What If?

[elmhurre]

hello,

I'm here again with a question.

1. What if i dont have a light meter (actually i really don't have a light meter, too expensive and i also don't know how to use) and you want to meter your flash exposure to match your choice of aperture and shutter speed. Do i have any other options to get the right exposure for my subject

because most of the time, when i'm practicing portraiture i usually set my speedlight to 1/4 power then i will just increase or decrease the output, Am I doing right or there's an easy way for low key and high key lighting.

Thanks

 

[tirediron]

No other way that I'm aware of; you can get smart 'phone applications that will function as an ambient light meter, but I'm not aware of any of them doing flash. You can get some very nice flash meters used for very little money. I picked up a MIB Luna Pro F (a $500 meter in the early 80s) for ~$75, not long ago, and found a Minolta Flash V on Craig's List for $150... both top-notch meters. Flash metering is, unfortunately, one of the very few things that can't be done any other way (except for trial and error).

 

[beachrat]

edit nevermind.
I think i misunderstood the question.

 

[MatthewSimes]

Yes. There is a number with flashes called a guide number. You can use this to approximate correct exposure.
Is basically an equation using the GN, f stop and distance to the subject.
If a flash has a full power GN of 160, you divide that by distance to the subject. (Say 10 feet for ease). So 160/10 equals F-16. This is all based on ISO of 100

If you go down to half power, the GN becomes 110 I believe (this is where my recollection is starting to fail me). Also note that the GN changes if you have a flash that can match focal lengths.

Feel free to Google to get the full scoop on this. I don't want to continue with possibly wrong info.

 

[elmhurre]

@ tirediron & Matthew - thanks for the reply..... well i think i will stick on the trial and error thing until I master it..... i'll check what matthew advised and i think it will help me a lot on putting the right power of the flash but i need to brush up my mathematics first. thanks guys. keep shooting and God Bless.

 

[pgriz]

The guide number works only as long as the flash is pointed at the subject (ie, direct flash). As soon as you bounce, it's a whole different ball-game. Before I got a flash meter, I'd guess an exposue, then iterate until it looked right. Was really a pain when I shot more than 1 flash, AND was combining with ambient.

 

[elmhurre]

thanks guys, that's answer my question what if..... light meter is really important, well i need to invest on that next time..... Christmas is coming and I might get a nice Christmas bonus this year.:mrgreen: