The Sony FS7 ND filter wheel problem and fix

How to fix the insane Sony FS7 ND wheel problem? Here is our solution to avoid being caught with such trouble?
There are plenty of great feature packed in the Sony FS7 camera. One of them are the internal ND wheel allowing you to shoot under very sunny condition with a large aperture and slow shutter speed.  There is no way to go out under such sun without ND filters. Here I’m using the 10-18 mm F4 Sony lens which can’t hold external neutral density filters, so the use of internal is the only way.


The ND filter wheel come in 2 different ways depending on which version of the Sony FS7 you have. I have a long post that explain the differences there.
On both Sony FS7m1 and FS7 M2, it’s a physical wheel that come in front of the sensor. For the FS7m1, each steps of the wheel hold a different ND filter to let you get 4 different steps. On the Sony FS7 mark 2, it’s a unique step but it can be electronically controlled. It works a bit like a LCD display to let more or less light passing through. That’s also why yo don’t have a smooth ND filtering when using the Electronic one on the FS7mk2 or FS5 camera.

The ND filters wheel problem Sony FS7

This is often a faulty mechanical design that kills even the most prepared electronics. This issue is one more time a proof of it. The ND filter wheel hosted on your Sony FS7 is not moving in front of the sensor by an internal motor as the Canon C300 for example. It’s an mechanical wheel that you will manually rotate with your fingers using an almost direct knob. And as all knobs are; you have a link to its axis. For some unknown reasons, the engineers at Sony decided to use two super tiny screws to block the knob to its axis. Nothing so wrong here except the axis is completely rounded and do not have any ways to let the screw firmly lock into it. If they where to get a simple flat surface, the screw could have been getting a bit inside and avoid the now to slip at one point.
Even if Sony put 2 screws to lock it, it do not really matters. As each screw is pushing at different direction, if one get loose, the second is useless too.

So, in a middle of a shooting, when you are going outside with more light, your DN filter wheel suddenly do not respond to your rotation. The wheel get stuck in the current position at most. In worst case, it can be stuck in the middle of 2 position and you can’t even just add more ISO to balance the ND presence… This is a very big issue if you are not prepare to deal with such.
With a bit of luck, it will not happen all of a sudden. It will start by some slight loose movements before it get all disconnected from it’s axis.

Temporary solution to the Filter ND Wheel not responding.

When this happen on a shooting, you may want to find the fastest way to solve it by knowing what is behind the knob.
The first temporary solution, you can try is to turn the ND wheel knob and bend it a bit when doing so. You may have a bit of luck with one of the screw still able to grip the axis and get the ND out of the sensor. The Sony FS7 ND filter wheel need a lot of force to move as it’s a direct connection and no helps from any motor. Still that may be the safe move.

Next solution is to try to remove completely the knob if you can. As it’s loose, it may actually come out by itself. Try to not loos it if this happened. There is a little gap in the axis, so it’s actually not so simple.
You can try a toothpick or very small metal screwdriver to try to unscrew the very little Allen screws. There are 2 of them only at 90 degrees. I suggest you to remove the wheel as there is a little flat area on the axis itself. It  may be easier with even a tiny coin to still keep flipping the FS7 ND wheel. By trying to lock back with a unconventional tool, you may save your day once, but not sure when it will be stuck again. Here is the way it looks like when fully removed.

As you can see the axis have a way to make it rotate with a simple larger screwdriver if you need to keep shooting.

Solution when the ND wheel is getting loose.

Prevent a problem before it actually happens will be my first advice. If you feel that the wheel is not so responsive; you may want to go and buy right away a set of Allen tools. The one you are looking for is number 0.9. Allen key are also called 0.9 hex wrench. It can come as a set as below or as a regular screwdriver with only one size. I strongly suggest to get such in your camera bag if you are planning some traveling!

The set is very cheap at less than USD $ 5 by following these online links. It could be great to keep part of it in your camera bag. When you go for renting another FS7, it may be the day you will using this to save your shooting. The screwdriver is nice and offers yo more power but it’s also bigger to bring alone.
Don’t be over optimistic, this issue is so common on the Sony FS7 that it will happens to you. It’s just a matter of time.

You only have these two tiny screws to take care . You can see them when you choose the position clear on the Sony FS7 ND wheel. On this picture, you can also use the other side of the hex number 0.9 wrench for a stronger force. As the axis is actually round, it may never be able to lock firmly for the next 5 years anyways.
To my understanding; this is a design flaw on the version one of the FS7, at least.
If your camera is quite old, you may soon also experiment the hand grip slipping problem where your FS7 hand-grip can’t be locked to a specific angle anymore and keep slipping. I also have found a way to fix it here.

Thanks for reading.
If you like this kind of article, feel free to click on one of the Google advertising on this page to support the blog. It cost 2 second of your time to say thanks.