I need a crash course in using flash...

tarmac_chaser

tarmac_chaser

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After a long time of doing outdoor photography, I've only just entered the world of flash photography having just purchased a 580EX.

I have no idea how to use a flash properly, that counts for the built in flash as well. Does the flash automatically adjust its power?

Any links to a tutorial would be great :thumbs:
 
On ttl it will adjust the exposure-but on manual it wont and youll have to guide it by the distance-not sure about how the canon flashes work-but a good guide is read the manual too.
 
I just bought one last week. I've been blown away by how much there is to them. Here's a link a mate put me on to.
 
There's a lot to getting your head around all the possibilities which a modern TTL electronic flashgun offers. A good starting point would to be get a handle on just how good they are without any interference from you.

Put the camera on 'P' (Programme), the flash on TTL, then go out and shoot some pics in a variety of situations. Let us know how you get on. ;)
 
Thanks CT. It's like starting all over again. I cannot explain how amazed I was with some test shots the other night.

My room was in total darkness, and I took some shots of everyday objects. The result? They 100% look like they were taken in daylight, no evidence of artificial light what so ever! Amazing
 
glad your enjoying it :)

It's a lot more kit than you realise, next you'll be after a 430EX to remote with ;)
 
The thing is your DSLR has a focal plane shutter and without boring you with the technicalities, it used to be a PITA to do fill in flash in daylight for daylight shots, continually mentally dividing the aperture into the Guide No to give you the distance at which you had to take your shot, or dividing the distance into the guide no to give you the aperture you had to use. Very easy to cock up when you were under pressure to begin with.

In TTL mode these days, your camera will meter for the ambient light, while a separate flash sensor will regulate the flash output so that it blends nicely with the ambient light. It gives very acceptable results, but you may just want to dial the flash output down about a stop and a half for a more subtle effect, which is what I tend to do.

There are other ways to use your gun, but try this first, there's nothing wrong with relying on the technology if it gets you the results and saves you going around in circles. ;)
 
CT said:
The thing is your DSLR has a focal plane shutter and without boring you with the technicalities, it used to be a PITA to do fill in flash in daylight for daylight shots, continually mentally dividing the aperture into the Guide No to give you the distance at which you had to take your shot, or dividing the distance into the guide no to give you the aperture you had to use. Very easy to cock up when you were under pressure to begin with.

In TTL mode these days, your camera will meter for the ambient light, while a separate flash sensor will regulate the flash output so that it blends nicely with the ambient light. It gives very acceptable results, but you may just want to dial the flash output down about a stop and a half for a more subtle effect, which is what I tend to do.

There are other ways to use your gun, but try this first, there's nothing wrong with relying on the technology if it gets you the results and saves you going around in circles. ;)
Click to expand...

Not to confuse the O/P but is there such a rough guide for full manual flash shooting?...

I have recently entered the (sometimes very rewarding) Tarzan / FULL manual mode and would like to know about such a guide if it exists...

Cheers all!:thumbs:
 
Anton Roland said:
Not to confuse the O/P but is there such a rough guide for full manual flash shooting?...

I have recently entered the (sometimes very rewarding) Tarzan / FULL manual mode and would like to know about such a guide if it exists...

Cheers all!:thumbs:
Click to expand...

The only guide you need is the Guide No for your flashgun Anton.

You then divide the aperture (you want to use) into the guide number to give the correct shooting distance for proper flash exposure. OR

Divide the distance at which you wish to shoot into the Guide Number to give you the aperture for proper flash exposure at that distance.

Bear in mind that the Guide No differs whether you're working in feet or meters and it's quoted for a specific ISO - usually 100 ISO. The Guide No changes with the ISO but unfortunately it's nothing so convenient as the halving and doubling you might think.

It's not an exact science either, and certainly for fill flash you'd probably need to adjust flash output a little to avoid over-flashing your subjects.

Can't honestly think why you want to do it most circumstances. ;)
 
CT said:
Bear in mind that the Guide No differs whether you're working in feet or meters and it's quoted for a specific ISO - usually 100 ISO. The Guide No changes with the ISO but unfortunately it's nothing so convenient as the halving and doubling you might think.

It's not an exact science either, and certainly for fill flash you'd probably need to adjust flash output a little to avoid over-flashing your subjects.

Can't honestly think why you want to do it most circumstances. ;)
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It's not quite as simple as doubling and halving but it's not much harder either - you just multiply or divide the working distance by 1.4 for each doubling or halving of ISO. This is just following the standard principles of the inverse square law, so instead of doubling and halving you multiply and divide by the square root of 2.

e.g. a 580EX has a guide number of 58m. If we were to shoot at 100 ISO and f/5.6 our working distance would be very close to 10m (58/5.6=10.36). so let's call it 10m exactly. If we then doubled the ISO to 200 the distance would increase by the square root of 2, which is 1.414. Let's call it 1.4. So multiply 10m by 1.4 and you get 14m. If you doubled the ISO again you'd get 14m x 1.4 = 20m. Double the ISO again and you multiply 20m by 1.4 and get 28m. Do you see a pattern here? It's just the same as the f/stop progression - 1.0 - 1.4 - 2.0 - 2.8 - 4 - 5.6 - 8 etc. etc.

Being able to work out the working distance can be handy when you are shooting at a constant distance but your subject reflectance keeps changing - shooting portraits at a dinner/dance or wedding, for example. If you're shooting wildlife and need some flash then you need to know how far your flash will reach. Suppose there is something 20m away and you're using your 100-400 lens, which maxes out at f/5.6 at the long end. What ISO will you require as a minimum? Well with a GN of 58, a 580EX will only get you to 10m at f/5.6 if you shoot at 100 ISO. Even 200 ISO will only get you to 14m, but 400 ISO will get you to the 20m you need.

Of course, if you're using a 580EX it will give you a distance scale on the back so you don't really need to do the maths, just look at the scale. But if you were using a more basic flash you might well need to do the maths.
 
I endorse that tutorial ^^. I think you linked to it a few days ago, and I've found it incredibly useful :)
 
i have aquestion ....

what would you do to use the flash with a "better bounce card" and a (i) ttl flash.

I have an old sunpac flash (waiting for a sb600 to arrive) and I made a bounce card fro mthat online vid thing. Have to say got some nice toning from it BUT took quite a few attempts to get the exposure right on the sunpac (which only gives me manual mode) funily enough the best one was almost the first, when I had the iso set at 800 (from playing about earlier) adn hte flash set at 1/16 power (aperature was about f4 and shutter was about 100 i think) I was about 4 foot away from the "model" (my Partner doing her best to look unphotogenic)

So if I wanted to use the flash card with I-ttl (on a d70) what would be the correct thing to do?

I thought maybe use ttl then dial it up a little bit? I shoot in raw so a little underexposure isnt the end of the world
 
CT said:
Can't honestly think why you want to do it most circumstances. ;)
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Fair point CT:lol: I suppose it is just one of those things I thought I had to do for a while and it does slow me down and cause me to think a bit more before pressing the shutter button...

Very rewarding when you nail it nicely...:thumbs:
 
To be fair Anton I'm one of those ancient togs who had to use early manual electronic flashes with the Guide No, because it was the only way to use them, so I embrace the TTL flash technology and I don't look backward. I must say though that using the Guide No and doing the mental arithmetic, will give you a far better understanding of why and how flashguns work in their more automated form. Flashguns do so much for you right out of the tin these days, that there's little incentive to go back to basics and grasp a real understanding of how they work.
 
Except TTL flash gets fooled just as easily by subjects at the tonal extremes (white wedding dress, black tux, or bright reflections) that in situations where manual exposure keeps things simple, without having to ride EC all the time, manual flash keeps things simple, without having to ride FEC all the time - if your subject distance remains constant.

I admit, I'm an ETTL-2 kind of guy, but results can disappoint if I'm not watching what I do. That FEC control does need to get exercised.
 
CT said:
To be fair Anton I'm one of those ancient togs who had to use early manual electronic flashes with the Guide No, because it was the only way to use them, so I embrace the TTL flash technology and I don't look backward. I must say though that using the Guide No and doing the mental arithmetic, will give you a far better understanding of why and how flashguns work in their more automated form. Flashguns do so much for you right out of the tin these days, that there's little incentive to go back to basics and grasp a real understanding of how they work.
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That is very true CT

I am sure you have shot a good few rolls of film more than me but I have found that digital made me stop thinking about photography because this here nice kit will do it all for me...

For this reason I suppose I might well be overcompensating to the other extreme but I enjoy full manual everything from time to time...especially when I get it right:lol:

Also, as has been said, ETTL and all those clever little gadgets can get it wrong on occasion:eek::suspect::lol::D
 
LOL. Well props to you for trying to get to grips with it. Understanding flashguns causes more confusion than any other single subject probably, unless it's basic exposure technique, and the two things are so tied together anyway.
 
CT said:
LOL. Well props to you for trying to get to grips with it. Understanding flashguns causes more confusion than any other single subject probably, unless it's basic exposure technique, and the two things are so tied together anyway.
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I suppose if you understand the inverse square law and apply a healthy dose of educated thumbsuck it all falls into place nicely:thumbs:
 
Anton Roland said:
I suppose if you understand the inverse square law and apply a healthy dose of educated thumbsuck it all falls into place nicely:thumbs:
Click to expand...

LOL. It's one way of looking at it.
 
I've been trying to get to grips with this as well lately, thanks for the links and the pearls of wisdom everyone.:clap:
 
Anton Roland said:
Not to confuse the O/P but is there such a rough guide for full manual flash shooting?...

I have recently entered the (sometimes very rewarding) Tarzan / FULL manual mode and would like to know about such a guide if it exists...

Cheers all!:thumbs:
Click to expand...


As petebarnes says above, first thing to do is check out David Hobby's excellent Strobist: Lighting 101 tutorial. It's also worth having a look at Don Gianatti's Lighting Essentials website and Lighting Essentials Magazine as well as Bert Stephani's Confessions of a Photographer which has some excellent videos showing off-camera lighting setups
 
if you want practical training try the experience seminars, they are extremley useful.
 
I think the thing which has helped me enormously when shooting with Canons (and possibly other camera brands too) was understanding:

1. Shutter speed does not affect how bright the flash is (as the flash duration is so quick).
2. Vary the aperture and ISO to alter how far the flash will affect.
3. If you shoot in Av mode (even with a flash attached) the camera will set the aperture / shutter speed for the lighting conditions.

So, what I do is the following

1. Outdoors, if using flash, I shoot in Av, and use the flash for fill - all on auto
2. Indoors, I often shoot manual, knowing the flash will simply vary in power to ensure the exposure is correct.
3. If you want to shoot indoors, and not worry about whether you shoot in Av or manual, shoot in P, and all will be fine.
 
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