Bracketing

Bracketing is a process of taking more than 1 photograph to ensure the likelihood of having an exposure that is of good enough quality to print. It is not real important for making photographs where the end use is a website or email attachment. This is a process of primary importance where prints are being made that are 8” x10” or larger. With printing there is always a gap between an image on a display screen and one on paper. It is very difficult to bring up the full contrast range and to preserve the richness of the colors when going from a display screen to paper. Bracketing makes this gap smaller, but does not close it entirely. I am not aware of any printing process that closes this gap entirely.

Bracketing can be done around exposure, focus, lighting or a combination of the 3. Exposure bracketing is the most widely used of the 3. With a digital camera bracket the exposure in .3 steps. A good starting point is to first exposure at meter setting, second exposure at +.3 and a third exposure at -.3. This can be extended to also include +.7 and -. 7, as well as +1 and -1. Full steps are adequate for black and white film – metered setting, -1 and +1.

How this is done with the camera varies. With an SLR this can often be done by holding done a button that has both a + and a – on it while rotating the command dial wheel. The settings appear on the display and change as the wheel is rotated. With a point and shoot camera there is often an exposure compensation scale running from –2 to +2 that can be controlled by the multi selector control. Some cameras have an automatic bracketing setting.

© 2009 Paul Light all rights reserved

ISO

The ISO is an easy control to overlook. For most uses setting the ISO on a point-and shoot camera to “Auto” is adequate. Most, if not all, point-and shoot cameras will go to the lowest ISO possible when set at an ISO setting of “Auto” while automatically making a good choice of shutter speed and aperture. The result will be a technically accurate photograph – the best that the camera is capable of with totally automated setting. Choosing the ISO makes more sense with an SLR where the camera operator can choose to manually set the shutter speed and aperture. Choosing the ISO also makes more sense with an SLR, if “Program” or any other automated setting is chosen, since it can be observed as to what shutter speed and aperture the camera plans to use.

ISO does matter. The lower the ISO the brighter the colors and the less noise. I find the noise above ISO 400 on cameras costing less than $1000 to be unacceptable. What level of noise is tolerable is relative to output. My files are made into 13”x19” prints. If my intended output was only screen display, such as email, I could tolerate a much higher ISO.

© 2009 Paul Light all rights reserved

Focusing

Out of focus photographs should be carefully watched for. With today’s cameras focus often feels like a resolved issue. On view cameras this was an enormous issue requiring a high quality magnifying devise to accomplish the task. Autofocus on digital cameras has made this issue less significant, but not fully resolved. I have two Nikon digital cameras – an s52 and a D80. The D80 is clearly the better of the two cameras in terms of image quality, but with it the focus as at best pretty good. With the s52 the autofocus works great. I loose many more photographs than I care to loose from focusing issues on the D80, although this can always be corrected with a second shot if I have a chance to check the first shot on the camera monitor.

Focusing is changing the distance of the lens from the sensor to make the photograph appear sharp. Focusing becomes increasingly more difficult to manage with low light and/or longer lenses. For most photographs focus is important. Although since around 1990 there have been many photographs publicly displayed that were intentionally out of focus and were stronger photographs as a result of this technique. If a sharply focused photograph is the intended objective, this must be watched carefully.

A preliminary focus check can be made with the camera by using the control that magnifies the image on the camera monitor. On the s52 I check at maximum magnification. This is pretty accurate. On the D80 there are 8 levels of magnification. If it appears accurate at the 6th level, it is usually in focus. The most accurate way to check focus is after transferring the files to the computer view them on the computer monitor at 100% magnification in Photoshop or other image editing programs. If they are out of focus, there is no way to correct this with image editing software.

© 2009 Paul Light all rights reserved