[Penview52]

Thanks mark, I do not know how to include the data. All was taken auto mode, afternoon sunny outside the room and the camera sets all the parameters.
I just want to know why black photo occurs at some of my photos but not all are black, all in auto mode.

[photogem]

Av mode of K-S2 has F5.6 lowest and highest not the same as KS1.

That is not the case but you think this because you use AUTO mode only.
AUTO-mode kind of self-limiting the K-S2 to toy functions.
Any good smart-phone might give you more pleasing results.


Av mode (aperture priority is defined by how fast your lens is.
If your lens is very fast such as f1,4, then of course both, the K-S1 and K-S1 can use it from f1,4 - f22 or 32 (the last number depends what is the minimum aperture size of your lens, for example f22 for the FA1,4/50, but f32 for the DAL18-50 which is your kit lens)

If you want to know about aperture failure, then you need to make the effort to apply the correct tests,
the one with Liveview is utmost simple, it is so-to-say foolproof.

Or you upload one of your total dark pictures.

People here on this forum are able to help and willing to help.
But "one hand washes the other"!

The EXIF-Data don't need to be included. If you take a photo with low resolution so you can upload it they are already included.
That is why Marc was able to read those from your uploaded photos.

[MarkJerling]

Thanks mark, I do not know how to include the data. All was taken auto mode, afternoon sunny outside the room and the camera sets all the parameters.
I just want to know why black photo occurs at some of my photos but not all are black, all in auto mode.

My post listed the EXIF data of your two photos. As noted, the one was shot at 1/8 of a second and F4.5, while the other was shot at 1/80 of a second and F5.6.
You should not be surprised, therefore, that your two images do not appear to be lit identically. What you're seeing in your one image is not a "black photo" as you put it, but rather a partially poorly lit photo as is expected if you have an image with a bright light source (the window) on one side of the image and a shadow area on the other side of the image.

I'd suggest you follow photogem's advice to determine if there is a fault with your camera. From the photos posted, I can see no fault with your camera.

[photogem]

I'd suggest you follow photogem's advice to determine if there is a fault with your camera. From the photos posted, I can see no fault with your camera.

I also wrote a tutorial how to find out with the K-70:
How to detect aperture-block failure/stuck solenoid on Pentax K-70 - PentaxForums.com

The K-70 and K-S2 are almost identical (menu, casing, functions)

[sergiogonzalez]

Penview52's Album: KS2 - PentaxForums.com

One photo with out dark part and the other with dark part. Do you think this is a failure of aperture or the light sensor ( pixels ) not activated to compose the photo. Needs your analysis.

Hello Penwiew52
Your camera works properly. If the diaphragm was close in f22/32, which is the situation where the solenoid fails, the two photos would be identical and only the window would come out very dark.
You are photographing a backlight, the lighting differences are very large.
If you are working in auto mode, you must set the exposure operating method in menu 1 (AE Measurement). I suggest the midpoint that mostly uses the central part of the sensor (p. 55 of the user manual)
You can make an interesting combination, which is to combine the exposure measurement with the focus point. You'll find that in menu C1, item 5. See also page 55 of the user manual.
If you select this combination, the camera evaluates the light at the place in the focus where the red index of your viewfinder is turned on.
You'll get a well-lit photo at the focus site, but places that have too much light will come out overexposed.
Don't forget that you can also use Flash with different intensities as fill light. That's a powerful weapon for these circumstances.
You have to train with these situations and see what the best compromise is.
I hope this helps.
Best Regards

[Penview52]

I don't have the lens with F1.8 to F22 to test it but I believed that aperture and solenoid is not the culprit. It works good in some instances is bad. The time ( speed ) of exposure make sense to me and investigate further. I will go beyond auto mode and the future will tell until i found the cause of the failure. Your ideas are appreciated.

[photogem]

I don't have the lens with F1.8 to F22 to test it but I believed that aperture and solenoid is not the culprit. It works good in some instances is bad. The time ( speed ) of exposure make sense to me and investigate further. I will go beyond auto mode and the future will tell until i found the cause of the failure. Your ideas are appreciated.

You don't need a fast lens with F1,8!

You can use your Kit-Lens, and lens with an A-ring no matter how fast.

What is the difficulty?


If your Kitlens DA-L 18-55 is used, then you use Av mode and set aperture on f4.0
That's all that is needed.
And best after the K-S2 was not used for a time.

You have complained about aperture issues in the past, even gave advice how to deal with it.

So now you can apply your knowledge on your own K-S2

------------------------------------------------------------------------

Hello Penwiew52
Your camera works properly. If the diaphragm was close in f22/32, which is the situation where the solenoid fails, the two photos would be identical and only the window would come out very dark.

No, the very opposite but I think this is a matter of language only because of course you understand the issue:

The DA18-50 has a range of f4,0 - f22 at 18mm (and f4,5 - f 32 at 50mm)

The solenoid, if healthy, will actuate from f4,0 - f16 in 18mm position

and f4,5 - f 22(or 27) at 50mm

It does not have to actuate at the minimun aperture of f22/32

and will give perfect results if the lens in AV-mode is set to f22/32!


So the possible results will be (here 18mm focal length):


f4,0 very dark
f5,6 pretty dark
f8 dark
f11 some light
f16 almost fine
f22 fine

Also at the beginning of the stuck solenoid there will be almost fine photos in Live-View mode but Exif-data will show the wrong metering, because metering is with f22 (18mm) but should be f4.0

I just repaired 2 x K-S2's very recently.

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Last edited by photogem; 12-10-2020 at 11:48 AM.

[MarkJerling]

I don't have the lens with F1.8 to F22 to test it....

As photogem noted, you can do the test procedure with virtually any A lens.

... but I believed that aperture and solenoid is not the culprit.

You're most likely correct, but do the test to know for sure.

It works good in some instances is bad. The time ( speed ) of exposure make sense to me and investigate further. I will go beyond auto mode and the future will tell until i found the cause.....

What you're seeing is perfectly normal when you have a strong light source in one part of the image.

.....the failure.

The only failure is not understanding the operation of the camera. I would suggest that you consider reviewing your camera's operation manual and experiment with your photography so as to learn to understand the parameters under which the machine operates. Start with the TAv setting and then move on the M setting and experiment with various aperture ranges and shutter speeds. Observe how that impacts the ISO setting and subsequently the light sensitivity of the sensor and what that does to your images. Then bring metering into the mix. Experiment with spot metering versus whole scene metering.

I feel, if you do that, you'll start to see that your images do not suggest a failure of the camera.

[Martell]

Long story short! What sould I observe or avoid with my S2?

[MarkJerling]

Long story short! What sould I observe or avoid with my S2?

S2 or KS2? Two very different cameras.

[photogem]

Long story short! What sould I observe or avoid with my S2?

You probably mean the K-S2:

Use it regularely.

That goes for any Pentax using a solenoid.

If you feel you would be able to repair it yourself, if the solenoid gets stuck, then I'd recommend to

have the Japan DSLR solenoid ready so that the repair can be done within a day (well, depending on skill and fear... lets say it can be done within an hour)

If ever not needed, you can sell it again.
It will not really loose value!

[Martell]

S2 or KS2? Two very different cameras.

Yes, K-S2 of course.

[swanlefitte]

Well my ks-2 has been affected exactly 2 times now. I mostly use my plm lens so forgot about it after the first time. Any info on temperature change? Both times was out in below freezing temps. Both times it warmed up and is fine. I do not have hope it will last but has temperature variation been looked at for correlation? Cameras left in hot cars or taken on cold walks?

[photogem]

Well my ks-2 has been affected exactly 2 times now. I mostly use my plm lens so forgot about it after the first time. Any info on temperature change? Both times was out in below freezing temps. Both times it warmed up and is fine. I do not have hope it will last but has temperature variation been looked at for correlation? Cameras left in hot cars or taken on cold walks?

The standard neodymium magnet in the solenoid (which is too strong) will not lose any strength if not below -138 degrees Celsius.
Nor do they lose magnetic up to 80 degrees Celsius, well, your Pentax would probable get other defects then as well.

But low temperatur has an effect on the battery which has less power then, particular Li-Ions are affected.
The lack of surge-power in cold temperaturs = higher risk that the solenoid will remain stuck.
If it started once, it will come back.

Happy New Year!

[swanlefitte]

I am trying to collect data on the change as my solinoid dies. Tested the fa77 today. Worked first click in 20 hours. Battery at 7.84 volts. (Need a resistor) then put on my plm lens for a cold walk. After the battery was down to 7.72 and the 77 was dark. Switched out battery to one at 8.29 volts with no change. Let the camera warm up 45 minutes, no change. Manually moved the actuator and it worked.
Will see what happens tomorrow. I think all data is worth noting. Perhaps noting the manually moving the actuator works vs the rapid shot cure will help someone if their camera fails in the field when the shot is important.