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08-23-2009, 01:48 PM   #16
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QuoteOriginally posted by k100d Quote
my concern is only because you have mentioned that you use ETTR technique, which involves overexposing without clipping and then bringing the exposure back down in post which reduces noise.

it is discouraging that you actually had to use +1.7 EV in (matrix metering?) to get an image that bright.

thanks for the tests, the results do look pretty clean.
It was center weighted metering, so even worse. Also, I did not bring the exposure down by much (just some minor recovering the clippings that appeared in LR using the recovery slider, no clippings in camera)

The camera usually doesn't need this much for usual ETTR. This was taken in a non-lit room with the lights coming through the slightly open door. The viewfinder was towards the door, so I am sure it is light leaking through the viewfinder that threw the metering in Av. In real life, the light will be more even.

But, the test results would be identical if I used manual mode and dialed in iso 3200, F4 and 0.3 or 0.8 sec. This would be the ideal exposure in the manual mode, going by the histogram.

08-23-2009, 01:55 PM   #17
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QuoteOriginally posted by k100d Quote
my concern is only because you have mentioned that you use ETTR technique, which involves overexposing without clipping and then bringing the exposure back down in post which reduces noise.

it is discouraging that you actually had to use +1.7 EV in (matrix metering?) to get an image that bright.

thanks for the tests, the results do look pretty clean.
Using +2 EV does not mean anything other than the metering has underestimated the CORRECT exposure required to get the shot right (unless the +2 EV DOES overexpose and has to be pulled DOWN in PP).

So it really shouldn't be a concern - as seen on the images taken, they're mainly high-key, which means correct exposure WILL be to the right of the histogram anyway...
08-23-2009, 03:03 PM   #18
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QuoteOriginally posted by rawr Quote
Where to begin...
Pentax K-7 Digital Camera Raw - Full Review - The Imaging Resource!

'Competitors aggressive NR' is, I think, not a real issue when you look at RAW output. It is probably the case for in-camera JPEG NR default options though.
Exactly, IR does a good job and looks at RAW, many other reviews don't. They just look at JPEG, and just criticize the noise and don't notice the detail that can be brought out. When I don't feel like processing RAW, I'd much rather process detailed albeit noisey JPEGs.
08-23-2009, 03:47 PM   #19
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QuoteQuote:
pcarfan: The exposure is iso 3200, F4, 0.3 sec. , needed 1.7 +EV to expose to the right with no clipping in-camera. (so, fairly dark, at f1.9 it would need a 1/13 shutter). I think this is a fair dark frame test.
Nice work--thank you--unearthing some of the secrets of nice, high ISO shooting for all! You do not get this level of understanding in the camera reviews.

08-24-2009, 12:04 AM   #20
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loved the stuffed animals

thanks for sharing your comparison results. Do you have RawTherapee latest version ? wonder how those images you posted would fair in RawTherapee's noise reduction functions ?
08-24-2009, 04:13 AM   #21
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QuoteOriginally posted by eva2000 Quote
loved the stuffed animals

thanks for sharing your comparison results. Do you have RawTherapee latest version ? wonder how those images you posted would fair in RawTherapee's noise reduction functions ?
I don't know the answer for this. I know even the noiseware community edition (free) can get almost the same results.
08-24-2009, 04:31 AM   #22
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pcarfan ?

What is your technique for noise removal, you did a great job !


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08-24-2009, 09:13 AM   #23
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what is it with black and noise

i find it puzzling that an objects that reflects the least amount of light is the one that provides the greatest amount of noise

or is that the caveat, that the only thing reflected is the noise?

08-24-2009, 09:34 AM   #24
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Excellent job and post. This should help me with my high iso shots... i'd be very grateful if you would post your noise reduction technique also. This is some of the best high iso tweaking i've seen
08-24-2009, 09:56 AM   #25
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QuoteOriginally posted by Gooshin Quote
what is it with black and noise

i find it puzzling that an objects that reflects the least amount of light is the one that provides the greatest amount of noise

or is that the caveat, that the only thing reflected is the noise?
Probably that it's just easier to see on a black background, although it's still there amongst other colours, just less noticeable.

Wouldn't see it much with whites as the signal's already saturated. Just a guess - would this be right?
08-24-2009, 10:07 AM   #26
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We need Falconeye...
08-24-2009, 10:54 AM   #27
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QuoteOriginally posted by Gooshin Quote
We need Falconeye...
Do we have a special searchlight or something?
08-24-2009, 12:18 PM   #28
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QuoteOriginally posted by pcarfan Quote
LOL, No.

Anytime high iso and exposing to the right comes to play, this always crops up.

The consensus is that proper exposure is more important than the lowest iso and then pulling out the detail.
So what is the point to take the snap to the right with high iso if you can take at lower iso and EV to the right - unless you can not....(to long shutter?) besides you have actually showed the pictures at about iso 800 if you really, during the processing, lowered exposure.

QuoteOriginally posted by pcarfan Quote
Also, think of it this way. +EV is totally arbitrary. If I used the spot metering, then it would meter off the darker areas and I may have to dial in -EV. So, EV compensation is totally dependent on my choice of metering. In the extreme, the spot metering can be run to the extreme by either getting the meter reading from the brightest part of the image or the darkest.
So, only thing we can do is to expose by the histogram. This is what I kept mentioning as having no clippings. So, +2 EV is irrelevant, what is important is whether the exposure renders the ideal histogram.
Again, why to take the snap with higher iso if you can do it at lower using histogram - only benefit i can see out of this thread is advice: when one take the photo at high iso one need to set the exposure as much as possible to the right using histogram as a measuring device

QuoteOriginally posted by pcarfan Quote
So, if I had 0 EV with the chosen metering, then it would mean underexposing the scene by two stops and using iso 800. This will require +2EV in post processing to get the ideal exposure. It is always better to use a higher iso to get proper exposure which will give the least amount of noise than to underexpose and recover which will show more noise. So, using 800 will be the wrong choice.
and then again - who makes you set 0 exposure at iso 800? Sorry if i didn't get something - you can call me bone-head, but please explain.... if the conditions makes you to set iso3200, 1/5s, f4, EV+2 why not to set it at iso 800 and EV0 if you at both cases would obtain similar histogram on the final picture? Am i wrong?
08-24-2009, 12:31 PM   #29
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QuoteOriginally posted by filorp Quote
and then again - who makes you set 0 exposure at iso 800? Sorry if i didn't get something - you can call me bone-head, but please explain.... if the conditions makes you to set iso3200, 1/5s, f4, EV+2 why not to set it at iso 800 and EV0 if you at both cases would obtain similar histogram on the final picture? Am i wrong?

you are right to a point, however keep in mind that "EV" compensation is basically you telling the camera

"whatever you are metering, you are wrong, so add a stop"

if you just set it to 800 and Ev 0, you will be one stop undre exposed still.

however, should this be used in manual mode, perhaps then you really are better off using lower ISO.
08-24-2009, 12:39 PM   #30
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QuoteOriginally posted by pcarfan Quote
LOL, No.

Anytime high iso and exposing to the right comes to play, this always crops up.

The consensus is that proper exposure is more important than the lowest iso and then pulling out the detail.

Also, think of it this way. +EV is totally arbitrary. If I used the spot metering, then it would meter off the darker areas and I may have to dial in -EV. So, EV compensation is totally dependent on my choice of metering. In the extreme, the spot metering can be run to the extreme by either getting the meter reading from the brightest part of the image or the darkest.

So, only thing we can do is to expose by the histogram. This is what I kept mentioning as having no clippings. So, +2 EV is irrelevant, what is important is whether the exposure renders the ideal histogram.

So, if I had 0 EV with the chosen metering, then it would mean underexposing the scene by two stops and using iso 800. This will require +2EV in post processing to get the ideal exposure. It is always better to use a higher iso to get proper exposure which will give the least amount of noise than to underexpose and recover which will show more noise. So, using 800 will be the wrong choice.

I knew the +2EV would throw some off, and thus me mentioning histogram, no clippings etc. Hopefully this clears things up for you.
not true at all. if you read up on the sensors (i don't know about the k7), they have a 'push' limit before you start degrading the image. the k10d for example can do 2 stops, i believe the k20d is only 1-1.5 stops.

these aren't full frame cameras, keep your iso below 800 if you want details.

histograms are generally useless. they're an output graph, not an input graph.
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