How to KNOW the light is right 4 an Olympus OM20 Manual camera?
OM-20 was basically a upgraded OM-10 with the manual adapter built in and a number of other refinements.
The viewfinder has LED's to show the shutter speed recommended by the camera's lightmeter for the ISO and aperture selected. It also has an exposure compensation indicator (the +/- symbol) and an indicator for flash ready which doubles up as a post-exposure flash confirmation. There is also the indicator lamp to show manual mode has been selected. OM-10 lacks the manual mode lamp and the +/- indicator.
Like the OM-10, the OM-20 is primarily an aperture priority automatic camera. In this mode you set the ISO film speed, choose which aperture you wish to use (with the ability to use the lens depth of field preview button) and then the camera selects the correct shutter speed. The +/- exposure compensation control allows the user to tell the camera to modify the recommended shutter speed by up to two stops either way.
In manual mode, there is no manual metering. The light meter behaves exactly as it does in aperture priority mode and the viewfinder shows the recommended shutter speed and not the manually selected one. Correct metering is therefore a case of adjusting the aperture first, and then choosing the correct shutter speed indicated in the viewfinder. If the user then decides to select a different shutter speed, then the aperture ring must be adjusted to maintain the correct exposure. For example the aperture is set to f8 and the camera recommends 1/60th of a second. The user decides that a faster shutter speed is required and chooses 1/250th, but the viewfinder remains showing 1/60th. In order to keep the same exposure value the user must open the aperture by two full stops to f4. The camera's light meter will detect the new aperture setting and providing the light on the object is unchanged the viewfinder shutter speed display should now show 1/250th as well to confirm the correct adjustment. Alternatively, the user can choose the shutter speed first by looking at what has been set on the control ring (or by turning the ring to the end of its travel and then counting the clicks from there as all experienced OM users do) and then turning the aperture ring until the shutter speed shown in the viewfinder matches what's been manually set.
It all sounds clumsy and complex but is done far more quickly than I've taken to type this and becomes second nature.
Aperture priority metering is selected on the camera by choosing AUTO on the mode selecter. In this mode the shutter speed ring has no effect and the viewfinder always displays the automatically selected shutter speed.
May 09, 2009 |
Olympus OM-2000 35mm SLR Camera