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02-28-2016, 06:31 PM   #46
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QuoteOriginally posted by D1N0 Quote
@chris mak the d800 sensor has the following specs:100 - 6400 in 1, 1/2 or 1/3 EV steps (50 - 25600 with boost) the a7r 100-25600. The k-1 100-204800. It is not the same sensor. Not with three extra stops iso. It is probably a new incarnation. So no the same as the d810 either.
The above means nothing. All you need to do to change ISO is boost amplification.

02-28-2016, 06:36 PM   #47
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QuoteOriginally posted by audiobomber Quote
The above means nothing. All you need to do to change ISO is boost amplification.
I hear from strong sources it is the same base sensor as the D810 with extensive customization by Pentax (as you described). It was stated Pentax considers it essentially a 'new' sensor. I of course don't claim to KNOW.

Last edited by monochrome; 02-28-2016 at 06:48 PM.
02-28-2016, 06:46 PM - 1 Like   #48
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QuoteOriginally posted by audiobomber Quote
The above means nothing. All you need to do to change ISO is boost amplification.
I don't think Ricoh would do that. It would get very crappy. They want to deliver, not bullshit.
02-28-2016, 07:07 PM   #49
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QuoteOriginally posted by D1N0 Quote
I don't think Ricoh would do that. It would get very crappy. They want to deliver, not bullshit.
Sensors don't actually have a ISO like film. The sensitivity does not change as you change ISO like it does with film. All manufacturers boost the gain as you increase ISO.

02-28-2016, 07:30 PM - 1 Like   #50
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This link posted by rawr yesterday has a paragraph on K-1 sensor ISO specifics. It appears the K-1 does not amplify the signal digitally to achieve higher ISOs. The English translation is less than perfect but it is chock full of nuggets:

?????????????????????????????????PENTAX K-1 ????????????? - ??????????by????????
02-28-2016, 08:13 PM   #51
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QuoteOriginally posted by jbinpg Quote
This link posted by rawr yesterday has a paragraph on K-1 sensor ISO specifics. It appears the K-1 does not amplify the signal digitally to achieve higher ISOs. The English translation is less than perfect but it is chock full of nuggets:

?????????????????????????????????PENTAX K-1 ????????????? - ??????????by????????
Then the K-1 has a revolutionary sensor in it that has never been seen before. I wouldn't believe everything the marketing dept. says.

ISO 12232:2006 is a document written by the International Organization for Standardization (ISO)

This document specifies the method for assigning and reporting ISO speed ratings, ISO speed , latitude ratings, standard output sensitivity values, and recommended exposure index values, for digital still cameras . ISO 12232:2006 is applicable to both monochrome and color digital still cameras.

The Recommended Exposure Index (REI) technique, new in the 2006 version of the standard, allows the manufacturer to specify a camera model’s EI choices arbitrarily . The choices are based solely on the manufacturer’s opinion of what EI values produce well-exposed sRGB images at the various sensor sensitivity settings. This is the only technique available under the standard for output formats that are not in the sRGB color space. This is also the only technique available under the standard when multi-zone metering (also called pattern metering) is used.

The Standard Output Specification (SOS) technique , also new in the 2006 version of the standard, effectively specifies that the average level in the sRGB image must be 18% gray plus or minus 1/3 stop when exposed per the EI with no exposure compensation . Because the output level is measured in the sRGB output from the camera, it is only applicable to sRGB images—typically JPEG—and not to output files in raw image format. It is not applicable when multi-zone metering is used.

The CIPA DC-004 standard requires that Japanese manufacturers of digital still cameras use either the REI or SOS techniques.

A sensor only has one sensitivity setting. All the ISO does on a modern camera is tell it how much gain to apply to achieve a brightness of 50% (sRBG) or RGB values of (128,128,128).
02-28-2016, 09:26 PM   #52
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JPT, thanks also for the report. One question I have is on the high ISO performance of the K-1. I gather the rep will make the claim that the K-1 is a lot cleaner than the K-5 IIs but did you try shooting at ISO 12,800 and look at the noise pattern on the image? I do believe that if Pentax get this part right on their FF camera then it will be a serious addition to the professional kit lineup.
02-28-2016, 09:43 PM   #53
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Thanks for the report, JPT!

02-28-2016, 09:45 PM   #54
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QuoteOriginally posted by Winder Quote
Then the K-1 has a revolutionary sensor in it that has never been seen before. I wouldn't believe everything the marketing dept. says.

ISO 12232:2006 is a document written by the International Organization for Standardization (ISO)

This document specifies the method for assigning and reporting ISO speed ratings, ISO speed , latitude ratings, standard output sensitivity values, and recommended exposure index values, for digital still cameras . ISO 12232:2006 is applicable to both monochrome and color digital still cameras.

The Recommended Exposure Index (REI) technique, new in the 2006 version of the standard, allows the manufacturer to specify a camera model’s EI choices arbitrarily . The choices are based solely on the manufacturer’s opinion of what EI values produce well-exposed sRGB images at the various sensor sensitivity settings. This is the only technique available under the standard for output formats that are not in the sRGB color space. This is also the only technique available under the standard when multi-zone metering (also called pattern metering) is used.

The Standard Output Specification (SOS) technique , also new in the 2006 version of the standard, effectively specifies that the average level in the sRGB image must be 18% gray plus or minus 1/3 stop when exposed per the EI with no exposure compensation . Because the output level is measured in the sRGB output from the camera, it is only applicable to sRGB images—typically JPEG—and not to output files in raw image format. It is not applicable when multi-zone metering is used.

The CIPA DC-004 standard requires that Japanese manufacturers of digital still cameras use either the REI or SOS techniques.

A sensor only has one sensitivity setting. All the ISO does on a modern camera is tell it how much gain to apply to achieve a brightness of 50% (sRBG) or RGB values of (128,128,128).
Reading the translated link seemed to indicate that the gain is applied before tha a/d conversion as opposed to applying it to the digital data. Not sure if that is any different to what has been done elsewhere. It will be interesting to see how well it works.
02-28-2016, 11:02 PM   #55
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QuoteOriginally posted by monochrome Quote
I made another assertion that will be justified if Roger Cicala tears down a K-1.
I surely hope he will. His tear-down of the A7ii was quite telling and I would expect that one of the K-1 will be equally so.


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02-28-2016, 11:08 PM   #56
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QuoteOriginally posted by Winder Quote
The Recommended Exposure Index (REI) technique, new in the 2006 version of the standard, allows the manufacturer to specify a camera model’s EI choices arbitrarily . The choices are based solely on the manufacturer’s opinion of what EI values produce well-exposed sRGB images at the various sensor sensitivity settings. This is the only technique available under the standard for output formats that are not in the sRGB color space. This is also the only technique available under the standard when multi-zone metering (also called pattern metering) is used.
Thank you for pointing this out. Most folk believe that the ISO settings on their dSLR are traceable to some sort of standard, but that is not the case. About all that might be expected is that good exposure will result when metered to a particular EV at that EI and that EV will be similar to reference meter set to the same EI.

As a result, stated base ISO and minimum ISO are not directly comparable across brands and maybe not even between cameras of the same brand.


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02-29-2016, 01:23 AM   #57
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QuoteOriginally posted by stevebrot Quote
I surely hope he will. His tear-down of the A7ii was quite telling and I would expect that one of the K-1 will be equally so.
I'd also settle for an iFixit.com and/or Chipworks [sometimes they partner] hardware teardown and components report. Chipworks has an electron microscope for studying chips in depth - even Roger Cicala doesn't have one of those.

Last edited by rawr; 02-29-2016 at 01:28 AM.
02-29-2016, 02:29 AM   #58
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QuoteOriginally posted by D1N0 Quote
I don't think Ricoh would do that. It would get very crappy. They want to deliver, not bullshit.
They simply have to.
Shooting at a higher iso settings essentially means only one thing: you shorten the exposure, as a result you have a weaker signal, and you have to apply a certain amount of gain to get to the desired brightness level.
You can also simply use a low iso setting and change the exposure time manually, and then in your raw converter bump up the exposure. The result won't be that much different. Shorter exposure time means a weaker signal and a darker image unless you apply gain to the signal.


It's a whole different story however, if you want to achieve a lower native iso that has a large dynamic range: here you do just the opposite, you increase the exposure time, and get a stronger signal. This will always decrease noise as you need less gain to get to the desired brightness of the image, but the sensor has to have the neccessary higlight headroom to allow for a lower native iso. If not, saturation in the highlights will occur and you will have clipping, loss of information. The ability to store photons is a part of the silicon design in a sensor and cannot be as far as I know, artificially stretched. That is why expanding the iso range to below the native iso of a sensor will not increase but decrease the dynamic range: you no longer increase DR by having a stronger signal and thus less noise, but you decrease DR by introducing saturation of the photon collecting wells.
Just check the behavior of sensors when iso is artificially expanded: the dynamic range in the highlights decreases. When however you check the D810 sensor setting at iso 64 (which is not an expanded iso), you will see that it tops the DR curve at that setting: it still has the neccessary highlight headroom, which will have to be designed into the sensor's silicon.
The K1 may well do better at high iso settings compared to equivalent 36mp sensors if Pentax controls the noise better in relation to applying gain to the weaker source signal. But it would surprise me a lot if they can reach the Nikon D810's DR of 14.7 ev at iso 64.


Chris

Last edited by Chris Mak; 02-29-2016 at 02:35 AM.
02-29-2016, 02:34 AM   #59
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QuoteOriginally posted by JPT Quote
According to the rep, the K-1 is at ISO 12,800 like the K-5 IIs is at 3200
Well, thats what I wanted to hear !
Sounds almost too good to be true though and the fact that it's "according to the Rep" is suspicious...but I want to believe in Ricoh !

Thanks for the report JPT.

Last edited by DimC; 02-29-2016 at 02:42 AM.
02-29-2016, 03:36 AM   #60
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I just remembered another important thing. When pixel shift and movement correction is enabled, the camera takes several seconds to process the file, and I think you have to wait for it to finish before you do anything else. You may well be able to use pixel shift handheld in some situations, but you're not going to be running and gunning in pixel shift mode.

If the high ISO capability, combined with the 5-stop SR and a fast lens, enables you to keep the shutter speed high enough for pixel shift, a lot of that noise is going to disappear. That might explain why Ricoh choose to time the sensor towards higher ISO performance compared to the D810.

I'm going to be very interested to see reports of how usable pixel shift is in real situations.

Ash - I'm afraid I didn't attempt to evaluate the ISO performance on the screen. I was more focused on the physical aspects of the camera.
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