Enlightenment

Enlightenment

David Candler

Good close-up photography of a flower bloom is more complex than a picture of people at medium distances. There are more elements for the photographer to consider before shooting, and there are fewer effective automatic features to produce consistent good results with Point-and-Shoot. Providing the correct exposure is the key to good results, and the cornerstone of proper exposure is sufficient light. This article discusses ways to prioritize techniques to attain that goal.

Provide enough light to allow for a good photograph. This means a properly exposed photograph. There are four elements for proper exposure:

1- ISO Setting: for film cameras, the ‘speed’ of the film is usually expressed as an ISO number such as 100, 200, 400. The smaller the number, the smaller the ‘grain’ of the film which will result in sharper pictures, but with a smaller number, more light is required to make a proper exposure. For digital cameras, the same ISO numbers are used (by convention). In this case the reference is to the acuity and recognition differential of the camera’s electronic sensor to light. The equivalent of grainy film photos in electronic cameras is ‘noise’, or random colored pixels that can diminish the result. In either film or digital cameras, you want to avoid an ISO rating of higher than 200. You can do this by having more light.

2- Aperture: this has to do with the size of the opening in the lens. On film cameras, aperture was a vital setting, and better photographers considered it carefully. It is key for digital cameras as well, but “Automatic” camera modes (in “Fully Automatic,” the camera picks all settings; or what is often termed the “P” mode, where you can do some modifications, if desired) generally have allowed good results without a full understanding. With some understanding, you will be able to take much better photos, especially for close-ups. Aperture is designated by the term “f/stop”. The slant is there because the number associated with the f/stop is a reciprocal, and is the ratio of the aperture in the lens to the focal length of the lens. It is usually expressed as one of the numbers from this sequence:
1.4     2.0     2.8     4     5.6     8     11     16     22
Since it is a ratio, small numbers indicate more light passing to the film/sensor. However, small numbers also result in smaller “Depth of Field” and focus issues. To gain greater Depth of Field for a close-up of a rose bloom select an f/stop like 16, or higher- but this will require more light than larger lens openings. More information concerning f/stop can be found at: http://www.uscoles.com/fstop.htm.

3- Shutter Speed: this is how quickly the shutter opens and closes. It is properly expressed as a fraction of a second, such as 1/60, 1/125, 1/500. But if the shutter must be open for a ‘time exposure’ it will be in multiples of seconds, such as 2 seconds. Clearly, the longer the shutter is open, the more light can fall on the sensor. But the longer the shutter is open, the greater the problems with blur associated with camera or subject movement.

4- The final, and most logical parameter related to proper exposure is: the brightness of the light arriving at the camera from the subject- that which is seen through the viewfinder. It makes no difference how bright other things may be, only the light available from the area being photographed is significant. For example, major differences can be seen between a subject in bright sunlight and those in shade. Hence, you can influence this element by the position of your subject (rose), the brightness of the background that is also seen through the viewfinder, the closeness of the sources of light and the brightness of light sources. Generally, bright midday sun will be too bright for most flower photographs, and the portions that are in the shade of other petals may be too dark (in comparison). This results in too great a contrast and sometimes a less pleasing photo than one taken before 9 AM, after 3 PM or in bright shade. The shade can be created by your environment, or by a sheet of semi-transparent material.
Given the four elements of light quantity, here is a way of prioritizing them. First, if you can select your timing, think of #4 first: pick a time when the light will be sufficient, but not too bright with garish shadows (morning, evening, bright shade or well lighted indoors). Pose your rose (think of it as a formal rose portrait) in a pleasing direction- once again to provide lots of light, but diffused so as to avoid heavy shadows. Set up a fill light (or reflector, such as a white paper) opposite to the main light, to ‘fill in’ the shadows. You can test this by looking to see that the inner portions of the petals have some lighting instead of just being black.
Next, pick your ISO setting. The lowest number will be the best, given enough light. Usually you can use 100 outdoors, 200 in shade or good indoor lighting. Avoid 400 except in extremis- provide more light if possible. (A camera made after 2006 can use much larger ISO settings with little grain degradation).
Next, select an appropriate aperture. This is discussed before shutter speed, because it is a basis for Depth of Field (range of acceptable focus). If your subject is a rose bloom, as this article emphasizes, then usually you will want the whole bloom in focus. For almost all cameras, in order to have a bloom to be large in the frame, you will have to be about as close to the bloom as the camera will allow and still be in focus. If that is true, your Depth of Field is heavily constrained. The closer you are to the subject, the shallower the DOF. So if you are close, you will want a large f/stop number (like f/16, not f/4) to provide better DOF. Bonus hint: if you have a zoom lens, use a wide angle setting instead of max zoom to expand DOF.
Next, select shutter speed. Most cameras now have an integral light meter. Many use the meter to automatically select the combination of f/stop and shutter speed for good exposure. If you are using a camera-shooting mode that allows you to specify the aperture (say f/16), this lets the camera select the shutter speed to allow sufficient light for proper exposure. For most cameras this measurement is activated by pressing the shutter button down half way. Evaluate the camera’s selection. If the speed is equal to or shorter than 1/125 second, you are good to go (if you are at a zoom of more than 100 mm, use 1/250 or shorter if not on a tripod; you can use almost any slow shutter speed if you are using a tripod and there is no wind).
If you cannot meet the shutter speed considerations above you may need to make some changes. Go back to the other criteria- can you open up the aperture and give up some Depth of Field? Can you brighten the scene by adding light- perhaps using a reflector, adding an additional light if not using the sun, putting the rose in the sun if necessary (giving up some softness), using flash (this may wash out the photo if flash is on the camera for a close-up)… Can you place the camera on a stable setting (for example, a bean bag) instead of hand holding? This can simulate a tripod (you may have to sacrifice the optimum camera location and angle). By changing to a larger ISO rating you may be able to gain sensitivity, compromising some graininess. Going from ISO 100 to 400 simulates increasing the available light by a factor of four.
Controlling and capturing light is the essence of photography! Modern photography allows a number of ways to go about the process, but leveraging one feature may often require a compromise in another area. If you appreciate the various compromises, you may make your photography much easier, and the results much better, by going to the basics and providing an abundance of light from the start. When this is the case, you may then deliberately control the other parameters, rather than be constrained by the darkness.