Question: Slowest shutter speed for portraits

Sony 24-70mm F4 Vario-Tessar T* FE OSS

01/06/2009 10:33:05 AM · #1

This always comes up, but I keep forgetting to ask... 'till now!
How slow will you go when doing outdoor portraits with strobes?

Sometimes, in an effort to allow just the right amount of ambient light... without wanting to up my ISO any further... I find that my shutter speed is getting rather slow. I am using (often two) strobes to throw additional light on the subject. But I am afraid to let the shutter speed dip down to 1/60 or longer. I am often using a tripod in such situations, so it is subject movement I am worrying about (and I HATE telling anyone to stay very still).

Do you have a particular cut-off shutter speed when doing outdoor strobe-assisted portraiture?

Bear_Music

Samsung Galaxy S24 Ultra

01/06/2009 10:35:29 AM · #2

Back in the day, I went as slow as half a second with a tripod, shooting film at twilight. I'd always warn the subject to stay still, of course...

R.

Man_Called_Horse

Canon EOS-300D Rebel

01/06/2009 10:43:12 AM · #3

Back in the day, when cameras were made of wood, and the timer was in the head of the photographer...

That photographer used devices, I don't know the correct terminology, to keep the models in place.

I can't say if they were attached to the device, but maybe more of a reference point for the model so as not to move while the image was being burned onto the silver plates.

So, in theory, you can have your camera on bulb, as long as the model doesn't move.

That is what I did here in this image with my greatest model of all.

01/06/2009 11:57:32 AM · #4

But let's assume that I want to end up with an image that doesn't include any motion blurring of the subject (a good percentage chance of that being true). What's the slowest shutter you would consider using? My thinking is that I should stay faster than 1/60 and tell the subject to strike a pose - hold for the flash - and strike another.

dwterry

Canon EOS-1D Mark III

Sony 24-70mm F4 Vario-Tessar T* FE OSS

01/06/2009 11:59:13 AM · #5

It all depends on how much ambient light is hitting the subject, and how fidgeting the subject is. If you can keep the ambient light off of the subject, you can shoot very slow. Seconds long even. Because only the strobe light matters and it's nearly instantaneous. But the more ambient light you have, the more you have to worry about whether the subject will move.

Bear_Music

Samsung Galaxy S24 Ultra

01/06/2009 12:11:10 PM · #6

Originally posted by dwterry:

That's the point, yup. If the ambient light, say is an after-sunset sky, and the subject is essentially silhouetted against it, you can get away with really slow speeds. But you want to be sure to use rear-curtain synch, since you're "releasing" the subject to move after the flash goes off, and if you're flashing on conventional synch then the flash is at the beginning of the exposure and the "drag" is all after, when subject is likely to begin moving once more.

R.

Ken

Canon EOS-7D

Pentax D-FA* 70-200mm f/2.8 ED DC AW

01/06/2009 12:45:25 PM · #7

Originally posted by Bear_Music:

Thank you - I never knew which to use in this situation.

SaraR

Sony Alpha a7R III

Sony FE 24-70mm f/2.8 GM

01/06/2009 01:48:04 PM · #8

Originally posted by Ken:

Thank you - I never knew which to use in this situation.

Ditto. I am a complete eejit as far as assimilating knowledge regarding artificial lighting and flash, but threads like this are slowly sinking in.

K3Master

Pentax K-3

01/06/2009 01:49:56 PM · #9

Originally posted by Man_Called_Horse:

Good god man, getting a child to not move on Bulb? I salute you.

01/06/2009 02:13:12 PM · #10

It all depends on how much ambient light is hitting the subject

Yes, that is exactly where I was headed with the initial post... I am trying to balance with the (mid-to-late sunset) ambient so I do want some natural light falling on the subject... I do not want to speed things up so much that the flash is completely canceling the ambient. On those occasions I am wondering about how long I can leave my shutter open. I am still thinking that anything slower that 1/60 would mean trouble.

dwterry

Canon EOS-1D Mark III

01/06/2009 04:13:07 PM · #11

Originally posted by Bear_Music:

But you want to be sure to use rear-curtain synch, since you're "releasing" the subject to move after the flash goes off

That's a very good point, and one easily missed. Many people will hold still right up until the flash goes off and then they figure the picture has been taken. So first curtain sync means they are HIGHLY likely to move during the ambient light exposure. Second curtain sync fools them into holding still until the flash exposure takes place, which means the ambient exposure is already done.

Excellent tip!

dwterry

Canon EOS-1D Mark III

01/06/2009 04:17:28 PM · #12

Originally posted by Bernard_Marx:

I do want some natural light falling on the subject...

Do you? You are front lighting them with ambient light?

In a sunset situation, you typically have the sunset behind them. They effectively become silhouettes. So even if they do move during the ambient light exposure, all you see are black edges surrounding them (no detail).

If you're front lighting them with ambient light, then there's the possibility of the ambient light being a different color from your flash (that can be good or bad, but you need to be aware of it).

Basically, I'd only worry about movement if the ratio of the ambient front lighting is close to the back lighting (like in a lit room where you want the room details to remain even while properly exposing the people with flash). But where back lighting overpowers the front lighting, you really don't need to worry about shutter speed so much.

Sony 24-70mm F4 Vario-Tessar T* FE OSS

01/06/2009 04:39:37 PM · #13

Rear-curtain sync is the same as second curtain sync on a speedlight - right? I seem to recall that you can't use second curtain sync when you have your 580EX set to Master and are using it to control slaves... but I can't be sure about that.

Sunset. I knew I shouldn't have said that. I am not strictly talking about typical sunset portraits. Let me try and communicate what has happened to me before:

There I am shooting my model and the light is starting to fade a bit. I want to expose the background as is or just a stop lower and use the speedlights to mostly light the subject and add some drama and pop. But the resultant shutter speed (exposing the bg as I like) now says 1/15 (imagine). I think to myself... damn, that's going to cause subject-motion-blur. But if I increase my shutter speed to 1/100 then my lights are going to contribute more light then what I want and the bg will be darker than what I would like.

I think maybe I am missing a subtle point somewhere...

Bear_Music

Samsung Galaxy S24 Ultra

01/06/2009 04:48:05 PM · #14

Originally posted by Bernard_Marx:

Yes, they are the same thing. And if 580EX as a master won't allow you to do it, then you need a different setup. But it can be done,a nd should be done.

Originally posted by Bernard_Marx:

There I am shooting my model and the light is starting to fade a bit. I want to expose the background as is or just a stop lower and use the speedlights to mostly light the subject and add some drama and pop. But the resultant shutter speed (exposing the bg as I like) now says 1/15 (imagine). I think to myself... damn, that's going to cause subject-motion-blur. But if I increase my shutter speed to 1/100 then my lights are going to contribute more light then what I want and the bg will be darker than what I would like.

I think maybe I am missing a subtle point somewhere...

Maybe you are, yes: the ambient light controls the exposure on the surround and there isn't a thing you can do about it except: bump the ISO, or; open the aperture. Those are your only options for getting a quicker shutter speed, since the light is what it is, you can't control it.

But using rear-curtain synch will minimize the drag problems a LOT, if you take the time to make your model aware of what the situation is. If you're looking for the ability to freeze frames within long, flowing, extended motions, you are gonna have problems every time if the ambient lighting is too dim; but if your model can move-and-hold, move-and-hold, you can get a pretty good rhythm going. Good models can do this. If you're talking portraiture of amateurs, you need to be on location a little earlier or adjust your expectations of the shot.

R.

Mephisto

Nikon Coolpix A

Panasonic Lumix G 14mm F2.5 ASPH

01/06/2009 05:17:46 PM · #15

it also depends on what lens you're using, or rather what focal length.
for example in this shot

i was using my 20mm sigma prime which allowed me to use 1/15sec to get enough ambient light while using an 11 aperture to balance with the 2 flashes i set up to light the model.

01/06/2009 06:03:31 PM · #16

This sort of conversation is what I love about dpc. Thanks guys!