Light meter help

ndwgolf

ndwgolf

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Neil Williams
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Yesterday when at the beach in 36 deg sun I was trying to get a flash meter reading using my Sekonic L308S meter. I had it set to T at 125 and in flash ready mode i.e. meter waiting for the flash to fire. I then fired the flash and it would then give me numbers like 22 30 33 etc etc never once did it give me say 5.6 or 11...why would it do that.
When I used it the day before it worked like i would expect it to work ?
 
It was probably metering the ambient light which was completely dominating the flash.

Top tip from Frank Doorhof from a workshop last week:
What you can do is turn your flash up to maximum - assuming it'll go bright enough to defeat daylight - and take a reading. Then measure the ambient. Then calculate how many stops to reduce the flash by to get the ambient : flash ratio you're after. And calculate the aperture & ISO accordingly, too.
 
juggler said:
It was probably metering the ambient light which was completely dominating the flash.

Top tip from Frank Doorhof from a workshop last week:
What you can do is turn your flash up to maximum - assuming it'll go bright enough to defeat daylight - and take a reading. Then measure the ambient. Then calculate how many stops to reduce the flash by to get the ambient : flash ratio you're after. And calculate the aperture & ISO accordingly, too.
Click to expand...

I was just going to put the same, were you at St. Albans?
 
juggler said:
It was probably metering the ambient light which was completely dominating the flash.

Top tip from Frank Doorhof from a workshop last week:
What you can do is turn your flash up to maximum - assuming it'll go bright enough to defeat daylight - and take a reading. Then measure the ambient. Then calculate how many stops to reduce the flash by to get the ambient : flash ratio you're after. And calculate the aperture & ISO accordingly, too.
Click to expand...

This is known as 'balanced flash' it's a very useful technique.
 
juggler said:
It was probably metering the ambient light which was completely dominating the flash.

Top tip from Frank Doorhof from a workshop last week:
What you can do is turn your flash up to maximum - assuming it'll go bright enough to defeat daylight - and take a reading. Then measure the ambient. Then calculate how many stops to reduce the flash by to get the ambient : flash ratio you're after. And calculate the aperture & ISO accordingly, too.
Click to expand...
Can you please give me an example of this calculation so that I can get my head wrapped around this and I will give it a go today??
 
Meter ambient. Say it's f8 at ISO 100.
Turn flash up to max. and meter it: suppose it's f32.
If you want it at 1 stop above ambient - which is fairly common - then you want it to be f11.
So knock the flash down three stops (f22, f16, f11) and bob's your mother's brother.

This will only work well if the flash is of sufficiently quality to adjust accurately.

My case was complicated by (a) Frank measuring at ISO50 and my camera having a base ISO of 200, and (b) by having a 3 stop ND filter on, but the same principles apply.
 
juggler said:
Meter ambient. Say it's f8 at ISO 100.
Turn flash up to max. and meter it: suppose it's f32.
If you want it at 1 stop above ambient - which is fairly common - then you want it to be f11.
So knock the flash down three stops (f22, f16, f11) and bob's your mother's brother.

This will only work well if the flash is of sufficiently quality to adjust accurately.

My case was complicated by (a) Frank measuring at ISO50 and my camera having a base ISO of 200, and (b) by having a 3 stop ND filter on, but the same principles apply.
Click to expand...
Simon the Profoto B1 heads just have a dial of 3 to 10 so where can you figure how much say 1 stop is when you move from 10 to say 8 on the B1 head
 
ndwgolf said:
Can you please give me an example of this calculation so that I can get my head wrapped around this and I will give it a go today??
Click to expand...

There are many variables. In the first instance you need to meter for the ambient light this will be your starting point e.g 1/125 @ f/8 or f/11. The shutter speed will control the amount of light that is let in. When using flash the shutter curtain will determine the max shutter sync speed. Fire a flash in manual setting using a flash meter, take an incident reading from the subject and balance accordingly. Either reduce the exposure by a stop or increase / decrease the flash output by a stop. In addition, one under. one over will also work as a general rule of thumb.
 
Blank_Canvas said:
There are many variables. In the first instance you need to meter for the ambient light this will be your starting point e.g 1/125 @ f/8 or f/11. The shutter speed will control the amount of light that is let in. When using flash the shutter curtain will determine the max shutter sync speed. Fire a flash in manual setting using a flash meter, take an incident reading from the subject and balance accordingly. Either reduce the exposure by a stop or increase / decrease the flash output by a stop. In addition, one under. one over will also work as a general rule of thumb.
Click to expand...
Hi Nick I got that bit. Its just a few days ago the meter was giving me weird numbers like 33 so I was trying to figure out how to adjust the heads buy 2 stops without a meter i.e. ambient f8 at 125 and ISO100 (max flash at setting #10 is f22) how much do you adjust the flash setting to equal f 8 without a meter.............do you go to 5.9 8.3 4.7 bla bla bla
 
ndwgolf said:
Hi Nick I got that bit. Its just a few days ago the meter was giving me weird numbers like 33 so I was trying to figure out how to adjust the heads buy 2 stops without a meter i.e. ambient f8 at 125 and ISO100 (max flash at setting #10 is f22) how much do you adjust the flash setting to equal f 8 without a meter.............do you go to 5.9 8.3 4.7 bla bla bla
Click to expand...

I don't even know what your flash system is or what distance you're shooting from. You're going to have to experiment but try this :

Meter for the background ( ambient light reading )

Underexpose on camera by one or two stops ( close aperture e.g from f/5.6 to f/8 or even f/11.

Fire flash manually if subject is too bright, turn the power down. If the subject is to dark up the power.

Some experimentation is required but you get an exposure you are happy with with two- three test shots.

If you can't get your flash power down you will need to move back from the subject.

Hope that helps.
 
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Cheers Nick
Thats pretty much what I have been doing and it has worked out okay............just sometimes when out in the field in bright sunlight the histogram shows a great exposure then when you get home the subject looks photoshopped as the flash was to strong................ and hear in asia looking on the back of a cameras 3" LCD it can be tough to see anything due to the bright sunlight.

Wait a minute I think I still have one of those hoodman thingies (I think thats what they call it) I will try and find that and pop it in the bag and try that.
 
ndwgolf said:
Simon the Profoto B1 heads just have a dial of 3 to 10 so where can you figure how much say 1 stop is when you move from 10 to say 8 on the B1 head
Click to expand...

Sorry, I don't know the Profoto system. With Elinchrom Skyport each button press is a 1/10 stop adjustment. It'd be fairly easy to do a test to see whether each integer on the Profoto dial corresponds to a single stop, though.
 
They do.

Each of the
ndwgolf said:
Simon the Profoto B1 heads just have a dial of 3 to 10 so where can you figure how much say 1 stop is when you move from 10 to say 8 on the B1 head
Click to expand...

3 to 4 is + 1 stop
4 to 5 is + 1 stop
8 to 10 is + 2 stops
10 to 8 is - 2 stops

Works really well
 
Cheers Pete
This forum is so frigging good with a wealth of knowledge......... Thanks guys
I am taking a hot Russian chick out on a shoot net week and crapping myself so trying to get my crap together before next week
 
ndwgolf said:
Yesterday when at the beach in 36 deg sun I was trying to get a flash meter reading using my Sekonic L308S meter. I had it set to T at 125 and in flash ready mode i.e. meter waiting for the flash to fire. I then fired the flash and it would then give me numbers like 22 30 33 etc etc never once did it give me say 5.6 or 11...why would it do that.
When I used it the day before it worked like i would expect it to work ?
Click to expand...


The 308 is pretty poor at flash metering in bright sunlight. Get a L478, as it gives you the difference between ambient and flash readings when metering flash, so you can see what's going on. Basically, when flash metering in bright sunlight, it display s BOTH ambient and flash readings on the screen at the same time.
 
Pookeyhead said:
The 308 is pretty poor at flash metering in bright sunlight. Get a L478, as it gives you the difference between ambient and flash readings when metering flash, so you can see what's going on. Basically, when flash metering in bright sunlight, it display s BOTH ambient and flash readings on the screen at the same time.
Click to expand...
Cheers David.
I looked at one of those before but decided not to get it as I can't trigger the B1 heads with it to test the flash. I was hoping that this light meter could do that............I will look at it again
 
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ndwgolf said:
Cheers David.
I looked at one of those before but decided not to get it as I can trigger the B1 heads with it to test the flash. I was hoping that this light meter could do that............I will look at it again
Click to expand...

As Pete said, you can adjust the flash heads as well... that will work, but seeing the ratio of ambient to flash on the meter is really useful sometimes.
 
Pookeyhead said:
The 308 is pretty poor at flash metering in bright sunlight.
Click to expand...

That's putting it mildly :D

I totally gave up using mine within minutes of testing it outside, in fact I don't even use it inside now either - must be time to sell it lol

I don't bother with a flash meter at all now

Dave
 
Pookeyhead said:
The 308 is pretty poor at flash metering in bright sunlight.
Click to expand...

That's putting it mildly :D

I totally gave up using mine within minutes of testing it outside, in fact I don't even use it inside now either - must be time to sell it lol

I don't bother with a flash meter at all now

Dave
 
ndwgolf said:
My quote above was meant to say I CANT trigger the B1 heads with the L478 light meter
Click to expand...


Wasn't referring to that... I meant post #17 in conjunction with the L308.

However... why can't you trigger the B1s with the L478 if you can with the 308? Just use a sync lead or a simple radio slave... they're about £10 on Ebay. Does the B1 not have a simple sync lead input?
 
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ndwgolf said:
17 times now..........wait 22 now
Click to expand...

Nope.... only once here, but the forum is being slow to respond after posting... I've accidentally clicked again this morning, and double posted.
 
Pookeyhead said:
Wasn't referring to that... I meant post #17 in conjunction with the L308.

However... why can't you trigger the B1s with the L478 if you can with the 308? Just use a sync lead or a simple radio slave... they're about £10 on Ebay.
Click to expand...
Because then you have something dangling off the bottom of it. I believe it has a pocket wizard inside so only works with that system and not with Profoto
 
DG Phototraining said:
in fact I don't even use it inside now either - must be time to sell it lol

I don't bother with a flash meter at all now

Dave
Click to expand...

I have no problems with the L308 in the studio.. It';s been flawless for nearly 15 years now. It's just got got no way of telling you that the ambient is overpowering the flash when shooting in bright sunlight.
 
ndwgolf said:
Because then you have something dangling off the bottom of it. I believe it has a pocket wizard inside so only works with that system and not with Profoto
Click to expand...

Yeah, but a little dangly thing never did anyone any harm :). Seriously, is that all that bothers you? £10, problem solved.

Incidentally, if you use the pocket wizard functionality, then you don't really need a flash meter at all, as surely you can just use them TTL in conjunction with a AC3 controller?

I assumed you wanted to use them manual, hence the flash meter. If so... £10 dangly thing... solved :)
 
I don't know if it's relevant here, but you can't use a flash meter to measure high speed sync flash. Neil has been using that recently. Or at least, you won't get anything reliable or consistent.

HSS is effectively a short burst of continuous light, that the shutter/sensor only see a small and variable part of, which the meter knows nothing about. The only reliable way is to take a picture.
 
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