The Q is almost 1-stop brighter than the Q2

[jaapv]

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The point is: they didn't rewrite the standard. Nor did other camera makers. This standard is open to multiple interpretations.

[bags27]

1 minute ago, jaapv said:

The point is: they didn't rewrite the standard. Nor did other camera makers. This standard is open to multiple interpretations.

Right, it's post-modern, not Platonic!

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[IkarusJohn]

3 minutes ago, jaapv said:

The point is: they didn't rewrite the standard. Nor did other camera makers. This standard is open to multiple interpretations.

Still doesn’t answer my light meter question, Jaap. EV is EV- sensor sensitivity aside, that doesn’t change and isn’t “open to interpretation”. Film wouldn’t work otherwise. 

[jaapv]

Light meters is a totally different thing. Not even the same ISO sheet. I couldn't answer your question, I have never researched it.

BTW, Film ISO isn't an absolute either. Development is decisive, and some films benefit by overexposure, some by underexposure.

[IkarusJohn]

Another red herring.

What we all knew and relied on was that for a given EV reading, the recommended ISO (processed as the packet recommended) would result in consistent exposure.  Using a good incident light meter and 1° spot meter, you should get a consistent light reading - that is not subjective.  Similarly, film was expected, not unreasonably to perform to its ISO rating.

Fast forward to the M10 and Q2 (we’re talking about the Q2, right?), and it appears that Leica is re-writing the ISO scale on its cameras.  Why? and why should we care?  My guess is that (1) Leica has decided that its sensors perform better if images are under-exposed, and rather than leaving it to users to scale in -2/3EC, they’ve moved the ISO scale (odd, but I guess possible), or (2) it wants the boasting rights of high ISO performance for the spec-sheet readers (sadly, plausible?).

Do I mind?  Not really, though I am curious.  Provided Leica has accurately identified base ISO (where I usually live) and I set max ISO at a better than usable measure, I don’t actually care.  I’m only using an incident light meter with my M-A and SWC ... but ... it does mess up with what is instinctively going on in my head when I view a scene and think - f/4 at 1/250.  ISO has become so movable, that those mental adjustments which informed so much of my 50 years of photography is getting scrambled.

Perhaps it’s age.

Edited March 9, 2019 by IkarusJohn

[Chaemono]

For the benefit of John, let's just copy paste form another thread.

See here: https://www.dpreview.com/forums/thread/2838786

"...about digital camera ISO determinations . It all depends on which Standard did the manufacturer of a DSLR decided to adhere to , the REI or the SOS and whether the user is creating RAW files or JPG for output. Please read on.

ISO 12232:2006 is a document written by the International Organization for Standarization (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 colour digital still cameras.

 

This publication can be obtained from the International Organization for Standarizationhere: 
http://www.iso.org/iso/catalogue_detail.htm?csnumber=37777

 

What follows is an excerpt from it:

 

The ISO 12232:2006 standard

The ISO standard 12232:2006[15] gives digital still camera manufacturers a choice of five different techniques for determining the exposure index rating at each sensitivity setting provided by a particular camera model. Three of the techniques in ISO 12232:2006 are carried over from the 1998 version of the standard, while two new techniques allowing for measurement of JPEG output files are introduced from CIPA DC-004.[16] Depending on the technique selected, the exposure index rating can depend on the sensor sensitivity, the sensor noise, and the appearance of the resulting image. The standard specifies the measurement of light sensitivity of the entire digital camera system and not of individual components such as digital sensors, although Kodak has reported[17] using a variation to characterize the sensitivity of two of their sensors in 2001.

 

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. Consequently, the three EI techniques carried over from ISO 12232:1998 are not widely used in recent camera models (approximately 2007 and later) . As those earlier techniques did not allow for measurement from images produced with lossy compression, they cannot be used at all on cameras that produce images only in JPEG format.

 

The saturation-based technique is closely related to the SOS technique, with the sRGB output level being measured at 100% white rather than 18% gray. The saturation-based value is effectively 0.704 times the SOS value .[18] Because the output level is measured in the sRGB output from the camera, it is only applicable to sRGB images—typically TIFF—and not to output files in raw image format. It is not applicable when multi-zone metering is used.

 

The two noise-based techniques have rarely been used for consumer digital still cameras. These techniques specify the highest EI that can be used while still providing either an “excellent” picture or a “usable” picture depending on the technique chosen."

[dancook]

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'ISO Performance' has become a measurable trait of cameras, how much noise it displays at a certain ISO - whether that is a red herring or not, it is still considered by people for low light performance.

Of course as we have concluded this means nothing, because it is not comparable. Matt Granger's video suggests the Q2 has better ISO performance than the Q1, but I would now conclude that is false, because that would rely on the opportunity to have a slower shutter speed to compensate for the lower exposure.

So, for the Q and Q2, if you maintain a constant aperture and shutter speed, the performance appears the same regardless of where the ISO lands.

Edited March 9, 2019 by dancook

[IkarusJohn]

25 minutes ago, Chaemono said:

For the benefit of John, let's just copy paste form another thread.

“...

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.

...."

Interesting, thank you for the quote.

So from this do we assume that Leica is using the REI technique (presumably not something Leica will tell us), and more critically that the ISO scales on the new cameras are meaningless, save in the relativity of an ISO setting in one camera, but not between cameras?  As Dan says, set the aperture and shutter the same on the Q and Q2, while the ISO values differ, the exposure will be the same?  I guess the Q2 still has a stop improvement in performance, and better resolution, so we shouldn’t mind?

Should we care?  I guess not, but it’s odd - I’m too old-fashioned, but I do prefer a world in which an EV rating is constant ...

Edited March 9, 2019 by IkarusJohn

[M11 for me]

vor 8 Minuten schrieb dancook:

'ISO Performance' has become a measurable trait of cameras, how much noise it displays at a certain ISO - whether that is a red herring or not, it's considered by people.

Of course as we have concluded this means nothing, because it is not comparable. Matt Granger's video suggests the Q2 has better ISO performance than the Q1, but I would now conclude that is false, because that would rely on the opportunity to have a slower shutter speed to compensate for the lower exposure.

So, for the Q and Q2, if you maintain a constant aperture and shutter speed, the performance appears the same regardless of where the ISO lands.

As we learned above, for evaluating noise performance you should first of all adjust the pictures that you want to compare to the same brightness (in post). You might like to make the settings on 2 different cameras the same (same ISO, Aperture and Speed). Before looking at noise adjust their brightness. 

What I always dislike in these discussions: I understood that ISO Standard is quite open and there are different methods of how to measure ISO. But one might assume that a producer (Leica with Leica Q and Q2) would stick to ONE  method for its product range and not change from model to model. So I rather think that there are marketing considerations behind. Have a look at one of the recent Youtube videos by Northrup: He calls it the "Fake ISO". 

However once you have a camera this does not matter too much. In practice I am not going to compare settings but I am happy with a correctly exposed image that has little noise.

[jaapv]

1 hour ago, IkarusJohn said:

Another red herring.

What we all knew and relied on was that for a given EV reading, the recommended ISO (processed as the packet recommended) would result in consistent exposure.  Using a good incident light meter and 1° spot meter, you should get a consistent light reading - that is not subjective.  Similarly, film was expected, not unreasonably to perform to its ISO rating.

Fast forward to the M10 and Q2 (we’re talking about the Q2, right?), and it appears that Leica is re-writing the ISO scale on its cameras.  Why? and why should we care?  My guess is that (1) Leica has decided that its sensors perform better if images are under-exposed, and rather than leaving it to users to scale in -2/3EC, they’ve moved the ISO scale (odd, but I guess possible), or (2) it wants the boasting rights of high ISO performance for the spec-sheet readers (sadly, plausible?).

Do I mind?  Not really, though I am curious.  Provided Leica has accurately identified base ISO (where I usually live) and I set max ISO at a better than usable measure, I don’t actually care.  I’m only using an incident light meter with my M-A and SWC ... but ... it does mess up with what is instinctively going on in my head when I view a scene and think - f/4 at 1/250.  ISO has become so movable, that those mental adjustments which informed so much of my 50 years of photography is getting scrambled.

Perhaps it’s age.

Whatever. <bless>

[nicci78]

Q2 and Q ISO difference, is only due to how Leica measure ISO since the M10 

I also notice an almost 1 EV difference since the M10, all Leica cameras made in Germany will have this 1 EV bias.

T and Q with the same settings : same aperture and same speed will produce the same histogram 

However CL will need 1 more stop (aperture or speed) to produce the same histogram. 

CL @ ISO 3200 has same noise level as Q @ ISO 1600

Exposure wise against the Q ISO range of 100-50000 the CL is a 64-25000 in Q ISO standard

All manufacturers are cheating this way, because reviewers are just plain dumb, and compare image ISO value against ISO value, even if exposure value are different. m4/3 cameras are using this kind of tricks to appear not too bad in comparison. Leica since M10 decided to do the same, otherwise their cameras will start to look bad in review. 

 

[jaapv]

Indeed. Remember the M8? It got hammered for poor high-ISO performance by numbers. In reality it outperformed the Canon 5D of the time both in detail and colour. But reviewers took the ISO rating of the camera at face-value and judged by severely underexposed images.

[Daedalus2000]

8 hours ago, dancook said:

Looks similar to me

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

Q1 Crop by Daniel Cook, on Flickr

Q2 Crop by Daniel Cook, on Flickr

 

I would be very careful when doing such comparisons, because you seem to have exported  the same crop at the same dimensions from two different sensors, with different megapixels. So in a sense you may have given the advantage to Q2, because the exporting step averaged the noise over more pixels. Other reviewers have reported the Q being 2/3rds of a stop better than the Q before reducing to the same size. I do not know if they adjusted for the difference in the ISO

 

Edited March 10, 2019 by Daedalus2000

[nicci78]

It is the way to compare. export at the same size, for normal viewing or printing experience. Nobody should look at a picture at 100% magnification. 

[Daedalus2000]

4 minutes ago, nicci78 said:

It is the way to compare. export at the same size, for normal viewing or printing experience. Nobody should look at a picture at 100% magnification. 

It is a way of comparing, but it does not tell the full story, especially in combination to the differences in iso.

Edited March 10, 2019 by Daedalus2000

[xaradaisy]

2 hours ago, Daedalus2000 said:

I would be very careful when doing such comparisons, because you seem to have exported  the same crop at the same dimensions from two different sensors, with different megapixels. So in a sense you may have given the advantage to Q2, because the exporting step averaged the noise over more pixels. Other reviewers have reported the Q being 2/3rds of a stop better than the Q before reducing to the same size. I do not know if they adjusted for the difference in the ISO

 

 

I was about to point out the same.

He needs to downsize the Q2 file to the same size as Q files to make comparisons.

Even in the files, as it is without downsizing, I see colors holding better in the Q2 files.

[xaradaisy]

Once I get my Q2, I will simply go out at night for a couple of nights and shoot between ISO 6400 and 12800 to test its high ISO capabilities.

Once I get back home, and look at the files, I should know if I am happy with the results.

With my Q, I was rarely happy with IQ above ISO 6400.

That real world test should be enough for me and my needs.

Edited March 10, 2019 by xaradaisy

[Chaemono]

vor 7 Stunden schrieb nicci78:

I also notice an almost 1 EV difference since the M10, all Leica cameras made in Germany will have this 1 EV bias.

You are wrong. One user who wrote a review of the M10 and compared it to his α7R III in his blog started a thread on this forum and complained that the M10 needs +0.6 EV adjustment to match his Sony. See #1 here: https://www.l-camera-forum.com/topic/284201-m10-vs-sony-a7riii-iso-differences/. He used the M10 with the Summilux 50 ASPH and the α7R III with the Zeiss Sonnar FE 55/1.8. He set the same aperture to compare. But 'f/' value is simply the ratio of focal length to the diameter of the entrance pupil and doesn't measure the light a lens lets through. It's T-Stop values that express this and T-Stops vary from lens to lens (we are assuming that they are the same for the Q1 and the Q2 lenses in this thread, BTW). When the same lens is used, the OP of the thread in the first link concedes that the difference between the M10 and the α7R III is only about 0.2 EV, #121 in another thread here: https://www.l-camera-forum.com/topic/288283-high-iso-m10-vs-q/?page=7 😀.

It is more like -0.3 compared to the α7R III, I'd say, and I have tons of RAW files that I can link to.  Also, the α7R III underexposes relative to the Z7 by about 1/3 EV (same lens used, obviously). So, Sony is a bit ISO cheating when compared to Nikon. 🤣 Again, RAW files are available upon request.

 

 

[nicci78]

I only compare within Leica’s cameras. Not with any other brand. 

Just make a look at DXOmark to know how much each cameras ISO is off from their “standard” ISO value. 

Everybody are “lying” except Leica before the M10. 

Since M10, Leica shift its ISO value to almost 1 stop 

 

DXOmark is nice for comparison, because it use its standard ISO to compare cameras, not what the manufacturers specified. 

But Photons to Photos only use manufacturer ISO, making comparison impossible. 

Edited March 10, 2019 by nicci78

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[Fedro]

9 hours ago, jaapv said:

Indeed. Remember the M8? It got hammered for poor high-ISO performance by numbers. In reality it outperformed the Canon 5D of the time both in detail and colour. But reviewers took the ISO rating of the camera at face-value and judged by severely underexposed images.

so basically it is in the ISOf the beholder