Photographing flourescents

[DonO1]

How do you go about photographing flourescents in the dark under a black light. I have an Olympus C-7070 wide zoom. All I can get is a blob of unfocused light.

[Ron Eagle Elk]

Don,

Not sure, but I think maybe your digital camera is designed to focus on light that is visible to the human eye. When you photograph under blacklight (UV) you change the focal distance due to the wavelength of the light. I know when shooting with Infrared film, there was a focus shift for that same reason. Not sure how you'd correct for it. Might be a good question for Canon.

[TyroneFly]

You will need to switch over to manual focus. If the subject is close enough you can turn on the focusing aid which will project a beam for the sensor to focus on. For tricky lighting situations I switch over to the RAW format and edit according to how my mind eyes saw the scene.

[doftya]

As mentioned, you will have to turn off the auto focus. The best way to do it is to prepare everything, and with the regular lights on, set the focus. Then you can turn the lights off leaving the blacklights on, and take your picture. With the focus locked in manual mode, it will not change, only the exposure settings will change. If it were me, I would also set the aperture manually to as small as possible to assist in retaining focus, but the exposure will be very long. You may have to adjust the exposure manually. For the best pictures of flies, remember to turn the macro mode on as well. I quickly checked the specs on your camera, in standard macro mode, the object still needs to be at least 30cm from the lens (about a foot). There is the option of using super macro mode where the object can be as close as 3cm (just over an inch) but in my experience, it is best to stay within normal ranges. Keep the flies just over a foot from the camera and use macro mode. If need be, you should still be able to use the zoom in macro mode to get a closer picture.