Help me understand metering with no flash meter

I have a very good grasp of general photography and my flash and how to use it attached to my camera. How to read the light to a degree. SOOOO, I stepped to a whole new ballgame. Off camera flash. I bought a Westcott 43" umbrella and stand can cactus v4. Welcome to the world of manual flash.

here is the questions I have so far. I have been reading Strobist.com A LOT. have a good idea. I have a grey target that I have been using to read exposure and white balance. I don’t' have a flash meter. I have been playing around and have my flash (580exii) set to 1/8 power. camera around 800 iso/ 100-125 shutter / f4-8 (lens goes to 2.8) just tinkering around.

now you know what I have. here is the question
1) what is good basic setting. let’s say I have umbrella as a shoot through. umbrella high subject left behind me, roughly 6-8 feet from subject (wife) what is a good setting to have flash set to?

2) good way to meter? put camera on center point metering and meter her face. snap picture and see what it does, then adjust shutter, or f-stop (depending on DOF I want) and or iso.

3)lets say I want background 1-2 stops underexposed of subject. what is best way to do that without having to run to flash and adjust that. meter background ( ex: iso 800/125/f5.6) and I want wife to be proper exposed based on flash, speed up shutter speed one stop to underexpose background one stop?

4) off subject question. one change in iso is equal to how many stops of light? if I want from iso 100 to iso 200. what is that equivalent to say f-stop. one stop of light is f1.8 to f2.0 or one click faster in shutter speed. is that equivalent to one stop of iso? (sorry camera is not in front of me so don't have exact numbers.

Q4
Light is Measured in Stops
you have aperture (whole stops 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 44 etc)
Shutter speeds (whole stops 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1sec 2 sec etc)
ISO (whole stops 50, 100, 200, 400, 800, 1600, 3200, 6400 etc)
you camera will actually adjust these in 1/3 or 1/2 stop increments (the clicks you refer to earlier or f1.8 - f2 is 1/3 of a stop)
A whole stop is a doubling or halving of the amount of light (changing from Iso 100 to iso 200 makes the sensor twice as sensitive, requiring half the light so either a whole stop of aperture, or a whole stop of shutter speed to adjust.

Q3
yes that will work sometimes.
when you make a picture exposed by flash there is actually 2 things happening.
the ambient exposure, and the flash exposure.
adjusting the shutter speed will only affect the final picture if there is enough ambient light to do something with.

lets use a basic example - a room lit to give a correct exposure at 400 ISO 1/125 and f4
and the flash set to give the same amount of light at the right distance.

Adjusting the ISO or Aperture in the above example is going to affect the flash exposure, but the shutter speed will only affect the ambient.
so adjusting the shutter speed to 1/250 will cause the background to be underexposed one stop, with the subject still being lit by the flash.
you will probably notice any shadows on the subject getting darker too.

if the room is too dark, then the only way to adjust the background exposure is to either set up a second flash to light the background, or adjust the flash - subject and flash - background distances.
if the subject is exactly halfway between the flash and the background, the background will be 2 stops underexposed (due to the inverse square law) moving the background closer will result in less underexposure, and further away will result in it being darker.


Im not going to start on the first 2 questions, as i dont really use enough manual flash - i know the theory, but dont use it much.

hope this helps though

bphillips330 wrote in post #9305379
I have a very good grasp of general photography and my flash and how to use it attached to my camera. How to read the light to a degree. SOOOO, I stepped to a whole new ballgame. Off camera flash. I bought a Westcott 43" umbrella and stand can cactus v4. Welcome to the world of manual flash.

here is the questions I have so far. I have been reading Strobist.com A LOT. have a good idea. I have a grey target that I have been using to read exposure and white balance. I don’t' have a flash meter. I have been playing around and have my flash (580exii) set to 1/8 power. camera around 800 iso/ 100-125 shutter / f4-8 (lens goes to 2.8) just tinkering around.

now you know what I have. here is the question
1) what is good basic setting. let’s say I have umbrella as a shoot through. umbrella high subject left behind me, roughly 6-8 feet from subject (wife) what is a good setting to have flash set to?

2) good way to meter? put camera on center point metering and meter her face. snap picture and see what it does, then adjust shutter, or f-stop (depending on DOF I want) and or iso.

3)lets say I want background 1-2 stops underexposed of subject. what is best way to do that without having to run to flash and adjust that. meter background ( ex: iso 800/125/f5.6) and I want wife to be proper exposed based on flash, speed up shutter speed one stop to underexpose background one stop?

4) off subject question. one change in iso is equal to how many stops of light? if I want from iso 100 to iso 200. what is that equivalent to say f-stop. one stop of light is f1.8 to f2.0 or one click faster in shutter speed. is that equivalent to one stop of iso? (sorry camera is not in front of me so don't have exact numbers.

Start here:

http://super.nova.org …hnique/BasicMet​ering.html

Use his white towel method.

bphillips330 wrote in post #9305379
One stop of light is f1.8 to f2.0 or one click faster in shutter speed.

One stop is from f/1.4 to f/2, for example. f/1.8 to f/2 is 1/3 of a stop.

If you're going to use a manually controlled flash setup and attempt to blend the light from it with ambient light, you really should invest in a good handheld meter such as the Sekonic L-358. Using a good meter that can measure the light from the flash as well as ambient light is the ONLY way you can stop guessing.

The alternative is an endless game of trial and error.

"now you know what I have. here is the question
1) what is good basic setting. let’s say I have umbrella as a shoot through. umbrella high subject left behind me, roughly 6-8 feet from subject (wife) what is a good setting to have flash set to?"


With that example you can bring the Umbrella in much closer drop the flash power and use ISO 100 you are getting harsher light with the source further from subject .

David

apersson850 wrote in post #9307155
One stop is from f/1.4 to f/2, for example. f/1.8 to f/2 is 1/3 of a stop.

yeah, i realized that after i typed it. i remeber the 1 and 1.4 are startint point... oops hehehehe

dpds68 wrote in post #9307452
"now you know what I have. here is the question
1) what is good basic setting. let’s say I have umbrella as a shoot through. umbrella high subject left behind me, roughly 6-8 feet from subject (wife) what is a good setting to have flash set to?"

With that example you can bring the Umbrella in much closer drop the flash power and use ISO 100 you are getting harsher light with the source further from subject .


David

Thanks! I just have to play around. went to a seminar once and remeber him saying something about 6-8 foot range is a good full light scenario. problem, he had a high power flash in a soft box, not a little 580 exii (i know not small, but not power of a studio flash)

Echo63 wrote in post #9306243
Q4
Light is Measured in Stops
you have aperture (whole stops 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 44 etc)
Shutter speeds (whole stops 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1sec 2 sec etc)
ISO (whole stops 50, 100, 200, 400, 800, 1600, 3200, 6400 etc)
you camera will actually adjust these in 1/3 or 1/2 stop increments (the clicks you refer to earlier or f1.8 - f2 is 1/3 of a stop)
A whole stop is a doubling or halving of the amount of light (changing from Iso 100 to iso 200 makes the sensor twice as sensitive, requiring half the light so either a whole stop of aperture, or a whole stop of shutter speed to adjust.

Q3
yes that will work sometimes.
when you make a picture exposed by flash there is actually 2 things happening.
the ambient exposure, and the flash exposure.
adjusting the shutter speed will only affect the final picture if there is enough ambient light to do something with.

lets use a basic example - a room lit to give a correct exposure at 400 ISO 1/125 and f4
and the flash set to give the same amount of light at the right distance.

Adjusting the ISO or Aperture in the above example is going to affect the flash exposure, but the shutter speed will only affect the ambient.
so adjusting the shutter speed to 1/250 will cause the background to be underexposed one stop, with the subject still being lit by the flash.
you will probably notice any shadows on the subject getting darker too.

if the room is too dark, then the only way to adjust the background exposure is to either set up a second flash to light the background, or adjust the flash - subject and flash - background distances.
if the subject is exactly halfway between the flash and the background, the background will be 2 stops underexposed (due to the inverse square law) moving the background closer will result in less underexposure, and further away will result in it being darker.

Im not going to start on the first 2 questions, as i dont really use enough manual flash - i know the theory, but dont use it much.

hope this helps though

Thanks!

I would suggest that if you don't have a light meter, or if you're saving up for one, a perfectly acceptable metering method is to use a white balance target specifically designed for metering as well. Check this link:

https://photography-on-the.net …php?p=9240606#p​ost9240606

111t wrote in post #9308061
I would suggest that if you don't have a light meter, or if you're saving up for one, a perfectly acceptable metering method is to use a white balance target specifically designed for metering as well. Check this link:

https://photography-on-the.net …php?p=9240606#p​ost9240606

I own one of those that is what i use

This is a good series on lighting

http://www.youtube.com​/watch?v=uH84-pA7p-c

bphillips330 wrote in post #9308073
I own one of those that is what i use

Did you watch the video that came with the photovision target? Do you have questions beyond the scope of that video?

Let me look at the actual questions in the op.

1,2&3) You decide what the ratio is in advance. The only time i set the camera to the light is when i can't change the light. (outdoors for example.) There you set your camera to the sunlight and then decide what you want you're other light to be. (more less or equal) then adjust your secondary light source to that reading. You can set the iso up or down or the sutter speed to try and get the ambient light to cooperate outdoors. Keep in mind that with a focal plane shutter (all canons) you can only go as high as the sync speed if you are filling with flash. Those lucky enough to have a medium format camera with a leaf shutter don't suffer from this limitation.

In the studio: Say you want f-8 on your fill... set the target at the subject position aimed mostly towards the camera position and slightly towards the light. Set the camera at 8. Modify the light to get the proper exposure. You can turn the flash up or down, slide the umbrella in or out, (this focuses the light like a maglite and is most effective with silver umbrellas) or move the light closer or further. These last 2 adjustments affect the quality of light so be aware. Then move on to the main light. Set the camera for that target exposure. (lets say 11) Then repeat the process you used on the fill. I do this with the fill off. When the main is set, switch both on and point the target straight toward the camera position for a final reading. (This will be a little more than the main reading say, 13 or 14) As far as the background reading, You can control that by varying the distance of the whole subject/main/fill combo from the background. Put the target up against the background in an area that will be in the frame. I find about 5 feet is a good starting point. Unless you are using highly directional light sources (snoots or grids) the main and fill will illuminate the background also. Because it is further from the lights, it will be less than the subject exposure. As i said, to alter the amount, you alter the distance of the main/fill/subject combo as a group. If you want an equal or higher reading on the backdrop, it is necessary to light the background separately. Keep in mind that the further you are from the backdrop, the larger it needs to be especially for wider shots. To makimize the size of the background be sure to be working in the telephoto range of your lens (very likely you'd be doing this anyway with a portrait)

4) Depending on what camera you have the ISO may be in full or 1/3 stops. The 50d has 1/3 stop increments. Think of the old film speeds to keep in mind what's what. 50, 100, 200, 400, 800, 1600, were the common ones. The settings in between are the 1/3 stop increments. You can adjust this, but keep in mind that in general the quality goes down with higher iso's. Also, with higher iso's it becomes possible to start recording ambient light which is probably not what you're after in a studio setting. I like to keep it around 100-200.