How to use flash with long exposure?

[vinunleaded]

I am picturing a photo with the main subject in the middle of the crowded city street and everyone moving around him. Obviously I need to do a long exposure but I want to use implement Flash as well. How do I do that?

[Jmark11207]

http://lithe.files.wordpress.com/2008/05/nike-just-do-it.jpg?w=300&h=300

lol

The flash will freeze your subject so it wont look like they moved at all
I would also use Second curtain sync

[vinunleaded]

I tried doing long exposure with just regular flash before. The flash will just fire first then the long exposure kick in. I did achieve the mood I was going for but the colors were not how I wanted because it did not capture the flash for some reason. Ill give 2nd curtain a try

[gooble]

You can try isolating the flash to your subject only with something like a snoot, that way your subject will be frozen by the flash while the surrounding moving objects will blur.

[Jmark11207]

I shot this one with a bare 430exII

Not the greatest pic but I think its close to what you want to achieve
http://lh5.ggpht.com/_-KM4Guk9iyE/SoODV_1ia2I/AAAAAAAARWE/xDjszbrvU04/s576/Dan000001.jpg


ISO: 400
Exposure: 1/3 sec
Aperture: 4.0
Focal Length: 22mm
Flash Used: Yes
Latitude: n/a
Longitude: n/a

[vinunleaded]

Is there anyway I can fire my Flash manually during the exposure NOT before. Because when I fire the Flash regularly it will just do it before the exposure and not get captured in the picture.

[vinunleaded]

jmark what were your settings?

[FlyingPhotog]

Second Curtain Sync with the Flash in Manual mode so that you don't get an ETTL Pre Flash.

[Jmark11207]

Vin the Exif info is under the pic

This was also handheld (no tripod)

[Jmark11207]

Is there anyway I can fire my Flash manually during the exposure NOT before. Because when I fire the Flash regularly it will just do it before the exposure and not get captured in the picture.



If the exposure is long enough you can time it and fire the test flash while the shutter is open but your flash SHOUD be firing while the shutter is open anyway

[vinunleaded]

http://farm4.static.flickr.com/3438/3819581608_42fb87a069_m.jpg

http://farm3.static.flickr.com/2557/3819581956_3b275658d5_m.jpg

The first picture the Flash was implemented correctly. But when I tried to do it with a long exposure on the 2nd pic the colors look totally wierd. The Flash might have fired during the exposure but the subjects still blurry for some reason. Perhaps im doing something wrong?

[Jmark11207]

You moved and there was enough ambient light to pick up on that movement. Thy this shot when its darker out

[gooble]

Slightly larger pictures with EXIF would help. What were your WB settings?

What do you mean by "flash was implemented correctly"?

[vinunleaded]

I always shoot RAW with Auto WB. How do I extract the EXIF info?

The flash lit the main subject without lightning anything else such as the guy on the outside of the car already lit by the ambient light.

[wickerprints]

As others have pointed out, you need to underexpose the ambient lighting more, so that the parts of the subject illuminated by flash are rendered sharp, and the same subject illuminated by ambient is too dark to contribute much to the image.

You have to experiment and find just the right ratio of flash to ambient, as well as the correct exposure time.

[vinunleaded]

yea i think i got enough information from this post to give it a second try. This is why I love this forums so much. Everyone shares their knowledge.

[niqqunos]

Here's a trick I've used before...

Ideally you will have a very dimly lit scene (think the middle of the night with few streetlights) so that you can pretty safely use a 30 second (or even better, bulb) exposure without over-exposing the image. If 30 second exposure is overexposing, drop the ISO as low as it can go and boost up the aperture.

You will need a tripod, the flash off the camera (but still turned on) and a matte black card (or at least something dark that will cover the front of your lens). Set up the scene how you want it, but leave the subject out of the frame to start with. Take the shot then wait till the 20-25 second mark (counting is the key here!) then cover the front of the lens with the black card so that your subject can walk into shot without any light trails of them. Remove the card and fire a test flash at the subject which should illuminate them sufficiently for the relatively short time they will be in the frame. Hopefully this all happens before the shutter closes!

Using the black card to block light into the lens is basically the same as doing the shot in 2 exposures, without the need to combine them in photoshop later.

Some tips: position the subject where you want them first, then set focus to them (with an aperture of between f8-f22 minor changes in their position later won't matter too much). Once you've got them in focus, set the lens to manual focus and don't change anything!

If you're getting adventurous (and can do slightly shorter exposures), set a very wide aperture (f2.8-f4) and mark exactly where they subject will be standing so you can have a nice shallow DOF with the subject still sharp but bokeh on the cars/streetlights etc in the background.

Hope this all makes sense and is of some use to you!

I had fun doing it when I last did (several years ago) and I was doing multiple flash fires in the 30 second exposure with subjects moving around so it looked as though there were several of the same person in the shot :)

Also, this technique works well with fireworks to get nice sharp (non-light trail) shots too!

[niqqunos]

I shot this one with a bare 430exII

Not the greatest pic but I think its close to what you want to achieve
http://lh5.ggpht.com/_-KM4Guk9iyE/SoODV_1ia2I/AAAAAAAARWE/xDjszbrvU04/s576/Dan000001.jpg


Where did that severed leg crossing the road come from?! :p

[jdear]

with canon - you need to use TTL for achieving 2nd sync. It has something to do with what pins on the flash are used.

The only other way, triggering remotely is using a PW multimax unit.
The MM unit has an intervalometer where you can specify in how many seconds (up to 9.999) after the trigger is triggered, the remote flash will fire. You only need one MM unit and it will talk to the others (tried it with a MM+PLus II)

The interval will be sligthtly shorter than the exposure time. Eg. 8 secs will be around 8.899 not 8.999 which misses the closing of the curtain.

as said previously, flash will freeze any movement that happened before the flash went off.

Gonna do something similar, and hopefully video it coming up.

[gooble]

Here's a trick I've used before...

Ideally you will have a very dimly lit scene (think the middle of the night with few streetlights) so that you can pretty safely use a 30 second (or even better, bulb) exposure without over-exposing the image. If 30 second exposure is overexposing, drop the ISO as low as it can go and boost up the aperture.

You will need a tripod, the flash off the camera (but still turned on) and a matte black card (or at least something dark that will cover the front of your lens). Set up the scene how you want it, but leave the subject out of the frame to start with. Take the shot then wait till the 20-25 second mark (counting is the key here!) then cover the front of the lens with the black card so that your subject can walk into shot without any light trails of them. Remove the card and fire a test flash at the subject which should illuminate them sufficiently for the relatively short time they will be in the frame. Hopefully this all happens before the shutter closes!

Using the black card to block light into the lens is basically the same as doing the shot in 2 exposures, without the need to combine them in photoshop later.

Some tips: position the subject where you want them first, then set focus to them (with an aperture of between f8-f22 minor changes in their position later won't matter too much). Once you've got them in focus, set the lens to manual focus and don't change anything!

If you're getting adventurous (and can do slightly shorter exposures), set a very wide aperture (f2.8-f4) and mark exactly where they subject will be standing so you can have a nice shallow DOF with the subject still sharp but bokeh on the cars/streetlights etc in the background.

Hope this all makes sense and is of some use to you!

I had fun doing it when I last did (several years ago) and I was doing multiple flash fires in the 30 second exposure with subjects moving around so it looked as though there were several of the same person in the shot :)

Also, this technique works well with fireworks to get nice sharp (non-light trail) shots too!

Good tips. I'll also add that when using your black card to block the lens, even if it is matte it could amount to a reflector if you have it angled to a significant light source as you place/remove it from in front of the lens so be sure not to point it towards any light. Doing so can reduce contrast and light spots in the image.

[Jmark11207]

Where did that severed leg crossing the road come from?! :p


Well it WAS shot in NY :)

[mahanee]

2nd curtain

http://img6.imageshack.us/img6/5313/82201268737917017142217.jpg