the foreground/subject will stand out.

You can experiment with this in your house at night. With the flash on, choose M mode, and set an aperture of 2.8 (or your widest aperture), and set the shutter speed to 1/60. No matter how dark or light the room is, the flash will properly expose your subject. Change the shutter speed, and the foreground exposure remains constant, but you get more or less light in the background.

Also note that the wider the aperture, the more effective the flash will be (or the greater distance it can cover). Also, increasing youer ISO setting will allow you to get more exposure for dark backgrounds (assuming the same exposure setttings) when using this method.

Finally, this method I describe is just as useful outdoors during the day (AKA "Fill Flash") , when you want to your make your subject pop. Keep in mind that in daylight, you will probably need a flash with "high sync mode" as your shuter speeds outdoors will be greater than 1/200. This with a wide aperture for background blur produces a really cool effect.

So to summarize, think of a flash shot in M mode as 2 separate exposures. The flash exposure is handled automatically and exposes the forefround. Then you pick the background exposure by tuning the aperture, shutter speed, and ISO.

Hope this helps.

Chris M
www.imagineimagery.com
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Old Jul 8, 2006, 4:38 AM   #6
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Hi Chris,

I am really sorry for missing this thread. I mean I did not come back to the thread to see if there was any reply and it was your post. I find you advice very useful.

Thank you very much for your help.

Kind regards,

Quan






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Old Jul 8, 2006, 12:27 PM   #7
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Quan Tran wrote:
Quote:
Hi Chris,

I am really sorry for missing this thread. I mean I did not come back to the thread to see if there was any reply and it was your post. I find you advice very useful.

Thank you very much for your help.

Kind regards,

Quan






Thanks Quan. After gaining quite a bit of flash experience since writing this, I would like to amend some of my post. I have also discovered that Av mode is very useful for outdoor fill flash. It works just like P mode, except of course you get to choose the aperture. Also, unlike like P mode, you must set the flash to high-speed sync mode if shutter speeds go above 1/200th.. The shutter speed will blink "200" if this is the case.And remember, this is just for applying fill flash wen there is plenty of ambient light. For nighttime situations, M mode is the way to go.

I'm glad you found this helpful, thanks for saying so.



Chris M

http://www.imagineimagery.com
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Old Jul 8, 2006, 10:49 PM   #8
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Dear Chris,

I got confused about the outdoor fill flash in Av mode in situations on which we got switch to h-speed sync if the meter was higher than the flash sync speed of the camera. I digged out recently on the net and got some advice and now that you have just added reinforced my confidence and belief.

Thanks again for your kind advice.

Regards,

Quan




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