Hi,
You write and repeat that, generally speaking, between the average exposure recommended by the digital camera's spotmeter and the maximun exposure authorized by the sensot, there is approximately +3EV. Insofar as the average exposure recommended by the digital camera's spotmeter serves as an absolute reference, I feel it's necessary to specify the conditions under which it is obtained.
Let's assume that everything take place indoors, in a studio with black-painted walls and ceiling, with fully controlled homogeneous light such as that provided by a studio contineous lightsource. Based on this, I assume that you determine the exposure addition that leads to optimun exposure for a given digital camera by varying the power of the studio contineous lightsource in 1/10 EV steps until the first signs of clipping appear in the raw file. In any case, we need an absolute regerence, which is either the flashmeter meassurement, or the mesasurement of an 18% mid-gray chart - with precise instructions on how to apply either measurement.
Correct positionning and orientation of the flashmeter in relation to the lightsource is essential. Likewise, the correct positionning and orientation of the plane 2D 18% mid-gray chart in relation to the lightsource, and the correct positionning and orientation of the spotmeter - be it a Sekonic flashmeter or the camera's built-in spotmeter - in relation to this plane chart are equally crucial.
How do you measure light in order to photograph three-dimensional objects and subjects in the case of a frontal mono contineous lightsource positioned in the optical axis, and then in the case of a frontal mono contineous lightsource positioned laterally in relation to the optical axis :
- with a Sekonic flashmeter,
- with a 18% mid-gray chart, which is a 2D plane accessory, using either Sekonic spotmeter and/or camera's buil-in spotmeter.
Best regards,
Precise details of your existing light measurement
Hi,
You write and repeat that, generally speaking, between the average exposure recommended by the digital camera's spotmeter and the maximun exposure authorized by the sensot, there is approximately +3EV. Insofar as the average exposure recommended by the digital camera's spotmeter serves as an absolute reference, I feel it's necessary to specify the conditions under which it is obtained.
Let's assume that everything take place indoors, in a studio with black-painted walls and ceiling, with fully controlled homogeneous light such as that provided by a studio contineous lightsource. Based on this, I assume that you determine the exposure addition that leads to optimun exposure for a given digital camera by varying the power of the studio contineous lightsource in 1/10 EV steps until the first signs of clipping appear in the raw file. In any case, we need an absolute regerence, which is either the flashmeter meassurement, or the mesasurement of an 18% mid-gray chart - with precise instructions on how to apply either measurement.
Correct positionning and orientation of the flashmeter in relation to the lightsource is essential. Likewise, the correct positionning and orientation of the plane 2D 18% mid-gray chart in relation to the lightsource, and the correct positionning and orientation of the spotmeter - be it a Sekonic flashmeter or the camera's built-in spotmeter - in relation to this plane chart are equally crucial.
How do you measure light in order to photograph three-dimensional objects and subjects in the case of a frontal mono contineous lightsource positioned in the optical axis, and then in the case of a frontal mono contineous lightsource positioned laterally in relation to the optical axis :
- with a Sekonic flashmeter,
- with a 18% mid-gray chart, which is a 2D plane accessory, using either Sekonic spotmeter and/or camera's buil-in spotmeter.
Best regards,