DON'T MISS: Italian conceptual portrait photographer Sara Lando is coming to the US to teach in Atlanta (8/16) and Baltimore (8/23). Highly recommended.

Monday, September 01, 2008

Lighting 102 - 7.2: Time in a Bottle

Before we get to the assignment for this last unit in Lighting 102, I have one more technique for you to consider when using time as a variable for your flash photos. It's very useful, because it acts as a gear multiplier for those of you who may not have as many strobes as you'd like.

Given that a flash can record it's subject in an instant -- even if the exposure is spread out over a long time -- there are several ways to stretch a flash into looking several light sources when shooting a static object.

You'll remember Jonathan Boeke's cool shot from July in which he ran around during a time exposure popping his green-gelled flash from behind several trees to create this photo. It's a great idea, and you can easily see how it can make one flash look like a whole bag full of lights.

But you'll need a very dark environment and a long shutter to have time to make all of your locations for popping the flash. And if you screw up one pop, your whole photo is shot.

Another way to approach this is to use your camera's multi-exposure setting, if it has one. Some do, some don't. If your camera is so equipped, this gives you great flexibility and time to spare when you are lining up your various light locations.

If you do not have three PW's (one to manually trigger, one on the camera in relay mode and one on the flash) you'll want to wrangle a button-pushing friend to help. The camera, obviously, should be on a tripod.

If you'll remember, we set up a tag cloud for others who wanted to try this technique. You can see their resulting photos here.


For my take on Jonathan's night woods shot, I chose the multiple exposure route because it allowed me to control the ambient light. There was still plenty of twilight when this photo was taken, but since I shot each multi-exposure pop at a 250th of a sec, I could totally control my ambient.

I could even have chosen to lay down a, say, three-stop-underexposed ambient frame to flesh out the rest of the photo if I wanted. But I liked it better on black.

I tried the straight multiple exposure method about ten times (all pretty time consuming, too) and never got one I liked. So I decided to cheat. I use that term loosely, as there are no real "rules" for this kind of shot.

As far as I am concerned, any tool you have is fair game. So I decided to do this multi-exposure on separate frames and combine them in Photoshop. I shot each frame separately, and added each new photo a layer at a time, and combined them using the lighten mode. This simply compares the two layers, pixel by pixel, and the lightest pixel in a given location wins.

Which means it pretty much works like a multi-exposure -- except you can tweak each layer / flash pop before you add it to the final photo. You can shift the color, exposure, etc. It's a fantastic trick for shooting large scenes with one speedlight. I used my single loaner SB-900 for this one. (It turned back into a pumpkin last week and had to go back to Nikon.)

Thanks much to Photoshop Honcho Ben Willmore for the heads-up on the lighten technique.


The best way I can explain the advantage of being able to build this exposure around the totally controlled ambient is to say that I shot the photo at left almost an hour after the multi-pop photo. I think that kind of control is pretty cool, when you consider you are getting it with just one speedlight.

The soft look in this photo came from the fact that I used a plastic Holga lens (more on that here) on my D3. Kind of ironic, really - a $50 Holga lens on a D3. But I love the look, when combined with hard strobe.

And that's exactly what I did here -- camera on tripod, ambient underexposed a stop or two and a 30-second exposure. Just tripped the shutter and walked up to the side of the tree (out of the frame, tho) and popped the flash manually.

My choice of shutter for the multi-exposure shot above turned day into night, and the long shutter for this one turned night into day. Understanding flash / ambient control lets you do some cool stuff.


Speaking of Doing Cool Stuff

Now, it's your turn. You have just about everything I have to give on time manipulation of your flash photography. So for this, our last L102 assignment, your job is to shoot a still life. Your photo should contain a combination of flash and some form of time-based manipulation.

That's pretty wide open, I know. I wanted it to be that way because I thought we would make this one a little more interesting.

At the close of this assignment I will choose one shot, and the winner gets a set of Lighting Seminar DVDs, shipped anywhere in the world. Hopefully that will add a little layer of fun to the last assignment.


The Details

The deadline for this assignment is midnight, local, September 20th. Please make sure your photos are in Flickr and tagged before then. If you are a newb to Flickr, go ahead and sign up now (it is fast and free) and drop some photos in so you can get through the week-or-so waiting period before they let your tagged photos show up.


Here are your tags:

Strobist
Lighting102 (Note: no spaces)
Assignment
TimeInABottle (Note: no spaces)

and for your best shot, include the tag:

Final

You can see all of the take here. You can see the final edits here. Discussion is here.

Judging will be by a committee of one (yours truly). I will choose based on technique, creativity, how badly I wish I would have taken it myself, my general disposition at the time, what I may have had for breakfast in the morning, etc.

PLEASE NOTE: Please do not enter pre-existing photos into the running for the DVDs. I would like to award them to the best photo shot specifically for this assignment. We are doing this one on the honor system, but make sure your EXIF can back you up...

Best of luck to all, and I am looking forward to seeing what you come up with!


__________

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20 Comments:

Blogger Leigh Moore Photography said...

David,

Are we to see a Lighting 103?

All this talk of "last assignment" is a little worrying.

Cheers,
Leigh

September 01, 2008 12:55 PM  
Blogger Leigh Moore Photography said...

David,

Are we to see a Lighting 103?

All this talk of "last assignment" is a little worrying!

Cheers,
Leigh

September 01, 2008 1:00 PM  
Blogger Sean "Madman" Sullivan said...

Hi, David..just a thought when it comes to PW and this particular assignment...

Instead of multi-exposure or running around popping thed flash..if you have mulitple flashes and PW's, it's simple to set up say 3 flashes with 3 PW's, each on a different channel. Then you can stand behind your camera, start the long exposure and use a 4th PW to pop each flash in order. Just another thought..of course, this is assuming yoiu have multiple flashs and PW's...:) Doesn't everyone?

September 01, 2008 1:20 PM  
Blogger Ken said...

How about mixing flash with continuous lights over a timed exposure?

September 01, 2008 2:00 PM  
Blogger ProfRick said...

Dave, are you planning to develop a new program, using the questions that we submit (that you mentioned earlier), rather than a Lighting 103?

September 01, 2008 2:39 PM  
Blogger Richard said...

Danny Bird's already set the bar pretty high.

September 01, 2008 3:01 PM  
Anonymous Nathanael Gassett said...

Let's just say I am way late to the Lighting 102 thing (started from the beginning a few days ago). If I make it through all the delicious back copies, could I enter, or is it a 'class' thing?

_Nathanael

September 01, 2008 3:48 PM  
Anonymous Ben Willmore said...

Hi David,

Just an FYI for your readers. There are two blending modes that I use when combining multiple exposures:

Lighten: Compares each layer and only uses the content of a single layer depending on which one is brightest in a given location.

Screen: Combines the brightness of each layer as if the shutter was left open the entire time and the shot was done as a single exposure.

I also like to adjust the opacity of each shot to control how much they contribute to the scene and I often add Layer Masks to each layer and paint with black to hide areas of an individual layer that are not improving the image.

I use this technique all the time when I do light painting with a flashlight. You'll see many examples of that on my blog at www.whereisben.com I haven't been posting there all that much since I've been busy writing a new book. You'll find a few larger examples on my photography site at www.thebestofben.com

Let me know if you'll be at PhotoshopWorld since I'll be presenting a bunch of ideas similar to this one during my Shooting for Photoshop pre-conference session. This has been one of my large passions lately... coming up with different ways of approaching photography, knowing that I'll end up in Photoshop.

-Ben Willmore

September 01, 2008 3:49 PM  
Blogger David said...

Nathanael (got it right this time):

Jump right in -- the water is fine.


Ben:

Thanks much! I will try that technique, too!

-D

September 01, 2008 4:46 PM  
Anonymous Nathanael Gassett said...

@David,

Wicked! This should be fun. Time to study and experiment

I award you a chevron for spelling my name right, and on the second try no less! Nice work, commander. :D

_Nathanael

September 01, 2008 4:50 PM  
Blogger Pat Morrissey said...

Ah - a Jim Croce reference. Time to dig out the old vinyl ...

September 02, 2008 12:08 PM  
Blogger Michael said...

A note about using the "Lighten" technique: it doesn't give natural-looking results when there's subtle movement involved.

Early this summer I shot a sequence of about 50 frames over a field with firefly activity and combined them using "Lighten" to get the effect I wanted. It worked wonderfully for the fireflies, but the clouds turned into a strange blob that looked almost posterized. In some cases only a little more Photoshop might fix it right up, but I can imagine some problems depending on the composition.

September 02, 2008 4:48 PM  
Anonymous Dave Scarlett said...

One slight correction to what Ben Willmore said; the "screen" blending mode is not quite like leaving the shutter open. Screen is like the inverse of multiplication, and doesn't really have an equivalent in technique that I can think of (except maybe sandwiching together two film negatives before printing). The "linear dodge" blending mode, however, will act exactly like leaving the shutter open. This mode adds the individual RGB values of each layer.

So if you consider two layers containing 50% grey, a screen will take the inverse of the multiple of their inverses, giving 75% grey, while a linear dodge will add then, giving white. (Of course, the screen mode may still give good results.)

Another option is to take the average the exposures, which would be good if the illumination of each of your images overlaps a lot, and gives sufficient brightness in each image before merging. To do this, use the "normal" blending mode, setting the opacity to 100% on the base layer, 50% (1/2) on the 2nd lowest layer, 33% (1/3) on the next layer, then 25% (1/4), 20% (1/5), 17% (1/6), etc.

One nice benefit of the averaging technique is that it reduces noise. Here's an example where I took a series of 15 second exposures of the night sky at ISO 3200 on a Canon 400D. (For reference, I consider ISO 800 to be bad on the 400D and 1600 almost useless.) I then rotated the images to align the stars, so that I wouldn't get star trails, and merged them together using the above technique. The merging of 9 ISO 3200 shots brings the noise level down to the equivalent of about ISO 350! (I also did a lower ISO long exposure for the foreground, which I light-painted with a flash, and merged this image on top of the others using a mask.)

http://www.flickr.com/photos/7308212@N05/2132560825/

September 02, 2008 8:45 PM  
Blogger Chris Peters said...

For the rest of us who can't afford a $50 Holga or the thought of tearing it apart, there's plastic wrap! It even comes in colors: red, green, blue, yellow and orange, depending on the season or holiday.

September 06, 2008 8:54 PM  
Blogger shutterblade123 said...

I am not sure where to ask this question. I am new to this blog/forum. How want to purchase my first strobe lights. Do you have any suggestions.

September 14, 2008 9:06 PM  
Anonymous Dave Scarlett said...

Shutterblade123 - See that section at the top right of the page that says, "FIRST TIME HERE"? That's a good place to start, especially the "Lighting 101" link. ;-)

September 19, 2008 10:24 AM  
Blogger Meds Davidson said...

I have just finished the entire 101 & 102 a few days ago, wonderful & thank a lot DAVID to share such encyclopedic like info with us the whole world . Thank you a bunch & I keep reading on the entire things you put regularly.

July 02, 2012 5:40 PM  
Blogger Meds Davidson said...

I have just finished 101 & 102 Thank you David for this encyclopedic like site to teach us how to light Thank you a lot. I read the blog regularly everyday & night I can't imagine my photographic life without it anymore. Thak youuuuuuuuuuuuuuuu

July 02, 2012 5:45 PM  
Blogger Reuben said...

I've just finished reading through 101 and 102 (in preparation for learning to use my first speedlight) and I must kindly thank you for all of your hard work on these lessons.

It feels like I've learned a lot about flash in a few short days of reading straight through each article.

Now I won't be like a deer in the headlights when I first turn my speedlight on :D

July 05, 2012 7:06 PM  
Blogger Nicholas Caldwell said...

Who won? :-) I just finished reading 101 and 102 for the first time. I say for the first time because I am now going to go back and re-read them. Fabulous series and I am working through the assignments and learning soooo much. Thank you, David!

July 25, 2012 2:33 PM  

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