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THE FEUTEX TOOLKIT

Macro Extension Exposure Compensation

Estimate magnification and exposure increase from lens extension beyond infinity focus.

Photography workspace● Runs in your browser
01 Your input
02 Your result
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FormulaApproximate magnification = e/f; Exposure multiplier = (1+e/f)**2; Exposure compensation = 2*log2(1+e/f)
Sources and model references

Worked example

Inputs

Focal length
50 mm
Extension
50 mm

Expected results

Approximate magnification
1 ×
Exposure multiplier
4 ×
Exposure compensation
2 stops

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Estimate magnification and exposure increase from lens extension beyond infinity focus.
  2. Set focal length, extension in the indicated units.
  3. Calculate and compare approximate magnification, exposure multiplier, exposure compensation.

Try this example

{
  "f": 50,
  "e": 50
}

Accuracy and scope

Idealized educational model. Enter measured values in the displayed units; real systems may require additional corrections.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.