Back Focus Chart
I have received a number of messages asking if my back focus chart is still available. The answer is yes. I printed the chart several years ago because I wanted one that went as close to infinity as possible without a large dot in the center. Your camera’s back focus may need adjustment if the image goes in and out of focus as you zoom.
To use it, place the chart 10 to 12 feet from your camera. Zoom to full telephoto and focus the lens normally until the “circle of confusion” (the fuzzy area in the middle) is as small as possible. Next, zoom all the way in and use the “flange focus” adjustment on the back of your lens to refocus, correcting any changes that occurred during the zoom. You might want to check the wide angle focus again and then you are done.
If you would like a PDF file from which you can print your own, e-mail me at DVTips@nbmedia.com with “Back Focus” in the subject line.
Depth of Field
As professional image maker, “civilians” frequently ask me technical questions about how they can make better pictures themselves. The relationship between f-stops and depth of field is always difficult to explain because f/2 is a bigger hole than f/22.
Bruce Emery gave this explanation during a photo class on the Star Princess: “If you put 22 people in a line away from you, at f/2, only two would be in focus. At f/22, all 22 would be sharp.” Works for me.
Repairing equipment often involves disassembling it, which entails keeping track of small screws and other parts. Remembering which part goes where and in what order is much easier with this idea from Melissa Patrick of Macungie, Pa. As she removes parts, she puts them in a weekly medicine organizer. The parts from each stage of removal go in a new section. When it comes time to put the gadget back together, just start with Friday and work your way back to Monday. An additional benefit of using a pill container is that its compartments can be closed to keep the parts from spilling.
What Did He Say?
“When playing back the video of a seminar, I found it almost impossible to follow the speaker,” writes Jack Malory of Washington, D.C. “He had a very busy PowerPoint presentation and used a laser pointer to indicate the items he was referring to. Of course, the laser did not show up on the graphics file copy from which we planned to insert the slides during editing. Do you have any ideas?”
Well, Jack, the horse is sorta out of the barn on this one, but perhaps these tips will help you next time.
The most obvious need is a visible pointer. Ask the speaker to forgo the laser and instead use the computer cursor as a pointer so it will show up on the recording. I usually go to the computer’s display function and select the biggest, fattest cursor available.
When using the cursor is not an option, we have created a scratch track showing the editor when to change slides and which points to highlight by training an inexpensive consumer camera with an open microphone on the graphics screen.
If you can get in really early in the presentation planning stage, you can help the person creating the graphics communicate by reminding him or her of the “Rule of Six”: no more than six speaking points on a slide, no type smaller than 1/6th of the frame height, and no more than six words per point. This will also encourage the speaker to talk to the audience rather than read the slide.
Does anyone out there have other ideas to help Jack? Share them with me and I will put them in a future column.