Light Metering

veryrandom

Hi there, i just wanted to know if anyone can tell me, in very simple terms how to use a light meter? The light meter in question is a polaris. Or even if there are any simple easy to follow sites anywhere?
Its something i should know, and always wanted to get the hang of but every time i approach it it gets very confusing. I am using a nikon D90 if that helps and would be using it mostly in a studio.

Any help appriciated!

melekalikimaka

set the shutter and iso on it
stand with it in position of subject, facing camera
click it ( connect it to lights in lights being used)

it will tell you then the aperture to use for correct exposure

AnimalRights

That sounds so much hassle, thank allah I have the top of me head.

melekalikimaka

AnimalRights wrote: »

That sounds so much hassle, thank allah I have the top of me head.

with studio work its handy, especially with mf cameras, studio lights throw off your mental metering

AnimalRights

Fair enough G'uv

melekalikimaka

medium format is a funky mofo

charybdis

Why does this become more difficult with medium format cameras?

stcstc

you need to meter each light seperatley, not both at once

Heebie

stcstc wrote: »

you need to meter each light seperatley, not both at once

Don't forget your maths.. then you need your maths!

Oh now.. now it's sounding a lot like work!

veryrandom

Cool, thanks for that! Do i have to set the shutter speed to the cameras sync speed tho? Or something? This is where it starts to confuse me.

Also with regard to connecting it to the lights, do i connect it to all or just one of them?

Thanks again.

Heebie

Your camera should have a "minimum sync speed" which is the fastest exposure you can use where the camera will synchronise with the flash.

Generally, if you're using longer exposures, it's not important that it fully syncs.

By "sync" that means that the shutter will be fully open when the flash goes off. If your flash isn't sync'ing, you can get flash photos where half the picture is exposed.. often badly..and the other half is completely black because the shutter curtain has already partially closed before the flash actually went off.

Maybe someone else will be more succinct than me.

veryrandom wrote: »

Cool, thanks for that! Do i have to set the shutter speed to the cameras sync speed tho? Or something? This is where it starts to confuse me.

Also with regard to connecting it to the lights, do i connect it to all or just one of them?

Thanks again.

veryrandom

Ok cool, but how would one go about finding their cameras sync speed?

stcstc

rtfm

if you look in the manual it will be in the spec of the camera

a good guide starting point would be

ISO100
shutter 1/125

and then meter the keylight to F8
then the fill light at around f5.6

veryrandom

Thanks

Heebie

veryrandom wrote: »

Ok cool, but how would one go about finding their cameras sync speed?

As states, it should be in the manual.

BUT.. if the manual isn't available:

Start at 1/250, with the flash equipment hooked up.

Put a plain white backdroppy something-or-other in front of the camera.

have low or no lighting in the room.

Shoot a frame at 1/250, 1/126, 1/90 etc.. until you start seeing part of the image being black & the rest white. (or some shade of grey.)

An average run-of-the mill camera with an average run-of-the mill flash will generally be around 1/125. I've seen some specs claim that with a flash from the same manufacturer as the camera, sync can be as fast as 1/4000 (I've never bothered to test.. what would I ever need a flash for that would need a sync that fast anyhow? I'm not trying to stop bullets mid-flight.)

veryrandom

Sadly the manual isnt available but thanks for the advice!

stcstc

is it a slr or something,

a safe bet is 125 or 160th, some medium formats will fo quicker like 500th etc

but for most this 125 or 160 will be spot on

veryrandom

Yah its an slr so this should work, thanks again!

mdebets

Heebie wrote: »

Your camera should have a "minimum sync speed" which is the fastest exposure you can use where the camera will synchronise with the flash.

Generally, if you're using longer exposures, it's not important that it fully syncs.

By "sync" that means that the shutter will be fully open when the flash goes off. If your flash isn't sync'ing, you can get flash photos where half the picture is exposed.. often badly..and the other half is completely black because the shutter curtain has already partially closed before the flash actually went off.

Maybe someone else will be more succinct than me.

Trying to explain it, as I understand it.

Your shutter has 2 courtains. It starts with the first curtain opening, starting the exposure. Then the second curtain closes, ending the exposure, when it is fully closed.
If your shutter speed is slow, your first curtain opens fully, the camera waits for a while and then the second curtain closes.
If you shutter speed is too fast, the second curtain starts closing, before the first curtain is fully open, so you'll have never the full picture exposed at the same time.
If you take your picture without a flash, that's no problem.
If you use a flash, the second scenario is a problem, as only part of the picture, the one that is exposed at the time the flash fire would benefit and the rest wouldn't, so you would get a picture with a small line being exposed correctly with flash and the rest being too dark.
THe max Sync speed is the fastes shutter speed at which the second curtain will only start closing after the first curtain has been fully opened.

You can also might have a high speed sync on your flash, in which case the flash would not fire once, but several times, however each time with less than full output (=darker).

Slidinginfinity

veryrandom wrote: »

Sadly the manual isnt available but thanks for the advice!

You might be able to find a manual online somewhere, most likely as a PDF.