The Latency Test

Are you trying to determine which document camera is right for your classroom? Then I suggest you try the latency test on several competing document cameras the next time you are in a conference exhibit hall. 

To conduct a latency test, just place your hand on the left side of the document camera’s display area. Your hand should now be clearly visible on either the demonstration projector or monitor screen. Next, pick up your hand about ¼ inch from the surface and quickly move your hand to the right side of the document camera’s display zone. Repeat this action several times. How blurry is the resulting display? Can the capture or frame rate of the document camera keep up? Is the resulting visual experience an unseemly blur? Or does the image abruptly and uncomfortably time shift into focus, a split second or two after your hand stops moving?

A document with low latency is important in classrooms. Here’s why. Blurred images and refocusing waste instructional time. Instructional demonstrations of brush strokes, cutting and folding techniques, micro-images, or food preparation require sharp clarity, so blurring is quite counter-productive. Abrupt images can cause visual upset. Constant rapid movement of hands or materials in a high latency environment can create visually induced motion sickness (just like grandpa’s old home videos). You see, latency matters. And you want low latency. It’s sometimes easy to get bamboozled by a cute low-cost document camera, only to pay the piper when it won’t perform quite the way you want it to in the classroom setting. So before you buy, conduct the latency test.

Warning: wireless document cameras provide a slower frame rate than cable-connected document cameras, which is expected. What you lose in frame rate, you gain in flexibility for positioning—so don’t be overly alarmed. A wireless document camera is still a great tool for your class.

Simplicity

 One new finding I uncovered during my annual rounds at the ISTE educational conference was the arrival of Recordex _USA on the national document camera scene. This company features a new “SimplicityCam Series,” which starts at $225, yet sports many desirable features. Although some of these features are only available in Windows-compatible environments, I felt that the most intriguing  features (presented in order of uniqueness) were the following:

The Snapset Creator. This feature enables the teacher to put any number of pages down one at a time (for example, a 20-page science lab packet), hit a single button, and instantly generate a 20-page PDF  that can be emailed, posted online, or reused in the future. The Snapset Creator can also capture every document shown during an entire class and, at the end of the class, create a PDF of every document/object reviewed to send home to absent students.  I am certain educators will love this capability.  Here is a video demonstrating that feature.

Large Viewing Area. Two of the Simplicity models offer a large viewing area, with the ability to view up to 17.5” x 23.5” document or subject. This enables the teacher to easily display a children’s picture book, a large student project, over-sized realia, or even an outsized map.

AnnoZoom. You can annotate live images or videos, and then perform real-time zoom-in with your subject. The annotation remains.

Other positive features of this document camera include picture in picture video conferencing and an optional microscope adapter, just to name a few.

The Recordex simplicity series includes three doc cam models: the SC5i+, the SC5z, and the SC5z Duet. (A sample spec sheet is included here.) Besides its advantages for the regular classroom, this document camera offering goes a long way to support both the “flipped classroom” and the distance learning classroom. You can learn more about Recordex document camera options at this link.