HinesLab Covert Wide-Angle Lens Adapter patented

This simple wide-angle camera adapter was invented by Steve Hines for covert photography where a picture must be taken through a small opening.. The device can be inexpensively improvised using a plastic tube, then discarded drawing little attention if found.. The tube is an afocal adapter and can be used with any camera or format.

The wide-angle adapter can be any cylindrical tube, with a specular interior surface.. The camera photographs the direct view (the zero-order image) directly through the hole in the tube.. The camera also sees the multiple reflections inside the tube.. Alternate circular images, starting with the open-hole, are erect and right reading (zero, second, fourth-order, etc.).. Alternate odd-numbered images (first, third, and fifth-order, etc.) are inverted and reversed left-to-right, giving the appearance of being rotated.

The angle of view is dependent only on the lens coverage, therefore a wide angle lens should be used to exploit the optical properties of the tube.. A clear cast acrylic (Plexiglas, etc.) tube, painted black outside, or wrapped with black electrical tape, to absorb second-surface reflections is reflective enough near grazing incidence to reflect images 3X - 5X wider than the field of view of the open hole.. Wider angle views may require a polished metal tube, or a glass tube silvered inside using the same process to mirror thermos bottles or Christmas tree ornaments.. Image quality in the reflected rings is greatly dependent on the internal surface quality, accurate centering of the tube on the lens, and the lens aperture being stopped down.

Uncorrected video segment shot through tube showing a car passing from right to left across the camera's field of view.

In this animation above of a photograph taken through a hole in a wall, initially the field of view is restricted by the size of the hole.. When the hollow tubular adapter is placed on the lens, wider parts of the scene can be seen in the reflections inside the tube, shown progressively.. Alternate bands of reflections are upside down, and reversed left to right.. These reflected rings can be corrected with dedicated camera electronics, or later with a 180° rotation using Photoshop.

The photographer may get the illusion that the tube is transparent in the 2nd and 4th-order reflections which conform to the 0th-order image through the open hole, and which are concentric with the 1st and 3rd order reflections which will later be rotated 180°. The increased field coverage of the adapter allows the photographer to compose for off-axis subjects, and to know before compositing if the intended subject was captured in the photograph.

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Increased coverage using Hines' Covert Wide-Angle Adapter

Image order

"0", zero order

(open hole)

1st Order

(1 reflection,

image must be rotated)

2nd Order

(2 reflections)

3rd Order

(3 reflections,