Metabones Speedbooster and Auto Iris Problem on the FS700

Metabones Speedbooster and Auto Iris Problem on the FS700

I am an FS700 owner with a LOT of Canon glass on hand. When the first Metabones adapter came out I rushed to get mine and I must say I was delighted. So when Metabones announced the Speedbooster I got even more excited.

For one thing the Speedbooster makes the lens faster, and the second feature is that it gives you the full coverage that you are used to on the 5D, i.e. no crop factor. So I got my Speedbooster just days after it was announced. I have had one issue with it, the auto iris buttons on the FS700 give me this error:

“Cannot execute functions due the the condition of the lens.”

Now I know what you are thinking, “What wimp needs an auto iris button?” Me for one. I find it helpful just to touch it to quickly get to a starting point rather than whirling the iris dial. Then I fine tune it. It really speeds things up. Now I am speaking here of the IRIS PUSH AUTO button to spot check, not turn on auto iris for an extended period.

There are times you want to keep the camera on auto iris for a period and you use the IRIS button. It enables you to automatically adjust to expected sudden lighting changes during a shot like during the move-in visit during my Eagle Ridge Builders infomercial. Absolutely invaluable! Note Canon glass is unsuitable for this purpose. (See comment below.)

I just thought my Speedbooster was broken since it worked fine on my original Metabones. I had contacted Metabones tech support before and the solution they offered seemed radical as it involved hot swapping the lens. I was worried that something got lost in translation. I hot swap my Canon lenses all the time on the 5D (always in a hurry), but I hesitated to do so on the FS700. So I did nothing.

After a while I wondered if it was just me, so I reached out to my friends on Twitter and found that others have experienced it. So once more I contacted Metabones to see if they had a solution.

Turns out it was global warming:

It turns out that Metabones disabled the auto iris button as some sort of macabre upgrade. They now have 2 modes “Green Mode” and “Advanced Mode.” Green mode is enabled by default which does not let you auto iris. Evidently using the auto iris button contributes to Global Warming.

To turn on auto iris:

You can enable the Advanced Mode which turns on Auto Iris capability by a simple step. Turn off the camera. Push the Wide Open button (the only little tiny button on the Speedbooster), hold it down and turn on the camera. You are now in Advanced Mode and have use of the both the IRIS and the PUSH AUTO IRIS buttons.

If you turn off the camera or change lenses, poof you are back in “Green Mode” and goodbye auto iris. Metabones tells me they way to change the default mode from “Green” to “Advanced ” which I have renamed “Common Sense Mode.”

Instructions from Metabones for firmware version 24 and above:

To change the default mode,
1, turn camera on,
2, hold down the WO button while attaching the adapter/lens,
3, while still holding down the WO button, turn camera body off,
4, detach adapter/lens.

Apparently my firmware version 16 does not support this. To determine your firmware version connect the Metabones, turn on the FS700, then MENU > OTHERS > VERSION DISPLAY.

Metabones contacted me via As of 25 Aug 2013 they are on firmware 30. I was instructed to send my Speedbooster in for a free upgrade. They want prepayment of $25 via paypal to pay for return shipping. I will send mine in and update this blog when it returns.

Please leave a comment if you have had similar problems so I know how to reach out to you.


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  1. August 24, 2013 at 12:19 am

    The instructions you cited were an undocumented feature added to firmware version 24. You may display the adapter firmware version with the MENU button.

    • Swainhart
      August 24, 2013 at 3:17 pm

      Excellent. My firmware is version 16. So what do I do now?

  2. August 24, 2013 at 12:23 am

    In any case, it is a pretty bad idea to use auto iris. Canon apertures are noisy and they are not stepless but move in 1/8 stops. Aperture changes would have been visible in the footage, and there would be audible clicks too.

    • Swainhart
      August 24, 2013 at 3:13 pm

      Excellent comment. I have edited the article to indicate that I when I used the auto iris continuously for the Eagle Ridge Builders shot I used the Sony kit lens. That kind of this is impossible with the Canon lenses unfortunately.

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