As many as 135 Pi members and guests crowded into the Cultural Center Forum at Northern Virginia Community College on July 31st to participate in a lively Q&A session on digital photography. The presenter was Chris Butcher, who works for Penn Camera at their headquarters in Beltsville, MD. Interest in Apple products for digital photography is such that Penn Camera has recently become an Apple reseller.
Chris laid out an array of cameras ranging from a shirt-pocket point and shoot model to a Single Lens Reflex model with interchangeable lenses. Rather than making a formal presentation cataloguing features of various models, Chris encouraged audience questions from the outset and the audience responded enthusiastically. A number of the more experienced photographers on hand could not resist the temptation to interject the occasional editorial comment or operational hint. This is par for the course when a number of photographers gather in one place.
One of the first issues raised was "Why is there a delay before the scene is recorded?" It turns out that many cameras require that the CCD chip be reinitialized after the image has been used for focusing and exposure metering. Some modern cameras ameliorate this problem by allowing the user to shoot a sequence of shots, up to as many as 8 per second, and buffering the data into RAM while writing to the removable memory card. It should be noted that a delay is present on even classical cameras, it is just not so noticeable, amounting to perhaps 30 ms while the mirror flips out of the way on an SLR, for example. The delay is enough so that a well-trained trigger finger is needed when shooting rapid sports action.
Chris gave a very clear explanation of this "feature" of many cameras, arriving at the conclusion that one should not use it unless one is willing to suffer the image degradation that results from using mathematics to make a small number of pixels mimic a larger number. Although the feature is basically useless, it makes for good advertising copy by camera manufacturers. It was noted that the price of cameras scales upward with increasing optical zoom. Optical zoom capability is a function of the arrangement of lens elements and the mechanical bits needed to arrange them to vary the telephoto effect.
Chris discussed RAW and JPEG image formats, although he did not go into much depth on this subject. RAW images, as the name implies, contain all of the information that the camera can possibly record. Some professional photographers prefer them for this reason, although their large size can cause them to eat up storage space. Since they contain all of the information RAW images are the best starting point for correcting things like color imbalance or lens distortions.
A question about shooting Black and White images brought the response that this is accomplished with mathematics in the camera and that the image sensor is still seeing the same patterns of reds, greens and blues. I inferred from Chris's response that it might be better to capture the images in color and do the conversion to grayscale images after the fact.
Chris went on to demonstrate Adobe's Photoshop Elements 2 software. He had taken a panoramic series of three shots of the theater and the audience prior to the start of his presentation. He then showed how the Photoshop Elements software could stitch these images together into a convincing panoramic image.
This brought up the point that the red, green, and blue pixels on image sensors do not necessarily see the same image details because they are displaced from one another. Chris also used the cloning tool to demonstrate how Elements could be used to doctor images to remove distracting items.
A question about attaching annotations to images brought Chris to the discussion of the various ways that different image cataloguing programs treat the "metadata" - data describing the image, that cameras record. There are generally two pieces to the metadata - EXIF and IPTC. The EXIF data captures information that the camera knows about, while IPTC data has to be entered from other sources. Chris showed how this data could be edited in Elements, Graphic Converter and iPhoto. Chris alluded briefly to iView Media Pro as a higher end cataloguing product. This discussion leads into the issue of asset and workflow management, a subject that the Pi's Graphic Arts SIG expects to take up later this fall. It was obvious that the audience could have kept asking questions for another hour or more, but the session had to be gaveled to a close. Chris passed out 100 booklets on digital photography from Nikon. Unfortunately his stock ran out before everyone was able to get one.
The meeting closed with a short business session that highlighted upcoming programs and recent activities. The usual raffle and drawing closed out the day. Audience members crowded around the table to continue quizzing Chris and admiring the display of cameras.
So far there has been quite a lot of member feedback from this meeting, which has uniformly judged it to have been outstanding. The choice of subject had a lot to do with it, but the presenter was engaging to the point where scarcely anyone walked out early. Any member who has an idea for a meeting that is equally likely to interest our membership is welcome to drop it into the suggestion box at firstname.lastname@example.org.