Stereoscopic Software

lrCompare is a utility for Stereoscopic Photographers who shoot photos using dual camera rigs. It identifies the matching pairs of photos from the left and right cameras. raw2jpg is a utility that converts raw photos to jpg, optionally rotating them (since left and right cameras are sometimes rotated 90, 180, or 270 degrees when mounting them), optionally appending _L or _R to their names (for convenience in importing into StereoPhoto Maker), and optionally converting pairs of photos to MPO.

You can download the software for Mac and Windows.

To overcome the limits of stereoscopic cameras such as the Fuji W3, stereoscopic photographers sometimes mount a pair of cameras on a bar and arrange to trigger these cameras simultaneously. Such a dual camera rig offers several benefits, including the ability to achieve either wider or narrower lens spacing than is possible on the W3, the ability to choose lenses (including zoom lenses) with shorter or longer focal length than is possible on the W3, and the ability to capture photos in raw format.

However, the triggering systems for dual camera rigs don't always trigger both cameras. This results in images on one camera that may be missing from the second camera. Thus, image number 123 on one camera won't always match image number 123 on the other camera. If the time on the two cameras were perfectly synchronized, it would be easy to identify matching images based upon the timestamp, and discard any images for which no match is present. Unfortunately, it is not realistically possible to achieve perfect time synchronization. Even if it were possible to set the identical time (to the nearest second) on both cameras, unless the clocks on the two cameras run at precisely the same rate (unlikely), the two clocks will drift apart over a period of days, weeks, or months.

lrCompare addresses this problem by requiring the photographer to identify a single matching pair of images from the batch of images being imported. For example, the photograhper might specify that IMGP2145 on the left camera matches IMGP2203 on the right camera. lrCompare computes the time difference between left image IMGP2145 and right image IMGP2203, and uses that time difference to identify the remaining matching images from the batch. For example, if the time stamp on left image IMGP2145 is 194 seconds later than the time stamp on right image IMGP2203, lrCompare assumes that all matching image pairs will differ by this same amount, within a user specified tolerance (to allow for slight shutter lag between the two cameras). For example, if the user specifies a tolerance of +/- 5 seconds, then any left photo with a time stamp between 189 and 199 seconds later than a particular right photo will be considered a match for that right photo.

lrCompare can be run in a non-destructive mode which simply reports the matching pairs without making any changes to the set of photos being imported, or in can automatically delete non-matching photos, and rename matching photos so that the matching left and right photos have the same name.

In addition to matching left and right photos, lrCompare examines the EXIF data from the matching photos, and reports any potentially problematic differences; for example, mismatched exposure time, aperature, focal length, etc. This allows the photographer to more closely examine pairs of photos with mismatched EXIF data to determine whether the photos are usable, require correction, or must be discarded.

One of the advantages of shooting using a dual camera rig (compared with the Fuji W3) is the ability to shoot in raw format. Raw files have greater dynamic range (12 to 14 bits, or 4,096 to 16,384 levels, depending on the camera) vs. only 8 bits or 256 levels for JPEG. When the lighting and exposure are perfect, the JPEG file may contain all the information needed. However, when the lighting or exposure are less than perfect, the additional dynamic range in raw files allows better adjustment of brightness, contrast, highlights, and shadows.

After running lrCompare to match up the left and right images, run raw2jpg to convert the left and right raw photos to JPEG, rotating them if necessary, and optionally convert the resulting left and right JPEG pairs to MPO.

Note that lrCompare requires ExifTool ( to read the EXIF data. ExifTool is free software for Windows and Mac.

raw2jpg requires the legacy convert command that is part of ImageMagick ( to perform the conversion and rotation. ImageMagick is free software for Linux, Windows, and MacOS. Here's some information on Using ImageMaick with Windows.

On the Mac, the Finder displays preview images for Photoshop (PSD) files, raw files and MPO files. Although Windows Explorer does display preview images for JPEG files, it does not display preview images for Photoshop (PSD) files, raw files or MPO files. The FastPictureViewer Codec Pack ( is inexpensive software for Windows that adds fast thumbnail and preview support for Photoshop (PSD) files, raw files, and other formats. It is also possible to update the Windows Registry so that it will display thumbnails for MPO files; instructions and downloads are available from