KS2 dark images with Live View


jimfisch

Link Posted 14/12/2020 - 14:04
Over the past year or two, I was getting dark images, but couldn't figure out the cause. Seemed random. Figured out it was the Live View. Using the view finder/objective, only, allows much faster shooting. I'm a neophyte with photography, so forgive the following non-technical explanation. Without LV, there is only a short auto focus upon halfway depressing the capture button, followed by the shutter actuation upon fully depressing the button. With LV on, there is are all sorts of adjustments and delays at halfway depressing the button (before the shutter clicks). However, the pics look fine (not great though) with LV. I updated the firmware and did a full reset. This did not resolve the problem. It happens with either lens and with a fully charged battery. Shooting in Auto mode.

pschlute

Link Posted 14/12/2020 - 15:42
LV is slower focussing than through the viewfinder. How much longer does it take to focus ?

Random dark images sounds like aperture block failure.
Peter



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jimfisch

Link Posted 14/12/2020 - 16:25
These are not random dark images. This is very repeatable. When I use LV, the images are not dark, at least not in Auto mode. When I leave LV off and shoot through the view finder, they are always dark. If I had to guess, I'd say the delay in focusing with LV is 200-500ms...total WAG. I'm sure the delay is shorter than it seems, but it's noticeable.

MrB

Link Posted 14/12/2020 - 18:05
"KS2 dark images with Live View." "I was getting dark images.....Figured out it was the Live View."
"When I use LV, the images are not dark.....When I leave LV off and shoot through the view finder, they are always dark."

?? These statements seem contradictory.
Last Edited by MrB on 14/12/2020 - 18:09

johnriley

Link Posted 14/12/2020 - 18:09
There are various things you can do. First off, wipe gently the contacts on the back of the lens and on the camera mount using a dry, soft, lint-free cloth. A microfibre lens cleaning cloth is ideal. Then I would do a factory reset of all the settings - you'll find the reset button in the menus.

As regards settings, consider using centre point only for the focusing and definitely not spot metering for the exposure. In the latter case, spot metering if not applied precisely may lead to random metering problems. I would also set to best quality JPEG and daylight white balance, plus a fixed ISO value, say 200 as a starting point.

Then you are ready for some test shots, starting with normal outdoor scenes. If there's still a problem, do please post some examples and we can perhaps see what's going on.
Best regards, John

HarisF1

Link Posted 14/12/2020 - 20:11
Also if your LV images are giving you longer exposure times and high ISOs to get a 'usable' image, then it's likely that it's just aperture block failure.

Put your camera in Manual mode and use the same settings for a shot taken in both LV and viewfinder modes. If there's no difference then again it points to the aperture block.

Another test is to look into the front of the lens as you take an image that is wide open. The lens blades should open up when the shutter snaps. Try this for the lowest f stop, then slowly move to high f values. If there's no change then it's the fault mentioned above.

If the camera passes these tests then the fault lies elsewhere.

richandfleur

Link Posted 15/12/2020 - 21:47
To hear of aperture mechanism failings in newer cameras is really disappointing. Pentax should have been all over this after the K-30 issues.

If all else fails, you can still use the camera with (typically older) lens which have mechanical aperture selection dials.

There are fixes for this, but not sure on price if it's no longer under warranty.

jeallen01

Link Posted 18/12/2020 - 19:16
Unfortunately, this problem (generally known as "Aperture Block Failure" or "ABF") is very well known for occurring in the KS1, KS2, K-30, K-50/K-500 and (to a somewhat lesser extent - so far!) in the K-70 due to the use of an inferior (as compared to what was previously used in Pentax DSLRs) "green solenoid", and where fitting of the (now hard to come by) earlier "white" version is now the recommended "definitive fix"
.
There is a long-running series of threads in the relevant model sections of this US forum, and there is at least one UK repairer (Asahi Photo in Brentford) which can do the relevant repairs (although I would recommend that a white solenoid is sourced from an older DSLR and supplied to them since they may otherwise use the "non-recommended" method of filing a part of the existing green one).

That said, Asahi Photo successfully fitted a white solenoid to my K-30 (which had not actually suffered ABF at that point, but "pre-emptive action" seemed a good idea!) and no ABF was then apparent or seemed likely to occur.
K-3 II, K-3 and a K-70 from SRS (having now relegated the K-30 /"K-50" to a backup body), & some Sigma and Pentax lenses (and a lot of old 35mm gear!)
Last Edited by jeallen01 on 18/12/2020 - 19:18
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