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08-13-2010, 05:29 AM - 1 Like   #61
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QuoteOriginally posted by MSM Quote
I have a question for the Kx users. Hope it is not too basic. Does anyone use the extended ISO (ie 100-12800)? What is the trade off? I assume that there is or there wouldn't be any option. Instead it would be just the 100-12800. Any thoughts?
Well, the higher ISOs are of course a bit noisy, though they can still give some decent results in certain situations.

The lower ISO 100 setting, however, is something special. Unlike artificial low ISOs in most previous cameras that reduced the highlight range and tonality of the files, it seems Pentax has done something interesting with the tone curve and sensor response, which showed up in Falk Lumo's RAW analysis and which I can attest to in my own experience. The highlight range is not reduced much, if at all, but the clean shadow detail available for manipulation is fantastic (even better than ISO 200).

Consequently I shoot at ISO 100 most of the time, as long as the lighting is decent.

08-13-2010, 05:46 AM   #62
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QuoteOriginally posted by er1kksen Quote
Well, the higher ISOs are of course a bit noisy, though they can still give some decent results in certain situations.

The lower ISO 100 setting, however, is something special. Unlike artificial low ISOs in most previous cameras that reduced the highlight range and tonality of the files, it seems Pentax has done something interesting with the tone curve and sensor response, which showed up in Falk Lumo's RAW analysis and which I can attest to in my own experience. The highlight range is not reduced much, if at all, but the clean shadow detail available for manipulation is fantastic (even better than ISO 200).

Consequently I shoot at ISO 100 most of the time, as long as the lighting is decent.
That's interesting, and I'd like to read the thread on Falk's findings. I notice, though, that if you set the K-x to preserve highlights, ISO 100 is not available. This would seem to indicate that Pentax feels the highlight range is reduced at ISO 100.

There have been several threads on the K-x under or over exposing. I found that without the setting to preserve highlights, that I (or the K-x program line) tended to set ISO at 100 in bright light, and using the metered exposure would blow highlights or let them fall at their max in a way that I considered overexposing, and with the preserve highlight setting, exposures are darker in a way that many (not me) would say is underexposed, but preserves a larger range of values in the raw file. How does locking out ISO 100 fit into this?
08-14-2010, 04:14 AM   #63
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QuoteOriginally posted by GeneV Quote
That's interesting, and I'd like to read the thread on Falk's findings. I notice, though, that if you set the K-x to preserve highlights, ISO 100 is not available. This would seem to indicate that Pentax feels the highlight range is reduced at ISO 100.

There have been several threads on the K-x under or over exposing. I found that without the setting to preserve highlights, that I (or the K-x program line) tended to set ISO at 100 in bright light, and using the metered exposure would blow highlights or let them fall at their max in a way that I considered overexposing, and with the preserve highlight setting, exposures are darker in a way that many (not me) would say is underexposed, but preserves a larger range of values in the raw file. How does locking out ISO 100 fit into this?
Well, the highlight preservation setting is also based on manipulating the RAW data. I would suspect that it won't work with ISO 100 because ISO 100 is a RAW-data manipulation itself, not necessarily because Pentax feels the range is reduced. The K20D had highlight preservation as well, and it was also limited to ISO 200 and up, despite the fact that it natively had an ISO 100 that did have better highlight (and shadow) range than ISO 200. So I'm really not sure what the deal is with that. Either way I tend to leave those settings alone: they're generally nothing you can't achieve by exposing carefully and doing the data manipulation yourself later in post.

ISO 100 has been shown to have slightly reduced highlight range as compared to ISO 200, but the important thing is that it's not as significant as the improved shadow range. Therefore, simply exposing ISO 100 to preserve highlights and then correcting the exposure in post will give the same results (but with cleaner detail) than shooting ISO 200 with highlight preservation.

It can be a bit counterintuitive, at first. Shooting outside, especially, since the LCD isn't great in bright light, you feel sure that even though you got that sky preserved you must've stuck the main subject way down into the irretrievable bottom of the shadow range. Then you go home and download it and it turns out you've got clean usable data throughout the image. It was really a revelation for me in how I expose with the K-x. I'd never think of doing such a thing with the K20D!
08-16-2010, 06:39 AM - 1 Like   #64
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QuoteOriginally posted by er1kksen Quote
It can be a bit counterintuitive, at first. Shooting outside, especially, since the LCD isn't great in bright light, you feel sure that even though you got that sky preserved you must've stuck the main subject way down into the irretrievable bottom of the shadow range. Then you go home and download it and it turns out you've got clean usable data throughout the image. It was really a revelation for me in how I expose with the K-x. I'd never think of doing such a thing with the K20D!
Actually, I would expose the K20d or K10d something like that, as long as I was at ISO of 400 or less. The K-x is better, but the shadows for all of the recent Pentax DSLRs are usually far more usable than the blown highlights.

What I've found with my K-x is that, without Highlight Preservation, it will expose a brightly lit landscape with highlights at the absolute max of what the sensor can hold, and sometimes it overshoots. With highlight preservation, it doesn't just apply curves, but exposes for the highlights more conservatively, often resulting in exactly the kind of dark scene that is easily retrieved in ACR to form clean images. Granted, I can do all of this myself with care and attention, but there is some significant value to having a usuable automatic mode, especially on vacation.

It is nice to know that the ISO 100 option is there for scenes where you can take the time to use it properly.

08-16-2010, 06:50 PM   #65
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I found shadow recovery operations almost painful with the K20D, sadly. It wasn't that the shadows were terribly noisy (though it was certainly noisier than the K-x), it was just as much that I really disliked the character of the noise that resulted. It just clashed with my visual preferences. For some reason I like the K-x noise and often leave it be.
08-17-2010, 06:44 AM   #66
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QuoteOriginally posted by er1kksen Quote
I found shadow recovery operations almost painful with the K20D, sadly. It wasn't that the shadows were terribly noisy (though it was certainly noisier than the K-x), it was just as much that I really disliked the character of the noise that resulted. It just clashed with my visual preferences. For some reason I like the K-x noise and often leave it be.
I agree completely about the K-x noise. It is like grain on my favorite films. I often leave them alone. If I run Noise Ninja at all, it is with very low strength settings that basically just allow me to apply some sharpening without increasing the visibility of the noise.
08-17-2010, 06:49 AM   #67
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I recently looked into BushHawk stock.

Using heavy manual lens this stock would have been perfect. Holding grip with finger on the button with one hand and focusing lens with the other.....
But than I realized that my K-x is low end DSLR that does not have a remote shutter release socket...... Sucks.

I'm might sell it and get something better.

Last edited by fiveseven; 08-17-2010 at 08:30 AM.
08-17-2010, 11:46 AM   #68
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You might be able to rig a release using a Pentax remote, a few wires and some solder, but I agree that there should be a better way.

08-17-2010, 01:14 PM   #69
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QuoteOriginally posted by er1kksen Quote
Well, the higher ISOs are of course a bit noisy, though they can still give some decent results in certain situations.

The lower ISO 100 setting, however, is something special. Unlike artificial low ISOs in most previous cameras that reduced the highlight range and tonality of the files, it seems Pentax has done something interesting with the tone curve and sensor response, which showed up in Falk Lumo's RAW analysis and which I can attest to in my own experience. The highlight range is not reduced much, if at all, but the clean shadow detail available for manipulation is fantastic (even better than ISO 200).

Consequently I shoot at ISO 100 most of the time, as long as the lighting is decent.
Thanks to you and GeneV for you helpful comments.
If I understand your posts, you would suggest setting the ISO at 100. Then leaving the highlight preservation and shadow recovery off. Expose to avoid clipping the highlights and then PP to bring out the highlights. Given that the noise is not bad at ISO 100, it shouldn't be an issue with any exposure correction in post-processing. Did I get that right?

Why does Pentax not just set the ISO default to 100? Can you comment on what the camera base ISO is and what happens with expanded ISO and with the highlight preservation and shadow recovery process? It seems confusing and I may have missed it but the manual just indicates how to turn it on and off. I got that part.

Thanks again. ( I gave you guys some rep points.)
08-17-2010, 01:19 PM   #70
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QuoteOriginally posted by er1kksen Quote
It can be a bit counterintuitive, at first. Shooting outside, especially, since the LCD isn't great in bright light, you feel sure that even though you got that sky preserved you must've stuck the main subject way down into the irretrievable bottom of the shadow range. Then you go home and download it and it turns out you've got clean usable data throughout the image. It was really a revelation for me in how I expose with the K-x. I'd never think of doing such a thing with the K20D!
Are you shooting with JPEG or just RAW? I wonder if I can get the same results if I continue to use JPEG.
08-17-2010, 01:43 PM   #71
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QuoteOriginally posted by GeneV Quote
You might be able to rig a release using a Pentax remote, a few wires and some solder, but I agree that there should be a better way.
You could always just get a cheap ebay remote that works for the K-x...

QuoteOriginally posted by MSM Quote
Thanks to you and GeneV for you helpful comments.
If I understand your posts, you would suggest setting the ISO at 100. Then leaving the highlight preservation and shadow recovery off. Expose to avoid clipping the highlights and then PP to bring out the highlights. Given that the noise is not bad at ISO 100, it shouldn't be an issue with any exposure correction in post-processing. Did I get that right?
That is what I find produces optimal results, yes.

QuoteOriginally posted by MSM Quote
Why does Pentax not just set the ISO default to 100? Can you comment on what the camera base ISO is and what happens with expanded ISO and with the highlight preservation and shadow recovery process? It seems confusing and I may have missed it but the manual just indicates how to turn it on and off. I got that part.
Traditionally, camera makers do not set their cameras to use "artificial" ISOs (like 100 and 6400 and 12800 in this case) by default. In a lot of other DSLRs aritificial low ISOs have somewhat flattened tones and reduced highlight headroom, so you're better not using it with those models.

ISO 200 is the "base ISO" for the sensor in the K-x. ISO 100 is essentially created by overexposing at ISO 200 and setting the curve lower, but Pentax did something weird with the K-x's ISO 100 that avoids the traditional negatives of artificial low ISOs. I don't fully understand the technical side of it (I'm more interested in the results ) but Falk Lumo did some extensive sensor testing and you can find his results, including an examination of the unusual ISO 100, here.

Highlight preservation simply underexposes an image (preserving the highlights) and then uses a tone curve to bump the midtones and shadows up to where they would have been with a normal exposure. Similar to the technique I described for use with ISO 100, but automated. Shadow recovery simply takes a normal exposure and boosts the shadows (and possibly the midtones a bit) with a similar curve. Both are things that are easy to do with far more control in postprocessing.

QuoteOriginally posted by MSM Quote
Are you shooting with JPEG or just RAW? I wonder if I can get the same results if I continue to use JPEG.
I generally only shoot RAW. You could get a crude version of the same effect in jpeg by using highlight preservation and shadow recovery together, but you're restricted to ISO 200 and up and the camera doesn't always make the best aesthetic decisions when you're doing that much automated data manipulation. The contrast and colors can start to look pretty unnatural. The noise reduction also seems to be less effective on the noise that those two settings introduce. For optimal quality RAW is the way to go.
08-17-2010, 05:13 PM   #72
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QuoteOriginally posted by er1kksen Quote

Highlight preservation simply underexposes an image (preserving the highlights) and then uses a tone curve to bump the midtones and shadows up to where they would have been with a normal exposure. Similar to the technique I described for use with ISO 100, but automated. Shadow recovery simply takes a normal exposure and boosts the shadows (and possibly the midtones a bit) with a similar curve. Both are things that are easy to do with far more control in postprocessing.

.
The curve is fairly easy to duplicate in ACR or other programs, but a blown highlight is often not fixable at all. That is why I have gone to the highlight preservation and RAW. I'll work the curves myself, but I want my highlights to be usable. Without highlight preservation, which does darken a raw image, I was getting way too many blown highlights on grab shots. I can always adjust the exposure upward, too, the same way I could adjust it downward with the highlight preservation off. It is just a question of where each of us is comfortable.
08-17-2010, 05:26 PM   #73
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QuoteOriginally posted by GeneV Quote
The curve is fairly easy to duplicate in ACR or other programs, but a blown highlight is often not fixable at all. That is why I have gone to the highlight preservation and RAW. I'll work the curves myself, but I want my highlights to be usable. Without highlight preservation, which does darken a raw image, I was getting way too many blown highlights on grab shots. I can always adjust the exposure upward, too, the same way I could adjust it downward with the highlight preservation off. It is just a question of where each of us is comfortable.
Understood, but you could just underexpose your image manually to preserve the highlights. It's the same thing, just you have more control over it.

It's not as if it matters that much, but I feel like things like this are the difference between going out to eat at a restaurant that serves good burgers, and buying the ingredients and making a good burger yourself. The outcome may be an equally delicious piece of food in either case, but in the case of making the burger yourself you understand the process and appreciate it more and can also tailor the process and results to your specific preferences. That's why I tend to feel that consciously doing things like, say, lowering the exposure compensation (or changing shutter or aperture if using manual mode) are more fruitful in the end than simply using the automated setting that does the same thing.
08-17-2010, 05:40 PM   #74
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QuoteOriginally posted by er1kksen Quote
Understood, but you could just underexpose your image manually to preserve the highlights. It's the same thing, just you have more control over it.

It's not as if it matters that much, but I feel like things like this are the difference between going out to eat at a restaurant that serves good burgers, and buying the ingredients and making a good burger yourself. The outcome may be an equally delicious piece of food in either case, but in the case of making the burger yourself you understand the process and appreciate it more and can also tailor the process and results to your specific preferences. That's why I tend to feel that consciously doing things like, say, lowering the exposure compensation (or changing shutter or aperture if using manual mode) are more fruitful in the end than simply using the automated setting that does the same thing.
I'd more see it that I buy the ingredients and usually make the burger myself by changing the settings as I see fit, but I have the bought burger as a backup in case I forgot the meat or the bun.
08-18-2010, 10:46 PM   #75
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QuoteOriginally posted by er1kksen Quote
...
I generally only shoot RAW. You could get a crude version of the same effect in jpeg by using highlight preservation and shadow recovery together, but you're restricted to ISO 200 and up and the camera doesn't always make the best aesthetic decisions when you're doing that much automated data manipulation. The contrast and colors can start to look pretty unnatural. The noise reduction also seems to be less effective on the noise that those two settings introduce. For optimal quality RAW is the way to go.
Thanks, for the info. My last question was really about using JPEG without the highlight or shadow feature and simply using the ISO 100 and exposing for the highlights. Then in PP pull up the shadows. I wonder if the results would be that different if I use JPEG v. RAW.
I am using Aperture 2 which doesn't support RAW files from the Kx but will accept JPEG's. I really don't want to upgrade to Aperture 3 if I don't have to. I have a nonupgradeable version and that would require a full license $300 software. Perhaps I could use the silkypix/ppl software and import the photos into aperture. Seems too laborious. Thoughts?
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