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01-19-2012, 09:44 PM   #1
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Double slap in live view

Hi, gang -

I've been puzzled by some behavior of my K-r. I don't think it's broken, but I'd like your feedback on why it's happening. In live view, I essentially get a "double" mirror slap on every shot.

When live view is turned on, I get a single slap, which is expected since the mirror must get out of the way for continuous live view. But when a picture is taken, it sounds like it puts the mirror back, then takes a picture, and returns to live view.

So my questions...

1) Is all of this necessary?

2) Since the mirror is already up, why can't it do the equivalent of an electronic shutter? (Given the decibel level of the K-r shutter, this option would be particularly welcome. )

Thanks!
Ryan

01-19-2012, 10:27 PM   #2
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Yes, it is necessary DSLRs don't have electronic shutters, so the actual shutter mechanism has to be used. What happens is the shutter closes, then it opens, then it closes, then it opens again. The mirror doesn't move at all, AFAIK.

I don't have a problem with the system except that I think the delay between actually taking the picture and returning to live view is a bit big. Maybe it's because of SR?

Adam
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01-20-2012, 08:08 AM   #3
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Thanks, Adam. Agreed about the delay...this factor was what caught my attention the most.

I'm confused about the mirror, though. I had thought that the (rather loud) noise during shooting was mirror slap, not the shutter. In fact, when switching to live view--when the mirror must get out of the way--I hear this very same noise. Is this not correct? If it is just the shutter, (a) why is it happening upon switch to live view, and (b) why is it loud? If, on the other hand, it's the mirror, why is live view flipping it willy nilly?
01-20-2012, 05:43 PM   #4
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To elaborate on Adam's reply, my guess is the K-r exposure meter only works from the prism. If so, to take a photo from live view, the camera has to first turn off live view, do its thing, then turn live view back on. That's a lot of flipping and clacking of the mirror and shutter to take one picture. I've noticed that exposure doesn't seem to adjust when I am in movie mode - - although I've only used movie mode once.

01-20-2012, 06:00 PM   #5
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The mirror is deffinetly dropping back down. Turn live view on and look through the view finder while taking a picture. You will see TTL for an instance. So all that noise is the mirror and shutter.
01-20-2012, 07:40 PM   #6
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the K-r and the K-x both do this double slap of the mirror. The behavior is different if you are using continuous or single AF.

Here is what happens.
(AF-S), you have liveview on, so mirror is up and shutter open. If you are using phase detect AF, the shutter closes, the mirror comes down, and the lens focuses. After focusing, the mirror goes back up and shutter opens again to show live view. Then you press the shutter fully, and the shutter closes, mirror comes down, then mirror goes back up, shutter open, take photo, shutter close, mirror down, then mirror back up again and open shutter to start live view again. (if you look through the viewfinder when this is happening, you will notice you can see through the viewfinder 2 times because the mirror comes down 2 times)

(AF-C), you have liveview on, so mirror is up and shutter open. If using phase detec AF, shutter closes, the mirror comes down and the lens focuses, but since this is AF-C, the mirror doesnt go back up to show liveview again. Once focused, if you press the shutter fully, the mirror will go up, shutter opens and closes, mirror back down, saves image, then mirror back up and liveview starts.

There are also other variables like if the autoreview is on after each shot. But I leave it on AF-C so that it doesnt do the double mirror flop
01-21-2012, 01:49 AM   #7
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That doesn't make much sense. The K-r is using CDAF in Live View, focusing is done prior to actually taking the shot. There's no refocusing done using PDAF when you actually push the shutter release.
01-21-2012, 09:54 AM   #8
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the double flip happening depends if liveview is on the moment right before the picture is taken.

In contrast detect, yes the focusing is done in liveview, then picture is taken and the double flip happens.

but if you change it to phase detect in live view from the menu, then it is the way I described above.

In the case of contract detect live view focus, here is what happens

You have live view on, so mirror is up, shutter open. You focus with CDAF, and after focusing press the shutter button fully. The following sequence happens: shutter close > mirror down > ((mirror up > shutter open (at shutter speed to take photo) > shutter close ))> mirror down> mirrow up> shutter open for liveview.

The parts in double bracket is the normal picture taking sequence, the parts before and after are for disabling and enabling the liveview, before and after the exposure

I understand why the shutter has to close from liveview before opening again for the exposure, but dont see why it is necessary to drop the mirror down two times in this sequence. I think the shutter mechanism is somehow linked to the mirror mechanism, which is why they must function together or something.


Last edited by mpmetro; 01-21-2012 at 12:51 PM.
01-21-2012, 12:29 PM   #9
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QuoteOriginally posted by ofer4 Quote
Thanks, Adam. Agreed about the delay...this factor was what caught my attention the most.

I'm confused about the mirror, though. I had thought that the (rather loud) noise during shooting was mirror slap, not the shutter.
Use 2 second delay, you first hear the mirror slap and 2 seconds later the shutter.
01-21-2012, 12:32 PM   #10
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QuoteOriginally posted by mpmetro Quote
I understand why the shutter has to close from liveview before opening again for the exposure, but dont see why it is necessary to drop the mirror down to times in this sequence. I think the shutter mechanism is somehow linked to the mirror mechanism, which is why they must function together or something.
I doubt that because with the 2 seconds delay it does a mirror up function, so they aren't connected.

It's probably just lazy part in not coding it or maybe it's for P-TTL flash or the lightmetering?
01-21-2012, 12:54 PM   #11
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QuoteOriginally posted by Anvh Quote
I doubt that because with the 2 seconds delay it does a mirror up function, so they aren't connected.

It's probably just lazy part in not coding it or maybe it's for P-TTL flash or the lightmetering?
good point about the mirror-lock up in the 2sec delay mode.

I think the way it should be is that since mirror is already up in liveview, it should just close the shutter, take the exposure, then open the shutter again to start live view.

I doubt it could be doing this for lightmetering of P-ttil, because when using AF-C in phase detect, it doesnt do the double flip.
01-21-2012, 02:30 PM   #12
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QuoteOriginally posted by mpmetro Quote
I doubt it could be doing this for lightmetering of P-ttil, because when using AF-C in phase detect, it doesnt do the double flip.
Oh really, hmmm.
Does it maybe do a focus check?
Although i believe it also does a double flip when on manual focus...
01-21-2012, 02:54 PM   #13
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The double flip happens if liveview is on right before the photo is taken. If its off (like in AF-C), then it doesnt need to do the double flip, but when using (AF-S or AF-A) the liveview starts again after focusing and has to do the double mirror flip.


I looked at a video of a K5 and it seems it doesnt do it (any k5 owners want to chime in?)

or perhaps the K5's mirror is so fast and quiet, I cant notice it.

Pentax K5.MOV - YouTube

here is a video I found showing the k-x doing it
http://www.youtube.com/watch?feature=player_detailpage&v=2Jbk3nBAI1Q#t=4s
01-21-2012, 05:04 PM   #14
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mpmetro, are you sure? I just tried using AF-C, and I still get the double flip. In fact, as Anvh stated, I get a double flip even in manual focus.
01-21-2012, 06:01 PM   #15
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QuoteOriginally posted by ofer4 Quote
mpmetro, are you sure? I just tried using AF-C, and I still get the double flip. In fact, as Anvh stated, I get a double flip even in manual focus.
If you are using Contrast Detect AF, then it doesnt matter if its AF-C, AF-S, or AF-A. Because in contrast detect, after it has locked focus, the live-view stays on, then you press the shutter fully and the double flip happens

But if you change the focus to Phase Detect for liveview and use AF-C, then when you press the shutter half-way, the screen will go blank, lock focus, and the screen will stay blank. Then the double flip should not happen

The only reason the double flip happens is because live-view is on right before the actual shot is taken, so the the camera has to do the double flip to turn off liveview, take the shot, the turn live-view back on. It doesnt really have to do with the Focus settings, but the focus settings determine if live-view will be on right before the actual shot is taken or not.

here is a quick video i made showing it on my kx

Last edited by mpmetro; 01-21-2012 at 07:04 PM.
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