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08-01-2018, 07:35 AM   #1
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the k-50 shake reduction and long exposure questions

i tried to read as much as possible before posting this, assuming there are tons of similar questions around, but i couldn't find exact needed answers for k-50.
1. is shake reduction turning automatically off when using 2 or 12 sec timer?

2. is it ok to turn/leave it off if i'm sure my hands are not shaking at let's say, 1/30 and shorter exposure times?

3. how exactly acts long exposure noise reduction on k-50? does it soften the noise like a filter? does it heal hot pixels on raw files? is overall sharpness lost during this process? or is this only about colour noise?

i definitely will test all that, but teoretical information is a must before to know which direction to take in experiments.

08-01-2018, 07:44 AM   #2
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1. Yes
2. Your choice
3. I don't know, I believe it to be about colour noise but won't swear to it.
08-01-2018, 07:52 AM - 1 Like   #3
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QuoteOriginally posted by ignath Quote
3. how exactly acts long exposure noise reduction on k-50? does it soften the noise like a filter? does it heal hot pixels on raw files? is overall sharpness lost during this process? or is this only about colour noise?

i definitely will test all that, but teoretical information is a must before to know which direction to take in experiments.
Long exposure noise reduction takes a second picture with the shutter closed (called a darkframe) and then subtracts the darkframe from the first picture. It reduces hot pixels, grain, and color noise. It has absolutely no effect on sharpness although some think that the resulting images look smoother because the grain is reduced.
08-01-2018, 08:12 AM   #4
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QuoteOriginally posted by MrMojo Quote
1. Yes
2. Your choice
3. I don't know, I believe it to be about colour noise but won't swear to it.
QuoteOriginally posted by photoptimist Quote
Long exposure noise reduction takes a second picture with the shutter closed (called a darkframe) and then subtracts the darkframe from the first picture. It reduces hot pixels, grain, and color noise. It has absolutely no effect on sharpness although some think that the resulting images look smoother because the grain is reduced.

thank you both MrMojo and photoptimist for quick answers! and one final 2part question about long exposure. i'm always suspicious about all auto functions, but perhaps this shouldn't be the case. so:

is it better just on or auto?

from how slow shutter speed camera count it as long exposure?

08-01-2018, 11:23 AM   #5
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QuoteOriginally posted by ignath Quote
thank you both MrMojo and photoptimist for quick answers! and one final 2part question about long exposure. i'm always suspicious about all auto functions, but perhaps this shouldn't be the case. so:

is it better just on or auto?

from how slow shutter speed camera count it as long exposure?
auto is fine UNLESS you are taking a lot of long exposures since it doubles the time needed to take the pictures. If you are taking a lot of similar exposures in a short timeframe you can make your own darkframe and use post processing to subtract this from all of the images in your post processing. Auto I think turns on darkframe subtraction at 30 seconds and longer.
08-01-2018, 11:25 AM   #6
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Note that the 2 second self timer also does a mirror up at the start of the timer which reduces the impact of the mirror slap if I recall correctly. The 12 second version of the self timer doesn't raise the mirror until the exposure.
08-01-2018, 03:03 PM   #7
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QuoteOriginally posted by UncleVanya Quote
Note that the 2 second self timer also does a mirror up at the start of the timer which reduces the impact of the mirror slap if I recall correctly. The 12 second version of the self timer doesn't raise the mirror until the exposure.
thanks, that is useful to know! also, it appears that i've been lucky at my first digital all night long exposure session. i used 2 second timer not to shake camera on tripod without knowing it reduces the mirror slap impact and disables shake reduction at the same time. but mirror slap wouldn't affect 20 second exposures anyway i guess.
08-23-2018, 04:49 AM   #8
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I turn off shake reduction on very long exposures when doing night sky shots because the sensor tray gets really upset about being aimed up and vibrates. I also agree on the dark frames/long exposure noise reduction. You want off if you are doing a series, especially if you are doing star trails, but it can be convenient if you are doing singles, like dark streets etc.
I've also found an external intervalometer to be very useful as it also acts as a remote trigger. I still put it in 2 sec mode as well, as it acts as a sort of mirror lockup.

One thing I wish they would fix in firmware is the liveview mirror motion. Silly thing drops the mirror just so it can raise it again. Shooting live mode should just lock it up as it's already there anyway!

08-23-2018, 06:24 AM - 1 Like   #9
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QuoteOriginally posted by blues_hawk Quote
I turn off shake reduction on very long exposures when doing night sky shots because the sensor tray gets really upset about being aimed up and vibrates. I also agree on the dark frames/long exposure noise reduction. You want off if you are doing a series, especially if you are doing star trails, but it can be convenient if you are doing singles, like dark streets etc.
I've also found an external intervalometer to be very useful as it also acts as a remote trigger. I still put it in 2 sec mode as well, as it acts as a sort of mirror lockup.

One thing I wish they would fix in firmware is the liveview mirror motion. Silly thing drops the mirror just so it can raise it again. Shooting live mode should just lock it up as it's already there anyway!

!thank you for the insight, blues_hawk
08-23-2018, 09:30 AM   #10
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QuoteOriginally posted by blues_hawk Quote
I turn off shake reduction on very long exposures when doing night sky shots because the sensor tray gets really upset about being aimed up and vibrates. I also agree on the dark frames/long exposure noise reduction. You want off if you are doing a series, especially if you are doing star trails, but it can be convenient if you are doing singles, like dark streets etc.
I've also found an external intervalometer to be very useful as it also acts as a remote trigger. I still put it in 2 sec mode as well, as it acts as a sort of mirror lockup.

One thing I wish they would fix in firmware is the liveview mirror motion. Silly thing drops the mirror just so it can raise it again. Shooting live mode should just lock it up as it's already there anyway!
Which camera? I thought this was a function of the midrange bodies (k30/k50/ etc.
08-24-2018, 04:46 PM   #11
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QuoteOriginally posted by UncleVanya Quote
Which camera? I thought this was a function of the midrange bodies (k30/k50/ etc.
Do you mean the intervalometer? The k-50 does have one and I've used it, but it uses manual shutter settings which are limited to 30 seconds. The external lets me do the very long exposures needed deep space astrophotography (dso/ap). Also works as a remote to limit shaking on light portable mounts.
08-24-2018, 05:07 PM   #12
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QuoteOriginally posted by blues_hawk Quote
One thing I wish they would fix in firmware is the liveview mirror motion. Silly thing drops the mirror just so it can raise it again. Shooting live mode should just lock it up as it's already there anyway!
Alas, this may not be fixable in firmware.

To make a camera as compact, lightweight, and simple as possible, some designers use a single motor to operate BOTH the shutter and the mirror. It's all very clever and compact but it means that the only way to cock and fire the shutter is to cycle the mirror.

And unless the sensor (and camera) have an electronic front curtain shutter, the only way to collect clean image data is to close the shutter, reset the sensor, and then cycle the shutter-mirror system.
08-24-2018, 06:47 PM - 1 Like   #13
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QuoteOriginally posted by blues_hawk Quote
Do you mean the intervalometer? The k-50 does have one and I've used it, but it uses manual shutter settings which are limited to 30 seconds. The external lets me do the very long exposures needed deep space astrophotography (dso/ap). Also works as a remote to limit shaking on light portable mounts.
QuoteOriginally posted by photoptimist Quote
Alas, this may not be fixable in firmware.

To make a camera as compact, lightweight, and simple as possible, some designers use a single motor to operate BOTH the shutter and the mirror. It's all very clever and compact but it means that the only way to cock and fire the shutter is to cycle the mirror.

And unless the sensor (and camera) have an electronic front curtain shutter, the only way to collect clean image data is to close the shutter, reset the sensor, and then cycle the shutter-mirror system.
I'm pretty sure the more advanced bodies actually have separate motors and do not behave this way. I just tested my K-3 and I'm pretty sure (not 100% mind you) that the mirror does not drop before the shutter closes and reopens in live view even when using the 12 second self-timer. I know that was not the case with my K-50 - I had started to write an article ages ago and didn't complete it ( due to the dullness of it ) on how to get the K-50 mirror slap to be minimized etc. This is what I was referencing not the interval timer in my quote.
08-24-2018, 09:23 PM   #14
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QuoteOriginally posted by photoptimist Quote
Alas, this may not be fixable in firmware.

To make a camera as compact, lightweight, and simple as possible, some designers use a single motor to operate BOTH the shutter and the mirror. It's all very clever and compact but it means that the only way to cock and fire the shutter is to cycle the mirror.

And unless the sensor (and camera) have an electronic front curtain shutter, the only way to collect clean image data is to close the shutter, reset the sensor, and then cycle the shutter-mirror system.
Isn't the 2 second delay a bit of a wrench in your theory?
08-24-2018, 10:04 PM   #15
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QuoteOriginally posted by blues_hawk Quote
Isn't the 2 second delay a bit of a wrench in your theory?
My recollection is that in this mode on the k50, the mirror drops and immediately reopens while the shutter is closed then after 2 seconds the shutter is released. This behavior isn't inconsistent with what he said, they don't have to be close in time but they do have to sequentially operate the 12second in the k50 I think drops the mirror counts the time then goes back up and fires the shutter. The k-3 doesn't do that. It seems to more directly control the mirror.
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