Extension Tube Calculator
Ever since I tried the Phottix Close-Up Filter, I've been looking for something better. A dedicated macro lens was just out of my budget - and I wouldn't want to carry it on my travels either - so I started thinking about extension tubes.
But while there were some extension tube calculators out there, none of them showed me what I wanted to know: what would the final image look like? They also never mentioned how the extension tube would affect the focusing distance and thus the working distance[1]. So I wrote my own, and here it is. Be aware that the calculator uses simplified lens formulas[2], which will not give precise results for actual real-world lenses but should give you at least a feel for what the end result will be. The focus distance is measured from the entrance pupil of the lens.
Camera | |
---|---|
Sensor | |
Camera Lens | |
Focal length (mm) | |
Near Focus Limit (mm) | |
Extension Tube | |
Length (mm) | |
Focus | |
Near | |
Far | |
Span | |
Reproduction Ratio | |
Near | |
Far |
Image preview at near focus distance.
Image preview at far focus distance.