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11-09-2017, 12:10 PM   #31
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QuoteOriginally posted by GUB Quote
Yeah I think it makes sense - thing is I am pretty well always M mode. One thing with my K1 in M mode and using liveview the brightness of the screen doesn't change with settings change so seeing and focusing the subject isn't an issue.
I use an LCD viewfinder and when chimping I can see enough of a -3EV to know whether I have a good one.
If you are going Manual focus and liveview then a Lcd viewfinder is a real bonus. Aftermarket LCD Viewfinder for K1 - PentaxForums.com
I have a friend who does a bit of opera photography with her FF nikon. She grasps the potential of utilising iso invariance but she struggles to find the confidence to actually commit to it and these crazy almost black images. I think she is using the TaV -3 sort of approach.
But think about it - if you have the aperture as open as you dare and the shutter as slow as you dare , then so long as the resulting image is actually underexposed how does Iso or the final EV matter- that is the whole point of utilising Iso invariance. Sure if the image ends up -5EV then there is no chimping but that is not the end of the world.
Expected to see that Swivi thing cost the earth, but actually its priced similarly to a Tenpa 1.36 OVF magnifier, and they seem to be gold dust currently. I would really like to see the Swivi in action before buying but I can definitely think of a few scenarios where it would help immensely. Focus Peaking is really useful and I imagine when coupled with this it becomes a wicked combo.

By the way what MF glass are you using with your K-1?

11-09-2017, 12:39 PM   #32
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QuoteOriginally posted by TonyW Quote
Interesting thread GUB, thanks. You have obviously put a lot of thought and work on this. Just a couple of thoughts that may be of general interest:

1. The raw editor you use is also important as some such as Adobe (ACR and LR) use a Base Line exposure compensation which may be either negative or positive and can be close to 2/3 of a stop. Couple to this the actual raw conversion factors (Process Versions) where exposure and contrast applied prior to display (Sliders will still appear zeroed) per camera and you may find that what appears to be a correct exposure is already less than optimal potentially up to -2.0 EV.
The values may be different per manufacturer and even per camera model.

2. ETTR was mentioned a few times in this thread. IMO worth revisiting the principles of ETTR at least from my understanding as expounded by Thomas Knoll (early 2000's):

a. ETTR only applies at base ISO
b. ETTR is only really useful when the scene dynamic range will fit comfortably within the sensors DR range

Although I believe that these statements still valid a lot has changed in digital acquisition in the years since this published. Camera Dynamic range has probably doubled, sensors improved, ADC advanced etc.
So perhaps ETTR not quite as important as it used to be?
It is when something becomes a dogma that things get out of perspective. ETTR makes sense quite simply that by maximising your appropriate aperture and minimising your appropriate shutter speed you have created best practise as far as signal to noise ratio is concerned. ETTR achieves this. But only at base Iso.
I set my exposures by watching the light end and getting my highlights as close to it as possible but being 100% sure they are not clipping. The rest of the histogram falls where it falls. I think I have been practising ETTR as it should be without realising it.
11-12-2017, 01:41 AM   #33
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QuoteOriginally posted by JensE Quote
Yes, routinely/extensively - ever since I got the K-5. Many of my landscapes, available light macros, indoor sports shots and - yes - night sky pictures are nominally 'underexposed' and lifted up by typically 1EV to 3EV in post-processing and/or tone-mapped. See e.g. this thread for macro examples with up to +3.5EV processed in darktable - you have to enter that numerically as it's out of the exposure tool slider range


In-camera, it is what it is and I only rarely review pictures on-screen to determine what to delete. Before importing files from the card, under Windows, I like to use Fast Raw Viewer for culling. It is specifically designed for that purpose and allows to adjust exposure and/or selectively check shadow and highlight detail using keyboard shortcuts very quickly. It also allows to define custom thresholds to highlight raw underexposed areas, very useful.
Hi JensE,

Just trialling this piece of software now. I have taken a heap of shots all ETTL, is there a way to your knowledge to quickly highlight all the files and autoexpose them all in one go, so that I may sift through the shots more easily and select which ones to cull and which to keep? It's getting a bit tedious to Alt++ every file just to check up on things etc.
The idea would not to be to save those exposures, just quickly bring all the under exposed files up for better scrutiny.

Ta!

Bruce
11-13-2017, 11:08 PM   #34
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QuoteOriginally posted by GUB Quote
It is when something becomes a dogma that things get out of perspective. ETTR makes sense quite simply that by maximising your appropriate aperture and minimising your appropriate shutter speed you have created best practise as far as signal to noise ratio is concerned. ETTR achieves this. But only at base Iso.
I set my exposures by watching the light end and getting my highlights as close to it as possible but being 100% sure they are not clipping. The rest of the histogram falls where it falls. I think I have been practising ETTR as it should be without realising it.
I just took a heap of pictures over the weekend of an indoor event I capture. I did a lot of ETTL shots, underexposed to around 1.7-2.3, mainly on the DFA 100mm shots (the pictures where the shot is closest to the speakers). You can see here (Science at the Local | Flickr)
The ones with Aaron Greenville (blue chequered shirt) and Kerryn Wilmot (black top, red pants) are from the weekend and the ones using ETTL (compared to the previous speakers without).
I think they came out fine, not sure if better or worse than the others tho. One slightly annoying hurdle when shooting ETTL however is when Post Processing, especially during the initial inspection and cull process, I had to increase exposure on every file just to get an idea if the shot was worth keeping or not. Tedious.

11-14-2017, 12:57 AM - 1 Like   #35
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QuoteOriginally posted by BruceBanner Quote
I just took a heap of pictures over the weekend of an indoor event I capture. I did a lot of ETTL shots, underexposed to around 1.7-2.3, mainly on the DFA 100mm shots (the pictures where the shot is closest to the speakers). You can see here (Science at the Local | Flickr)
The ones with Aaron Greenville (blue chequered shirt) and Kerryn Wilmot (black top, red pants) are from the weekend and the ones using ETTL (compared to the previous speakers without).
I think they came out fine, not sure if better or worse than the others tho. One slightly annoying hurdle when shooting ETTL however is when Post Processing, especially during the initial inspection and cull process, I had to increase exposure on every file just to get an idea if the shot was worth keeping or not. Tedious.
I don't know whether ETTL is the correct term - it implies it is the opposite of ETTR and it isn't - it becomes relevant when increased Iso is needed - that is the point ETTR ceases to be relevant. But it needs a term - how about UII - utilising iso invariance.
Oh and I missed your question earlier on what MF glass I use on the K1. I chose the K1 to best use the leagacy glass collection I have. In fact the only prime AF lenses I have is a F50 1.7 and a DA40xs. The default lenses on the camera is anA28 2.8 , A50 1.7 and a Rikenon 105mm macro. But there is dozens of other lenses to play with.
11-14-2017, 01:11 AM - 1 Like   #36
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QuoteOriginally posted by BruceBanner Quote
I think they came out fine, not sure if better or worse than the others tho
UII shots will end up with the same amount on noise as a correctly exposed (+iso) shot so don't expect to see any improvements that way.
The main IQ gain is an ability to control your highlights. A "correctly" exposed shot may well have clipped them irreversibly and the reduced dynamic range of higher Iso will increase this likelihood.
If the light at your function is variable, then to "correctly " expose you will need to be in an auto expose mode meaning you will lose a lot of control on those highlights.
If you set to M and lightly underexpose for the brightest scenario then the other shots will just fall into place courtesy of UII
11-14-2017, 09:24 AM   #37
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QuoteOriginally posted by GUB Quote
It is when something becomes a dogma that things get out of perspective. ETTR makes sense quite simply that by maximising your appropriate aperture and minimising your appropriate shutter speed you have created best practise as far as signal to noise ratio is concerned. ETTR achieves this. But only at base Iso.
I set my exposures by watching the light end and getting my highlights as close to it as possible but being 100% sure they are not clipping. The rest of the histogram falls where it falls. I think I have been practising ETTR as it should be without realising it.
The problem with using the LCD histogram to view exposure is that it is based on the camera generated JPEG.

So a 'correctly' exposed JPEG is an underexposed raw - possibly up to -2.0 EV making your ISO 100 shot the equivalent noise of ISO 400

A 'correctly' exposed shot cannot by definition have clipped highlights unless that was the photographers intention. A lot of scenes may contain clipped highlights but these should only be from specular reflections, areas devoid of detail. But the photographer has to make the decision where scene DR exceeds sensor DR capability and either sacrifice detail in shadows or highlights or resort to making more than one exposure to deal with the potential for clipped information or to enable better detail in problem areas

Last edited by TonyW; 11-14-2017 at 09:52 AM.
11-14-2017, 10:48 AM   #38
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QuoteOriginally posted by TonyW Quote
A 'correctly' exposed shot cannot by definition have clipped highlights unless that was the photographers intention.
That is why I put "correctly" in quotation marks. The point is with UII you have more control of these highlights with no other loss of quality.

11-14-2017, 12:02 PM   #39
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QuoteOriginally posted by GUB Quote
I don't know whether ETTL is the correct term - it implies it is the opposite of ETTR and it isn't - it becomes relevant when increased Iso is needed - that is the point ETTR ceases to be relevant. But it needs a term - how about UII - utilising iso invariance.
Oh and I missed your question earlier on what MF glass I use on the K1. I chose the K1 to best use the leagacy glass collection I have. In fact the only prime AF lenses I have is a F50 1.7 and a DA40xs. The default lenses on the camera is anA28 2.8 , A50 1.7 and a Rikenon 105mm macro. But there is dozens of other lenses to play with.
UII sounds fine

Ok, so here's what I was taking from this thread and idea in principle;

- When letting the camera choose 'autoexpose' a dynamic range scene will often involve a section with blown out highlights, even if that's just a slither. By going under that recommended exposure given by the camera you avoid the clipping entirely, consequently also typically receiving the shot with a lower ISO that suggested.

- Because the shot is now under exposed, when post processing, bringing the EV value up to a level that is acceptable might still mean a level less than suggested by the auto expose given by the camera. Therefore the picture overall could have less noise than what it was shot at if left in suggested exposure mode. For example; pretend the aperture and shutter speed cannot be altered for the scene, they are as they are needed to be to capture the right shot and are therefore fixed, but by going with the suggested exposure for the scene we are left with an ISO 1600. By pressing the +/- EV comp button and reducing - 2 EV, the screen gets very dark, harder to see, however the ISO is now showing 200 (or whatever, I'm guessing here). The shot is taken, for sure there are no blown out highlights anywhere (an additional bonus of using this strategy) and time to visit LR (or whatever). The EV value is now increased, but instead of pushing the full +2 back, the user finds +1.7 is enough, the shot is still ISO 200 but the added EV has brought back some noise, but overall that noise level is still less than if taken with suggested exposure and ISO 1600. The noise now feels like 800 ISO etc. Had you brought the exposure down from the suggested exposure ISO 1600, you'd still be stuck with ISO 1600 grain and blown out highlights in some of the scene.

Having shot for awhile with the K-1 now, I almost feel I'd rather take every shot slightly underexposed, regardless of the context, putting blinkies on and almost every shot taken the review is blinking (tho this is jpeg blinking and if it's not much then RAW is actually fine). But yeh a slightly underexposed image feels safer and prolly cleaner picture than what is often recommended.

Oh, I have a silver DA40xs en route, will look wicked on my silver KP and I too have a A50 1.7, lovely little lens
11-14-2017, 03:37 PM - 1 Like   #40
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QuoteOriginally posted by GUB Quote
So I have had a bit of playing around with the camera with an awareness of using iso invariance as a possible tool. Come up with a couple of examples where underexposing stopped my highlight being unexpectedly clipped.
In the fern I underexposed about 2 stops - f5.6 1/8 sec Iso 200. I think you will agree that I couldn't afford to give the sensor more light than that. (f5.6 1/8 sec) And also notice how the brightest area of highlit hairs is already bight enough. I think this is a great example of utilizing Iso invariance.
And with the gas station there was a 3 stop difference in the shots. Here it is a moot point what actually is the correct exposure for the subject - it is almost inevitable that something will be burned out. But that 3 stops gave me a heck of a lot more control of the details. This is a 3shot panorama with the 40mm xs.
Spot the detail and colours difference in the 100% crop shot.
Thanks GUB, this thread is very useful.
11-15-2017, 04:16 AM   #41
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QuoteOriginally posted by BruceBanner Quote
The EV value is now increased, but instead of pushing the full +2 back, the user finds +1.7 is enough
I think this is where your and my practical approaches differ. I suspect you are just using the exposure slider (presumably LR) whereas I commit some of the exposure recovery to it but finish via the colour curves tool and histogram. Using this I can hold back the highlight end and still give the dark end 100% of the +2 required. There must be a way to do this in LR?. (I use Gimp)
11-15-2017, 12:12 PM   #42
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QuoteOriginally posted by GUB Quote
I think this is where your and my practical approaches differ. I suspect you are just using the exposure slider (presumably LR) whereas I commit some of the exposure recovery to it but finish via the colour curves tool and histogram. Using this I can hold back the highlight end and still give the dark end 100% of the +2 required. There must be a way to do this in LR?. (I use Gimp)
Yes I imagine there is, I do see the curve tool but have not yet delved into it, I must find a tutorial on it. 'Till now I have just adjusted the main sliders Exposure, Contrast, Highlights, Shadows, Whites and Blacks and use Highlight Clipping in LR to notify me when I have went too far etc. I think the curve tool adjusts all of these (or perhaps all except Whites and Blacks) but is just another method of doing it?
11-15-2017, 02:24 PM   #43
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QuoteOriginally posted by BruceBanner Quote
Yes I imagine there is, I do see the curve tool but have not yet delved into it, I must find a tutorial on it. 'Till now I have just adjusted the main sliders Exposure, Contrast, Highlights, Shadows, Whites and Blacks and use Highlight Clipping in LR to notify me when I have went too far etc. I think the curve tool adjusts all of these (or perhaps all except Whites and Blacks) but is just another method of doing it?
Yes just another way of doing it. It is a more graphical and much more flexible way of tuning the tones. I use a combination with the exposure slider primary because the slider is better at getting the white point and black point roughly established leaving the fine tuning to the curves. Rather than just using the highlight clipping warning try keeping a histogram up on the screen somewhere(I don't know LR) and watch it interact with what you do.
11-15-2017, 11:47 PM   #44
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QuoteOriginally posted by BruceBanner Quote
I think they came out fine, not sure if better or worse than the others tho. One slightly annoying hurdle when shooting ETTL however is when Post Processing, especially during the initial inspection and cull process, I had to increase exposure on every file just to get an idea if the shot was worth keeping or not. Tedious.
Can't you just select all of the "underexposed" photos and then increase the exposure on them all at once? (Though I don't know what software you are using at this stage of your process.)
11-16-2017, 12:42 AM   #45
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QuoteOriginally posted by leekil Quote
Can't you just select all of the "underexposed" photos and then increase the exposure on them all at once? (Though I don't know what software you are using at this stage of your process.)
Yeh that's what I was hoping for, I asked FastRawViewer for advice regarding this and he sent me this message with this picture;

"Checking "ETTR-style autoexposure" in FastRawViewer Preferences Exposure "Auto Exposure" "ETTR-style autoexposure (shift histogram to the right)" might help:"

I tried this but unless you need to quit and restart or do something else I couldn't get it to work...
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