So What Does it Mean to Drag the Shutter?

Title of thread speaks for itself.
Scenario: night. Minimal light on rear deck of house.
600 ex on 5D3 with 24-70.
Distance from group of ten friends ten feet max.
What mode in camera? What mode on flash?
What ISO?

And whatever concrete answers you can provide. Thank you.
Mark

"Drag the shutter" basically means to use a longer shutter speed than normal to brighten up the ambient light.

If you took the picture of your friends at night with flash, they'd be lit up, and the background would probably b e pitch black... let's say the shutter speed was at 1/60. If you slowed the shutter speed down to let's say 1/8, you're letting in about 3x more light than at 1/60, so the background would be brighter. Your flash should be on ETTL mode so if you dragged the shutter, the flash knows to decrease the strength of the flash since less power is needed.

MDJAK wrote in post #16419464
Title of thread speaks for itself.
Scenario: night. Minimal light on rear deck of house.
600 ex on 5D3 with 24-70.
Distance from group of ten friends ten feet max.
What mode in camera? What mode on flash?
What ISO?

And whatever concrete answers you can provide. Thank you.
Mark

Manual
Manual
Depends on how much light you want on the censor and how long you want to drag the shutter.

MDJAK wrote in post #16419464
Title of thread speaks for itself.
Scenario: night. Minimal light on rear deck of house.
600 ex on 5D3 with 24-70.
Distance from group of ten friends ten feet max.
What mode in camera? What mode on flash?
What ISO?

And whatever concrete answers you can provide. Thank you.
Mark

Minimal light on the rear deck is difficult since we have no idea how much light exists and the reflectance of the background and existing objects.

Since we do not wish to give too bright of flash to the subjects, I'd read the ambient light levels and then adjust to a sufficient ISO level that will allow a balanced look.

Set to Aperture priority so the flash can auto adjust and allow the shutter to automatically set itself according to an acceptable level you calculated when you determined the ISO.

Since you have ten friends, you still want adequate DOF, so normally I'd try for f8, shutter speed on about a third of a second and ISO that will allow this.

Since there are too many unknowns, this is how I'd attempt the shot. I'd prefer a second flash to the side to allow better dimension, but you stated only one flash so you will just have to deal with flat lighting.

fashionrider wrote in post #16419495
If you took the picture of your friends at night with flash, they'd be lit up, and the background would probably b e pitch black... let's say the shutter speed was at 1/60. If you slowed the shutter speed down to let's say 1/8, you're letting in about 3x more light than at 1/60...

A technicality, but an important thing that should be understood...

Going from 1/60 to 1/30 is 2x more light
Going from 1/30 to 1/15 is 2x more light
Going from 1/15 to 1/8 is 2x more light

So going from 1/60 to 1/8 is +3EV or 8X more light (2*2*2), not 3X

MDJAK wrote in post #16419464
Title of thread speaks for itself.
Scenario: night. Minimal light on rear deck of house.
600 ex on 5D3 with 24-70.
Distance from group of ten friends ten feet max.

...And whatever concrete answers you can provide. Thank you.
Mark

'Dragging the shutter' does not enter consideration necessarily...at least not by the questions posed.

MDJAK wrote in post #16419464
What ISO?

You could pick ISO 100 or ISO 1600, ISO 1600 particularly if you wanted to capture some of the dim ambient light.

I would suggest M on camera...
because I hate it when a Canon in Av mode decides to select such an infernally slow shutter speed (in an attempt to capture some of the dim ambient light) that only someone who had turned to stone could hand hold the camera without visible blur from the ambient light! It took a very long time for Canon to address that shortcoming!

No reason to need anything different than ETTL.

Now to the Subject of the thread...Dragging the shutter means to use a slower shutter speed to allow ambient light to register more and more; not 'use a longer shutter speed than normal '...after all, what defines what is 'normal' in these circumstances?!

fashionrider wrote in post #16419495
Your flash should be on ETTL mode so if you dragged the shutter, the flash knows to decrease the strength of the flash since less power is needed.

ETTL is good choice for the flash but the italicized statement is wrong. Below sync speed shutter has no impact of flash exposure. The flash duration is much less than the shutter speed and it gets shorter as the power is reduced.

For your situation manual on the camera and, depending on the ambient light "drag" the shutter to get the ambient within -2 EV of 0 on the camera meter. Have the FEC set to 0 or maybe just a little on the plus side defending on how dark the background is and the average tonality of the subjects in the foreground. Depending on your camera (newer is better) higher ISO shouldn't be a problem. If practical, bounce the speedlite into a wall to your side and maybe a little in front. The bounce flash will help light up the background.

Wilt wrote in post #16419773
A technicality, but an important thing that should be understood...

Going from 1/60 to 1/30 is 2x more light
Going from 1/30 to 1/15 is 2x more light
Going from 1/15 to 1/8 is 2x more light

So going from 1/60 to 1/8 is +3EV or 8X more light (2*2*2), not 3X

Ah, my fault. You are right. Stupid math :P

dmward wrote in post #16419861
ETTL is good choice for the flash but the italicized statement is wrong. Below sync speed shutter has no impact of flash exposure. The flash duration is much less than the shutter speed and it gets shorter as the power is reduced.

I see what you're saying... but that depends. If there is ambient light on the subject, then the subject will get darker/brighter with the shutter speed since ambient light hitting the subject is affected by shutter speed. If 1/60 shutter almost kills ambient lighting (since it's so dim at night), then dragging the shutter to 1/8 will bring up the ambient. If the subject is properly exposed without flash at 1/8, adding flash will overexpose it. ETTL understands the ambient is bright enough and will weaken its flash.

fashionrider wrote in post #16420103
If the subject is properly exposed without flash at 1/8, adding flash will overexpose it. ETTL understands the ambient is bright enough and will weaken its flash.

Just that the flash still uses the same power - but for a shorter interval. It isn't the intensity but the time that is the adjustable parameter in the flash.

examples

http://neilvn.com …ues/dragging-the-shutter/

Well, first and foremost, thanks to all. And thanks for those examples by Neilvn.

I'm sorry that I cannot post pics taken last night, as I didn't take them. I was amongst the group and the pics were being taken with my buddy's 5D3 and 600 as I said.

What I didn't (and still don't to a degree) understand, is how when you slow the shutter to allow ambient light in, that doesn't create blur when any subject moves even slightly. That is something I always experience. It's either that or camera shake or both that result in lousy shots.

I now see how a commenter above said dragging the shutter may not have been the right thing in this circumstance. It was night. It was very dark. The only light falling on the subjects was front light from overhead "spots" under the roof eave. Behind was basically pitch black.

Slow shutter speeds is problematic when hand-holding the camera.

With a tripod you might collect more light from the non-moving background while the group is kept in the dark and so doesn't contribute to the image. The flash then burns and represents a short exposere of the people while the flash is to weak to add extra lighy to the far-away background.

So dragging-the-shutter isn't always applicable - if there is too much light on the people then they get overexposed or fuzzy while the background accumulates.

MDJAK wrote in post #16420591
What I didn't (and still don't to a degree) understand, is how when you slow the shutter to allow ambient light in, that doesn't create blur when any subject moves even slightly. That is something I always experience. It's either that or camera shake or both that result in lousy shots.

The general rule is this:

The smaller the ratio of Ambient exposure : Flash exposure, the less blur there will be.

If you take a photo at night at ISO 100, f/8 etc, 1/200. with flash only, you freeze basically anything.

But if you take a photo in a low light venue at ISO 1600, f/1.2, 1/10, then it will be a blurry mess even with flash

MDJAK wrote in post #16420591
What I didn't (and still don't to a degree) understand, is how when you slow the shutter to allow ambient light in, that doesn't create blur when any subject moves even slightly. That is something I always experience. It's either that or camera shake or both that result in lousy shots.

Precisely the problem that sometimes cannot be avoided. Like this example just taken, Av mode in low ambient light, camera meter wanted 1/5 f/5.6 at ISO 800. I used flash, so my hand was frozen at that moment, but because I was waving my hand rapidly back and forth, it would register at different positions during that 1/5 and the density at any one position was determined by the latent period that my hand was at one spot before moving back in the opposite direction -- this accounts for the three (or more) places where you can see one finger at different densities within the shot. In addition to subject motion, due to camera motion, one can see blur of background items. What smorter called the blurry mess.

MDJAK wrote in post #16420591
What I didn't (and still don't to a degree) understand, is how when you slow the shutter to allow ambient light in, that doesn't create blur when any subject moves even slightly. That is something I always experience. It's either that or camera shake or both that result in lousy shots.

You understand it perfectly. Any type of movement in the background can blur but it all depends on the flash strength and/or how many you use. Flash gets weaker over distance. The term is falloff. The flash will freeze objects that are close because it is the dominant light source. Once it becomes weaker over distance ambient becomes the dominant light source and the shutter speeds will produce the same results as not having a flash on at all.

That is an old photogs trick in a very low light situation. You shoot at slow shutter speeds like 1/15 and freeze subjects. As long as there is not much movement in the background a little background blur is acceptable. Guests standing around holding drinks is OK. People break dancing in the background is not so good unless that is the look you are going going for.

The solution is we can shoot with higher higher ISO's to keep the shutter speeds faster. Many shoot at 6,400 or higher if need be. If you get a good exposure (both ambient and flash) noise is not too difficult to fix.

Here is an image I shot at 1/15. I prefocused then swept the camera while pressing the shutter. Notice the flash froze the t shirt which was about 6 feet away. The xmas tree was about 12 feet and is blurred.