Effect f/numbers and Exposure Compensation

As the lens focuses closer to a subject the amount of light reaching the film decreases. Exposure Compensation is not necessary due to TTL (Through The Lens) exposure metering. When using a separate exposure meter or non-TTL flash, it is necessary to compensate the exposure reading .

Magnification and Exp sure Factors

The exposure factor refers to the amount of exposure compensation necessary for the proper exposure when using a separate meter or non-TTL flash. The tables below show the exposure factors covered into an aperture compensation number for various magnifications

*One exposure degree equals +1f/stop