XF1 (EXR) overexposed pictures - cause?

kitsios_spyros said:

I bought a lightly used XF1 a few months ago. I enjoyed the DR modes a lot as I am a huge fun of high DR capable sensors. SNR modes were not very convincing for me, probably due to my experience with the 14bit raw files of Pentax K5ii, which is excellent for an APSc sensor. I am making no comparisons here, just mentioning my experience and the reason I loved XF1 for day/good light scenes.

Due to the intended use for my needs, my only real problem with XF1 was the max shutter speed

1/2000 at f1.8 for DR100%

1/1000 at f1.8 for DR200%

1/500 at f1.8 for DR400%

So, I could not enjoy f1.8 at good available light, even when DR400% was enabled, due to the slow max SS.

However, this weekend I took a few shoots under strong morning light and everything was washed out. Next evening after some testing at much lower available light and after studing the exif I figured out that the camera overexposed constantly by at least one stop as

*) max SS that I managed was 1/1000 or slower for f1.8 and DR100%

*) -1EV to -2EV comp. was able to solve the problem if the SS was slow enough (1/1000), so this needed low ISO in low light, which was never enough for strong daylight of course

*) Noise was worse than I can remember for each ISO stop tested/used. Colour fidelity was also decreased

*) Trying to get stills while recording video, the exposure of both video and still was excellent. But for video the camera does not use EXR modes and stops down whenever needed

So, I believe that at least for my camera (if not all EXR cameras having overesposed images) that the root cause is not a stack wide open aperture but the EXR sensor getting stacked to SNR 200% mode (or even DR400%), so half of the pixels are shoot at higher ISO by one (or two) stops.

I follow the Fujifilm cameras for more than a decade (I chose a 6500fd as my first "serious" digital camera) as well as this forum, but I do not remeber any such discussions about sensor problem, only the locked lens error and the stacked wide open aperture.

Any thoughts?

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kitsios_spyros said:

...

We experienced the identical problem several months ago with our XF1. I was using settings very close to Kim's suggested settings. Upon my initial diagnosis, I thought that I had found -- and solved -- a very unusual cause for the matter: Report on disgnosis and treatment here. However, further investigation proved that my initial diagnosis was, though technically not incorrect, incomplete and masking a matter of coincidental correlation. The SD card was defective, but the main cause of the problem was not the defective card, but a stuck aperture blade.

The proof was that the camera overexposed more the smaller the indicate aperture (on the LCD screen and in the EXIF) was. When the LCD/EXIF said that the aperture was f/11, the entire picture was blown. When (at longer focal lengths) the LCD and EXIF said that the aperture was f/4.9, the images were just fine. At the widest setting of the lens (6.4 mm actual, 25 mm equivalent), when the LCD and EXIF showed f/1.8, the exposure was fine. When I had performed my initial diagnosis, I was taking test photos indoors, and the camera was usually trying to set aperture as wide as it could, which happened to be the range where the camera exposed properly with its aperture blades stuck wide open. I notice the f/11 settings in the EXIF of your beach scenes and very strongly suspect that you are experiencing the same syndrome.

I sent the camera to Fujifilm Service in Edison, NJ, enclosing a note explaining my (updated) diagnosis, and two weeks later the repaired camera showed up at my doorstep; no charge. We have seen zero problems with the XF1 since.

...

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Lightpath48 said:

I always set -1/3 or -2/3 on exposures with my X10 and X-S1 (same sensor and processor as your XF1). Sometimes on a rare occasion it even takes -1.0 to save extremely bright highlights outdoors. The exception is when zoomed into the scene and no sky appears in the frame. Then the overexposure seems to settle down.

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kitsios_spyros said:

Thanl you for the response.

I do have sticky apperture blades too aftet all.
But yhe sensor issue is there. Add another problem.
SS faster than 1/3 sec, image overexposed
1/3' or slower, image is black.
But stills grabbed while taking video and video itself have spot on exposure

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DS21 said:

kitsios_spyros said:

Thanl you for the response.

I do have sticky apperture blades too aftet all.
But yhe sensor issue is there. Add another problem.
SS faster than 1/3 sec, image overexposed
1/3' or slower, image is black.
But stills grabbed while taking video and video itself have spot on exposure

Click to expand...

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DS21 said:

Video is probably taken at maximum aperture to maximize brightness, and aperture does not have to close fast as when taking the photo.

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DS21 said:

You are at least the 15th poster on this forum whose XF1 has failed, some have had even repeated failures (repaired camera failed again). I know of only two forum posters whose XF1 has not yet failed...

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CAcreeks said:

DS21 said:

Video is probably taken at maximum aperture to maximize brightness, and aperture does not have to close fast as when taking the photo.

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XF1 video is surprisingly good, I mean for Fujifilm video. It is better than F900 video, even though the F900 is a much faster camera in all respects. If I need a video, the XF1 is my go-to camera - although the Nikon AW110 is good, the XF1 has better dynamic range, probably due to larger sensor.

CAcreeks said:

You are at least the 15th poster on this forum whose XF1 has failed, some have had even repeated failures (repaired camera failed again). I know of only two forum posters whose XF1 has not yet failed...

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Am I one of them?

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