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Camera: Olympus Pen E-PL1, nearly 8 years old (wikipedia).

I have two lenses, 40-150mm (amazon) and 14-42mm (amazon). I change between them frequently, but am careful when I do so.

It's recently started playing up. What can happen is this: the image shows fine on the screen (this model has no viewfinder) but when taken, it is incorrectly exposed by a large amount, usually over-exposed. Here are two images taken today:

Over exposed image

Normal image

According to the meta-data, both of these images have the same settings (they were actually taken as part of a "burst", but the exposure issue can occur regardless of that):

Top Image:
Flash used : No (auto)
Focal length : 32.0mm
Exposure time: 0.017 s (1/60)
Aperture : f/5.0
ISO equiv. : 1600
Whitebalance : Auto
Metering Mode: center weight
Exposure : program (auto)
JPEG Quality : 75

Bottom Image:
Flash used : No (auto)
Focal length : 32.0mm
Exposure time: 0.017 s (1/60)
Aperture : f/5.0
ISO equiv. : 1600
Whitebalance : Auto
Metering Mode: center weight
Exposure : program (auto)
JPEG Quality : 75

Obviously, given the age of the camera, I'm aware of the possibility that this is its gentle way of telling me that it is time for it to retire to pasture. But I quite like the camera so I'm hoping that it's something like needing to clean the contacts between the camera and lens.

Added in Edit: As requested in comments, here's the output of exiftool -FNumber -ApertureValue -Lightvalue -ExposureTime -ShutterSpeedValue -ISO -ISOValue -BrightnessValue -ExposureCompensation:

======== P5271839.JPG (normal image)
F Number                        : 5.0
Light Value                     : 6.6
Exposure Time                   : 1/60
ISO                             : 1600
Exposure Compensation           : 0
======== P5271847.JPG (over exposed)
F Number                        : 5.0
Light Value                     : 6.6
Exposure Time                   : 1/60
ISO                             : 1600
Exposure Compensation           : 0

No bracketting was set. The lens (as reported by exiftool since I was swapping between the two frequently this afternoon) was the Olympus M.Zuiko Digital ED 14-42mm F3.5-5.6 L. Looking through other images that exhibit the issue, they appear to be all with that lens.

For completeness, I dumped the entire output of exiftool on both images into separate files and then did a diff on the two. Apart from file name and the various dates, the differences are (< is the over-exposed image, > the other one):

< File Size                       : 655 kB
> File Size                       : 5.7 MB
< Special Mode                    : Fast, Sequence: 9, Panorama: (none)
> Special Mode                    : Fast, Sequence: 1, Panorama: (none)
< Preview Image Start             : 572800
< Preview Image Length            : 98426
> Preview Image Start             : 5362912
> Preview Image Length            : 590858
< Drive Mode                      : Continuous Shooting, Shot 9
> Drive Mode                      : Continuous Shooting, Shot 1
< Black Level 2                   : 64 63 63 64
> Black Level 2                   : 65 64 65 65
< Sensor Temperature              : 46.7 C
> Sensor Temperature              : 46.0 C
< Thumbnail Length                : 1507
> Thumbnail Length                : 5946
< Preview Image                   : (Binary data 98426 bytes, use -b option to extract)
> Preview Image                   : (Binary data 590858 bytes, use -b option to extract)
< Thumbnail Image                 : (Binary data 1507 bytes, use -b option to extract)
> Thumbnail Image                 : (Binary data 5946 bytes, use -b option to extract)

From that, you can see that they were images 1 and 9 of a burst (but I've seen this effect in single images). In comparing with other images, the sensor temperature is at the high end (the range seems to go from 20 to 50) but the difference is slight. I don't know what Black Level 2 means, but again comparing with other images says that those numbers aren't unusual. The most significant difference is the file size, but given the whiteness of the image that could be down to jpeg compression (I have images which exhibit the same issue that are larger than images which don't).

Added in edit (2018-05-28): From the comments it would appear that my underlying question, as in the title, is difficult to answer so let me pose a variation. Of course, if someone can answer the question in the title that would be best, but the following would still be useful to have answers to in the absence of that:

What could be causing this effect?
How could I test for a possible cause?
What could I do to remedy a possible cause?

I realise that because the effect is intermittent, if I take some action then it'll be hard to verify that that was the correct action. Nevertheless, it would be good to know some possible actions to take, given that I'd prefer to delay the "buy a new camera" option for as long as possible.

  • @flolilolilo The above is the output from jhead. I've just run exiftool on them both and there's no significant difference between the outputs from the two images. I can post any relevant fields from the exiftool output that you think would be useful, but posting the entire lot seems excessive. The exposure time reported by exiftool is 1/60. – Loop Space May 27 '18 at 20:39
  • Which lens was used for each of the photos? Both are capable of zooming to 35mm. – Michael C May 27 '18 at 20:51
  • @flolilolilo I've added the requested info. (The images that I uploaded did have the EXIF info, but perhaps imgur processes them and so removes it.) – Loop Space May 27 '18 at 22:25
  • Check that the aperture is closing when you press the shutter. – Mr_Thyroid May 27 '18 at 22:42
  • 2
    The stuck aperture theory is reasonable, except for the fact that in this particular case, the lens seems to be functioning at or near its maximum aperture. – junkyardsparkle May 28 '18 at 5:09
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Based on the fact that the selected aperture value of f/5 is at or near wide open for the 14-42mm f/3.5-5.6 at 32mm, we can eliminate the stuck aperture theory.

Based on your statement that it only ever seems to happen with one specific lens (but not the other lens that you regularly use), we can probably eliminate the stuck shutter theory (if the PEN E-PL1 even has a mechanical shutter).

That leaves some kind of weird interaction between a specific lens and the camera. Here are two things you can try to see if it helps:

  • Look for any pieces of dust/debris that might be interfering with the connection between the lens' electrical contacts and the contacts on the camera.

  • Examine the contact points on the lens and camera for excessive wear. Either the lens or the camera (but not usually both) will be spring loaded. Check for broken springs or springs that aren't pushing the contact all the way out as it should.

  • Clean the contacts between the camera and lens with a soft dry cloth. Use dry or only with a drop or two of approved cleaning fluids applied to the cloth. Never apply any type of cleaning fluid directly to a camera or lens! Nikon recommends a general cleaning fluid such as surgical spirit applied to a lens cleaning tissue wrapped around a small wooden stick. Canon recommends a clean soft cloth. I could find no specific instructions regarding cleaning lens contacts from Olympus, but for the camera and lens in general the Pen E-PL1 Manual does generally warn against using "... strong solvents such as benzene or alcohol, or a chemically treated cloth."

  • Be sure you are not pressing the lens release button when connecting a lens to the camera. The Olympus Pen E-PL1 Manual specifically warns that doing this can allow the lens to rotate past the proper alignment.

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