Fuji GX680III with a digital back

I tested a Phase One p25+ digital back on a Fuji GX680III recently.  Here are the results:

First, the camera had to be synchronized to the back.  This was the challenging part.  Typically, a sync cable would be connected from the pc port on the camera to the pc port on the back.  That does not work in this case.  The flash sync pulse duration is not proportional to the shutter speed with this camera so the digital back does not know how long to record the image.  The pulse duration is very short and is the same for all shutter speeds.  To work around this, you can use a shutter speed sync pulse equalizer like the kind that Davin at DPI has.  But I found a way to do it without one of these.  Here are the steps to do it:

1. The P25+ is a ‘two shot’ back so a wake-up signal is required to prepare the back to record an image.  I connected a pig tail mulitsync cable to the back and then connected a sub-mini plug on a Canon Digital Rebel cable release to the pig tail.

2. Connect a Fuji GX680III cable release to the camera.

3. Set the shutter on the camera to 1/8 sec with aperture at f/11.

4. Press the Canon cable release to wake up the back.

5. Press the Canon cable release again and hold it down.  I did this to simulate the duration of the sync pulse from the camera since the actual sync pulse is too short.

6. Press the cable release on the camera to fire the shutter.

7. Let go the the Canon cable release so the back will stop recording the image.

This worked great since the back was ready to record the image the whole time I was holding down the Canon cable release.  The shutter speed on the camera was SHORTER than the length of time I was keeping the back active with the Canon cable release.  When the shutter fired, the image was recorded.

But if the duration of the shutter speed is LONGER than the time the back is recording, an error occurred.  This error can be seen as purple stripes across the image.  To get this to happen, I put the shutter speed on B, opened the shutter, THEN pressed the Canon cable release timed for 1/8 sec., then closed the shutter.  I believe this happened because the back thought the shot was finished recording but light was still falling on the sensor while the black calibration was happening.

Fuji GX680 III and 50mm lens with a Phase One P25+ attached with an adapter plate

Fuji GX680 III and 50mm lens with a Phase One P25+ attached with an adapter plate

Fuji GX680 III and 50mm lens with a Phase One P25+ attached with an adapter plate

Fuji GX680 III and 50mm lens with a Phase One P25+ attached with an adapter plate

Fuji GX680 III and 50mm lens with a Phase One P25+ attached with an adapter plate

Fuji GX680 III and 50mm lens with a Phase One P25+ attached with an adapter plate

Fuji GX680 III and 50mm lens with a Phase One P25+ attached with an adapter plate

Fuji GX680 III and 50mm lens with a Phase One P25+ attached with an adapter plate

multi sync and pc port on a Phase One P25+ attached to a Fuji GX680 III with an adapter plate

sub mini port on a Phase One P25+ attached to a Fuji GX680 III with an adapter plate

Fuji GX680III camera dial set to ‘multi’ shot

Canon 350D cable release with sub mini male connection used with a Phase One multisync to sub mini female adapter

Fuji GX680III digital back adapter plate with Hasselblad V mount

Fuji GX680III film back

Fuji GX680III (L) and Hasselblad 555 (R) P25 Masks

Fuji GX680 III and 50mm lens with a Phase One P25+ attached with an adapter plate

Thanks to Mark at K&M Camera for letting me use their gear to do this test.

Advertisement