SONY a6400 getting overexposed at lowest iso in daylight ! ! Help

[lilaquath]

I have been using sony a6400 for about an year now ! during the past couple of months i encountered this issue , The problem is when i turn on the camera the  image / video appears overexposed like white all over the place  : My settings are  HLG3 , f2.8 . shutter speed double for smoothness and did both iso auto and the lowest iso possible then also the image appear over exposed , i also changed the picture profiles to slog 2 and cine4 , pp off but the issue did not changed ,  The Lens was  Sony fe 50mm 1.8 . The only thing i did was cranked the shutter speed way up and it fixed it, but it was way sharp movement. -- The issue appeared like 2 times in past two months from time 11am-4pm !! i have attached an image of how it appeared in these settings . The image showed below is in a terrace viewing to coconut trees nearby and the second image is after i cranked the shutter speed like hell - please help me with this , one of my friend said this could be a board level problem - any idea ???

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[Pieter]

Since you have aperture and shutter speed fixed, the only parameter your camera can use to adjust exposure is ISO. Since ISO can't go any lower than 100, your footage will become overexposed during bright daylight and ISO 100 (which is plausible given the timeframe you're having this issue). Try using a smaller aperture, or use a neutral density filter if you want to shoot with a wide aperture.

[lilaquath]

What you are saying is to adjust aperture  but i am going for that 2.8 cinematic look !! And i also tried iso auto which did not fixed the problem !!  Only way was to adjust shutter speed at high ! 

 

[Pieter]

Or to use a neutral density filter.

Not trying to be rude but maybe you should educate yourself a bit more on the exposure triangle. You can't just choose some parameters you like and expect the camera to magically fix exposure for you. It just doesn't work that way.

[lilaquath]

so you are saying sony a6400 cant handle daylight at noon lol  ?? i know the exposure triangle and always use it !  but my issue happend two times when i followed everything properly. -  my question is it because of the chip  / sensor problem ? or anything related to lens ??  because all my in cam settings are followed correctly

[lilaquath]

You saw the first image right its crazy overexposed or i dont know what to call it !

[Pieter]

Yes of course it was crazy exposed because obviously you do not understand the exposure triangle. This has nothing to do with the camera / chip / sensor, pure user error.

Have a look at this chart: in light clouds at f/2.8, you need a shutter speed of 1/1600 sec for proper exposure at ISO 100. The only way to get proper exposure at f/2.8 and ISO 100 at a slower shutter speed is to use a neutral density filter.

 

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Edited June 6, 2021 by Pieter

[lilaquath]

You dont understand , the first setting was at iso auto mode where camera selects the iso - in this method the image appeared same as i have uploaded !  i always do iso auto because clouds come and go fast - light changes - tropical country !!  i was freaked out by this and switched to iso manuel and keeped on reducing to fix this issue - but it appeared the same throughout till iso 100 , lowest iso possible in a6400 !!! i was not keeping the iso at 100 , the iso was in auto mode - 

.

After this i cranked the shutter speed to fix ! but my question is when my camera is in iso auto mode - at f2.8 . at shutter speed 100 - how can it overexpose like this

[lilaquath]

or like you are saying iso 100 is too much for daylight at  shutter  speed - 100 / f2.8 ?  and cranking shutter speed was a normal thing ?? and please i am not in a situation to buy nd filters 

[Pieter]

You're starting to get it: ISO 100 at F/2.8 with a shutter speed of 1/100 sec is about 4 stops over-exposed in lightly clouded conditions, or 5 stops in bright sunny daylight. Setting ISO to Auto doesn't help here: it can't go any lower than 100 so if shutter speed and aperture are fixed, the outcome will look good in darker conditions but as soon as the sun comes out, ISO drops to 100 and then hits a wall where it can't compensate for exposure anymore and your image will overexpose.

[lilaquath]

okay now i understand ! so i should adjust the aperture / shutter speed when this situation comes right ? and i always try to balance with the histogram , thats why i cranked the shutter in the first place ! anyways let me try this and ill come back - Thanks Pieter

[Pieter]

Exactly! This is why I suggested you'd delve a bit more into the exposure triangle and why I showed you the indicative exposure values in that diagram. This diagram is not specific to the A6400, it is valid for ALL cameras and brands (disregarding some variations in ISO-calibration and lens transmission). No camera can just 'fix' the exposure if you use inappropriate exposure parameters.

In the example above (lightly clouded conditions) there are 3 possibilities to achieve a good exposure:

1. Increase shutter speed to reduce exposure:
   ISO: 100
   Aperture: F/2.8
   Shutter speed: 1/1600 sec
2. Stop down the aperture to reduce exposure:
   ISO: 100
   Aperture: F/11
   Shutter speeld: 1/100 sec
3. Add 4-stop neutral density (ND) filter to reduce exposure:
   ISO: 100
   Aperture: F/2.8
   Shutter speed: 1/100 sec

As you can see, only the option with an ND-filter allows you to use the exposure parameters you so desired (aperture F/2.8, shutter speed of 1/100 sec). Any of the other options will require some compromise with regard to aperture or shutter speed.

[lilaquath]

Yea after playing around 2-3 days , i got it man ! thank you so much - and looking forward to buy a nd filter !! there is so much to explore this camera

[lilaquath]

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and a final doubt , this is the kit wide lens that comes with sony a6400 !! i know that vignetting occurs at wrong settings , but is this type of vignetting normal ? sharp vignette ? 

[Pieter]

That's a stupid software thing and becomes especially apparent under those conditions: the in-camera vignetting correction does not seem to be gradual but compensates in discrete steps away from the center. When boosting the in-camera corrected image (either in post or by extremely high ISO in-camera), these concentric rings become very clear. I believe the in-camera shading compensation is baked into the RAW-file if you do photography, which renders an otherwise nice photo useless.

I always disable in-camera shading compensation (= vignetting correction) for this very reason. And because I often like a bit of vignette in my shots. If I don't want vignetting for some reason, I stop down the lens or correct in post.

[Nextguitar]

23 hours ago, Pieter said:

…the in-camera vignetting correction does not seem to be gradual but compensates in discrete steps away from the center. When boosting the in-camera corrected image (either in post or by extremely high ISO in-camera), these concentric rings become very clear. I believe the in-camera shading compensation is baked into the RAW-file if you do photography, which renders an otherwise nice photo useless.

That stepped vignetting has often annoyed me in skies when shooting jpeg, but it didn’t occur to me that the camera’s lens correction algorithm may be at fault. I need experiment with & without compensation to see how it affects blue sky.

I think Sony’s shading correction only affects the jpeg, not the raw file.