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03-27-2016, 12:09 AM   #1
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645z Live View RAW vs JPG

Hi,

So the live view histogram on the 645z gives a real time sensor read-out showing blown highlights. I use this to get a correct ETTR setting prior to exposure.

However, when I view that same photo once it has been taken in playback mode, those same highlights are clipped.

I assume that it is the JPG preview in playback that is causing this.

Is there any others here that experience this, and is there any particular JPG settings that I could set on the camera that would make the JPG view even remotely close to what I see in the live view histogram?

Basically right now, I am just trusting that the exposure is correct based on what I have seen prior to taking the shot, not on what I am seeing in playback. If I were to expose based on what I am seeing in playback and pull back the exposure to suit, I have heaps of raw headroom in Photoshop and its nowhere near ETTR.

03-27-2016, 12:21 AM - 1 Like   #2
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Do you also have the bright/dark area display enabled?

I've always been under the impression that it was the other way around: even if live view shows clipping, it's possible that the final product taken at the actual exposure settings will be fine.

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03-27-2016, 12:49 AM   #3
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When Luminous Landscape reviewed it he said that the live view histogram was direct readout from the chip, but yes even with that I think there may be a touch more highlight headroom in the file.
03-27-2016, 02:23 AM   #4
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QuoteOriginally posted by 2351HD Quote
When Luminous Landscape reviewed it he said that the live view histogram was direct readout from the chip,
I don't believe him, 2351.

What evidence did he back it up with?

AFAIK all cameras generate it with their JPEG engine, so it's only 8 bit and pessimistic.

Highlight warning's a bit different from the histogram.

03-27-2016, 03:33 AM   #5
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I think you might be wrong Clackers.

Edit: I will add, how is highlight warning different to histogram when all you want to see is clipping anyway, I don't really care about the rest of the histogram, it falls where it may.

The highlight blinkies are direct from the sensor and I think LL is right. It's a lot closer than Jpg ever is, I know that much.

Doesn't the Nikon cameras now support full sensor readout for highlight warning and histogram? I think it may have been the D810 and a firmware upgrade. Was it real or a rumor.

Last edited by 2351HD; 03-27-2016 at 03:51 AM.
03-27-2016, 03:49 AM   #6
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QuoteOriginally posted by 2351HD Quote
I think you might be wrong Clackers.

The highlight blinkies are direct from the sensor
Isn't that what I said?

QuoteOriginally posted by 2351HD Quote
.

Doesn't the Nikon cameras now support full sensor readout for highlight warning and histogram? I think it may have been the D810 and a firmware upgrade.
Genuinely interesting if true.

Again, what is LL's proof that Pentax do this?
03-27-2016, 03:52 AM   #7
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I just added an edit to my last post.

How are highlight blinkies different to histogram when all you want is to see clipping?
03-27-2016, 03:54 AM   #8
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QuoteOriginally posted by 2351HD Quote
I just added an edit to my last post.

How are highlight blinkies different to histogram when all you want is to see clipping?
I did not think the highlight blinky uses the histogram.

Happy to be shown otherwise.

03-27-2016, 03:57 AM   #9
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If it is showing clipping from the sensor then one would think that the upper part of the histogram would at least be close.

I am happy for just clipping blinkies really as that's all that matters.

I just wish the histogram in playback was close.
03-27-2016, 04:04 AM   #10
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QuoteOriginally posted by 2351HD Quote
If it is showing clipping from the sensor then one would think that the upper part of the histogram would at least be close.
But a tone curve of a JPEG's settings will often shift both the low and high values.

QuoteOriginally posted by 2351HD Quote

I am happy for just clipping blinkies really as that's all that matters.

I just wish the histogram in playback was close.
Agreed.

But what is this Nikon thing you were talking about? What do they attempt? How do they demosaic?
04-01-2016, 08:11 PM   #11
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QuoteOriginally posted by 2351HD Quote
When Luminous Landscape reviewed it he said that the live view histogram was direct readout from the chip
that whole thing is confusing... if the 645z had a true liveview histogram, it should also have *wysiwyg* liveview, like canon dslrs, and mirrorless cameras... you'd see the actual exposure of the shot before it was taken, in the lcd.

so is the 645z wysiwyg liveview, or is it just liveview? because no pentax dslr/slr has ever had wysiwyg liveview. https://en.wikipedia.org/wiki/Live_preview

fwiw, here is a copy of the article you mentioned: "Fortunately the 645z has real-time highlight warning blinkies in Live View mode, and this is taken directly from the sensor. In other words, if something blinks red in Live View it’s blown. If it doesn’t, it isn’t. When displayed along with the histogram in Live View (which also has a red line to the right when anything is blown), you will be able to make technically optimum exposures. (Some experiments have shown that the camera’s real-time indication of “blown” coincides almost exactly with that of the histograms in Lightroom or Rawdigger." https://web.archive.org/web/20150905183634/https://luminous-landscape.com/pe...-depth-review/
04-01-2016, 11:45 PM   #12
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There is no such thing as a WYSIWYG view. At best an EVF shows you what the JPEG looks like.
04-02-2016, 12:24 AM   #13
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QuoteOriginally posted by clackers Quote
There is no such thing as a WYSIWYG view. At best an EVF shows you what the JPEG looks like.
That's my experience also. The view through the EVF of my 7RII is different to what I see in RAW on my computer on upload, though the WYSICTWYG (what you see is close to what you get) is useful. I find exposures can be different when shooting in Live View when shooting in Av on the Z, and I'd also read that article. I think the blinkies are reliable, but my experience with histograms are that they are usually based on a basic process jpg.
04-02-2016, 12:41 AM   #14
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QuoteOriginally posted by itshimitis Quote
I think the blinkies are reliable, but my experience with histograms are that they are usually based on a basic process jpg.
+1.

That tone curve applied to JPEGs seems to be too pessimistic, showing clipping where there isn't in the RAW file.

The blinky presumably is a straight read off saturated pixels, ignoring colour.

Last edited by clackers; 04-02-2016 at 12:49 AM.
04-02-2016, 01:29 AM   #15
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I wonder if we were to manipulate the JPG file settings on the Z if there is a way to get it even closer, such as setting the contrast to lowest setting and playing with sharpness and colour.

I am still at a loss as to why the camera can't display the JPG render, but show the RAW histogram overlaid in review mode.
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