Oh, come brewing storm, come quickening night, the end is nigh, the end is high. This is it, the final, the fourth post, in our three part post about macro photography and depth of field! (Yeah, that's right, this is part four in a three part article!)
So to continue our discussion of advanced depth-of field tricks:
5) Another way to increase the amount of out-of-focus area is using a telephoto lens. The longer the lens in mm, the more narrow the focus range of any given aperture will be. That is, f/5.6 on a 17mm lens will capture way more in focus than f/5.6 on a 105mm lens! Like huge gigantic woolly mammoth difference!
That said, most people don't use long lenses for shooting macro work because (as you can see below) tele lenses drastically compress space, both in and out of focus. Basically meaning things look more like paper cut-outs than 3-D objects which means that images become simplified.
It's a fine line, and most people have to play around with what they like personally. If it counts for anything, I tend to shoot macro images with wide lenses jammed in really close. But often I'm trying to get more depth of field than not…
Here's a couple of images to demonstrate. I'm going to leave everything but the lens length the same, and move the camera to make the frame as close to the same as the lens will allow. Remember to click the images to make them bigger. Be looking for the way the lenses squash space, but also what objects are and aren't in focus as the same f-stop.
17mm, f/5.6, 1/3 shutter, ISO 100
40mm, f/5.6, 1/3 shutter, ISO 100
105mm, f/5.6, 1/3 shutter, ISO 100
Pretty drastic, neh?
6) Okay, moving in to the crazy underworld for the level-85-uber-photo-warlock-nerd, you could get a shift-tilt lens like a Lens Baby to really mess with the focus. What is this you ask? Well, basically that imaginary perpendicular plane that defines your focus, these lenses let you move that from parallel to other crazzzzzyyyyy angles. Basically, instead of the focus going forward and back, it can go sort-of left and right or up and down, or a combination of all three.This is really hard to visualize unless you know optics really well, but really easy to see in a photo. Keith Carter uses this trick for great artistic effect here (see how the pole is out of focus up and down, but stuff on the left in the back is in focus? Trippyyyyy):
Copyright to Keith Carter and whatever site I stole this image from years ago.
Basically it will allow you to place very specifically where the out of focus areas are. Now this option might work, but it's very severe and kind of gimmicky (a bit like a double-necked-guitar in rock), rather than natural. But these lenses aren't super expensive, so it might be a good tool to have in your kit if you like the look. The "Control Freak" is probably the best option for table-top.
7) Lighting, while not a technical nor camera concern, can often be used to accentuate or build similar visual readings to actual optica selectivel focus. If you check out any film noir movie you can see this used for a tremendously power effect. Even in a scene where you have a mid-range f-stop you can spotlight the main subject and "flag" your lights (which means using bits of foil to prevent light for going where you don't want it) to control where your eye will go.
You can blow areas out, making them too bright to determine details, or put areas in shadow to make them un-readable compared to the main subject. These aren't depth-of-field answers specifically, but in the viewer's brain they can function in a very similar way.
[Another portion of controlling your light is that all that ambient light bouncing around your house can muck up the color. Nothing like a whole set of frames with weird blue highlights and nasty yellow-green shadows to make you bash your head on your keyboard after a long day in the studio. So try to work in an area that is as dark as possible except for the lights on the subject. I often will shoot at night with the windows closed and all the house lights off for this reason. Then I can put gels on the lights if I want coloration. ]
Here's a pair of examples, which if you notice, are shot at the same aperture, f/11, which produces decent depth of field:
All house lights and studio lights on. 40mm, f/11, 1/4 shutter, ISO 100
Blinds closed and all house lights out but one snooted studio light. 40mm, f/11, 1.33 shutter, ISO 100
And if you want to see what I'm talking about snooting and flagging to control the light, you can see in the following image (which is a fake shot mimicking how I made the second shot) I've wrapped with front of the light in foil leaving only an inch or so opening so the lighting only hits the central subject. Additionally, I'm holding a bunch of sheets of paper just out of frame to block the light from slightly spilling on to the back area.
As a parting thought most artists combine and use many of these techniques to get the shots they want. Feel free to play around. Move your lights, move your camera. Experiment! This guide is just the smallest amount of what you'll discover on your own.
I hope these posts have been informative — My next two guides are going to be on building a digital darkroom at home (great for all of you new grads from photo school) and also a full guide on building an amazing, sensibly priced home stereo system. Follow my blog of grab my RSS feed and you'll be the first to see them.
You can check out my portfolios of art at http://www.eronrauch.com including my documentary photo project on anime conventions, "Bridges of Desire" and my work on virtual landscape photography, "Land to Die In" among others!