Assignment #14, lighting to isolate subject

Posted: Sun Jun 11, 2006 10:10 am

This assignment is about using your flash to isolate the subject against a black background. This is especially useful for closeup photos but has many other applications.

The method is thus:

1. You place your flash quite close to the subject matter (for closeup shots about 6" from the subject).

2. You set your camera for the lowest ISO available.

3. You set the smallest f/stop available

4. You use the highest shutter speed that will synch with your camera.

5. Make a test shot with the flash OFF. You should be grossly underexposed and the image should look mostly black.

6. Turn on your flash and aim it at your subject (side lighting or back lighting is good).

7. Take your shot.

Here is a picture showing the setup:

NOTE: I took this picture with my point and shoot camera against a white backdrop to best show the setup. For actual shooting you can use no backdrop or you can use a black backdrop. If you use a black backdrop then either paint the base black and rest it on the black backdrop or poke a hole in the paper and feed the dowel through the hole and into the base.

I don't know why it came out so small--someone should explain what I did wrong here. And NOW ITS TOO BIG!

You can shoot outdoors (but probably not in bright sun as you will have too much ambient light). If you shoot outdoors this is a very easy setup. Bring along a friend to hold the flash, then focus and shoot. Since the flash will have a duration as short as 1/10,000 of a second camera shake is a non-issue. Since you are using your smallest f/stop, depth of field is a non-issue. You are depending on the lighting to separate the object from the background and you will not have to worry about throwing the background out of focus.

If you are shooting indoors, then you will want to make the setup that I did for the picture above. It cost me 80¢.

I bought a 1/4" dowel from Lowes (80¢). I painted it matte black with some black latex paint.

I had a piece of 3/4" particle board (plywood or MDF will work also). The board is about 15" square. I located the center and drilled a 1/4" hole in the center. I simply pushed in the dowel and I was done.

If you have forgotten your High School geometry for locating the center, ignore that and guess. This is not a machine shop project. Try to make the hole as nearly vertical as possible.

The dowel comes in 4 foot lengths and I cut mine down to 3 feet for convenience. Since the dowel is interchangeable, you can use any lengths you choose.

I used rubber bands to attach the flower to the dowel. Electrical tape or twist ties will work fine.

Or sharpen the end in a pencil sharpener and use it to pierce an apple or veggie (no cauliflowers please).

If you cannot reduce your flash's output to the required levels, then resist the urge to move the flash further from the subject. Instead rubber band onto the flash a layer or two of white copy paper. This will reduce the output. If you have Rosco's Neutral Density gels, that will work also.

Your result should look like the subject is jumping out of a black background. You can add a reflector to fill the shadow side if you like.

This method will also work for some nature work. Say, for instance you want to photograph a bird at your bird feeder. Place one flash to the right of the feeder and one to the left. Have one on full power and the other on 1/2 power. The bird will be well lit and the background will go dark. All action will be frozen and the great depth of field will aid in obtaining good focus.

To add interest in flower shots bring along a spray bottle with water to mist the flowers or bring along a eye dropper bottle with mineral (baby) oil. Add the "water" drops with the eye dropper. This will not harm the plant.

Here's an example shot with my Canon PowerShot A540:

NOW IT'S TOO BIG!

NOTE: For this exposure I needed to place 3 layers of copy paper in front of the flash to cut down on the flash output which I had set on Manual (1/16th power).

Joined: 07 Jun 2004 Posts: 1016 Location: Newcastle, UK

*deleted image*
http://i66.photobucket.com/albums/h264/Packard_photos/IMG_0034.jpg
You linked to the smaller photobucket preview and not the destination file, as far as i can see, the link above works :)

Posted: Sun Jun 11, 2006 11:16 am

Yeah, can you fix the 2nd shot also?

Thanks.

Posted: Sun Jun 11, 2006 11:18 am

OMG!!!!
Packard took a digital picture and posted it.
I'm at a loss for words!!
I don't know if The End Is Near or it's The Second Coming.

He did it with his P&S, and it came out pretty darn good.

"You might want to check the shadows. I'd invite them back for a reshoot." (I've been dying to say that...)

Joined: 07 Jun 2004 Posts: 1016 Location: Newcastle, UK

*image deleted for tidyness*

Posted: Sun Jun 11, 2006 11:32 am

Thanks.

Joined: 07 Jun 2004 Posts: 1016 Location: Newcastle, UK

As circled copy that whole link and paste here instead of the whole right click>properties malarky.
Alternatively take the links you have and remove the "th_" after your photobucket account name in the link.
ie http://i66.photobucket.com/albums/h264/Packard_photos/IMG_0040.jpg
instead of http://i66.photobucket.com/albums/h264/Packard_photos/th_IMG_0040.jpg (thumbnail)

Joined: 07 Jun 2004 Posts: 1016 Location: Newcastle, UK

Oh and ive been dying to ask, did you really take Sean Connery's photo or do you just like the image?

Joined: 07 Jun 2004 Posts: 1016 Location: Newcastle, UK

Triple post ftw! anyway

I resized them to forum regs. doesnt seem to be distorted, oh and they were like twice the DPI visible on any standard monitor.
http://img.photobucket.com/albums/v293/Timmynoshoes/IMG_0041.jpg
http://img.photobucket.com/albums/v293/Timmynoshoes/IMG_0034.jpg

Those links just require [IMG][/IMG] either side to make them work.

EDIT: just hit 500 posts and almost missed it, weeeeeeeeeeee!

Joined: 07 Jun 2004 Posts: 1016 Location: Newcastle, UK

If you just download the images from my photobucket then upload to yours, then link them, should work perfectly.
Oh and any moderator can feel free to delete my messy posts when this is sorted :P

Just to re-iterate i think the problem you are having is the images are 180 DPI and web resolution is 72dpi (monitors cant see beyond 72dpi) therefore you are almost doubling your image size, photobucket conteracts this for images above a certain size (200kb i think) and then resizes them.
This may be the problem your having.

Posted: Sun Jun 11, 2006 2:11 pm

Is there any way to do this assignment without an external flash? All I have is the flash on my camera but I can't focus 6" away...

-cEc-

Posted: Sun Jun 11, 2006 2:46 pm

Cookz wrote:

Is there any way to do this assignment without an external flash? All I have is the flash on my camera but I can't focus 6" away...

-cEc-

Sure, you can get by with the onboard flash. You don't need to be 6" away. Just try stopping down to f/16 and beyond. See point #3 in Packard's post, that is very important. ;)

You could also use a lamp to help isolate your subject...

Or you can do a long exposure in a dark room and just paint your subject with a flashlight....

Or you could make a paper vignetter to help isolate your subject...

Many, many options...

:) keithwms

Posted: Sun Jun 11, 2006 6:07 pm

Timmynoshoes wrote:

Oh and ive been dying to ask, did you really take Sean Connery's photo or do you just like the image?

It was a gift; donated to the "Packard Avatar Response Team", and I don't remember who donated it. Plus (and this is the scary part) whoever donated the image has it on his//her Photobucket album and if they get angry at me they can delete it and there is NOTHING I can do about it. And I don't know where I'll be able to replace it. I am sick with worry as you can well imagine.

To answer your question, "Yes, I took the picture".

Posted: Sun Jun 11, 2006 6:27 pm

Cookz wrote:

Is there any way to do this assignment without an external flash? All I have is the flash on my camera but I can't focus 6" away...

-cEc-

You can isolate the subject with a tungsten light but you will have to do it in full darkness.

One of the reasons you want the flash so close has to do with light fall off. I've never been too good with the math end of photography, so if I am in error here, someone please point it out.

Light falls off at the rate of square of the distance. For instance if you have a light that is 3 feet from your subject and the background is 3 feet beyond your subject, then the distance from the light to the background is twice the distance from the light to your subject. But being twice the distance means that the background receives 1/4 the amount of light (2 squared = 4).

Now if the light is just 6 inches from your subject and your background remains 3 feet away, then the background is 6 times the distance from the light as is the subject. Then the background is going to receive 1/36th the amount of light that the subject is (6 squared = 36). I'm re-reading this and I think it should be 7 times the distance and 1/49th the amount of light.

In the first instance the fall off of the light is not sufficient to render the background fully black.

In the second instance the fall off of the light is sufficient to render the background black.

The second reason you want the flash so close is that the flash becomes fairly large relative to the subject and being large makes the light source soft. If you move the flash back the light source becomes hard (because the light is smaller relative to the subject). I can expand on this if it is not clear.

If you use a tungsten light it has got to be immensely bright in order to achieve this effect. I think you will need to borrow an off camera flash.

My camera will not fire an off camera flash. I used a peanut trigger and held it in front of my on camera flash and covered the flash with my hand while I shot. Very awkward, and my digital is not well suited for this task.

If, on the other hand, I used my Hasselblad I could shoot at 1/500th of a second and at f/32; I would use my extension tube which reduces the effective aperture to f/64. My background would definitely go black, I would only have to shoot a test roll of film to determine the correct exposure. Wait a week and and re-shoot once the correct exposure has been determined.

In this case I took the first shot at the lowest output of my flash and the image was completely blown out. I added 1 sheet of paper to reduce the output, then a 2nd sheet and finally a 3rd sheet. Once I had the correct exposure I saw that the rubber band I was using was showing up in the image. So I shucked off the sheath around the stem, re-rubber-banded it, and used the sheath to cover the rubber-band.

Then I took 2 shots and posted the better of the two. I spent 10 minutes setting up; 30 seconds shooting; and 2 hours figuring out how to post the damned things.

But in fine, I think that this assignment is going to require an external flash. The main advantage of this system is that once you have the exposure down pat you can work exceedingly fast. I had a girlfriend years ago that worked at an arboretum and she wanted me to shoot a catalog of about 1,500 plants. Instead I set her up with this lighting arrangement and she was able to shoot them herself. A neat way to get out of a huge freebie and she was so pleased that she could do such professional looking work.

Joined: 14 Apr 2006 Posts: 224

Packard I have a question.....

I have an exteranl flash, but unfortunately I have the Nikon D50 which does not have the flash commander. The external flash is an SB-800 which I can set to SU-4.

I don't know if it's clear in my head, but the idea I get is that you don't want the on-board flash to fire..is this correct?

If so can you give me an idea of how to do this shot with the set up that I have?