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07-13-2019, 06:19 AM   #46
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It certainly looks like Dark Image Syndrome - the entire histogram is squished into the left one-fourth. To see if this is the aperture control issue, you should follow the test described by @stevebrot;
QuoteOriginally posted by stevebrot Quote
The so-called gold standard for diagnosing an issue with aperture control is to put the camera in M mode (auto ISO off, aperture ring not being used) with aperture set wide open and shutter speed at something slow (e.g. 1-2 seconds). Release the shutter while observing the aperture opening through the front of the lens. Anything other than the aperture remaining wide open is indication of a problem with the controller. If the problem has been intermittent, it may help to do the test after a period of non-use. Even one failure is significant.

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07-13-2019, 10:18 AM   #47
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QuoteOriginally posted by alex74 Quote
Hello there.

I have been using K-70 for couple of weeks and I have experienced some issues. In random the photos are over or mostly under exposured.

Two photos with same settings:

Anyone had the same problem?

Welcome to the Pentax Forums!

As noted above, there may be a problem with aperture control by the body. Given that you also report overexposure, it might be good to also rule out sticky/lazy iris. This is done by taking the lens off the camera and using a finger to flick the aperture actuator lever while observing through the back of the lens. The action to open and close should be snappy and without hesitation.

As noted above by reh321, one can test aperture control by switching to "M" mode, setting the aperture to its widest setting, setting shutter to 1 second or longer, and observing the iris action through the front of the lens while releasing the shutter. Anything other than staying wide open indicates an error in aperture control. Whether the error is due to failure of the aperture control block requires a visit to a service center or expert amateur tear-down. I have added your report to the list of reported underexposure problems for the K-70 on the list maintained on a dedicated thread:

On the practical side, if the camera was recently purchased, I suggest contacting the seller for return and refund.


Last edited by stevebrot; 07-13-2019 at 10:28 AM.

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