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01-04-2010, 08:34 PM   #1
Igilligan
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Kx live view metering ?

Ok, I know Damn Brit will probably ?


Last edited by Igilligan; 04-27-2010 at 11:22 AM.
01-04-2010, 08:50 PM   #2
Damn Brit
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QuoteOriginally posted by Igilligan Quote
Ok, I know Damn Brit will probably move this to Beginners Corner and my ego can probably handle that...

But when I am using Mf lenses in Live view 'M' mode, how do I meter LIVE?

If you green button meter in live view, there is a weird clunk that happens that for the life of me cant figure out what it is. Sounds like the mirror box moving but I dont see why it would have to. It does change the shutter speed and there is a brief flash on the LCD.

Seems like I could meter live and see exactly what the changes are on the screen. Without the clunk.. Am I missing something?
I'm hurt (and tempted).
01-04-2010, 08:53 PM   #3
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I just checked it and I hear a double clunk. Is that what you're getting?
01-04-2010, 09:40 PM   #4
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QuoteQuote:
I guess the term I am looking for is "real time" metering. Live view where when you change the shutter you see on the LCD the effect. Is that possible?
I don't think so... After all, what you see in live view is with lens wide open - so how it's supposed to know how bright or dark it's gonna be when stopped down?

01-04-2010, 09:43 PM   #5
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And the two clunks, I believe, are when it drops the mirror to meter, and then lifts mirror back up.

Also, I think metering with at least "A" lenses are more or less "live" - in automatic modes, it gets darker or brighter when you change exposure compensation. (no effect in M mode when you change shutter speed or aperture)

And oh, you bought a K-x after all?
01-04-2010, 11:51 PM   #6
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QuoteQuote:
Yeah I got it... the darn K20 still in AZ still with a 4-6week tag on it.
Oh... that sucks! But it does give you a chance to... familiarize yourself with the K-x haha.

QuoteQuote:
Why I wonder, does it Live meter in AV mode without the mirror drop and up again, but not in M?
I don't know about that one... Firmware design? I think it would have been more useful to make it stop down to the chosen aperture with manual lenses in live view - but they stay wide open. In video, manual lenses close as controlled by the aperture ring - and you can see the screen brightening or darkening in response - but that doesn't happen in Live View.
01-05-2010, 12:06 AM   #7
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Yep, unfortunately you will have to use optical preview. It's dumb especially for lenses like M42 that stop down manually! Why couldn't they just enable the meter for you to see the current +/- exposure ! It's in my wishlist thread..

https://www.pentaxforums.com/forums/pentax-dslr-discussion/79015-k-x-firmware-wishlist.html
01-05-2010, 07:46 AM   #8
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QuoteOriginally posted by pbo Quote
I don't think so... After all, what you see in live view is with lens wide open - so how it's supposed to know how bright or dark it's gonna be when stopped down?
The K-7 LV knows it and shows real time blinkies and histogram or are we talking about something different (must be as Gus owns a K-7 and would have mentioned it, no?)

01-05-2010, 08:50 AM   #9
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QuoteOriginally posted by pbo Quote
And the two clunks, I believe, are when it drops the mirror to meter, and then lifts mirror back up.

Also, I think metering with at least "A" lenses are more or less "live" - in automatic modes, it gets darker or brighter when you change exposure compensation. (no effect in M mode when you change shutter speed or aperture)

And oh, you bought a K-x after all?
Since normal metering is handled off of the focusing screen (I think), I wonder if that is what it's doing, dropping the mirror down, metering and swinging it back out of the way. Weird to do that, but maybe simplier than writing new code to meter off the sensor ?... If that's the case, hopefully some correction factor is being applied to account for the lack of an eye at the viewfinder (or are folks supposed to put the viewfinder cover on when they switch to liveview ).


And oh, you bought a K-x after all Gus?

QuoteOriginally posted by pcarfan Quote
The K-7 LV knows it and shows real time blinkies and histogram or are we talking about something different (must be as Gus owns a K-7 and would have mentioned it, no?)
I don't believe Gus has a K-7, he's got a K20D in the shop and had to buy another camera to cover for the downtime...
01-05-2010, 09:37 AM   #10
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QuoteQuote:
Since normal metering is handled off of the focusing screen (I think), I wonder if that is what it's doing, dropping the mirror down, metering and swinging it back out of the way. Weird to do that, but maybe simplier than writing new code to meter off the sensor ?
I think that's exactly what it's doing. Because lens is not stopped down to the selected aperture (with manual lenses) when Live view is used - camera has no way to tell what aperture/shutter speed combination is needed unless it stops down the lens and meters. Now, why it drops the mirror to use the usual way of metering instead of sensor metering (like, without dropping the mirror, stop down the lens and meter off of that) - I'd guess because the former faster.
Say, when doing video with manual lenses - when you change the aperture, brightness shifts, and then camera adjusts back - but that takes quite some time, right? Maybe metering the latter way will require some time as well.

QuoteQuote:
The K-7 LV knows it and shows real time blinkies and histogram or are we talking about something different (must be as Gus owns a K-7 and would have mentioned it, no?)
Okay, try this. (I don't have a K-7, so just guessing right now)
Put a manual aperture lens on the camera (K-mount, non-preset), or an automatic one, with aperture ring off the "A" position. Set aperture to something other than wide open.
In M mode, switch to Live View. Now, look at the lens. If it looks stopped down, then yeah, K-7 sort of "knows" off the sensor what shutter speed to use (because the lens is stopped down in Live view; with K-x, all manual lenses are not stopped down to selected aperture when in Live view). If not - then it doesn't.
01-05-2010, 09:43 AM   #11
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QuoteOriginally posted by pbo Quote
Okay, try this. (I don't have a K-7, so just guessing right now)
Put a manual aperture lens on the camera (K-mount, non-preset), or an automatic one, with aperture ring off the "A" position. Set aperture to something other than wide open.
In M mode, switch to Live View. Now, look at the lens. If it looks stopped down, then yeah, K-x sort of "knows" off the sensor what shutter speed to use. If not - then it doesn't.
Ok, now I get it. I am at work, but I am pretty sure it cannot do this on non-A settings.

I am confusing Gus (the russian MF lens LBA victim) for someone else who also likes these older m42 lenses....anyhow, I know anytime I see pictures posted by either I get this urge to go out and buy the same lens..their LBA is highly conatgious

Last edited by pcarfan; 01-05-2010 at 10:21 AM.
01-05-2010, 10:01 AM   #12
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It's funny, I thought my K-7 changed apeture in real time (with A or later lenses), but maybe that was only during video recording. (I no longer have it, so I can't check myself now.) I just checked, and the Canon 5DII live view leaves the lens wide open, but meters off the sensor, so I have realtime exposure updates as I pan around a scene (just like you would in normal through-the-viewfinder use).
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