The Details: This device enables digital stereo photography with highly synchronized exposures, without modifying the cameras in any way. A big part of this goal is to have the camera electronic command cycles synchronized (reasons for this are a lengthy discussion in itself), and the LANC Shepherd displays the degree of sync while the cameras are powered up. The LANC shepherd also helps synchronize the two cameras'electronic cycles by powering the cameras up at exactly the same moment. By providing a camera "on" command at the same time, the cameras usually power up very closely in sync. Perhaps the cameras need to clear the cobwebs, but it seems that the first power-up often is way out of sync, and subsequent power-ups are closely in sync. If the sync is adequate for the shot, one can take an exposure immediately. If not, one can wait for the sync to drift to a more optimal interval, or cycle the power again. The controls on each camera continue to work as usual when this device is being used, and this device can be used as a wired remote for a single camera as well.
Using the Sync Display: The two sets of numbers on the LANC Shepherd display mean the same thing—they are just different ways of indicating the same interval of time. The interval displayed is the difference between the electronic command cycles of the two cameras, but typically this is the same as shutter sync for these cameras.
The top number is the fractional seconds, so 1/1000 means 1/1000th of a second, or 0.001 second. The bottom number is milliseconds or msec. 1000 milliseconds equals one second, so 1/1000 second is one millisecond. So if the top number is around 1/1000s, the bottom number should be around 1.0 msec. Most of the timing in photography happens on a millisecond scale, and I end up using the millisecond display almost exclusively, but I included the top number for comparison of the shutter sync to the shutter speed. I think that as long as the shutter sync is less than about one tenth of the shutter speed, disparity of the stereo images related to shutter sync will not be noticeable. So if the camera selected shutter speed is 1/100, then a shutter sync displayed on the LANC Shepherd of 1/1000 or smaller (say 1/2000, 1/4000, etc) will result in images with no noticeable motion disparity.
Most of the time, the cameras will sync on power up to less than 1/2000 (top display) or 0.5 msec (bottom display), and shutter sync will be excellent for typical point and shoot photos to a shutter speed of 1/200 or slower (say 1/125, 1/60, etc). If I use shutter priority mode on the cameras for really fast action with a shutter speed of 1/1000, I will want to work a bit to get the camera sync display to be as good as I can get it, say around 1/10000 (top) or 0.1msec (bottom).
The "M" for master or "S" for slave indicates which of the two cameras should trigger the flash. A much more detailed discussion of flash use is included below.
Care and Feeding of the LANC Shepherd: The LANC Shepherd does not contain a battery, as the little power required is provided by the cameras.
Caution: The LANC Shepherd cables are very flexible, but will not tolerate tension; Please do not allow the LANC Shepherd Pro to hang by the cables. Velco tape can be used to support the module, or a support plastic or aluminum block or angle can be glued to the back of the LANC Shepherd to allow bolting the LANC Shepherd Pro to a mount.
Power-Up: I find it best to have the camera mode selectors on "playback" on the Sony DSC-V1 while powering up initially, then changing the mode to one of the photo modes once I have good sync. This way, I can rapidly power up and down the cameras without the longer time required for the lenses to motor out and back in. The LANC Shepherd shows the degree of sync in fractional seconds and in milliseconds (one millisecond is 0.001 sec). Once I have the cameras in sync, I change to one of the exposure modes, and I'm ready to shoot. NOTE: When the cameras are attached to a battery charger or external power, the cameras are in some sort of stand by mode for charging, and cannot be synchronized by the usual LANC Shepherd power button. The cameras have to be on battery power for the power-up sync to function.
Offset Power-up: This technique allows one to compensate for a pair of cameras (video or still) that consistently power up at a sync offset from zero. This technique also significantly improves the probability of an on-sync power-up even if the cameras usually power up with good sync. The technique involves powering up one camera, then using the LANC Shepherd Pro to power up the other camera. Since the sync of the first camera is known, this technique improves power up sync probability by 200%.
Zoom: The zoom buttons can be used to adjust the zoom of both cameras at the same time. For stereo photography, the zoom has another function beyond decreasing the field of view of the photograph--it can have the effect of decreasing the stereo base (distance between the cameras). By stepping back and zooming in, there will be less depth effect for a given field of view. The cameras will receive a zoom command at the same time from the LANC Shepherd, and will adjust the zoom while the buttons are held down. There is no feedback from the cameras about the current focal length, so synchronization of zoom between the cameras will degrade with more zoom adjustments--after a few adjustments, it probably is best to reset the zoom by taking the zoom to a stop, then back to the desired focal length. Typical accuracy for my cameras is less than 1% image size difference between the two cameras for zoom adjustments, which I can easily correct if needed with my computer graphics program, but accuracy of the zoom will depend on how well the cameras are matched. Ideally, the cameras would have close serial numbers for the best chance of power-up sync and matched zoom.
Exposure: Once the cameras are in sync, and both cameras are set up the same way to take a picture, press the lock/shutter button half way down, wait for the cameras to achieve focus and exposure lock, then press the button all the way down to take a stereo picture. To have synchronized shutters, it is important to first press focus lock for a moment, wait until the cameras are fully locked (focus, shutter, aperture), and keep the focus lock down until the shutter is pressed.
Video Camera Support: The LANC Shepherd senses the type of device attached, and uses the appropriate commands.
Power-up sync works almost same way as with still cameras--again, the cameras must be on battery power to sync properly with the LANC Shepherd power button. Turn on the cameras with the mode switch set to "camera" (not playback mode), and use the LANC Shepherd to turn the cameras off. Then power up the cameras in sync using the ON button on the LANC Shepherd. The LANC Shepherd functions work the same whether recording to tape or to memory stick.
The red "Record" button on the LANC Shepherd toggles on or off video recording.
The LANC Shepherd can be used for still photo capture on Sony video cameras so equipped. Canon video cameras do not provide support through the LANC port for still image capture. Press the shutter/focus lock button down half way to capture an image, and press the button all the way down to save the image to tape or memory stick (depending on the cameras capability and mode setting).
The zoom rate with video cameras can be adjusted with the LANC Shepherd. The zoom rate adjust requires holding down the shutter button half way during the period of time needed to make the adjustment. With the shutter button held down half way, bring up the adjust screen by pressing "zoom in". Press "zoom in" or "zoom out" to make the adjustment. Then release the shutter button to save the new zoom rate to memory in the LANC Shepherd. Zoom rate can be adjusted from 1 (glacial) to 8 (mach).
Self-Timer: Digital cameras all have this feature on their own--set the timer, and then the photographer has ten seconds to scramble back to the group before the exposure--but this feature with stereo cameras will typically take an exposure seconds apart. With the LANC Shepherd, press the red "Timer" button to start the countdown, and again if needed to abort. The count down is displayed on the LCD. At three seconds, the LANC Shepherd initiates focus lock, and at zero on the counter, the LANC Shepherd triggers both cameras at exactly the same time for a synchronized exposure.
Interval Timer (Time Lapse Photography): This feature allows taking stereo photographs at set precise intervals. The interval time adjust requires holding down the shutter button half way during the period of time needed to make the adjustment. With the shutter button held down half way, bring up the adjust screen by pressing the red timer button. Press "zoom in" or "zoom out" to make the adjustment. The interval can be adjusted from 2 seconds to 24 hours. Then release the shutter button to save the new zoom rate to memory in the LANC Shepherd and start the timed exposures. Press the red timer button again to abort the interval timer if needed.
For interval times greater than about one minute, the cameras may shut down automatically because of inactivity. One can either plug in the battery charger to each camera, or one can plug in a dummy 3.5mm (1/8") stereo plug into the video output of the cameras to prevent the automatic shutdown.
During the interval timing, the hours:minutes:seconds remaining before an exposure is shown on the LCD display. Since the subject will presumably move very little during the interval timing so that sync is less of an issue, the sync is not displayed during the interval timing.
Flash Photography With Internal Flash: Synchronizing flash is probably the most difficult aspect of stereo photography, and discussion of flash can get complicated in hurry. Here is a more detailed description of flash sync with digital cameras.
Nonetheless, flash photography works well with the help of the LANC Shepherd. Since both cameras must be configured the same for exposure sync, both flashes must fire, but one flash must be blocked for best flash synchronization and best stereo quality. The LANC Shepherd indicates which flash to leave open to the subject, "M" for the right master camera cable or "S" for the left slave camera cable. Rather than switch back and forth blocking flashes, I usually just block the slave flash, and insist on "M" being displayed for a flash exposure.
Flash sync generally works well as long as the sync is less than about half the shutter speed (for example, if 1/500 sec shutter, sync less than 1/1000 sec). In reasonable light, I often use the regular flash mode to fill in shadows, and this works quite well and reliably to at least 1/500 sec exposure with the Sony DSC-V1. Using flash as the sole light source in darkness does not work as reliably. So I just use the regular flash mode in reasonable light with excellent results.
The shutter priority, and manual modes share some limitations when using them with flash. I find that they work reasonably well with flash as long as the EV (exposure value) hovers around zero and the subject has at least moderate contrast. The EV gives an indication of where the exposure is relative to those values the camera would choose in automatic mode without flash. If the exposure depends at all on flash to bring up the exposure to a reasonable level, I have trouble getting flash sync in these modes where shutter speed is specified. I can reliably predict the absence of flash on one of the exposures just by listening to the difference in shutter beeps, despite the high degree of sync displayed on the LANC Shepherd.
The work-around is to use either the fully automatic mode, the program shift mode, or the aperture priority modes. These modes also work well with an external flash (either LANC or regular hot shoe). The program shift mode is a bit frustrating to use however, as the camera will not let me choose a shutter/aperture combination that is outside a zero EV, it will not let me choose a shutter speed slower than 1/30 sec, and it requires the metering to be centered on the subject for an adjustment. Flash sync with these modes is, however, amazing.
Flash Photography With Third Party External Flash: A regular third-party external flash will of course work with the LANC Shepherd if the camera model has an active hot shoe (yes Sony DSC-F828 DSC-F717 DSC-V3 and DSC-V1, no Sony DSC-S75 or DSC-S85) in the same fashion as internal flash as discussed above. Configure both cameras in the setup mode to use the external flash on the hot shoe, and attach the flash to one of the hot shoes, then insist on a "M" displayed for flash on the master camera or "S" for flash on the slave cable.
Flash Photography With a Sony External Flash: Follow this link for detailed information about using the Sony external flash units with the LANC Shepherd. The Sony HVL-F1000 "External Strong" accessory flash, and the Sony HVL-F32X "High Grade" accessory flash can work well with the LANC Shepherd with attention to a few details. Both of these flash units share the "ACC" or "LANC" port. Both come with a small steel camera bar with a false flash shoe.
How Synchronized Is Enough? I've taken and processed hundreds of stereo photographs with the LANC Shepherd, and I can say with absolute certainty and authority that . . . it depends.
Initially, I insisted on absolutely perfect synchronization, and indeed, some situations require it to be so. On the other hand, some subjects become more lively and interesting with a bit of "retinal rivalry" produced by a mildly out-of-sync stereo pair. I suspect that as long as a most of the photograph shows no disparity, a small portion with disparity can enhance the appeal of the stereo pair with some subjects.
As a general guideline, I suspect that a displayed sync greater than 1/10th of the shutter speed will be potentially noticeable for average photography. For example, for a shutter speed of 1/250, a sync greater than 1/2500 (0.40 msec) will produce just noticeable disparity for an average city street corner with wind, people walking, and slow moving cars. Action photography, with considerably faster motion and shorter shutter speeds, needs to have a sync proportionally better, and I generally try to take these photographs with as good a sync as I can achieve (on the order of a 0.01 msec or 10 millionths of a second).
In the end, the LANC Shepherd allows really a remarkable degree of synchronization if it is required, and allows sync time to be a stylistic choice for stereo photography as well.
Mounting the Cameras: Here are a few tips:
The digital camera lenses are not necessarily aligned with the camera body. The lens on a digital point-and-shoot camera is mounted on an internal chassis, and the external camera body is just a shell. So count on shimming the cameras once they are mounted for proper stereo alignment, particularly if the cameras are not both mounted in the same orientation (such as over/under, bottom to bottom, etc).
Think about which parts of the camera you will need to access easily when planning your camera mount, or make provisions for limited access. Rather than have to remove my cameras from the mount for access to the memory sticks, I bought large capacity memory sticks right off. I have actually never removed the batteries or memory sticks from my pair of DSC-V1 cameras.
John Hart put together a detailed web page here showing how to get started in stereo digital photography, including a nice mount for a pair of digital cameras, and detailed instructions for using available software to process the images into stereo pairs . . . really an excellent review!
The Pictures: Here are a few sample images for your enjoyment. These pairs are big, 900x600, and I need to use a screen resolution of at least 1024x768 to view them on a web page. I apologize to those of you without broadband also--the compression is mild, because I can't stand to see JPEG compression artifacts in stereo. These images all open in a new window. The pictures were taken with a pair of Sony DSC-V1 cameras.
Parallel View 129k.
Marriott, Waikoloa Beach, Hawaii.
The ubiquitous gas torches. I took a tightly synchronized exposure initially. Then, as an afterthought, I waited for the sync to drift out a bit to about 0.4msec, then took this exposure. I like this exposure the best of the two, as the flames are quite a bit more interesting with a little retinal rivalry.
Parallel View 250k.
Mammoth Bar Off Highway Vehicle Area, near Auburn, California.
My brother was pretty excited about his new KTM 450EXC, and he nearly took me out as he passed by. 1/500 sec exposure shutter priority, with the three shot burst mode (second exposure shown).
Parallel View 198k.
Forest Hill, California.
My kids had a swim meet at this small city pool, but an entertaining part of the festivities is this "coaches race" in the middle of the meet, where the coaches swim in a relay race. With their pride at stake, they swim for all they are worth, raising an impressive spray for the kids and parents. 1/500 sec exposure, shutter priority.
Parallel View 377k.
Crossed View Parallel View 312k.
Yuba River, near Nevada City, California.
I've taken pictures here before with my pair of Sony DSC-V1's without a sync device, and I was anxious to try it again. Going back in February was probably not the smartest move though--slick rocks and c-c-cold fast water, with the sun only occasionally peeking through the clouds. DSC-V1 with LANC Shepherd, shutter 1/1000, aperture 4.6, sync around 0.02ms (1/50000 sec). The second set is with about 2x zoom.
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