XTi, 430ex while in manual mode? I'm a noob to this.

[Corbin Lane]

Alright, I've been playing with all of this for a while. I have tried to do it while the flash is in manual mode along with the camera, but all of the pictures are ether over exposed or underexposed. It takes a lot of shots just to get it close to correct exposure. I have tried to google it and I've read the manual, I have looked at strobist and I've read some of their stuff, maybe I'm missing something on the website. Would someone to care to explain how to get it correct on the first or second try.

Thanks

 

[Jaszek]

You were trying to do what?

 

[Corbin Lane]

You were trying to do what?

I'm basically trying to set the intensity of the flash, 1/1, 1/2 etc.. with out the flash doing it for me and getting a good exposure. Sorry for being vague, I'm watching house and I tend to loose focus easily.

 

[Jaszek]

just press the sel/set button and than left for the intensity you want

 

[Corbin Lane]

just press the sel/set button and than left for the intensity you want

haha, I realize that. But when it's in manual mode the photo is always over exposed or under exposed. Is there some sort of trick to getting the right exposure with out ETTL?

 

[TBAM]

The best advice I can give you is:

Your flash is going to expose the same things regardless of your shutter speed (in most situations).

So, your shutter speed is the main contributor on how you want to expose the parts that are not being lit by the flash i.e. backgrounds, items being lit by ambient light.

If you want to control how much your flash exposes, use either your aperture or your flash power.

It's a matter of thinking of the picture as two exposures. The exposure for your subject, and the exposure for the rest of the scene. Set your flash / aperture for the former, and your shutter speed for the latter, in most cases.

 

[Corbin Lane]

The best advice I can give you is:

Your flash is going to expose the same things regardless of your shutter speed (in most situations).

So, your shutter speed is the main contributor on how you want to expose the parts that are not being lit by the flash i.e. backgrounds, items being lit by ambient light.

If you want to control how much your flash exposes, use either your aperture or your flash power.

It's a matter of thinking of the picture as two exposures. The exposure for your subject, and the exposure for the rest of the scene. Set your flash / aperture for the former, and your shutter speed for the latter, in most cases.

I feel like a moron. That makes perfect sense! Thanks so much!

 

[TBAM]

Don't worry, i've been through that too. It's definately a "duh" moment.

It's pretty easy once you grasp that adjusting the shutter exposes the "environment" and adjusting the aperture / flash power exposes the subject.

The only annoying thing that I keep forgetting although I'm getting better at, is with using a zoom lens that isn't able to maintain a static aperture throughout the entire focal length, I would zoom in, and not notice until later that due to the difference in f3.8 to f4 or so, with a slight zoom in to compose, the subject would be a little under-exposed (ooh, that rhymed).

But just go nuts. You should find things a lot easier now that you've had that light bulb go off of how to expose the photo with reasonable accuracy.

I usually do a quick test-shot before I start shooting though, just to get a feel for the combination of Shutter / flash power, so I can decide whether I want the flash to dominate more, or be more of a fill.

You'll get better with practice too.

 

[JerryPH]

Using the flash off camera = www.strobist.com website, great for learning about strobism.

As far as getting it right, there are 2 basic ways:
- taking a picture, chimping and adjusting the strobe power until it looks good. Knowing how to read a histogram is a good idea.

- using a light meter. Simply pop the flash as you place the meter in the area that you want to take a picture of, set your camera aperture/ISO/shutter settings and then adjust your flash power to match current needs.

In a flash environment, you want to use ISO 100 or 200 in general and the aperture based on how much DOF you want. Shutter speed is easy... in general you want it at your maximum camera sync speed or slower. The slower it gets, the more ambient light gets into the pic. Read up on the strobist sight about how this affects your pics. The final step is to set flash strength based on your needs after the above 3 items have been decided.

People set camera shutter, ISO and aperture based on flash. WRONG! You set the flash to accommodate your camera ISO, shutter and aperture needs.

 

[chrisburke]

man, this past week has seen a lot of Beginner questions in the Beyond the basics forum....

 

[JerryPH]

I know... I don't know why either. I wish people would be more considerate and place their posts where they belong. It's not rocket science... each section has a description underneath the name. :er:

Wait... let me make a post asking for a crit in the BTB section and freak everyone out... lol

 

[chrisburke]

lol sounds like fun

 

[Village Idiot]

Did the world of photography suddenly lose the term "guide number"?

That's how you get it right on your first or second shot.

Each flash has a Guide Number (GN). It's rated in feet. It means how far the flash can fire at full power at ISO 100. It's a great little formula that can tell you everything you need to know. GN = distance x f stop (aperture)

So if your flash is rated with a GN of 100, you can use that to figure it out (and the formula, like so many great mathematical formulas, is interchangable(Distance = GN / f stop or F stop = GN / Distance)).

Say your flash is roughly 20' from the subject and you need to find the right aperture for a correct exposure and the GN is 100. At 1/1 power, F stop = 100' / 20'. 5 = 100 / 20. Aperture = f/5.

Now, changing the flash power affects this:
Multiply guide number by 0.70 to adjust - 1 f/stop
Multiply guide number by 1.4 to adjust + 1 f/stop

One stop of light is considered doubling the power. 1/4 - 1/2 is one stop 1/2 - 1/1 is one stop. 1/4 - 1/1 is two stops.

So say you have that GN of 100 at 1/1 but you want to shoot at 1/2. 100 x .7 = 70

At 1/2 power, your flash's GN would effectively be about 70'. That lets you use a wider aperture or less distance, because face it, 20' is a long distance away. So you want to still use an aperture of f/5 but don't know how far away the flash should be at 1/2 power? distance = GN / f/

x = 70 / 5

14 = 70 / 5

You can place the flash at 14 feet away at 1/2 power and use f/5 for a properly exposed shot.

There should actually be a chart in the 430EX manual. What you can do is use a cheat sheet and go from there. Say on average you shoot with your flash at 1/4 power and about 7' away from the subject.

Page 34.

At 1/4 power with the flash head zoom at 24mm, the GN is 41. Tape a piece of paper to your flash with the settings.

distance = 7'
f/6
Power = 1/4'

Of course, modifiers change all of this. And if you're trying to shoot in manual with the flash on camera and constantly moving around, you're better off using TTL for this.