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Slide projectors

Auto-focus doesn't work

There are a few simple reasons that the auto-focus feature on your projector may not work, or appear to work incorrectly.

First, be sure that your model projector actually has auto-focus. Many Kodak models look almost exactly alike, but many of them don't have auto-focus. Even if your remote control has a focus button that lets you electronically focus the projector, you may still have a model that doesn't have the auto-focus feature. The best way to be sure is to check your owners manual, although most models say auto-focus somewhere on the projector. Older Kodak projectors which have auto-focus have a model number starting with 'AF', and the newer ones have an 'A' in the model number(i.e. Ektagraphic IIIAMT). Other brands designate it in different ways.

Once you are sure your projector has auto-focus, look for an auto-focus switch on the machine and be sure it is in the 'ON' position. Many older machines didn't have this switch and it frequently confuses people that use a variety of projectors. On older style Kodak projectors, the switch will be located on the back panel near the power switch. On newer Kodak projectors the switch is located just left of the focus knob on the control panel. On Telex/Singer projectors the switch is usually on the top where the carousel tray is placed near one of the corners, although on viewer models it is usually on the side.

The most common problem with auto-focus on a slide projector is not understanding how it is supposed to work. Since auto-focus cameras don't require any user intervention, it is a common mistake to assume slide projector auto-focus will also work by itself. However, this isn't entirely true. For proper auto-focus operation the user must be sure to focus the first slide manually. After that, all the other slides will be focused automatically.

Another common problem is having some of your slides inserted differently than the others. There is a difference between the two sides of a slide, and if you look real close you will notice that one side is shinier than the other. If you don't have them all inserted the same way, due to the way auto-focus works, some of them may be slightly out of focus.

The final simple cause of auto-focus problems is the use of very old or poorly mounted slides. If your slides are extremely warped due to age or a poor slide mount, the auto-focus on your projector may not be able to focus the slide for you. A badly curved, or warped slide will never be in focus across the entire image and auto-focus can't fix that. Your slides may require remounting, or may not be salvageable.

The last tip we can give you on auto-focus is to understand a little bit about how it works. Auto-focus on a slide projector is done optically, using light reflected off of the slide emulsion surface. It must be able to detect extremely small changes in position of each slide. The mechanism that performs the focusing operation is very delicate and critically aligned. It can be thrown out adjustment if your projector is dropped or abused in any way. If your projector won't focus, but you suspect it may have received an impact, don't conceal this fact from the service center. Telling them this may save on the labor it takes to find the problem.


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