Digital Camera Support for UNIX, Linux and BSD

Digital camera support on UNIX system is not a simple matter. Most if not all of the manufacturers don't give any attention to non-Windows (and MacOS) systems. Most of them don't even provide the needed documentation to write proper support for their camera. And with the increasing number of models, it begins to be a real tower of babel. Luckily, these days, there seems to be two trends with major camera vendors when it comes to communication protocols: PTP and USB Mass Storage. However, many cheap (think less than 1MPix and less than 150 USD or 150 EUR) cameras still don't follow that trend and are likely to use another protocol. I'll try to explain how to find out if your camera may work or not under a UNIX system. Don't worry, I won't forget serial cameras.

USB Cameras

Nowadays USB cameras are the most common. Since every USB device is identified by vendor and product ID combination, it can be detected easily on the bus. Usually one can safely assume that devices with similar USB IDs are identical, from the USB protocol point of view, but we'll see later that there are notable exceptions.

For the protocol, there are 2 USB standardized protocols that digital camera uses: USB Mass Storage and PTP (aka Still Image Device). If a camera doesn't use one of these two protocols, it surely uses a proprietary protocol, and this is were things get uneasy: most manufacturers don't disclose these protocols for various reasons. So reverse engineering has to be performed.

USB Mass Storage

USB Mass Storage is the protocol used by hard drives and removable disks devices over USB. This is basically SCSI over USB. Linux 2.4.x and the *BSD systems handle it by default in their USB stack. All you need is to mount the correct device to the mount point of your choice. For Linux, please read the fine manual.

If you wish to use this kind of camera with Digikam from KDE, read the Digikam Documentation.

In 2001, Olympus, Nikon, Minolta, Sony, Casio and many others started to use that protocol for their cameras. This greatly simplified the use of these cameras with various operating system. Free OS users got one of the biggest benefits: the camera works as is, out of the box. One of the drawbacks is that given that USB Mass Storage protocol is for disk device, you can't manipulate settings and camera options, nor remote control it. We'll see later that there are some cameras that offer some alternative solutions.

For Casio cameras, please read the note about Casio specifics.

PTP

PTP, Picture Transfer Protocol, is a standardized protocol mainly developed by Kodak whose goal is to provide a standard way to access digital camera. This protocol has been adopted by the USB consortium to handle Still Image Device class (6). A complete specification of the protocol has been published. See the sourceforge project.

By 2001, Sony appeared to be the second vendor after Kodak to implement PTP on its digital cameras, offering it in conjunction with USB Mass Storage. By the end of 2002, Nikon seemed to have made the switch too, by offering several firmware upgrades to offer PTP support in addition to USB Mass Storage. Canon did the same, and that is great news as Canon was one of the last major vendors to not use USB Mass Storage, and the company had a heavy past of being really unfriendly with gphoto2 developers and the whole "non-Windows" developer community (yes, that also included Mac developers).

By the end of 2003, Olympus seemed to provide PTP mode for their cameras labeling it "Print" unlike Mass Storage labeling it "PC". I suspect this is related to direct camera to printer connections. Sometime it is also called "PictBridge".

Canon extensions

Canon has developed some extensions to support capture. This is crazy, but there is nothing that can be done but supporting this. See http://jalkapallo.org/superkolik/canon.html for software supporting them.

Other protocols

Canon

Canon was probably the last major vendor who stuck to a proprietary protocol. This is also the company that gave most of the headaches to developers of packages like gphoto2. They went recently to an almost complete switch to PTP so that now Canon cameras are more standardized when it comes to USB connectivity, but older models still use that protocol. Some models seems even to support both, transparently.

Stephen H Westin, the current maintainer of the gphoto2 Canon driver has published a comprehensive protocol documentation based on all the reverse engineering work done everyone.

STV0680

todo

Sierra

This is the protocol used by all the camera systems OEMed from Sierra Imaging. Various vendors did use it by the end of 2000. It is not being abandoned in favor of USB Mass Storage or PTP.

Olympus cameras have some specifics that still allow to use the Sierra protocol to perform operations not possible with USB Mass Storage.

Others

todo

Camera specific by manufacturers

Some manufacturers have their own specifics that make their product harder to use and harder to support. I'll describe these.

Casio

Old serial port based Casio cameras (QV-10, QV-100, etc.) use their own protocol. QVplay does implement almost everything. As of today, gphoto2 drivers are still broken because developers don't have a camera to test with.

Casio recent cameras all use USB Mass Storage device. Unfortunately, their implementation is substandard. Thankfully, for Linux users, there is a document (not endorsed by Casio) that describes problems and solutions.

Nikon

Switching a Nikon camera to PTP mode if available (this depends on both the firmware version and the camera): Go into camera's setup interface and specify the interface as "PTP". Default is "Mass Storage".

Olympus

Since 2001, all the USB cameras made by Olympus interface with PC using the USB Mass Storage standard protocol. However some might want to control them to perform remote capture.

While some model have a "PC Control" mode in the menus that allow that, disabling Mass Storage in favor of the Sierra protocol, some don't have this feature. For example Olympus C-750 require some trick to switch to "PC Control" mode. This is achieved by opening the card slot while holding down OK and View buttons. You might want to give it a try.

Some models are even able to support both protocols on the same USB interface without any switching required. This requires disabling USB Mass Storage for the device on the OS before trying to use control software (like gphoto2).

Starting at the end of 2003, Olympus started providing a "Print" mode for USB connectivity that switches the camera into PTP mode. This to supplement USB Mass Storage.

Proprietary image formats

Some camera allow storing pictures in a RAW file format that is proprietary. Some don't even give the choice. If for any reason you need or want to read these files without using the proprietary software that runs only on Windows and eventually on Mac OS, there is a solution: Dave Coffin RAW Digital Photo Decoder. It supports lot of models, including Canon, Nikon and Kodak. Of course, your mileage may vary.

Various links

• Digital Photography and Linux list comprehensive resource for using Digital Cameras with Linux

Special Thanks to

• all the people that reported info
• patrick for English spelling and grammar

This table summarize for digital cameras, how they are supported under UNIX operating systems: