I'm sorry, I already posted this series, but I could not resist saying a few things that might enhance this capability. You are probabloy aware of these methods if you understand photographic principles, but many people today take great photosas an artistic medium without having hte slightest clue about photographic principles. This might help them/you or hopefully somebody.
The author speaks of using the depth of field by averaging the focus for effect. He also points out what light differential results from the the effect of using the macro for both the subject and the foreground, which offhand looks about 1:8 or more to me.
I want to treat both of these phenomena with the same narrative and use the author's photo and set-up to make a few points.
First: You can also further control the depth of field by doing several things. One is that the further back you are from the subject(s) the greater your depth of field. So with a sharp lens you could get both images more sharply focused. The wider the angle of your overall lens, or the zoom setting you chose has a similar effect; the wider the nagle, the greater the depth of field. The converse is also true.
Using a smaller f/stop will give you a grater depth of field.That is, the larger the numerical value, the smaller the diaphram opening, and the greater the depth of field and the opposite logic also follows. This is like me, withpretty bad eyesite these days squinting to reduce "my visual f/stop" in order to make out the details of something without my glasses. Same principle (sort of).
Using a faster lens will also enable you to maximize this technique by offering an inherently larger opening to open the f/stop to--in order to further blur a background. Using a higher ISO setting will effectively increase your depth of field by allowing you to stop down further.
We use to double exposures with film stills and the aid of a matte box and block-outs to get two subject in focus. This is very easy to do in any decent image-manipulation software today, after the fact. You merely take two seperate frames and give some thought to how they will combine. We also would do this in the darkroom with two seperate negatives sandwiched together.
To make a good image you had to under-expose by about one value on one or both of the images in order to have a workable density with the two negatives so sandwiched. This screwed the color fidelity all to heck, and you then had to correct both the exposure and color the best you could inh the darkroom.
I might also point out that with the digital cameras (film too, but for different reasons) you get more distortive and larger funkier grain when using a higher ISO. The author of the article speaks of a "fuzzed" effect. This can be controlled almost to the nth degree by varying the ISO if you have the right equipment features and/or enough light. But just as with film, your color fidelity is not quite as good.
The background can be made lighter or darker by using a flash and one of the more sophisticated exposure features represented by the little sybols that many people say, "What the . . . is that for?" . They have different proprietary names, but what the features do is allow the lens to stay open a longer or shorter amount of time in conjunction with the flash sync speed, thus controlling hte amount of ambient light that is allowed to reach the CCD or film along with the flash. Many a photographer using film cameras with slow sync speeds had learned this "creative effect" accidntally when shooting fast-moving sports photographs just before dusk when you had to use a flash but at the sync speed you stil got a blurred ghost-image from the ambient light that was not wanted. I won't go into how to solve this problem since few people have such restrictions anymore.
Another way to reduce the lighting ratio from foreground to background is to change you exposure mode. By selectively using different averaging schemes or spot reading light-reading modes you can get varied results. As a matter of fact you can also use one of the different focusing modes in the same way to change the depth of field. I would choose manual focus for this.
Notice that the ratio of light from front to back in the writer's picture taken when he either backed off or changed from macro to standard mode is still evident, it is merely not as pronounce. His auto-flash/exposure scheme probably changed too. This gives me the chance to point out another useful bit of lighting knowledge too whether or not it fully explains the larger ration of far to distant components in the macro-image (I simply don't have enough information to do more than make a guess as to what caused it. The thing I want to hightlight however is called the inverse sqaure law of light.
If you know any physwics or math you ca probably guess what this is. If you don't, it is almost intuitive, but it is even better when you know how to quantitatively use this idea. The law merely means, stated in the simplist terms I know how, that as you double the distance (increase or decrease by ANY distance, but I am saying DOUBLE in order to make it simpler to explain) the fall-off of light decreases not at a simple half as one might think, but by the distance times itself--or exponentially.
For example, if the grindstone in the foreground is four feet away from the light source (assume a constant flash, with zero ambient light for simplisity sake) and the subject in the background is double that distance, eight feet away from the light source, the "fade-off" (dispersion) of light would be what?
The ratio from front to back would not be 1:2-- HALF as much light on the subject, which is DOUBLE the distance from the light source. It would decrease (thus we say it decreases inversly proportionate to the SQUARE, OF the difference INCREASE in distance. the distance increased by two times. So, 2 squared (2x2=4) means that it decreased four times or by one fourth. If the distance from the light source increased by three times (again for simplicity of calulations) it would not be a ration of 1: 3 it would be what? Three times squared or 3x3=9, tells us that the ration is now 1:9.
This Inverse Square Law of light is what makes a lot of things possible and easy to calulate in photography--such as using flash guide numbers.
I got carried away, so Iwill stop with that, but suffice it for me to say theat there are a lot of ways to skin felines.
