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 Exposure 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
|
Magnification
|
1:4
|
1:3
|
1:2.5
|
1:2
|
1:1.5
|
1:1
|
|
Exposure Factor
|
1.37
|
1.51
|
1.62
|
1.8
|
2.11
|
2.83
|
|
Practical Aperture Compensation
|
+0.5 s/stop
|
+1 f/stop
|
+1.5 f/stop
|
