Alignment mirror for film holders and copy stand – align camera

• Sensor plane parallel to the film: In Live View, the reflection of your lens shows you whether the angle is right, checked instead of estimated.
• Sharp into the corners: A tilted sensor plane costs sharpness on one side of the image and slightly skews the rectangle into a trapezoid, and you can't recover either of these in post-processing.
• No measuring tool and no app: Place the mirror, move the reflection of the lens to the center of the frame, remove the mirror. This works with any camera that has Live View.

Compatibility

For any setup in which a camera sits vertically above a negative lying flat, regardless of camera brand, lens and tripod head. From our range, among others:

• Copy Stand for analog digitization and scanning
• Film Scanner Set for 35mm
• Film Scanner Set for 120 medium format
• Film Scanner Set for 35mm Sprocket
• Film Holder Scanner Set for 110 pocket film
• Film Scanner Set for Minox 8x11
• Film Scanner Set Duo for 35mm and 120
• Format masks for Kaiser FilmCopy Vario

The mirror is placed loosely on top and not glued. The backing film on the adhesive side stays on. It needs a flat support surface of at least 50 x 50 mm.

Scope of delivery

1x alignment mirror 50 x 50 mm, with protective film on both sides.

Technical details

• Material: acrylic, mirror-coated
• Dimensions: 50 x 50 mm
• Shape: square, straight-cut edges
• Back: self-adhesive with backing film
• Front: protective film, peel off before first use
• Shatterproof

Description

Anyone who photographs negatives with a camera will sooner or later struggle with a corner that just won't come into focus. The cause is rarely the lens and almost always the angle: sensor and film are not parallel to each other. At 1:1 magnification and f/8, the depth of field is in the range of tenths of a millimeter; across the width of a 35mm negative, a tilt of about one degree is enough to fall outside this tolerance.

The mirror makes this angle visible. It lies where the film would otherwise lie and reflects the image of your lens back into the camera. If the reflection of the lens opening sits in the center of the frame, the optical axis meets the film plane at a right angle and the sensor is parallel to it. This is a geometric condition, not an estimate.

Compared to a spirit level, this has a real advantage: the bubble level aligns the camera and the film holder each separately against gravity, so you measure twice and add up two errors. The mirror directly measures the angle between the two: one measurement, one result.

Acrylic instead of glass, because the mirror is handled above the light table: it won't shatter if it does fall.

How to align

1. Set up the film holder exactly as you will for scanning. Peel off the protective film and place the mirror in the center of the film stage.
2. Position the camera vertically above it, switch on Live View and turn on the grid lines.
3. Focus on the reflection: not on the mirror, but on the front lens element you see in it.
4. Stop down the aperture, to around f/8 to f/16. The opening becomes smaller and therefore a more precise target point.
5. Adjust the tripod head until the lens opening sits exactly in the center of the frame. A geared head allows finer adjustment than a ball head.
6. Remove the mirror, insert the film and refocus. Don't adjust the tripod head after that.

Place a small lamp next to the mirror, shining upward: the lens is lit up and stands out clearly against the dark background in Live View.

Detailed guide with diagrams, a worked example and a cross-check: Photographing negatives: aligning camera and film parallel with a mirror

Short demonstration of the method with a geared head, in English: DSLR film scanner mirror leveling method