Need a Photographer Equivalent English Professor

Started Jul 14, 2014 | Discussions thread
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Need a Photographer Equivalent English Professor
Jul 14, 2014

Great Bustard wrote:

mostlyboringphotog wrote:

Great Bustard wrote:

Focal length equivalence are the focal lengths on different formats that result in the same AOV. F-ratio equivalence are the f-ratios on two different formats that result in the same aperture diameter for a given AOV, which results in the same DOF for a given perspective, framing, display size, viewing distance, and visual acuity, as well as putting the same total amount of light on the sensor for a given shutter speed (which will result in the same noise if the sensors are equally efficient).

You may have had that explained to you once, twice, or more times.

I've also explained that, exactly as many times, I don't buy your "F-ratio equivalence are the f-ratios .." as I have told you that "F-ratio equivalence had the well established meaning to the photographers well over 100 year as the reciprocity with shutter speed.

If you still think I'm wrong on facts, please make citation on a new thread. I'd be happy to engage.

The same f-ratio results in the same exposure for a given scene luminance and shutter speed, regardless of the focal length or format.

The equivalent f-ratio results in the same DOF, diffraction, and total amount of light falling on the sensor. One would think it's not that hard to understand. As a bonus, you don't have to buy it -- it's free.

BTW, this whole equivalent of total light sounds like 70-200mm zoom is equivalent to 55-300mm if we keep the zoom to between 70 and 200mm.

Equivalent lenses are lenses with the same AOV and aperture diameter.

* I quote the whole exchange so that there is no danger of out of context quote.

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