Lighting question

[dustin0479]

Have been playing with my strobes over the past week. One thing I am struggling with is that as I try to alter my DOF it requires me to take a ton of test shots to tune the exposure back in. Are there any tricks to make it quicker/smoother? If I set my exposure at say 1/250. F/5.6 and use EC to tune it, will I be able to use my meter to quickly capture the proper exposure moving forward since I have compensated for the strobe lighting?

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[KmH]

You can recalculate the exposure on the basis of stops.

If you stopped the lens down 2 stops you need 2 stops more light from your strobes if you want to maintain the same lighting ratio.

I recommend using a decent hand held light meter that can meter strobed light.

[katerolla]

I use a light meter but I also change my setting through out my shoot, these are the setting I use, 1/160 F2.8 ISO 50 | 1/160 F 3.5 ISO 100 | 1/160 F 5.6 ISO 200 | 1/160 F8 ISO 400 and so on, I have found using a shutter speed of 1/160 works better fo me that 1/200 as this couses a curtain shadow on some photos as the stobes are not consistent.

Hope this helps

[dustin0479]

I guess my question since I dot have a light meter is, can I just use EC to compensate so my exposure meter on camera is reflecting proper exposure?

[KmH]

Your camera light meter cannot meter the strobed light, unless you're using an iTTL flash mode.

What kind of strobes do you have?

[MLeeK]

I am with Keith on recalculating, but the numbers get me sometimes so here's my "stupid" method... I am praying it doesn't confuse you in writing because in action it's so incredibly simple.

I think in terms of clicks. Each click of shutter or aperture is 1/3 of a stop plus or minus light. Every 3 clicks is one stop. If I increase my aperture by 3 clicks I have to increase my light by one stop somehow.
If you are changing aperture AND shutter speed you need to keep a running tab: Increase 3 clicks in aperture and decrease 1 in shutter is taking away 2 clicks of light meaning you need to increase your light equal to 2 clicks. Your camera increases to the right and decreases to the left when changing settings-so do my strobes. If I go 6 to the right in one and 2 to the left in another then I have to go 4 to the right on the strobe or 1 1/3 stops.

So if you start out at your strobe on full power at f/6.3, shutter of 1/50 and you decide to decrease to f/2.8 that is 7 clicks or 2 1/3 stops to the left. You have to make your light equal 7 clicks or 2 1/3 clicks to the left. Depending on your strobe you may only be able to do full stops, but I know mine I can go in between.
If you decrease to f/2.8 but (-7) but increase your shutter to say 1/125 (+4) you then need to decrease your light by -3 clicks or one stop.

[dustin0479]

Great info! Where I get a bit confused is identifying exactly what is a full stop on the lights. Assuming I start at full power, if I need to drop one stop on the strobes what setting would I dial down to?

image-213475781.jpg

[MLeeK]

Each of those measurements is a full stop. The ticks in between are your partials.
If you are at 1/1 or full power and you want to drop one stop you'd go to 1/2

[dustin0479]

Thanks. I will continue practicing with them using this method, all great info! Last question, are there any good rules of thumb to make dialog in the proper exposure when first setting up quicker or is it just practice and knowing the numbers over time?

[MLeeK]

The guys may give you a rule of thumb, but for me-no. It all depends on the image I am trying to create how I set up.

[Helen B]

Great info! Where I get a bit confused is identifying exactly what is a full stop on the lights. Assuming I start at full power, if I need to drop one stop on the strobes what setting would I dial down to?

Some strobes are marked in light output, some in power (actually energy, but we call it power). Sometimes the two vary together, sometimes they don't. Going from 1/1 to 1/2 should give you one stop less of light, but it may not. It's a starting point, but don't trust it. The theoretical stop differences are 1/1 - 1/2 - 1/4 - 1/8 - 1/16 - 1/32 (sorry for stating the obvious). With some strobes as you turn the variator right down, not only does the light output not change in the proportion you would expect, but the output can become variable - ie two successive shots at 1/32 may not be at the exact same light output. This does not happen with strobes that switch capacitors in and out to vary the output, it only happens with some strobes that have variators. Neither of these are huge problems, just something to be aware of.

[KmH]

A 'stop' is 2 times more, or 1/2 as much.

Lens aperture stops are based on the square root of 2 (1.4142) because it's the lens apertures total area that changes, not the lens opening diameter. f/2 lets in 2x more light than f/2.8 does (2 x 1.4142 = 2.8).

Stops of shutter speed, ISO, or light output are times 2 or divide by 2. 1/2 power makes 2x more light than 1/4 power does. 1/1000 lets in 2x more light than 1/2000 does, ISO 1600 is 2x more sensitive to light than ISO 800 is.

[Helen B]

I am with Keith on recalculating, but the numbers get me sometimes so here's my "stupid" method... I am praying it doesn't confuse you in writing because in action it's so incredibly simple.

I think in terms of clicks. Each click of shutter or aperture is 1/3 of a stop plus or minus light. Every 3 clicks is one stop. If I increase my aperture by 3 clicks I have to increase my light by one stop somehow.
If you are changing aperture AND shutter speed you need to keep a running tab: Increase 3 clicks in aperture and decrease 1 in shutter is taking away 2 clicks of light meaning you need to increase your light equal to 2 clicks. Your camera increases to the right and decreases to the left when changing settings-so do my strobes. If I go 6 to the right in one and 2 to the left in another then I have to go 4 to the right on the strobe or 1 1/3 stops.

So if you start out at your strobe on full power at f/6.3, shutter of 1/50 and you decide to decrease to f/2.8 that is 7 clicks or 2 1/3 stops to the left. You have to make your light equal 7 clicks or 2 1/3 clicks to the left. Depending on your strobe you may only be able to do full stops, but I know mine I can go in between.
If you decrease to f/2.8 but (-7) but increase your shutter to say 1/125 (+4) you then need to decrease your light by -3 clicks or one stop.

Aren't we talking about strobes here? Changing the shutter speed should not make any appreciable difference as long as the shutter is at or slower than sync speed, unless the strobe is being overwhelmed by ambient light.

[MLeeK]

I am with Keith on recalculating, but the numbers get me sometimes so here's my "stupid" method... I am praying it doesn't confuse you in writing because in action it's so incredibly simple.

I think in terms of clicks. Each click of shutter or aperture is 1/3 of a stop plus or minus light. Every 3 clicks is one stop. If I increase my aperture by 3 clicks I have to increase my light by one stop somehow.
If you are changing aperture AND shutter speed you need to keep a running tab: Increase 3 clicks in aperture and decrease 1 in shutter is taking away 2 clicks of light meaning you need to increase your light equal to 2 clicks. Your camera increases to the right and decreases to the left when changing settings-so do my strobes. If I go 6 to the right in one and 2 to the left in another then I have to go 4 to the right on the strobe or 1 1/3 stops.

So if you start out at your strobe on full power at f/6.3, shutter of 1/50 and you decide to decrease to f/2.8 that is 7 clicks or 2 1/3 stops to the left. You have to make your light equal 7 clicks or 2 1/3 clicks to the left. Depending on your strobe you may only be able to do full stops, but I know mine I can go in between.
If you decrease to f/2.8 but (-7) but increase your shutter to say 1/125 (+4) you then need to decrease your light by -3 clicks or one stop.

Aren't we talking about strobes here? Changing the shutter speed should not make any appreciable difference as long as the shutter is at or slower than sync speed, unless the strobe is being overwhelmed by ambient light.

You are right and I wasn't even paying attention to what I was posting. I was more worried about not confusing... and there I went and did it anyway!

[480sparky]

............I think in terms of clicks. Each click of shutter or aperture is 1/3 of a stop plus or minus light. Every 3 clicks is one stop. ......

Not always. Some cameras it's 1/2, others a full.