The Blackmagic URSA Viewfinder Doesn’t Make Sense on the Sony FS7

November 15th, 2015 Jump to Comment Section 2
The Blackmagic URSA Viewfinder Doesn't Make Sense on the Sony FS7

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I recently made this video where I showed you how to use the Blackmagic URSA Viewfinder with any camera and in this article we make it work with C300 mark II. Here’s how the same EVF could be used with the Sony FS7. Unfortunately with this camera the solution is really not ideal.

Why did I attempt to use the Blackmagic URSA Viewfinder with the Sony FS7? It’s a great OLED viewfinder that gives you a nice 1080p image. Unfortunately it was made specifically for the Blackmagic URSA and Blackmagic URSA Mini cameras and with some cameras the hassle might not be worth it.

There are a few requirements to use this EVF:

  • The URSA Viewfinder needs an SDI source.
  • The Viewfinder only works with a 1080 progressive signal. Many cameras output an interlaced signal so this is a problem.
  • You will need some way to power the URSA Viewfinder with a 12V female 4-pin XLR.

The Sony FS7. Not really…

So if it doesn’t work why do I write about it? You can imagine testing this was a lot of work. So if anybody comes across this article maybe it will help you make a better decision about going forward with that idea.

The URSA Viewfinder would be a great match for the FS7, but unfortunately, just like the Sony a7S, it is not the ideal camera for this device as it only outputs interlaced signals via its monitoring ports. The Sony a7S, when used with an Atomos Shogun for 4K recording is much more ideal on the other hand, as the Shogun solves an essential problem.

On the FS7 there are also no ideal mounting points so you have to get additional accessories. The following modification is a way to achieve using the Viewfinder, but I must admit, there are other viewfinders better suited for the Sony FS7, like the Gratical X with a Zacuto Axis Mini attachment.

If you’re still interested in getting the URSA Viewfinder to work with the Sony FS7 read on…

So you need to transcode that signal to progressive somehow, but there is no converter I know of that does this in a nice way.

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I tried to achieve the progressive conversion via this scaling converter. Unfortunately it proved to be a failure. While the scaler successfully transcodes the signal to progressive, it also introduces ghosting artefacts that degrade the viewfinder quality. So the only way to do this on the Sony FS7 remains the same approach I used for the a7S.

You will have to output the signal in 4K to a device like the Convergent Design Odyssey or Atomos Shogun which can downscale and transcode it to 1080p. IF you’re using the FS7 with such a device anyway, then using the Blackmagic URSA Viewfinder is another story.

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If you use the XDCA extension unit you can output the feed via SDI to your 4K recorder and connect the URSA viewfinder to it.

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Alternatively if you use another V-mount adapter like the Tilta V-Mount Battery Plate you have to use 4K from the FS7 hdmi port and connect that to your recorder in order to downscale and convert to a clean SDI 1080p.

Either way you will need a V-Mount solution to power the camera and viewfinder and convert that 12V output to the viewfinder’s 4-pin XLR. For the Tilta plate you’d use this cable and for the XDCA you’d go from d-tap to xlr with this cable.

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Mounting

Here comes the part that makes this modification least attractive. To mount the viewfinder on the camera you would ideally also get the Blackmagic shoulder kit as it provides the best stability on the camera and offers a top handle. Otherwise you can’t mount the viewfinder nicely.

You would unscrew your FS7 top handle and replace it with the Blackmagic top handle / viewfinder shoe. The viewfinder shoe can only be mounted with a single screw as the other FS7 threads do not match its design. For improved stability I added a bit of sticky tape to the front. This way it proved to be a very very stable construction that would not get loose, even though you might think otherwise. Even without the sticky tape the handle didn’t move. The sticky tape should make it last as it can no more be moved to either side.

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That’s it!

I will not list the parts needed for this modification, as the news is that it basically doesn’t make sense to use the URSA Viewfinder on the Sony FS7. I wish it had. The Viewfinder makes much more sense on an a7S with Shogun or a C300 mark II as explained in this article.

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