Fuji Exposure Shift During Video Recording

[Luke Mason]

I was told that firmware updates for the lenses may have solved this issue. If you are using 18-55 kit lens or 16-55, the latest firmware updates are Oct 2016.

[fuzzynormal]

6 hours ago, Luke Mason said:

I was told that firmware updates for the lenses may have solved this issue. If you are using 18-55 kit lens or 16-55, the latest firmware updates are Oct 2016.

I'm using latest firmware on everything. The lens that's problematic is the 10-24. 

As far as I'm concerned, that lens is way too expensive to have this serious a flaw.  

[BTM_Pix]

6 minutes ago, fuzzynormal said:

I'm using latest firmware on everything. The lens that's problematic is the 10-24. 

As far as I'm concerned, that lens is way too expensive to have this serious a flaw.  

I've got the same lens.

I'll try it on the X-T20 and X-T2 when I get a chance today or tomorrow and see if its the same. I expect it will be similar and I've a feeling it might have some variance between the X-T20 and X-T2 because of the different crop. 

[Trek of Joy]

4 hours ago, fuzzynormal said:

I'm using latest firmware on everything. The lens that's problematic is the 10-24. 

As far as I'm concerned, that lens is way too expensive to have this serious a flaw.  

Its not weather sealed at all either, that's my main issue with it.

Although I will say I'm seriously considering heading back to Sony FF because the UWA zoom is so crucial to my work. The 16-35/4 is awesome, and the new GM looks even better.

[garywiz]

It's the aperture!  It took me a while to figure this out and signed up to the forum just to post this, as it's hard to find answers on the web.

Basically, I believe what is happening is that the firmware inside the lens is making an "aperture shift" decision during zooming.  For example, I'm using the 18-55mm 2.8-4.0.... which of course (and we all just accept this) has an aperture change during it's zoom range.   I believe that somehow the Fuji firmware is making this "gradual adjustment" to compensate for optics during the zoom process which is resulting in the "shifts" during zoom. 

Workaround:  Shoot wide open.  For example, if I shoot at F2.8, the problem disappears completely.  Even stopping down by a single stop makes it come back with a vengeance.   

This is, of course, a terrible flaw.  However, using the ISO and Shutter speed combined, you can at least (USUALLY) obtain a proper exposure.   At least it's better than the other way around.... with a narrow depth of field at least you can still pull focus effectively.

I don't use my Fuji for video much.  Thank goodness, because this is a real limitation.  I hope they fix it.  This is awful really.

[kjd]

Just picked up a xt3 2 months ago and noticed this, with all the latest firmware. :( Still the same problem. Using the 18-55. yes it is an aperture shift.

[TrueIndigo]

Anyone seen this video exposure shift when using manual adapted lenses, or is it just confined to Fuji auto lenses?

[DavidStachon]

I tested this quite extensively (it was keeping me up at night), and have reliable workaround.

(the shooting 'wide open' suggestion from above did not work for me)

using the: 16-55 F2.8 

Do this (no other combination works):

Manually Set Shutter Speed (i.e 1/60)

Auto Aperture.

Manually Set ISO: (i.e. 1000)

You'll need to experiment with the ISO values (zoom in and out of your scene) and watch what the camera does as it automatically sets aperture.

You'll need to ballpark it depending on the depth of field you need.

If you need a narrow depth of field, ISO lower,

If you need a wide depth of field set ISO higher.

(yes, this is kind of weird to think about, but it will make sense when you try it)

Obviously, this is really disappointing that this is required when using a zoom lens. Fuji desperately needs to smooth this out to work with all setting on manual.

Hopefully that helps somebody. 🙂