# Manaul vs TTL with Speedlights - Need Assistance



## LShooter (Jul 9, 2012)

I've been shooting for years, but mostly shoot art prints of objects, wildlife and street photos. For a couple months I've been trying to practice portraits with speedlights, both indoors and outside.  I have read every book, website, forum, etc., and still can't come up with a simple way to get it to stick and make sense in my brain!

I have a 580 EX II and a 430 EX II, softboxes, reflectors, stands, etc. Inside I have limted space. Outside, is well, outside.  I'm shooting a 5d Mk III and have plenty of glass.

What I struggle with is trying to figure out what is the best starting point for my camera settings and flash setting to obtain nicely lit portraits.  After moving lights up and back, tweaking settings, etc., I can get it.  But I can never seem to start in a close ballpark or make the right tweaks to move in the direction I'm trying to get to, without a headache.

Where do I start (with my settings) for indoor, outdoor, bright background, dark background, etc.???

Help me make sense of all this please!


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## Big Mike (Jul 9, 2012)

I would suggest using the lights in manual mode....that way, their output will be consistent, which allows you to get familiar with where they will need to be etc.  E-TTL can be great when you're in a fast paced 'event' type setting, where every shot might need different power from the last.  But when it comes to shooting portraits, it's likely going to be easier if you have full (manual) control over the output from your lights.
The camera, of course, should be in manual mode as well.

For example: after a while, you might find that if you use your 580EX at 1/4 power, in a soft box...that it will be correct exposure for a subject at 6 feet away and camera settings of F4 and ISO 100. (numbers just for example).  Some photographers get so they can nail it right off the bat, but if you get pretty close, it won't take long to just tweak it a bit from there.  

Another good option would be to get a flash meter.  An often recommended one is the Sekonic L 358.  Using this, you could set up your light(s), take a reading and then just dial those settings into the camera.  Nice and easy.


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## LShooter (Jul 9, 2012)

The other part of the equation with my confusion is this: is it true to say, that the in camera meter will never show a proper exposure when using flash and should I ignore the in-camera meter altogether when using flash?


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## o hey tyler (Jul 9, 2012)

LShooter said:


> The other part of the equation with my confusion is this: is it true to say, that the in camera meter will never show a proper exposure when using flash and should I ignore the in-camera meter altogether when using flash?




Yes, if you're using manual flash. It won't do you any good, because it's not calculating flash exposure for you.

There are a few exceptions to this rule, like if you're trying to expose for ambient light as well. In a studio though, you'd want to use a dedicated light meter that does strobed light and incidental (unless you're able to totally cut out incidental light in the studio)


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## Big Mike (Jul 9, 2012)

The in-camera meter shows your exposure for the ambient light.  So if you are in a situation where the ambient light/exposure will be part of your photo...then you should pay attention to it.  For example, if you are shooting a portrait outdoors and you want the background to be balanced with the flash exposure, or maybe slightly darker than your subject.  In that case, you would use your 3 in-camera exposure settings to get the ambient exposure you want.  You can then use your flash to get the exposure for the subject that you want.

The key things to remember in this scenario, is that ISO affects both flash and ambient exposure, Aperture affects both flash and ambient exposure, Shutter speed affects only ambient exposure (but keep the shutter speed under the max flash sync speed), the power on the flash, and it's distance to the subject will affect the flash exposure (of the subject).


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## LShooter (Jul 9, 2012)

Thanks for the info thus far! So then, why do I hear often, in a portrait session, indoors, folks start at f/8, ISO 200, 160? Why is that the magic number? Does that work both TTL and Manual? What gives? Please explain...


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## KmH (Jul 9, 2012)

f/8 is usually used because it delivers the sharpest focus, and acceptable DoF. 1/160 is good for eliminating subject motion blur and camera shake. ISO 200 is good because that helps get to 1/160.

To meter strobed light (flash) you need a flash light meter so you can measure the quick burst of incident light the strobe light produces. The in-camera meter only measures reflected light, and can't measure incident light.

The camera shutter speed controls the ambient light exposure, while the lens aperture and strobe light power output control the strobed light exposure. If strobe light power is increased, lens aperture is stopped down to maintain the same strobed light exposure. Camera shutter speed is often limited by the camera's flash x-sync speed.

For portraiture it is usually beneficial to have the ambient light exposure at least 1 stop darker then the strobed light exposure (a lighting ratio) so as to promote subject separation from the background.

Watch this video - Shutter/Flash Synchronization - YouTube


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## LShooter (Jul 10, 2012)

Keith, thanks for breaking it down. When you say to have the ambient light one stop darker than flash, how do I know what is one stop more than the flash? Via a meter? Flash settings aren't expressed in stops. Or just one stop less than the recommended dead center meter reading? And does it matter if it is stopped down via ISO, Tv or Av?


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## KmH (Jul 10, 2012)

Shutter speed controls the ambient light exposure, so using ISO and aperture priority would not work. 

A stop is a doubling or a halving. So speedlight power output that is reduced from full power to 1/2 power has been changed to deliver 1 stop less light. Changing speedlight power from 1/16 to 1/8 is a 1 stop increase in light.

Conversely, a 1 stop change in shutter speed would be from 1/160 to 1/80 and the longer shutter speed of 1/80 would brighten the ambient light exposure. As long as lens aperture and speedlight power is not changed the strobed light exposure also does not change.

When doing strobed light photography I pretty much ignore the camera's reflected light meter.

I couldn't afford to trust TTL flash because it is to inconsistent.
The flash and the camera are not intelligent, they are both just following a program some camera software engineer wrote several years back. The camera and flash have no clue what you are shooting, and they have no clue what your artisitic goals for the shot are. With each slight change in camera position the software gets differnt information form the camera's light meter and may change the camera settings.

That's what makes TTL inconsistent.

Learning to use TTL is a much steeper learning curve than learning how to control flash using manual camera and flash controls.


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