SLT -1/3 stop?

[Allan Olesen]

NAwlins Contrarian wrote:

ISO is the International Standards Organization.

Yes. We all know that.

And in photography terminology it is also a unit, just like seconds, mm and lumen.

So in context where ISO correctly is used as a unit, please do not derail the discussion by stating that the name of an organization was incorrectly used.

 

[Just Having Fun]

JJLMD wrote:

Look for yourself. Go to Conclusions page of SLT-a99 review. Go to yellow bars graphs at bottom of page. They state specifically comparisons of yellow bars are valid for cameras in same class. Compare D800 and 5DmkIII, which are in the same class as the SLT-a99, for high ISO performance.

Moreover, in the text of the Conclusions section, they repeatedly praise the SLT-a99's "particularly" "excellent" high ISO performance.

What am I missing?

The multi-shot high ISO mode.

"The camera captures six images in a fraction of a second. Combining the data from all six, it creates a single image with a reduction in noise equivalent to two additional steps of ISO sensitivity"

Of course you can do this with any camera and process the images later. People have been doing this for years, but the A99 doe sit in camera. If you subject is moving though, it is worthless.

If you compare apples to apples though the D600 and 6D are clearly better at high ISO. You need to read all the reviews instead of relying on a bar with little explanation.

 

[Just Having Fun]

TrojMacReady wrote:

Just Having Fun wrote:

The Nikon D600 image at ISO6400 is better focused (sharper) than the A99 at ISO3200.

Nice try. The d600 not only looks clearer and sharper

Like I said, anyone with eyes....

Anyone one with brains would realize I was talking about the DPR test pictures. The A99 shots for some reason are not focused very well which has nothing to do with the camera. Sadly, you didn't figure that out, or it was one of your classic strawmen.

Anyway, as anyone with eyes can see the D600 is almost (but not quite) a full stop better than the A99. People who work in Sony marketing will strongly protest but offer little to no evidence, while anyone can check sites like DxO for the truth. As others have pointed out...

"The difference between 1555 and 2980 is almost one full stop."



Maybe this is why Sony is dumping SLTs.

 

[Eleson]

Just Having Fun wrote:

JJLMD wrote:

Look for yourself. Go to Conclusions page of SLT-a99 review. Go to yellow bars graphs at bottom of page. They state specifically comparisons of yellow bars are valid for cameras in same class. Compare D800 and 5DmkIII, which are in the same class as the SLT-a99, for high ISO performance.

Moreover, in the text of the Conclusions section, they repeatedly praise the SLT-a99's "particularly" "excellent" high ISO performance.

What am I missing?

The multi-shot high ISO mode.

"The camera captures six images in a fraction of a second. Combining the data from all six, it creates a single image with a reduction in noise equivalent to two additional steps of ISO sensitivity"

Are you under the impression that the test shots was shot using MFNR ?



--

Cheers
Erland

 

[Just Having Fun]

Eleson wrote:

Just Having Fun wrote:

JJLMD wrote:

Look for yourself. Go to Conclusions page of SLT-a99 review. Go to yellow bars graphs at bottom of page. They state specifically comparisons of yellow bars are valid for cameras in same class. Compare D800 and 5DmkIII, which are in the same class as the SLT-a99, for high ISO performance.

Moreover, in the text of the Conclusions section, they repeatedly praise the SLT-a99's "particularly" "excellent" high ISO performance.

What am I missing?

The multi-shot high ISO mode.

"The camera captures six images in a fraction of a second. Combining the data from all six, it creates a single image with a reduction in noise equivalent to two additional steps of ISO sensitivity"

Are you under the impression that the test shots was shot using MFNR ?

--

Cheers
Erland

Huh???

Did you read what I said? HE wants to know how the A99 could do better in low light. IBIS or MFNR is how. For Apples to Apples the D600 is close to 1 stop better though, which you can see at DxO or the DPR test shots or almost any review site.

 

[JJLMD]

Just Having Fun wrote:

Eleson wrote:

Just Having Fun wrote:

JJLMD wrote:

Look for yourself. Go to Conclusions page of SLT-a99 review. Go to yellow bars graphs at bottom of page. They state specifically comparisons of yellow bars are valid for cameras in same class. Compare D800 and 5DmkIII, which are in the same class as the SLT-a99, for high ISO performance.

Moreover, in the text of the Conclusions section, they repeatedly praise the SLT-a99's "particularly" "excellent" high ISO performance.

What am I missing?

The multi-shot high ISO mode.

"The camera captures six images in a fraction of a second. Combining the data from all six, it creates a single image with a reduction in noise equivalent to two additional steps of ISO sensitivity"

Are you under the impression that the test shots was shot using MFNR ?

--

Cheers
Erland

Huh???

Did you read what I said? HE wants to know how the A99 could do better in low light. IBIS or MFNR is how. For Apples to Apples the D600 is close to 1 stop better though, which you can see at DxO or the DPR test shots or almost any review site.

You can disagree with DPReview's conclusions but based on the text AND bar graph, it's pretty clear (to me) that DPReview feels the SLT-a99 is at least on a par with Canon's and Nikon's FF offerings when it comes to high ISO performance. They classify the D600 as being in a different class so they offer no way to compare its high ISO performance with that of the a99. But the 5DmkIII and D800 ARE in the same class and they explicity state that their bar graph comparisons are valid.

 

[Just Having Fun]

JJLMD wrote:

Just Having Fun wrote:

Eleson wrote:

Just Having Fun wrote:

JJLMD wrote:

Look for yourself. Go to Conclusions page of SLT-a99 review. Go to yellow bars graphs at bottom of page. They state specifically comparisons of yellow bars are valid for cameras in same class. Compare D800 and 5DmkIII, which are in the same class as the SLT-a99, for high ISO performance.

Moreover, in the text of the Conclusions section, they repeatedly praise the SLT-a99's "particularly" "excellent" high ISO performance.

What am I missing?

The multi-shot high ISO mode.

"The camera captures six images in a fraction of a second. Combining the data from all six, it creates a single image with a reduction in noise equivalent to two additional steps of ISO sensitivity"

Are you under the impression that the test shots was shot using MFNR ?

--

Cheers
Erland

Huh???

Did you read what I said? HE wants to know how the A99 could do better in low light. IBIS or MFNR is how. For Apples to Apples the D600 is close to 1 stop better though, which you can see at DxO or the DPR test shots or almost any review site.

You can disagree with DPReview's conclusions but based on the text...

What text? The text comparing the A99 to the other cameras in the DPR review says the A99 is behind. I quoted it my earlier post.

"By ISO 6400 the A99 displays image smearing that is noticeably more aggressive than both its Canon and Nikon rivals."

That sounds like the A99 is worse to me. You think it means better?

Could you please quote what Text you are talking about where they specifically mention comparing the single shot modes?

I double checked other reviews too. This is from Image Resource:

"we can see the Sony A99 lags the Canon 5D Mark III and Nikon D600 a bit in terms of high ISO noise"

To be far (as I said repeatedly), the A99 has both IBIS and MFNR.

 

[EinsteinsGhost]

Allan Olesen wrote:

EinsteinsGhost wrote:

Allan Olesen wrote:

EinsteinsGhost wrote:

Allan Olesen wrote:

Try this thought experiment:

1. You set your camera at ISO 1600, illuminate the sensor with a given light intensity and measure the SNR.
2. You set your camera at ISO 6400, illuminate the sensor with the same light intensity and measure the SNR.
3. SNR result turns out to be the same in both situations.

How does ISO influence on the measurement if the result is the same regardless of chosen ISO?

This behaviour is the reality for most cameras.

SNR will not stay the same.

Yes, it will. And this fact is really important for your understanding of the topic.

SNR will NOT be the same at ISO 1600 compared to ISO 6400.

I don't see any point in continuing this yes/no discussion.

Take two raw photos. One with ISO 6400, "correctly" exposed. One with ISO 1600, with the same exposure (same shutter speed, aperture and scene lighting) as the first photo.

Increase brightness of the second photo 2 stops in PP (using software which doesn't make optimization behind the scenes). Disable all noise reduction for both photos. Result: They will have the same amount of noise. And they will have the same brightness = amount of signal.

So your SNR is the same in the two photos.

Something I spoke about in one of the very first posts. In fact, here is an example of this at use (so I'm very much familiar with the idea):

Sony NEX-3, Minolta 200mm f/2.8G HS (LA-EA2), ISO 800, 1/640s

Left to its own decision making (Auto ISO), the camera would have used ISO 1600. So, I underexposed by 1-stop (could have done 2, which I actually did in some other frames but there wasn’t much need for it). But see, I kept the lens wide open (f/2.8)… one exposure variable. I kept the shutter speed reasonably high (1/640s), another exposure variable. So, why did I have to bump up exposure? Here comes the third variable that you say you don’t need, but, clearly use (by choosing ISO setting, you’re making that choice).

The above example is an illustration of what is referred to as “ISO-less shooting”. However, it isn’t quite a depiction of that as you take what you could with camera ISO and do it in post processing (RAW conversion). All that is being done here is utilizing a relative flat read noise curve, and in case of NEX-3 (camera used for the image above), that curve is relatively flat thru 800. Do you think I could have used ISO 1600, or 3200 for faster shutter speed, without losing anything? I hope not.

But, my point really has to do with using, not dismissing camera ISO, even if you use 200 over 400 or 800 or 1600. The question is, when do you use “DXO measured” 1600?

 

[EinsteinsGhost]

ultimitsu wrote:

EinsteinsGhost wrote:

But, DXO quotes its other ratings based on sensor ISO.

This sentence has no logical connection to the sentence below.

So, if a sensor that can absorb a lot of white light before reaching saturation, will have lower sensitivity to white light,

This makes no sense. the deeper the well result in high DR, nothing else. The only thing lowers sensitivity is lower efficiency on the sensor, or if there is a translucent glass absorbing some light before it hits the sensor.

But, you mess it up by using DXO ISO as it relates to the DR. Allow me to explain (note the two numbers in bold). At Camera ISO 100, we have the following DXO ISO:

A900: 119

A99: 61

IQ180: 29

At Camera ISO 200, we have DXO ISO:

A900: 151

A99: 114

IQ180: 60

At Camera ISO 400, we have DXO ISO:

A900: 303

A99: 227

IQ180: 120

So now, plot a DR curve using DXO ISO. Now you will see that IQ180 has a DR of 11.45 at ISO 120 (measured). A900 has 12.31. Shouldn't the deeper well in IQ180 be better?

which gets it lower sensor ISO which affects its low-light noise rating because, not exposure but sensor ISO is used to quote the measurements.

As per above, lower "sensor iso" is a product of bad efficiency of light gathering ability, it has nothing to do with well depth. A very sensitive sensor - one with very high QE, could very possibly have a very shallow well and gets blown quickly.

Whereas, out in the field, a person doesn't select sensor ISO, rather an ISO that computes to a proper exposure.

ISO is not part of exposure. the only three things have a play in exposure are:

1. scene luminance
2. aperture
3. shutter time
4. ISO is the standard of brightness of the final image.

Brightness Value (Scene Luminance) = Aperture Value + Time Value - Speed Value

The speed value is where ISO matters.

And even if one chooses to shoot ISO-less (as I occasionally do), we're still exposing for a particular exposure ISO. For example, I use ISO 400 or 800 to shoot NBA action, at 1/500-1/640s, f/2.8. This is 1-2 stops underexposed, compared to ISO 1600,

They are 1 or 2 stops darker than ISO 1600, but the exposure are exactly the same - 1/500s F2.8.

but without any consideration to DXO ISO.

What is DXO ISO?

 

[EinsteinsGhost]

Just Having Fun wrote:

TrojMacReady wrote:

Just Having Fun wrote:

The Nikon D600 image at ISO6400 is better focused (sharper) than the A99 at ISO3200.

Nice try. The d600 not only looks clearer and sharper

Like I said, anyone with eyes....

Anyone one with brains would realize I was talking about the DPR test pictures. The A99 shots for some reason are not focused very well which has nothing to do with the camera...

Why is that even an issue? Your brain seems to be suggesting that noise is only an issue in focused areas.

 

[EinsteinsGhost]

ultimitsu wrote:

EinsteinsGhost wrote:

Wally626 wrote: Why the DXO ISO ratings are scoring the new Sony cameras so low I do not know.

That is primarily because of the way DXO measures ISO and then uses it for other measurements. And this applies differently to RX1 than to A99.

ISO is an final output brightness standard. DXO measures how close is an camera's RAW at a given ISO setting to the ISO standard brightness. That however has no influence to ultimate scores.

For example when comparing DR at ISO 800, we are talking about the actual ISO 800 standard.

Why? DR as measured by DXO is at their measured ISO, not at camera ISO. Considering that so many of you consider Camera ISO as being irrelevant, why even use it at all?

at this ISO standard, A99's image would have 10.7 stop DR, you can obtain it by shooting ISO 800 setting, which would generate a RAW image with iso 439's brightness, and brighten it by 0.9 stop to ISO 800's brightness, or you could shoot at ISO setting of 1250, which would generate a RAW image with brightness of ISO 686, you can then brighten that by 0.3 stop to ISO 800's brightness, but in each case your SNR, DR, colour depth will probably be the same.

If sensor is tuned to, or by design, saturate early, it will have a lower DXO ISO. And as a result, all other measurements are impacted since DXO does not use exposure ISO for these ratings (whereas people assume they are one and the same).

The flaw in this statement had been addressed previously.

By your argument that a deeper well sensor will have a higher DR?

 

[Just Having Fun]

EinsteinsGhost wrote:

Just Having Fun wrote:

TrojMacReady wrote:

Just Having Fun wrote:

The Nikon D600 image at ISO6400 is better focused (sharper) than the A99 at ISO3200.

Nice try. The d600 not only looks clearer and sharper

Like I said, anyone with eyes....

Anyone one with brains would realize I was talking about the DPR test pictures. The A99 shots for some reason are not focused very well which has nothing to do with the camera...

Why is that even an issue?

"which has nothing to do with the camera"

It has nothing to do with the camera. It does make the D600 image look clearer and sharper, but IMHO that is the focusing....and not a real issue.

I am not sure why some here have a hard time understanding the whole "better focused (sharper)" thing. Better focused images will tend to look sharper. Not a difficult concept to grasp...except for some. LOL!

 

[RedSkiesAtNight]

EinsteinsGhost wrote:

Just Having Fun wrote:

TrojMacReady wrote:

Just Having Fun wrote:

The Nikon D600 image at ISO6400 is better focused (sharper) than the A99 at ISO3200.

Nice try. The d600 not only looks clearer and sharper

Like I said, anyone with eyes....

Anyone one with brains would realize I was talking about the DPR test pictures. The A99 shots for some reason are not focused very well which has nothing to do with the camera...

Why is that even an issue? Your brain seems to be suggesting that noise is only an issue in focused areas.

Why are the A99 shots softer? Lens? User error? Camera? Noise Reduction? This bugged me when I first saw them. Oh, the A99 does seems to have more noise in all areas, but it is an SLT and they know for this.

 

[EinsteinsGhost]

Just Having Fun wrote:

EinsteinsGhost wrote:

Just Having Fun wrote:

TrojMacReady wrote:

Just Having Fun wrote:

The Nikon D600 image at ISO6400 is better focused (sharper) than the A99 at ISO3200.

Nice try. The d600 not only looks clearer and sharper

Like I said, anyone with eyes....

Anyone one with brains would realize I was talking about the DPR test pictures. The A99 shots for some reason are not focused very well which has nothing to do with the camera...

Why is that even an issue?

"which has nothing to do with the camera"

It has nothing to do with the camera. It does make the D600 image look clearer and sharper, but IMHO that is the focusing....and not a real issue.

I am not sure why some here have a hard time understanding the whole "better focused (sharper)" thing. Better focused images will tend to look sharper. Not a difficult concept to grasp...except for some. LOL!

... low light performance. But, your brain is leading you to believe that this thread is about...?

 

[Just Having Fun]

EinsteinsGhost wrote:

Just Having Fun wrote:

EinsteinsGhost wrote:

Just Having Fun wrote:

TrojMacReady wrote:

Just Having Fun wrote:

The Nikon D600 image at ISO6400 is better focused (sharper) than the A99 at ISO3200.

Nice try. The d600 not only looks clearer and sharper

Like I said, anyone with eyes....

Anyone one with brains would realize I was talking about the DPR test pictures. The A99 shots for some reason are not focused very well which has nothing to do with the camera...

Why is that even an issue?

"which has nothing to do with the camera"

It has nothing to do with the camera. It does make the D600 image look clearer and sharper, but IMHO that is the focusing....and not a real issue.

I am not sure why some here have a hard time understanding the whole "better focused (sharper)" thing. Better focused images will tend to look sharper. Not a difficult concept to grasp...except for some. LOL!

... low light performance. But, your brain is leading you to believe that this thread is about...?

sybersitzen pointed out: "The difference between 1555 and 2980 is almost one full stop."

If you want to know what the thread is about, start there. I like so many others am agreeing.

dpyy said:

It's quite an easy exercise to test for yourself. Just go over to the dp test pages and setting the A99 to 3200 and D600 at 6400. And you will see that the noise is very comparable.

In other words, at high ISO A99 is one full stop behind Nikons/Canons FF.

 

[EinsteinsGhost]

Just Having Fun wrote:

EinsteinsGhost wrote:

Just Having Fun wrote:

EinsteinsGhost wrote:

Just Having Fun wrote:

TrojMacReady wrote:

Just Having Fun wrote:

The Nikon D600 image at ISO6400 is better focused (sharper) than the A99 at ISO3200.

Nice try. The d600 not only looks clearer and sharper

Like I said, anyone with eyes....

Anyone one with brains would realize I was talking about the DPR test pictures. The A99 shots for some reason are not focused very well which has nothing to do with the camera...

Why is that even an issue?

"which has nothing to do with the camera"

It has nothing to do with the camera. It does make the D600 image look clearer and sharper, but IMHO that is the focusing....and not a real issue.

I am not sure why some here have a hard time understanding the whole "better focused (sharper)" thing. Better focused images will tend to look sharper. Not a difficult concept to grasp...except for some. LOL!

... low light performance. But, your brain is leading you to believe that this thread is about...?

sybersitzen pointed out: "The difference between 1555 and 2980 is almost one full stop."

What and how do you use ISO 1555 or 2980 for?

If you want to know what the thread is about, start there. I like so many others am agreeing.

dpyy said:

It's quite an easy exercise to test for yourself. Just go over to the dp test pages and setting the A99 to 3200 and D600 at 6400. And you will see that the noise is very comparable.

In other words, at high ISO A99 is one full stop behind Nikons/Canons FF.

 

[EinsteinsGhost]

RedSkiesAtNight wrote:

EinsteinsGhost wrote:

Just Having Fun wrote:

TrojMacReady wrote:

Just Having Fun wrote:

The Nikon D600 image at ISO6400 is better focused (sharper) than the A99 at ISO3200.

Nice try. The d600 not only looks clearer and sharper

Like I said, anyone with eyes....

Anyone one with brains would realize I was talking about the DPR test pictures. The A99 shots for some reason are not focused very well which has nothing to do with the camera...

Why is that even an issue? Your brain seems to be suggesting that noise is only an issue in focused areas.

Why are the A99 shots softer? Lens? User error? Camera? Noise Reduction? This bugged me when I first saw them. Oh, the A99 does seems to have more noise in all areas, but it is an SLT and they know for this.

Ask DPR. They took the images. I get some VERY sharp images out of my "original SLT" (A55), so why exactly do you believe A99 has an "SLT issue"?

If there is an issue, chances are, A99 test was focused slightly differently than D600, or vice versa, or the lens needed a micro adjustment.

 

[JJLMD]

Just Having Fun wrote:

JJLMD wrote:

Just Having Fun wrote:

Eleson wrote:

Just Having Fun wrote:

JJLMD wrote:

Look for yourself. Go to Conclusions page of SLT-a99 review. Go to yellow bars graphs at bottom of page. They state specifically comparisons of yellow bars are valid for cameras in same class. Compare D800 and 5DmkIII, which are in the same class as the SLT-a99, for high ISO performance.

Moreover, in the text of the Conclusions section, they repeatedly praise the SLT-a99's "particularly" "excellent" high ISO performance.

What am I missing?

The multi-shot high ISO mode.

"The camera captures six images in a fraction of a second. Combining the data from all six, it creates a single image with a reduction in noise equivalent to two additional steps of ISO sensitivity"

Are you under the impression that the test shots was shot using MFNR ?

--

Cheers
Erland

Huh???

Did you read what I said? HE wants to know how the A99 could do better in low light. IBIS or MFNR is how. For Apples to Apples the D600 is close to 1 stop better though, which you can see at DxO or the DPR test shots or almost any review site.

You can disagree with DPReview's conclusions but based on the text...

What text? The text comparing the A99 to the other cameras in the DPR review says the A99 is behind. I quoted it my earlier post.

"By ISO 6400 the A99 displays image smearing that is noticeably more aggressive than both its Canon and Nikon rivals."

That sounds like the A99 is worse to me. You think it means better?

Could you please quote what Text you are talking about where they specifically mention comparing the single shot modes?

I double checked other reviews too. This is from Image Resource:

"we can see the Sony A99 lags the Canon 5D Mark III and Nikon D600 a bit in terms of high ISO noise"

To be far (as I said repeatedly), the A99 has both IBIS and MFNR.

In the conclusions sections of their review, DPReview makes note of the a99's high ISO performance THREE times:

1. "excellent high ISO output in both JPEG and Raw images"

2. "the a99 gives very good image quality, particularly so at high ISO sensitivities, placing it among the best performing full frame camers we've seen to date"

3. The a99 is good for "photographers looking for outstanding high ISO performance"

Then in their bar graph where they state explicitly that comparisons are valid for cameras in the same class, one can see that they rate the a99 HIGHER for high ISO performance than the Canon 5DmkIII as well as the Nikon D800.

Look, I'm not trying to argue that the a99 is superior to the Canon and Nikon. I would, however, argue to those worried that SLT technology will sigificantly hamper the a99's high ISO performance based on DXO's ISO metric that the world's best review site (IMHO) is quite impressed with the a99's high ISO performance. I also have the Sony RX1 which has the same sensor minus the SLT technology. Setting identical f-stop and shutter speed the auto ISO for the RX1 will set at 4000 whereas for the a99 will set at 5000. Advantage RX1? Yes. Sigificant difference in IQ? No.

 

[Just Having Fun]

JJLMD wrote:

Just Having Fun wrote:

JJLMD wrote:

Just Having Fun wrote:

Eleson wrote:

Just Having Fun wrote:

JJLMD wrote:

Look for yourself. Go to Conclusions page of SLT-a99 review. Go to yellow bars graphs at bottom of page. They state specifically comparisons of yellow bars are valid for cameras in same class. Compare D800 and 5DmkIII, which are in the same class as the SLT-a99, for high ISO performance.

Moreover, in the text of the Conclusions section, they repeatedly praise the SLT-a99's "particularly" "excellent" high ISO performance.

What am I missing?

The multi-shot high ISO mode.

"The camera captures six images in a fraction of a second. Combining the data from all six, it creates a single image with a reduction in noise equivalent to two additional steps of ISO sensitivity"

Are you under the impression that the test shots was shot using MFNR ?

--

Cheers
Erland

Huh???

Did you read what I said? HE wants to know how the A99 could do better in low light. IBIS or MFNR is how. For Apples to Apples the D600 is close to 1 stop better though, which you can see at DxO or the DPR test shots or almost any review site.

You can disagree with DPReview's conclusions but based on the text...

What text? The text comparing the A99 to the other cameras in the DPR review says the A99 is behind. I quoted it my earlier post.

"By ISO 6400 the A99 displays image smearing that is noticeably more aggressive than both its Canon and Nikon rivals."

That sounds like the A99 is worse to me. You think it means better?

Could you please quote what Text you are talking about where they specifically mention comparing the single shot modes?

I double checked other reviews too. This is from Image Resource:

"we can see the Sony A99 lags the Canon 5D Mark III and Nikon D600 a bit in terms of high ISO noise"

To be far (as I said repeatedly), the A99 has both IBIS and MFNR.

In the conclusions sections of their review, DPReview makes note of the a99's high ISO performance THREE times:

1. "excellent high ISO output in both JPEG and Raw images"

2. "the a99 gives very good image quality, particularly so at high ISO sensitivities, placing it among the best performing full frame camers we've seen to date"

3. The a99 is good for "photographers looking for outstanding high ISO performance"

Then in their bar graph where they state explicitly that comparisons are valid for cameras in the same class, one can see that they rate the a99 HIGHER for high ISO performance than the Canon 5DmkIII as well as the Nikon D800.

Look, I'm not trying to argue that the a99 is superior to the Canon and Nikon. I would, however, argue to those worried that SLT technology will sigificantly hamper the a99's high ISO performance based on DXO's ISO metric that the world's best review site (IMHO) is quite impressed with the a99's high ISO performance. I also have the Sony RX1 which has the same sensor minus the SLT technology. Setting identical f-stop and shutter speed the auto ISO for the RX1 will set at 4000 whereas for the a99 will set at 5000. Advantage RX1? Yes. Sigificant difference in IQ? No.

The A99 is better than any APS camera for high ISOs. The A99 has IBIS. The A99 has MFNR.

but...the A99 is not better nor as good and the Canon and Nikon offerings...if IBIS and/or MFNR is not used. Personally I love IBIS and it saves us all a lot of money as well let's us use slower shutter speeds.

 

[ultimitsu]

EinsteinsGhost wrote:

But, you mess it up by using DXO ISO as it relates to the DR.

You really need to :

A, get the idea of "DXO ISO" out of your head, there is no such thing.

B, educate yourself on what "ISO" is. I have explained it several times and I do not know what part of it you do not understand.

Allow me to explain (note the two numbers in bold). At Camera ISO 100, we have the following DXO ISO:

A900: 119

A99: 61

IQ180: 29

At Camera ISO 200, we have DXO ISO:

A900: 151

A99: 114

IQ180: 60

At Camera ISO 400, we have DXO ISO:

A900: 303

A99: 227

IQ180: 120

So now, plot a DR curve using DXO ISO.

What you call "Camera ISO" is not camera iso, but actual ISO standard.

What you call "DXO ISO" has nothing to do with DXO. it is the actual ISO measured in the RAW file.

Now you will see that IQ180 has a DR of 11.45 at ISO 120 (measured). A900 has 12.31. Shouldn't the deeper well in IQ180 be better?

What makes you think IQ 180 has a deeper well at RAW ISO 120 than A900 at RAW ISO 119?

which gets it lower sensor ISO which affects its low-light noise rating because, not exposure but sensor ISO is used to quote the measurements.

As per above, lower "sensor iso" is a product of bad efficiency of light gathering ability, it has nothing to do with well depth. A very sensitive sensor - one with very high QE, could very possibly have a very shallow well and gets blown quickly.

Whereas, out in the field, a person doesn't select sensor ISO, rather an ISO that computes to a proper exposure.

ISO is not part of exposure. the only three things have a play in exposure are:

1. scene luminance
2. aperture
3. shutter time
4. ISO is the standard of brightness of the final image.

Brightness Value (Scene Luminance) = Aperture Value + Time Value - Speed Value

The speed value is where ISO matters.

You are completely lost, buddy.