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08-04-2012, 06:40 PM   #16
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QuoteOriginally posted by audiobomber Quote
It looks to me like your monitor is the problem, not the camera. The darker image is underexposed and I don't think the highlights are blown in the brighter image. Also, it looks like you're using a high ISO. which seriously reduces dynamic range.

You need to understand how the camera meters:
Understanding Camera Metering and Exposure
Oops, yeah reverse the data information for the images!


In the first image things don't look blown out or overexposed or anything, i agree on that, But the photo on the right is far closer to what I am actually seeing with my own eyes. In order to take photos that look like what I'm seeing i have to underexpose because the images often times come out far too bright or blown out. For casual shots, where post-processing isn't desired, I was hoping there was some setting that I could switch to to get more accurate to life shots.
Maybe I'll read up on metering some more and see where that gets me

I'll start with the article provided thanks!

08-05-2012, 05:35 AM   #17
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QuoteOriginally posted by Frogfish Quote
Recording to RAW format can ameliorate this problem to some degree, as can using a digital camera with a better sensor.
Which agrees with what I said, i.e. that a raw file has higher DR than a jpeg.

Cambridge Tutorials:
"Since the raw color data has not been converted into logarithmic values using curves (see overview section above), the exposure of a RAW file can be adjusted slightly — after the photo has been taken. Exposure compensation can correct for metering errors, or can help bring out lost shadow or highlight detail."
Tutorials – The RAW File Format

DPR review of K-x:
"There is usually slightly more dynamic range to be obtained from RAW capture compared to in camera JPEGs (thanks to the use of a consumer-friendly tone curve in the JPEG conversion). There is typically around 1 EV (one stop) or so of extra information available at the highlight end in RAW files. The application of some negative digital exposure compensation when converting such files can recover detail lost to over-exposure."
Pentax K-x Review: Digital Photography Review
08-05-2012, 05:50 AM   #18
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QuoteOriginally posted by jzackery Quote
In the first image things don't look blown out or overexposed or anything, i agree on that, But the photo on the right is far closer to what I am actually seeing with my own eyes. In order to take photos that look like what I'm seeing i have to underexpose because the images often times come out far too bright or blown out. For casual shots, where post-processing isn't desired, I was hoping there was some setting that I could switch to to get more accurate to life shots.
As Baron-ite mentioned above, the metering in a camera is very simple. It adjusts the exposure so that everything within the metered area averages to mid gray. As the photographer, it's up to you to understand how the camera meters and override if that's not what you want. The easiest way to do that on a K-x is with Exposure Compensation, but it can also be achieved by changing the metering mode or shooting in Manual.
08-05-2012, 07:24 AM   #19
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QuoteOriginally posted by audiobomber Quote
Which agrees with what I said, i.e. that a raw file has higher DR than a jpeg.
Dan. When did I say that RAW doesn't have a wider DR than a jpg ?!? Primary school children know that ! If you shoot in RAW (which I've told you I almost always do) it's for a reason, jpgs are the product of the processing engine that each manufacturer installs, with all that encompasses. Uncompressed RAW is almost pure data (there is still a small amount of manipulation performed in-camera) therefore, depending on the software you use, and the RAW processor, more DR can be extracted from those files and it is easier to recover data that is no longer recoverable in a jpg file. The only time I shoot in jpgs is at paid sporting events when the SD cards have to be rushed periodically back to the media desk for processing so they can get the shots out to print/web virtually as it happens.

What i think it happening here is that you are misunderstanding the terminology. What I am saying, however, which any Pro can tell you and which can be verified with just a little Googling, is that if you have 'blown' your highlights they are irrecoverable. To suggest otherwise is totally misleading. Slightly over-exposed is not blown ! Blown is 255,255,255 and is dead, nada, rien, mei you, history, etc. etc. etc. Literally there is no information left to be recovered.


Last edited by Frogfish; 08-05-2012 at 08:27 AM.
08-05-2012, 10:14 AM   #20
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QuoteOriginally posted by Frogfish Quote
What i think it happening here is that you are misunderstanding the terminology. What I am saying, however, which any Pro can tell you and which can be verified with just a little Googling, is that if you have 'blown' your highlights they are irrecoverable. To suggest otherwise is totally misleading. Slightly over-exposed is not blown ! Blown is 255,255,255 and is dead, nada, rien, mei you, history, etc. etc. etc. Literally there is no information left to be recovered.
- If you take a photo in jpeg and the highlights are blown, the highlights are irrecoverable, nothing can be done about it.

- If you take the same photo in raw (same exposure), the highlights appear to be blown in the raw viewer and will be blown if you convert to jpeg without adjustment. If, OTOH, you back off on the exposure before conversion, you can recover the highlights.

The OP is shooting in jpeg and complaining of blown highlights, which IME is fairly common with the K-x (rare with a K20D). All I was trying to say, is that he should shoot raw so the highlights can be recovered. The usual metering of the K-x will allow this.
08-05-2012, 11:28 AM   #21
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QuoteOriginally posted by audiobomber Quote
- If you take a photo in jpeg and the highlights are blown, the highlights are irrecoverable, nothing can be done about it.

- If you take the same photo in raw (same exposure), the highlights appear to be blown in the raw viewer and will be blown if you convert to jpeg without adjustment. If, OTOH, you back off on the exposure before conversion, you can recover the highlights.

The OP is shooting in jpeg and complaining of blown highlights, which IME is fairly common with the K-x (rare with a K20D). All I was trying to say, is that he should shoot raw so the highlights can be recovered. The usual metering of the K-x will allow this.
Dan. Totally blown highlights (as opposed to just over-exposed) are irrecoverable no matter whether you are shooting in 12 or 14 bit RAW or anything else. Typically you can recover 1 to 1.5 stops in RAW, more than that and it's toast. I agree he should should in RAW because there is far more latitude for recovery but even RAW and PS can not save totally blown pixels.

Quotes.

Photography on the Net
In the case of blown highlights, the starting image should not have completely blown highlights in it. Even if the photo is just not quite completely "blown" there is hope.
However – if those highlights are really, really blown – there's no hope of recovery. So here's a useful tip: If you are photographing something with lots of white (or nearly white) in it, underexpose it a little. By underexposing it you will be able to save the highlights, and still correct the rest of the image later on using software.

eHow - PS
Large areas of overexposure are very difficult to correct realistically. Small areas of blown-out whites can occur no matter how precise you set your exposure controls and are straightforward to fix, but an overall overexposed photo likely will not be able to be recovered.

digital-photography-tips.net
If you’ve overexposed you’ll end up with blown highlights– you can never recover detail in these areas of a photograph.

dpnow
Clipped highlights are those highlights that have saturated the A/D converters and have a value of 255.
There is no information contained in the clipped highlights and also there is no any type of post processing that can do anything, except trying to guess/fake of what probably has been there.
The RAW to JPEG converter simply discards the highlights present in the RAW data by compressing them all to the max value of 255.
RAW mode does offer a finer resolution of light levels and also a wider dynamic range and can somehow help in most situations, but not at all times.

Photocamel
Histograms from a camera do not show the RAW values but the JPG values if processed using the parameters set on the camera when exposure was made. They can show a blown area which is actually just potentially blown if not processed correctly.

Photoargus (talking about using PS to recover highlights)
While this technique has the potential to repair blown highlights, it is not a miracle worker. RAW format gives you a wonderful advantage over jpeg and other formats in the exposure correction area, but can only typically increase or decease the exposure by 2 full stops, maximum. If you’ve overexposed an area by more than 2 stops, then your photo could quite possibly be outside the realm of exposure correction.

I could go on and on but basically they are all saying the same thing. The reason I'm going to these lengths is because this is in the Beginner's Corner and they need to understand that totally blown highlights are exactly that, irrecoverable, and the only way to stop this happening .... is before it happens via the settings in their cameras and not relying on miracles in PP. There is a ton of information out there and many people will show you how to use different programs to recover over-exposed images. However they are not miracle workers and a totally blown image is not going to be recoverable simply because the information is not contained in that pixel !
08-05-2012, 12:57 PM   #22
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LOL you guys... You're both correct in what you're saying, but you're defining 'blown' slightly differently - marginally blown in the out-of-camera jpeg, vs irretrievably blown in the raw.
08-06-2012, 07:38 AM   #23
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QuoteOriginally posted by Frogfish Quote
digital-photography-tips.net
If you’ve overexposed you’ll end up with blown highlights– you can never recover detail in these areas of a photograph.
Only if you're shooting in jpeg. Highlights are recoverable in raw. Since you're trying to instruct beginners, you should not have posted this quote, or you should have explained it.

I don't know why you keep hammering at me, As far as I can see I haven't said anything that is incorrect. Your objection seems to be semantic.

08-06-2012, 11:10 AM   #24
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QuoteOriginally posted by audiobomber Quote
Only if you're shooting in jpeg. Highlights are recoverable in raw. Since you're trying to instruct beginners, you should not have posted this quote, or you should have explained it.

I don't know why you keep hammering at me, As far as I can see I haven't said anything that is incorrect. Your objection seems to be semantic.
Sorry if I seem to be hammering you - not my intention ! But quite clearly we are not on the same page yet and it is not just semantics. Shooting in RAW you can blow the highlights - they are not always recoverable unless they are simply over-exposed, I have NEVER been talking about jpgs ! I think the majority of the quotes above (and hundreds more articles if you scan the web) clearly illustrate this.
08-07-2012, 07:30 PM   #25
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I would set the camera up on a tripod, inside, aimed at something that's lit exactly the same during this entire test. Focus is not important so let AF spin away then switch to MF so each shot has the same focus. (AF might have trouble with a blank wall.) Put the camera in Av mode, and make sure ISO is fixed. Set the aperture to f1.7 and take a shot. Then change the aperture to f2.0 and shoot. Continue to take a whole series at each full stop: f2.8, f4, f5.6, f8, f11, f16 and f22.

Now you should have 9 boring shots. If the light was constant, the camera should meter each shot the same, so we can rule out metering. Each shot should be about the same brightness if the lens is really working. You'll see slight differences in the histogram, because contrast is better at f8 than f1.7. Brightness variations should be obvious even in thumbnails, and mean some trouble with the aperture not closing right.

Besides a lens problem, I can't think of any other cause except spot-metering, which the OP claims he stopped using. The problem is really typical of trying to use spot-metering as if it was scene-metering. Spot metering only cares about the spot being 18% gray.
08-07-2012, 08:36 PM   #26
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QuoteOriginally posted by Frogfish Quote
Sorry if I seem to be hammering you - not my intention ! But quite clearly we are not on the same page yet and it is not just semantics. Shooting in RAW you can blow the highlights - they are not always recoverable unless they are simply over-exposed, I have NEVER been talking about jpgs ! I think the majority of the quotes above (and hundreds more articles if you scan the web) clearly illustrate this.
If you can point to somewhere that I said highlights are always recoverable, I will retract it. I can't imagine I would have said that though, when I know it's not true. I said highlights are usually recoverable if they are a stop or a stop and a half overexposed.

I called your argument semantic, because you appear to object to using the term "blown" to describe highlights which are recoverable. Here's something to try; In the Playback menu, PLAYBACK DISPLAY > BRIGHT/DARK AREA. This will show you areas of over and underexposure. If an area of the image is flashing in your LCD, to me it is blown. If you are shooting jpeg, it is blown and non recoverable. If you are shooting in raw, it will show as blown in your raw viewer, and it will be blown if you convert to jpeg. If you reduce the exposure before conversion, you may be able to recover the detail.

I believe most people agree with my usage of the term "blown" to describe highlights that are recoverable before conversion to jpeg. There are many references on the net which use the term in this exact way:
https://www.google.ca/search?source=ig&hl=en&rlz=1G1GGLQ_ENCA251&=&q=can+blo...ac.ZU5RQQGANpo

Last edited by audiobomber; 08-08-2012 at 04:47 AM.
08-07-2012, 09:46 PM   #27
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QuoteOriginally posted by ihasa Quote
LOL you guys... You're both correct in what you're saying, but you're defining 'blown' slightly differently - marginally blown in the out-of-camera jpeg, vs irretrievably blown in the raw.
Exactly.

It might be useful to find out the difference between a level that causes the camera or PDCU to start blinking, and 255 in each channel. The camera doesn't seem to care if one channel is at 255 in my experience, but I've never explored further.
08-07-2012, 10:23 PM   #28
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QuoteOriginally posted by audiobomber Quote
If you can point to somewhere that I said highlights are always recoverable, I will retract it. I can't imagine I would have said that though, when I know it's not true. I said highlights are usually recoverable if they are a stop or a stop and a half overexposed.
Your post #11. Your post #20.

QuoteOriginally posted by audiobomber Quote
you appear to object to using the term "blown" to describe highlights which are recoverable.
I know - that's why I gave you the Wikipedia definition in post #19 ! What I will agree with lIasa and Dave though is that as many people are using that term to describe 'over-exposed' highlights as those using the correct definition of non-recoverable highlights. It's not semantics there is a distinct difference. The word 'Blown' itself gives a strong clue as to it's definition as in Blown Up And it's origins come from way before digital to describe non-recoverable highlights.

QuoteOriginally posted by audiobomber Quote
Here's something to try; In the Playback menu, PLAYBACK DISPLAY > BRIGHT/DARK AREA. This will show you areas of over and underexposure. If an area of the image is flashing in your LCD, to me it is blown. If you are shooting jpeg, it is blown and non recoverable. If you are shooting in raw, it will show as blown in your raw viewer, and it will be blown if you convert to jpeg. If you reduce the exposure before conversion, you may be able to recover the detail.
I don't doubt you are correct Dan. That is why, as I said, I always shoot in RAW (with that one exception I mentioned) and chimp often

QuoteOriginally posted by audiobomber Quote
I believe most people agree with my usage of the term "blown" to describe highlights that are recoverable before conversion to jpeg. There are many references on the net which use the term in this exact way
As mentioned above - try finding a pro or teacher that uses the word Blown to refer to recoverable highlights. I don't think anyone can be responsible for those that misuse the word. Again, though certainly not a definitive source, Wikipedia is correct in it's definition.

However I'm glad we are finally on the same page and that in the end it came down to how each of us is interpreting the word Blown rather than to a basic misunderstanding of what is and what is not recoverable.

Here endeth my contribution to Blowing UP this thread !

Have a good day Dan

Last edited by Frogfish; 08-07-2012 at 10:31 PM.
08-08-2012, 05:13 AM   #29
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QuoteOriginally posted by Frogfish Quote
Your post #11. Your post #20.
I can't agree with you, because one stop of highlights are recoverable in my definition of the word "blown", which, significantly, appears to be the common definition (i.e. people regularly talk about recovering blown highlights).

QuoteOriginally posted by Frogfish Quote
Again, though certainly not a definitive source, Wikipedia
We certainly agree on that.

QuoteOriginally posted by Frogfish Quote
However I'm glad we are finally on the same page and that in the end it came down to how each of us is interpreting the word Blown rather than to a basic misunderstanding of what is and what is not recoverable.
Yes, we have consistently agreed on what is recoverable (nothing in jpeg, one to 1.5 stops in raw).

QuoteOriginally posted by Frogfish Quote
Here endeth my contribution to Blowing UP this thread !
I'm done too. Hopefully someone has learned something from this. I have certainly learned to be more careful with the term "blown", lest it irritate the more pedantic among us. This discussion reminded me of a poster who wanted to halt the use of the word "prime" to describe a fixed focal length lens. I agreed with him that prime is not a suitable descriptor, but there's no use pushing the river.

QuoteOriginally posted by Frogfish Quote
Have a good day Dan
You too Kevin.

Last edited by audiobomber; 08-08-2012 at 10:29 AM.
08-09-2012, 12:38 PM - 1 Like   #30
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Stepping back with, the biggest problem when shooting RAW and trying to see what is potentially blown / over-exposed, is that the LCD screen on the camera is only showing you a JPG image from your RAW image. And, it is only showing you what is blown out in the JPG, but not necessarily in the RAW file.

That is important for photographers to keep in mind because it is easy to needlessly chase for having no "blinkies" on the screen when shooting RAW when you probably could recover highlights if the over-exposure is limited. As a general rule, I find that if the histogram shows very little on the far right, I assume I can fix it in PP. However, if the histogram on the right is dominating or showing higher than the remainder of the histogram it will be hopeless. Your results will mostly come from experience in the field and in post-processing especially on how much is too much when looking at your histogram.

I generally don't like using too much negative exposure compensation just for the sake of highlight control. Most "highlights" are by their nature going to be over-exposed. When done right they add something to the image. I find that highlights are usually an accent unless you have too many of them or you really are losing an important detail to your image. I also like using highlight controllers in RAW software over full on exposure adjustment. If I am exposing for the whole image, most of the image is correctly exposed. Highlight adjustments in software allow me to focus on those areas that are a bit bright without affecting the majority of the image.
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