In this PQT I'll very briefly touch on Depth-of-Field and then give some examples of how to manage DOF when photographing snakes. If you would like addition information on DOF a Google search will produce many excellent and informative websites.
Cameras work best in two dimensions (height and width) and can reproduce these two dimensions fairly easily and accurately. However, the illusion of depth that you see in a photo be it a slide, print or on your computer screen is simply that - an illusion.
DOF is defined as the area in front of and behind the subject that is in acceptable focus. The smaller the aperture, the greater the DOF. Now here's where it gets a bit confusing. The opening of the aperture is measured in F-stops. The larger the F-stop number, the smaller the aperture and the greater the DOF. Inversely the smaller the F-stop number, the larger the aperture and the shallower the DOF.
In short:
F45 = tiny aperture opening = deep DOF
F3 = large aperture opening = very shallow DOF
The cards in the below photos are positioned 1 inch a part. The camera is focused on the queen of hearts and I'll adjust the aperture to show how the DOF is effected.
This first photo was taken at F3. Note how only the queen of hearts is in sharp focus.
This photo was taken at F8. Notice that additional cards are becoming sharp.
This last photo was taken at F32. Now all the cards are in sharp focus.
So, why not always shoot at F32? Three main reasons, the first is the amount of light needed to shoot using such a small aperture, the second is the slow shutter speed required to allow the camera to gather enough light to make an image. At F32 and under fairly normal lighting, the camera has to be on a tripod and the subject must remain motionless. The third reason is creative control. Often it's preferable to blur the background and/or foreground so that all the viewer's attention is on the subject.
Now that the basics of DOF have been explained, we'll apply this info to some snake photos.
To keep things easy I've replaced a snake with a 3 foot section of rope.
This is a fairly standard scenario for a snake photo. Replace the tripod with a person holding the camera. The photo resulting from this type of set-up will produce an image in which the middle section of the snake is acceptably sharp, but the head and tail end of the snake are beyond the expectable DOF and will be blurry.
There are a few adjustments that we can make to the snake's position and to the substrate to help get the entire snake in sharp focus.
The first method is to coax the snake under a round lid, Frisbee, trash can lid, etc.
This places the snake in a natural looking coil pose while reducing the required amount of DOF.
Don't use boxes or rectangluar cover or you'll likely end up with an unnatural looking pose.
Another method to increase acceptable focus and improve your snake photos is to position the substrate parallel with the film plane.
Linear Mode
