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03-18-2013, 01:36 PM   #31
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QuoteOriginally posted by ChrisJ Quote
What's going on here? It seems that not many people know how to use these cameras as they were designed to be used. Sorry if that sounds blunt, but I'm so surprised by some of the answers.

Altering aperture or shutter speed won't work as the camera will just compensate in all modes except Manual Mode, use the EV compensation built in - see below.

The beauty of mirrorless cameras is you CAN alter exposure before you press the shutter, you don't have to take an image adjust, take another and adjust etc. etc. as you do with optical viewfinders.

Use Aperture Priority and set the aperture with depth of field in mind. You can use this in all modes, even manual mode.

Set ISO with noise in mind (i.e. as low as possible, just watch the shutter speed doesn't get too slow for hand holding).

Activate the histogram (Camera menu, page 3, Live view, right joggle key (>) check Histogram Display box and/or Bright/Dark Areas box for the blinkies.

Now the histogram will show on the live view screen.

Press and hold the Av button, next to the red button, the EV Compensation scale appears, and alter the e-dial right or left to shift the 'hump' of pixels so they are just short of the right hand edge, you will see the shutter speed altering, click to the left and shutter speed will increase, to the right shutter and speed will decrease, you are now 'exposing to the right' (ETTR - Google it to see the benefits), this setting will maximise the data that the camera will record without any pixels burning out to white, the blinkies serve the same purpose just alter the e-dial whilst holding down the Av button till the blinkies just stop flashing, the red (over-exposed) are more important than the green (under-exposed). You will now get a perfect exposure every time.

I tend to just use the histogram, i find the 'blinkies' distracting, but that's probably just me.

It totally gets around the problem of metering from the camera position which just gives you an average, taking no account of the tone of the subject. Normally any camera will under-expose light toned subjects, snow scenes for example and over-expose dark subject (the ubiquitous black cat on coal), leading to grey snow and grey cats respectively, this method corrects this problem.

There are other advantages to do with the A/D converter too, there being a greater bit depth with pixels on the right of the histogram than those on the left, ETTR maximises data.

Works with any lens.

Chris
You're wrong. I don't need lessons in shooting - I know what I'm doing. You're describing how to use blinkies and the histogram, both of which I understand. The problem is that when shot manually, with ISO selected for a fixed value, the histogram reflects the screen, not the settings chosen by the operator. That's simply wrong.

03-18-2013, 01:55 PM   #32
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QuoteOriginally posted by dgcom Quote
I'm afraid, you are asking too much of the current generation of cameras. Strange, that you do not see why "guessing" would not work - most lens are quite non-linear, take vignetting for example - how would you estimate the change in histogram (and not overall exposure!) for that? Histogram is just plain math - calculate how many pixels have certain value...

And it is possible to learn, of course - it is called profiling, and it might be feasible in the future... But for now, if camera has fixed lens, manufacturer can "profile" it once and be done with it, but if this is ILC - forget it.

I understand the desire to expose based on histogram shape... This is new technique, which came about with advent of digital P&S-style cameras. But most photographers, who used SLR for advanced amateur or professional shooting know what to do - use light meter... You can try spot metering and measure for highlights, adding +2 EV - this will get your highlights to the right...
I am surprised people are so accepting of such limited use of our camera's processors. Digital cameras really suffer by being designed and used as if they are the same as film bodies. They're not. The capabilities and limitations are very different. This is just one example.

As stated before - cameras already do this. Pentax doesn't have to innovate, just copy. The utility is being able to see which part of the image is exposed properly as well as the aggregate exposure information. It's not more exotic a demand than the desire to preview depth of field. In fact, it's odd that even when you do preview depth of field you still don't see the real exposure.

Regarding the utility of having a screen blow-out or go black, I'd call that good design. I've never wanted to take an exposure that wasn't properly set-up. If my screen is black I can quickly adjust the body to show the kind of image I want. That's why I shoot manual - total control.

Light meters are an option but still less flexible. Worse it's another piece of kit I shouldn't have to carry or worry about. The best light-meter for this task is the sensor in the body.

It's time camera manufacturers looked to people shooting digitally for input, not just journeymen old-timers who still rely on the techniques they learnt decades ago. I can produce images using the modern features of digital cameras that would be impossible without them. I simply want to use the tools I have as I choose to. Much of this thread sounds like shooters at the dawn of auto-focus laughing at those who wanted it to be better and suggesting they just focus manually.
03-18-2013, 07:47 PM   #33
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QuoteOriginally posted by dgcom Quote
You can only calculate exposure change with stopped down lens, you can't predict histogram.
It would only be an estimate for sure, but it won't be hard to make it more accurate than the completely misleading display there is now in manual mode. Also, there is still no excuse for the histogram not being 100% accurate for M42 lenses.
03-18-2013, 10:33 PM   #34
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QuoteOriginally posted by MrSkelter Quote
In fact, it's odd that even when you do preview depth of field you still don't see the real exposure.
Again - you are asking too much - the DOF preview function is just that - DOF preview. Yes, I understand that you want to see how your image would look with lens stopped down exposure-wise, but that's just you. Other person would want to see DOF and won't be able to because LCD image would be too dim... Sure you can make another custom setting specifically for that, however, I do not think the purpose of K-01 was to become high-level pro camera. It is missing too many features compared to other cameras even in Pentax line-up. We can argue here for hours, but the result is the same - if you really need real live histogram - you probably bought wrong camera for that.

QuoteOriginally posted by MrSkelter Quote
Light meters are an option but still less flexible. Worse it's another piece of kit I shouldn't have to carry or worry about.
You have light meter in camera and it can be used very conveniently via spot metering and AF/AL button.

So which interchangeable lens camera with live view shows correct histogram? Just curious.

QuoteOriginally posted by Ikarus Quote
Also, there is still no excuse for the histogram not being 100% accurate for M42 lenses.
Is it really that much different with correct exposure? I did not notice. Or are you saying it does not reflect exposure settings? But that's what we re discussing here, aren't we? Histogram is of an image on the LCD and camera compensates to display an image for framing and focusing, not estimating what picture would really look like...
I probably need to do more checks myself in different lightning conditions... And to see how other cameras with live view and manual mode behave - you got me curious.

03-18-2013, 10:51 PM   #35
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QuoteOriginally posted by MrSkelter Quote
I'm new to Pentax and have a question I can't see an answer to in the manual.

On my last live-view camera (a Canon G1 X) I shot in Manual mode almost all the time. I was used to using the histogram and screen to provide an exposure preview. I.e. if I opened the lens in bright light the screen would blow and the histogram would shift. I would use histogram and blinkies (via a hack) to expose to the right as far as I could.

On my K-01 the histogram seems not to meter the exposure, but instead simply reflects the live-view. The Live view does not provide a preview of the exposure. I.e. if I change the aperture the screen brightness stays the same.

I want the screen to show me what I'm going to capture and I want the histogram to respond as I change settings.

I have RTFM'd. I shoot Nikon, Hassy, Canon, Leica so I'd like to think I'm not a complete idiot when it comes to cameras. Thanks in advance, I'm sure it's 'obvious' but I'm missing it.
I've assigned the GREEN BUTTON to be PREVIEW (DOF). If you do this and hit the green button the histogram changes to reflect the exposure and DOF changes to allow more accurate Focus Peaking because you are actually using the working aperture. Unfortunately you have to continue depressing that button as it can't be locked in that mode.

PS: I'm guilty as charged. I tried manual mode and the Histogram does not change no matter the settings. Not that the Histogram is accurate enough anyway. I would rather use my experience and a few test shots to get things right re' exposure.

Last edited by bossa; 03-18-2013 at 11:43 PM.
03-18-2013, 10:52 PM   #36
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QuoteOriginally posted by dgcom Quote
Histogram is of an image on the LCD and camera compensates...
Yes, that's what it does, but why would I put it in manual mode, if I wanted the camera to do that? It's like the car showing me I'm in second gear, when I've in fact selected third, just because it thinks I should be in second. That's worse than useless, it is completely misleading.
03-18-2013, 11:52 PM   #37
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I doubt Pentax will be making many (if any) more firmware tweaks to the K-01 but this issue would be nice to have resolved before abandoning the machine altogether.
03-19-2013, 05:57 AM   #38
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QuoteOriginally posted by MrSkelter Quote
You're wrong. I don't need lessons in shooting - I know what I'm doing. You're describing how to use blinkies and the histogram, both of which I understand. The problem is that when shot manually, with ISO selected for a fixed value, the histogram reflects the screen, not the settings chosen by the operator. That's simply wrong.
What I was getting at is why use Manual mode at all? Manual Mode is useful for blending flash into ambient and for shooting video when I don't want the camera to compensate the exposure as I pan or when I fade to black. There's nothing 'better' about using Manual Mode when the camera is perfectly capable of optimising the exposure, Using Manual Mode won't make it better or get you any closer. It will just take you longer to get there.

Most of the time I use Aperture Priority, it's true that the screen will compensate to give you as clear as possible view, all digital cameras do, you can't rely on it for exposure, but the histogram and blinkies are accurate, that's the whole point of them. They tell you when those pixels will burn out to white, burnt out pixels carry no data, there's nothing you can do with them in Post, all Photoshop or any other image manipulator can do is make them a shade of grey, there will be no detail in them.

The histogram and blinkies tell you when you have exceeded the dynamic range of the sensor. Both are reading direct from the sensor before it gets to the image you see on the screen which, by default, can alter this data to give you as clear a view as possible for it's primary purpose of framing the shot.

Chris

03-19-2013, 08:19 AM   #39
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QuoteOriginally posted by ChrisJ Quote
What I was getting at is why use Manual mode at all? Manual Mode is useful for blending flash into ambient and for shooting video when I don't want the camera to compensate the exposure as I pan or when I fade to black. There's nothing 'better' about using Manual Mode when the camera is perfectly capable of optimising the exposure, Using Manual Mode won't make it better or get you any closer. It will just take you longer to get there.

Most of the time I use Aperture Priority, it's true that the screen will compensate to give you as clear as possible view, all digital cameras do, you can't rely on it for exposure, but the histogram and blinkies are accurate, that's the whole point of them. They tell you when those pixels will burn out to white, burnt out pixels carry no data, there's nothing you can do with them in Post, all Photoshop or any other image manipulator can do is make them a shade of grey, there will be no detail in them.

The histogram and blinkies tell you when you have exceeded the dynamic range of the sensor. Both are reading direct from the sensor before it gets to the image you see on the screen which, by default, can alter this data to give you as clear a view as possible for it's primary purpose of framing the shot.

Chris
I disagree. The camera isn't capable of optimizing exposure 90% of the time.

I shoot computationally. I.e., I recognize that RAW files are not negatives and that the old idea that the camera delivered a negative, and the computer developed a print, is wrong.

That means I'm aware of my cameras ability to amplify signals in the analog domain and where it switches to digital. Digital amplification can be handled far better in a computer than in the camera body. That limits the ISO I'm willing to use. In short - lifting shadows on an 800 ISO shot can produce a better result than shooting at ISO 3200 because in a computer I can use slow, floating point, calculations the camera doesn't.

(That also means I don't use Lightroom or Aperture for this stuff - where they use crude calculations in order to deliver speed and 'sliders'.)

That all means that often I'm exposing for highlights, at lower ISO than the camera thinks is right, in order to deliver a dark RAW file which I then lift afterwards. This gives me a better, less noisy, cleaner result. It's a product of treating the camera as a digital device and not pretending it's a film body.

If I let the camera decide exposures for me it'd damage my images. The camera could produce the same image I can but it uses the $50 processor in the body instead of the $500 processor in my Mac. I can use a range of programs and optimize the exposure via trial and error on a large screen at any level of zoom.

In camera digital amplification is cruddy. I avoid it at all costs and that's exactly what happens as soon as you reach a light level where your camera needs to leave its ISOless range. (Google ISOless if that makes no sense).

Finally - and simply - Av assumes I am prepared to compromise my shutter speed for my depth of field. Often I'm not.
03-19-2013, 02:19 PM   #40
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QuoteOriginally posted by ChrisJ Quote
What I was getting at is why use Manual mode at all?
For the same reason my cars must have a stick and a clutch. It's not just about getting from A to B, but about the fun that can be had along the way when being in full control of the process. That's beside the point, though - after all, the camera does claim to offer manual control, so one should be able to expect all relevant gauges to provide an accurate read-out that supports this functionality.

Last edited by Ikarus; 03-19-2013 at 02:38 PM.
03-20-2013, 09:13 PM   #41
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I like to use Manual mode on my DSLPs combined with Auto ISO so that I can choose the best aperture for the lens and the best shutter speed to freeze action but unfortunately the K-01 does not allow you to set EV Compensation in manual mode. A real bummer! [so Auto ISO is out of the question when EV Compensation is required in manual mode]
03-23-2013, 08:38 AM   #42
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QuoteOriginally posted by MrSkelter Quote
I disagree. The camera isn't capable of optimizing exposure 90% of the time.
Only true inasmuch as metering from the camera position doesn't take into account the tone of the subject. And that can be altered by using the built in EV compensation.

QuoteOriginally posted by MrSkelter Quote
I shoot computationally. I.e., I recognize that RAW files are not negatives and that the old idea that the camera delivered a negative, and the computer developed a print, is wrong.
So does your camera. I totally agree that digital is not like film, with a digital camera I expose to maximise the data, that means avoiding burnt out to white and blocked out to black pixels that carry no data, and the camera has all the tools to do it built in with the Histogram and the blinkies, which ARE accurate and will show you exactly when this is occurring at the settings you have, the threshold point for both of these is calibrated when the camera is assembled to take out the variations in sensors and A/D converters, they are VERY accurate. They show you graphically the limitations in the dynamic range of the sensor. Together with the EV compensation they allow you to optimize the data for whatever output you want.

QuoteOriginally posted by MrSkelter Quote
That means I'm aware of my cameras ability to amplify signals in the analog domain and where it switches to digital. Digital amplification can be handled far better in a computer than in the camera body. That limits the ISO I'm willing to use. In short - lifting shadows on an 800 ISO shot can produce a better result than shooting at ISO 3200 because in a computer I can use slow, floating point, calculations the camera doesn't.
Cameras only amplify the analogue signal from the sensor when adjusting the ISO, which accounts for some the noise at higher ISO values, the output only becomes digital to store the RGB data for every pixel, amplification plays no part, you can only re-map the RGB values in post processing, you can't alter their amplitude, nor do you need to.

QuoteOriginally posted by MrSkelter Quote
(That also means I don't use Lightroom or Aperture for this stuff - where they use crude calculations in order to deliver speed and 'sliders'.)
.
All any image editor is doing is re-mapping the pixels RGB data, aside from the fact that some of the algorithms used are far from crude, they are not altering the Raw file data one jot, you can't write to a Raw file, they are read only. What you are writing to is a 'sidecar' file, usually an .xmp file where the changes to the original data is stored, delete this .xmp file and the data will still remain unaffected, Photoshop will create a new .xmp file the next time you open the Raw file.

QuoteOriginally posted by MrSkelter Quote
That all means that often I'm exposing for highlights, at lower ISO than the camera thinks is right, in order to deliver a dark RAW file which I then lift afterwards. This gives me a better, less noisy, cleaner result. It's a product of treating the camera as a digital device and not pretending it's a film body.

If I let the camera decide exposures for me it'd damage my images. The camera could produce the same image I can but it uses the $50 processor in the body instead of the $500 processor in my Mac. I can use a range of programs and optimize the exposure via trial and error on a large screen at any level of zoom.

In camera digital amplification is cruddy. I avoid it at all costs and that's exactly what happens as soon as you reach a light level where your camera needs to leave its ISOless range. (Google ISOless if that makes no sense).
All the ISOless from DXO and others are saying is that if you you use plenty of light when you expose you will reduce or even eliminate sensor noise, which is true. Every sensor is different, most have less noise at 200 ISO than they have at 100, which is why 80 ISO is only available in the extended ISO range, even though it's using more amplification, the amplification adds less noise than the sensor has when exposed closer to the ever present sensor noise generated by heat in the sensor, 80 ISO is usually noisier than 800 ISO on most cameras. Run some low light tests on your cameras and you will be surprised.

I shoot a lot of video (and stills) for advertising and films, if you ever go onto one of our sets you'll be surprised at how bright everything is lit. This eliminates noise from most any sensor. It's also the case for my commercial stills, it's rare for me to accept the lighting 'as is', if possible I will always increase and alter the aesthetics of it.

QuoteOriginally posted by MrSkelter Quote
Finally - and simply - Av assumes I am prepared to compromise my shutter speed for my depth of field. Often I'm not.
Not true, you can always alter ISO. It is a compromise, but if you don't or can't alter the lighting it's the compromise you will have to choose. You can't just alter shutter speed and expect the maximum amount of data to be recorded. If you don't want to compromise shutter speed see below.

It's a problem we face when shooting video, bright light (for the reasons above), but I want to use a wide aperture for DOF reasons and I'm limited to 1/48th of a second shutter speed (180 shutter for that 'filmic' look the rest of the film is shot using), So we use variable ND filters to get correct exposure that maximises data. As I said in one of my first posts in this thread, I only ever use Manual Mode for shooting video and blending ambient to flash for stills, now you know why. You get a much cleaner image even for low key, dark and moody, shots, shoot it in bright light and turning down the exposure in Post is far better for image quality than the opposite you seem to advocate.

When shooting stills a variable ND filter allows you to have any shutter speed, ISO and Aperture you want if you have enough light available. Not lighting the scene well is the real compromise.

I realize that altering lighting is not always possible, or even desirable, then Aperture Priority and altering the EV compensation using the histogram is the best compromise, ETTR will optimize data, you are optimizing bit depth, the histograms and blinkies are calibrated for your camera and are a quick and accurate indication, avoid both for the maximum data which is the best possible start image for post processing as all pixels carry data, trying to expose for effect in camera is the real compromise, as you say digital is not film, so why use the old film way to get your shots? Even in the days of film photography was a two stage process, in camera and post processing, it still is.

80% of what makes a good image happens outside the camera, about the only thing the camera controls is DOF, the lighting, composition, an interesting subject, lighting angles, camera angles, the 'moment' etc. etc. are all outside of the camera, your camera is just an image recording device, it merely records what you point it at.

Chris
03-25-2013, 12:20 PM   #43
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QuoteOriginally posted by HSV Quote
Let's say that I wanted to do the "expose to the right" technique, how would I know how much overexposure would I need? (without bracketing upwards)
First of all the histogram preview seems more like an approximation.

Therefore I'd recommend some experimentation in order to understand its behaviour and limitations.

[1] Choose a scene and check the histogram preview. Notice where the peaks are and how it is distributed. Adjust the settings so that the exposure bar scale is neither under nor overexposed. Press the shutter. Check the actual photo's histogram, and notice that it isn't exactly like the preview, but approximate.

[2] For the same scene, adjust the settings in order to, say, overexpose by 1 stop. Then compare the actual photo's histogram with the preview.

[3] Repeat the steps above overexposing by 2 stops, or inbetween increments. And compare the actual histograms and the preview.

By doing such experiments, you'll be able to understand the relationship between the histogram preview and the histogram of the actual photo. You'll also come to know how exposure compensation affects the final histogram.

Cheers,

Last edited by slocant; 03-26-2013 at 05:25 AM.
03-25-2013, 10:21 PM   #44
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QuoteOriginally posted by slocant Quote
First of all the histogram seems more like an approximation.
In manual mode it's worse - it has no relationship whatsoever to aperture, shutter speed and ISO.

QuoteOriginally posted by slocant Quote
Therefore I'd recommend some experimentation in order to understand its behaviour and limitations.
Ditto.
03-26-2013, 01:49 AM   #45
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This thread makes my brain hurt
My K-01 is about to traverse the Pacific to my longing embrace, then I shall see for myself
what metering and exposure eventuate
Pete
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