How to properly compare RX-100 and NEX-6 kit high ISO noise?

Started Apr 29, 2013 | Discussions
FuzzyQball
Senior MemberPosts: 1,328Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to Vlad4D, Apr 30, 2013

Assuming the sensor technology is the same, the smaller sensor will never perform as well as the larger one.  This does not mean that the camera with the smaller sensor does not make good pictures in most cases.  I think a time will come where a smaller sensor will meet most needs.  The RX-100 is a great example of where technology is going.

-- hide signature --

Glenn

 FuzzyQball's gear list:FuzzyQball's gear list
Sony Alpha NEX-5N Sony E 18-55mm F3.5-5.6 OSS Sony E 55-210mm F4.5-6.3 OSS Sony E 16-50mm F3.5-5.6 PZ OSS
Reply   Reply with quote   Complain
FuzzyQball
Senior MemberPosts: 1,328Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to M. Mitchell, Apr 30, 2013

At F16 or 22 you will get defraction that will make the whole photo seem out focus on the NEX.  That is more likely the culprit in your picture quality.

-- hide signature --

Glenn

 FuzzyQball's gear list:FuzzyQball's gear list
Sony Alpha NEX-5N Sony E 18-55mm F3.5-5.6 OSS Sony E 55-210mm F4.5-6.3 OSS Sony E 16-50mm F3.5-5.6 PZ OSS
Reply   Reply with quote   Complain
Mel Snyder
Veteran MemberPosts: 3,439Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to Vlad4D, Apr 30, 2013

Vlad4D wrote:

Mel Snyder wrote:

"Reciprocity" - which those of us from the film era knew well - is key to dynamic range in sensors as well as film. The sensitivity of sensors and film is not linear. The NEX "jams" the reciprocity curve on only one factor, because it cannot open to an aperture wider than f3.5. That forces the worst case for the reciprocity of the NEX sensor. The RX-100 faces no such single-factor jam.

Yes, it forces worse scenario for NEX. But this was one of the points of the test: will the NEX manage to overcome limited aperture problem with a help of bigger sensor? Seems like no - it only managed to be about the same as RX or little worse (on wide end)

It's not just the "limited sensor/bigger sensor" - it's the way each measures the scene - as I pointed out in the part of my message you didn't mention. That's why the left edge of the RX-100 is overexposed.

This is especially prejudicial because you allowed the cameras to "choose" ISO 3200, which has a horrible dynamic range - anyone who has actually shot much at ISO 3200 understands that it's horrific on subjects with considerable peak-to-trough lighting challenges. Again, you jam the test against the NEX, but favor the RX-100 because it can admit more light.

It is possible that ISO800 on RX-100 is doing internally exactly same signal amplification as ISO3200 on NEX. Similar noise levels partially proves that. So most likely dynamic range should be also similar. It is just my assumption ...

These tests are absurd on the face of it, anyway. One device is an optimized tiny camera that is best of class. The other is an interchangeable lens mirrorless that is, in the opinion of all but the MFT crowd, best of class. Comparing the NEX and RX-100 is as absurd as if someone with a digital Hasselblad came came onto the forum and said, "let's compare." To which I'd say, "sure, I'll put my RX-100 in my pocket, you put your Hasselblad in yours, and let's go test cameras."

I think comparing always makes sense - it helps us to find right tool for our hobby or work.

Perhaps - but this kind of test doesn't prove anything. A camera optimized for a single lens versus one that can handle thousands of lenses? And a scene specifically picked to handicap one and favor the other? That's the way Florida Republicans set polling locations and hours.

Anyone for actually taking photos instead of optical arm-wrestling?

This is brand specific and actually camera line specific forum, and of course people discuss technical aspects here. For pure art we have several other forums on dpreview.com. But by some reason they are no so active as for example this one

Nice picture

Thanks. But this test isn't a technically balanced comparison. If you picked a scene that nullified the differences in metering systems, then - perhaps - the test might have been valid. But as I noted, the scene you selected favored the heavily center-weighted RX100, which is why the left edge blew out, but was properly exposed with the NEX-6. From that point on, the test proves nothing.

NEX-6 with 50mm Summicron, f2.8

 Mel Snyder's gear list:Mel Snyder's gear list
Sony Alpha NEX-6 Sony Alpha 7 Sony E 16mm F2.8 Pancake Tokina AT-X Pro 11-16mm f/2.8 DX Leica Summicron-M 50mm f/2 +13 more
Reply   Reply with quote   Complain
twald
Regular MemberPosts: 491Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to Mel Snyder, Apr 30, 2013

Mel Snyder wrote:

Vlad4D wrote:

Mel Snyder wrote:

"Reciprocity" - which those of us from the film era knew well - is key to dynamic range in sensors as well as film. The sensitivity of sensors and film is not linear. The NEX "jams" the reciprocity curve on only one factor, because it cannot open to an aperture wider than f3.5. That forces the worst case for the reciprocity of the NEX sensor. The RX-100 faces no such single-factor jam.

Yes, it forces worse scenario for NEX. But this was one of the points of the test: will the NEX manage to overcome limited aperture problem with a help of bigger sensor? Seems like no - it only managed to be about the same as RX or little worse (on wide end)

It's not just the "limited sensor/bigger sensor" - it's the way each measures the scene - as I pointed out in the part of my message you didn't mention. That's why the left edge of the RX-100 is overexposed.

This is especially prejudicial because you allowed the cameras to "choose" ISO 3200, which has a horrible dynamic range - anyone who has actually shot much at ISO 3200 understands that it's horrific on subjects with considerable peak-to-trough lighting challenges. Again, you jam the test against the NEX, but favor the RX-100 because it can admit more light.

It is possible that ISO800 on RX-100 is doing internally exactly same signal amplification as ISO3200 on NEX. Similar noise levels partially proves that. So most likely dynamic range should be also similar. It is just my assumption ...

These tests are absurd on the face of it, anyway. One device is an optimized tiny camera that is best of class. The other is an interchangeable lens mirrorless that is, in the opinion of all but the MFT crowd, best of class. Comparing the NEX and RX-100 is as absurd as if someone with a digital Hasselblad came came onto the forum and said, "let's compare." To which I'd say, "sure, I'll put my RX-100 in my pocket, you put your Hasselblad in yours, and let's go test cameras."

I think comparing always makes sense - it helps us to find right tool for our hobby or work.

Perhaps - but this kind of test doesn't prove anything. A camera optimized for a single lens versus one that can handle thousands of lenses? And a scene specifically picked to handicap one and favor the other? That's the way Florida Republicans set polling locations and hours.

Anyone for actually taking photos instead of optical arm-wrestling?

This is brand specific and actually camera line specific forum, and of course people discuss technical aspects here. For pure art we have several other forums on dpreview.com. But by some reason they are no so active as for example this one

Nice picture

Thanks. But this test isn't a technically balanced comparison. If you picked a scene that nullified the differences in metering systems, then - perhaps - the test might have been valid. But as I noted, the scene you selected favored the heavily center-weighted RX100, which is why the left edge blew out, but was properly exposed with the NEX-6. From that point on, the test proves nothing.

NEX-6 with 50mm Summicron, f2.8

I don't think that the cameras' metering is so much different, rather, it is just too dark for the NEX with the  kit lens to make a brighter picture that looks good, and the engineers knew it. At a certain point (ISO 3200, 1/25 for the NEX) cameras algorithms determine that a dark image will look better than one with a balanced histogram. ISO 3200 is as high as auto ISO will go and slower shutter speed begins to blur; it balances exposure with other aspects of image quality.

I recon that if light were to drop even further, the RX100 would make a darker picture and not maintain an ideal exposure either. I do understand your point, though; you are saying that a fair comparison would have been to drop the ISO of the RX100 to 1600 so that the cameras expose equally. The problem is that the NEX image already has more noise than the RX100 does. As I understand it, this noise is not caused by sensor inefficiencies, but rather, it is an accurate representation of the actual image; the photons are noisy because there are too few of them.

The RX100 is not mine; it is a friend's and I borrowed it for a try. I will try to make a better comparison when I have time, but it won't be today or tomorrow.

Don't expect a great difference from a another comparison. The Zeiss is a very nice lens that actually lets in a bit more light than the NEX kit lens, and it is coupled to a superb (if small) sensor. I also did an outdoors test in good lighting and discovered that it outresolves the NEX-5n at base ISO simply by virtue of more megapixels.

Two areas where the NEX--again with a kit lens--wins are dynamic range and color depth. I think the NEX raw files are a bit more malleable; they are easier to tweak in post-processing without completely ruining colors or contrast.

Reply   Reply with quote   Complain
danny006
Contributing MemberPosts: 814Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to Vlad4D, Apr 30, 2013

Vlad4D wrote:

danny006 wrote:

At 50mm (NEX-6) you get a F5.6, the RX100 gives a F4, so 1 stop difference. There is a 1 stop difference in noise, in favour for the NEX-6. If you look at these crops (imaging-resource), ISO800 for the RX100 and ISO1600 for the NEX-6, there is almost no difference, not in detail and not in noise.

Agree - no difference, because it is same picture (from NEX-6) copied twice

But anyway thank you very much for your research, it proves my initial assumption.

It also means that friend of mine who just have bought NEX-3N would be happier with RX-100

It is not the same picture, exif is not correct.

-- hide signature --

www.alex-digitalpics.be by Sony

 danny006's gear list:danny006's gear list
Sony RX100 Sony SLT-A77 Tamron SP AF 200-500mm F/5-6.3 Di LD (IF) Sigma 105mm F2.8 EX DG Macro
Reply   Reply with quote   Complain
Erik Magnuson
Forum ProPosts: 11,719Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to captura, Apr 30, 2013

captura wrote:

Erik Magnuson wrote:

captura wrote:

Some irrefutable law of physics should allow that the smaller sensored camera, in this case the RX-100, will have more pixel density, therefore much smaller pixels and resulting higher noise.

Nope, that's not the laws of physics.  Pixel size has little relation to noise - total sensor size and pixel efficiency (q3, fill factor, color filter loss) matters more.  For example, the NEX7 has smaller pixels than the NEX5 and also has lower read noise.  (See http://www.sensorgen.info/)

For the same reason, an APS-C sensor should outperform an m43, and a FF outperform an APS-C, all things being equal.

In the case of the RX-100, all else is not equal.  It has a very efficient sensor.

-- hide signature --

Erik

I disagree.

- borrowed from clarkvision.com

His data and/or analysis is obsolete.  The measurements from modern sensors do not match his theory.  If you want another opinion, try http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/noise-p3.html

"It was shown that for fixed sensor format, the light collection efficiency per unit area is essentially independent of pixel size, over a huge range of pixel sizes from 2 microns to over 8 microns, and is therefore independent of the number of megapixels."

This has been discussed many times on this site, mainly in  Open Talk, e.g. http://www.dpreview.com/forums/post/51322621

There are two main sources of noise: read noise and shot noise.  Shot noise is a principle of light and so dependent on sensor area and independent of the pixels.  Read noise depends on pixel design and can be measured as shown on the sensorgen.info site.   The data there is clear and newer than what Dr. Clark uses.

-- hide signature --

Erik

 Erik Magnuson's gear list:Erik Magnuson's gear list
Canon EOS 5D Mark II Canon EOS 450D Sigma SD10 Sony Alpha NEX-5 Nikon D3200 +24 more
Reply   Reply with quote   Complain
Vlad4D
Regular MemberPosts: 219Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to Mel Snyder, Apr 30, 2013

About differences in exposure:

In my opinion on both cameras RAW exposure was set to best possible for such low light test. Both cameras were set to widest aperture and some predefined and reasonable shutter speed. So both cameras were able to change only ISO and yes - they picked ISO differently what caused ever-exposure for one camera BUT only for JPEG - not for RAW. ISO value is not affecting RAW at all. AFAIU it is just software post-multiplier and it is not affecting over- or under- exposure of RAW. So we took those "virgin" RAW files and adjusted brightness so that both images have about same exposure. Those 2 final images in the end have very close exposure (or brightness) and IMO they CAN be used for judgment about low light capabilities or RX-100 vs  NEX+kit combo (even if initial JPEG exposure was different of wrong)

Vlad

 Vlad4D's gear list:Vlad4D's gear list
Sony Alpha NEX-6 Sony E 18-200mm F3.5-6.3 OSS Sony E 50mm F1.8 OSS Sony E 16-50mm F3.5-5.6 PZ OSS Sony E 35mm F1.8 OSS
Reply   Reply with quote   Complain
Vlad4D
Regular MemberPosts: 219Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to blue_skies, Apr 30, 2013

blue_skies wrote:

Vlad4D wrote:

danny006 wrote:

At 50mm (NEX-6) you get a F5.6, the RX100 gives a F4, so 1 stop difference. There is a 1 stop difference in noise, in favour for the NEX-6. If you look at these crops (imaging-resource), ISO800 for the RX100 and ISO1600 for the NEX-6, there is almost no difference, not in detail and not in noise.

Agree - no difference, because it is same picture (from NEX-6) copied twice

But anyway thank you very much for your research, it proves my initial assumption.

It also means that friend of mine who just have bought NEX-3N would be happier with RX-100

Vlad, under same lighting, both cameras would expose the same way.

If so, the Nex picture 'feels' more impressive, due to the shallower DOF, even with the kit lens.

I agree, but I wanted to compare only noise levels.

In your comparison, you also assume that the aperture (wide open) and shutter speed are 'maxed' out (at 1/60th), and that the camera will have to then increase ISO to match exposures.

Sensor sensitivity roughly relates by area, the APS-C is about 2.5x the size of the 1" RX-100 sensor, or the sensor sensitivity compares by root(3)=1.6x. That is about a stop-and-a-half.

This translates in ISO 800 on the RX-100 being roughly equal to ISO 2400 on the Nex.

True, but at the same time smaller sensor allows stop-and-a-half faster lens and in the end we have same amount of noise like with APS-C sensor and APS-C lens

And you noticed that the aperture drops off faster at tele-zoom for the Nex than for the RX-100, so there is slight aperture advantage for the RX-100 - but this is much less than a full stop, so not a big contributor.

Then, on non-moving objects, you can add in the OSS/OIS controls on both cameras and how they compare, and also add in the prime lenses on the Nex that have a 2-stop advantage over the zoom lenses at certain focal lengths.

What I am trying to say is that a Nex-3N with kit lens still has advantages over the RX-100, except for size and reach. The RX-100 is quite a bit smaller and definitely a very desirable 'pocket-camera'.

What I am trying to say is that low light capabilities of tiny sensor cameras like RX-100 is not worse than ANY!!! APS-C camera with typical kit zoom lens (18-50mm F3.5-5.6) and this is completely opposite to the general opinion in the net.

 Vlad4D's gear list:Vlad4D's gear list
Sony Alpha NEX-6 Sony E 18-200mm F3.5-6.3 OSS Sony E 50mm F1.8 OSS Sony E 16-50mm F3.5-5.6 PZ OSS Sony E 35mm F1.8 OSS
Reply   Reply with quote   Complain
Vlad4D
Regular MemberPosts: 219Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to danny006, Apr 30, 2013

Ok, sorry for my joke in this case

 Vlad4D's gear list:Vlad4D's gear list
Sony Alpha NEX-6 Sony E 18-200mm F3.5-6.3 OSS Sony E 50mm F1.8 OSS Sony E 16-50mm F3.5-5.6 PZ OSS Sony E 35mm F1.8 OSS
Reply   Reply with quote   Complain
Vlad4D
Regular MemberPosts: 219Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to M. Mitchell, Apr 30, 2013

That's normal. In some cases when huge DOF is needed the iPhone can do better picture than huge and expensive FF DSLR.

 Vlad4D's gear list:Vlad4D's gear list
Sony Alpha NEX-6 Sony E 18-200mm F3.5-6.3 OSS Sony E 50mm F1.8 OSS Sony E 16-50mm F3.5-5.6 PZ OSS Sony E 35mm F1.8 OSS
Reply   Reply with quote   Complain
Vlad4D
Regular MemberPosts: 219Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to CosmoZooo, Apr 30, 2013

Thanks for the info, it seems my question was already answered many times

 Vlad4D's gear list:Vlad4D's gear list
Sony Alpha NEX-6 Sony E 18-200mm F3.5-6.3 OSS Sony E 50mm F1.8 OSS Sony E 16-50mm F3.5-5.6 PZ OSS Sony E 35mm F1.8 OSS
Reply   Reply with quote   Complain
calterg
Regular MemberPosts: 419
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to Vlad4D, May 1, 2013

Vlad4D wrote:

There is common opinion that small sensor is bad for low light. But small sensor also allows to use smaller lens with bigger aperture value.

For example maximum aperture on RX-100 at 10mm (28mm equiv.) is F1.8. NEX-6 with kit lens can do only around F4.0 at 19mm (28mm equiv.). It means RX-100 sensor can gets about 2 stops more light than NEX-6 sensor? Am I right?

There is also a multiplier for the aperture, which advertising companies take care to ignore.

The rx-100 at 10 mm has a multiplier of 2.8 to get ff equivalent of 28mm; therefore also multiply its F1.8 by also 2.8, resulting in an equivalent aperture of F5.0.

The Nex 6 has a multiplier of 1.5, therefore its equivalent aperture is F4.0 x 1.5 = F6.0 at 28mm.

So it is an advantage of less than a third of a stop and not 2 stops at 28mm.

You just can't help loving the advertising industry.

Reply   Reply with quote   Complain
Jonn Quest
Regular MemberPosts: 300
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to calterg, May 1, 2013

What happens as you move from wide angle toward normal or tele focal lengths?

Reply   Reply with quote   Complain
tomhongkong
Senior MemberPosts: 2,401
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to calterg, May 1, 2013

Calterg

This seems to be an increasingly common  misunderstanding which has been brought about by some sites comparing DOF for lenses used on sensors of different sizes.

Let's get it straight.  An F2.8 lens is F2.8, whether it is used on a pinhead sensor P&S or on a Hasselbad medium format.  If you use an FF lens on an aps-c body or RX100 (if you could) you do not alter the maximum aperture.

It is common to multiply the focal length to compare the effective field of view. (so the equivalent FOV in FF terms of a 100mm lens used on a aps-c 1.5x crop body is that of a 150mm lens).  However the true focal length of the lens (in simple terms how far the lens has to be from the sensor to get a sharp image) does not vary.

This article explains the concept of DOF and says it better than I would

http://photo.net/learn/optics/dofdigital/

I hope this helps

tom

Reply   Reply with quote   Complain
CosmoZooo
Regular MemberPosts: 446
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to calterg, May 1, 2013

That logic is only relevant to DOF calculation not light gathering ability which is what this discussion is centered around.

If you perceive the multiplier as relevant to the effective lens speed or brightness as some refer that is an incorrect logic and one I have fallen for in the past. If you look at my previous post, you will find a link to that discussion. As far as light gathering ability per pixel f1.8 is indeed f1.8 and f3.5 is still that. NEX compensates by having a better sensor but the actual lens is faster on the RX100 across the entire range, but aside from the smallest focal lengh the NEX kit plus APS-C combo will be better.

Reply   Reply with quote   Complain
2eyesee
Senior MemberPosts: 1,260
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to CosmoZooo, May 1, 2013

CosmoZooo wrote:

That logic is only relevant to DOF calculation not light gathering ability which is what this discussion is centered around.

If you perceive the multiplier as relevant to the effective lens speed or brightness as some refer that is an incorrect logic and one I have fallen for in the past. If you look at my previous post, you will find a link to that discussion. As far as light gathering ability per pixel f1.8 is indeed f1.8 and f3.5 is still that. NEX compensates by having a better sensor but the actual lens is faster on the RX100 across the entire range, but aside from the smallest focal lengh the NEX kit plus APS-C combo will be better.

It's not that the NEX 'compensates by having a better sensor' - it's just that the NEX has a much larger sensor so it can gather more light, which compensates for it's slower lens.

Sensor sizes:

RX100
13.2mm x 8.8mm = 116.2 mm squared

NEX-6
23.5 x 15.6 mm = 366.6 mm squared

The NEX-6 sensor is therefore 3.2x larger than the RX100 sensor so gathers 3.2x the amount of light - which is around 1.66 stops.

At its widest focal length, the RX100 is around 2 stops faster then the NEX with kit lens (f/1.8 vs f/3.5), but as the NEX sensor gathers 1.66 stops more light this leaves the RX100 with a 1/3 stop advantage.

At the tele end, the RX100 is around 0.4 stops faster than the NEX with kit lens (f/4.9 vs f/5.6), but again as the NEX gathers 1.66 stops more light this leaves the NEX with the advantage this time of around 1.3 stops.

Reply   Reply with quote   Complain
GaryW
Veteran MemberPosts: 6,789Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to Mel Snyder, May 1, 2013

Mel Snyder wrote:

M. Mitchell wrote:

I spent yesterday shooting landscape and flower pictures with my Nex 6 and Rx100. I noticed something about shooting with each camera that is not mentioned in this discussion. Using my Nex6, I had to stop down to f/16 or even f/22 to attain the depth of field that I had at f/4 or f/ 5.6 with my RX100. In landscape

You shouldn't need f/22.  I don't know if this is hyperbole to make a point, but I would have thought f8 or f11 at the most would be equivalent.  Anything more than f11 and diffraction will adversely affect the result, which may explain your lack of sharpness.

photography I prefer a very wide depth of field keeping every thing sharp from closeup to infinity.  This required that I use a slower shutter speed with the Nex6, resulting at times with an unsharp photo. I had no unsharp photos with the higher shutter speeds of the RX100.

The day was slightly windy. Because I could use a faster shutter speed with the RX100, I could only use that camera for the flower pictures.

Are you surprised? The RX-100 has a 10.4-37.1mm lens. The NEX-6 has a 16-50mm. OF COURSE you have to stop down a longer lens to get the same DOF of a shorter focal length lens.

Let's make the test fair. Take the lens off the RX-100 and put my 11-16mm Tokina on both cameras. Then we can compare apples to apples.

It may not be apples to apples, but the RX-100 is what it is, and should be tested as it is.  Of course the Nex is being purposefully limited by forcing it to only use the kit lens, but it is a test.  Either the Nex plus kit lens is inferior at 18mm or it is not.

Now does it matter?  At 30mm or 50mm, the cameras may be equal.  With another lens, the Nex is now ahead.

But if I wanted a really small, portable P&S camera, I'd have to put the RX-100 at the top of the list, to be sure.

-- hide signature --

Gary W.

 GaryW's gear list:GaryW's gear list
Sony Alpha NEX-6 Sony E 16-50mm F3.5-5.6 PZ OSS Sony Cyber-shot DSC-V3 Sony Cyber-shot DSC-HX5 Sony Alpha DSLR-A100 +10 more
Reply   Reply with quote   Complain
Vlad4D
Regular MemberPosts: 219Gear list
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to calterg, May 1, 2013

This math looks correct to me. But only if we compare efficiency of lens+sensor combos (not just lens or just sensors). Third of a stop advantage of RX-100 on wide end is approximately same what we got in real world test made by twald.

 Vlad4D's gear list:Vlad4D's gear list
Sony Alpha NEX-6 Sony E 18-200mm F3.5-6.3 OSS Sony E 50mm F1.8 OSS Sony E 16-50mm F3.5-5.6 PZ OSS Sony E 35mm F1.8 OSS
Reply   Reply with quote   Complain
CosmoZooo
Regular MemberPosts: 446
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to 2eyesee, May 1, 2013

Allright 2eyesee let's have that discussion:

First of you're preaching to the choir: I perfectly understand that NEX is APS-C sensor but not only you're arguing semantics - you're just incorrect in a number of ways in your assessment of that sensor advantage. "Better" is a very general word which in this case implies many characteristics such as size, DR, ISO performance etc. which is a much better way to characterize the advantage of the NEX-5R sensor over RX100 then larger.

We all know that APS-C sensor performance is not the same across all APS-C size sensors...you see where I am going with this. Sony sensors are some of the best ones right now. It is not that the sensor gathers more light overall because that simply implies a larger area: each of the photo sensitive sites on that sensors that correspond to pixels perform better - each one gathers more light then the equivalent pixels on RX100. That is one misconception in your statement.

Second is your pointless math which would imply that every APS-C size sensor would have a 1.66 stops advantage over RX100 which is obviously false. There are many APS-C sensors that do not perform nearly as well as NEX sensors and would not carry the same advantage over RX100 as NEX. Even NEX-7 which packs more pixels onto the sensor would not carry the same advantage as NEX-5R sensor. Just think about the sensor scores on the DXOmark RX100 scores close to 400 on the ISO while NEX-5R almost 1000. Again not just the sensor size that matters here.

Which brings us to your third misconception about assigning a static value to the sensor advantage.    ISO performance is not necessarily linear if you look at DXO graphs as such the stop advantage could become even larger as the two sensors continue to push up the ISO scale. And the number you quantified is definitely meaningless because you based it on the size rather then actual sensor performance.

Theoretically speaking the small sensors of tomorrow may outperform the large sensors of today. Of course their larger counterparts will still keep the lead but my point here that ultimately its sensor performance that matters not sensor size which may or may not be a factor depending on which sensors are being compared.

For example the RX100 may already outperform or come extremely close to some of the significantly larger m43 sensors from previous generations.

Reply   Reply with quote   Complain
2eyesee
Senior MemberPosts: 1,260
Like?
Re: How to properly compare RX-100 and NEX-6 kit high ISO noise?
In reply to CosmoZooo, May 1, 2013

CosmoZooo wrote:

Allright 2eyesee let's have that discussion:

First of you're preaching to the choir: I perfectly understand that NEX is APS-C sensor but not only you're arguing semantics - you're just incorrect in a number of ways in your assessment of that sensor advantage. "Better" is a very general word which in this case implies many characteristics such as size, DR, ISO performance etc. which is a much better way to characterize the advantage of the NEX-5R sensor over RX100 then larger.

We all know that APS-C sensor performance is not the same across all APS-C size sensors...you see where I am going with this. Sony sensors are some of the best ones right now. It is not that the sensor gathers more light overall because that simply implies a larger area: each of the photo sensitive sites on that sensors that correspond to pixels perform better - each one gathers more light then the equivalent pixels on RX100. That is one misconception in your statement.

The individual photosite size is not so relevant on modern sensors with gapless pixels - it's the total amount of light gathered by the lens that's the most important factor in determining noise levels/DR. I'm no expert but I have been corrected on this in another thread and upon further investigation it seems to be true for modern sensors.

Second is your pointless math which would imply that every APS-C size sensor would have a 1.66 stops advantage over RX100 which is obviously false. There are many APS-C sensors that do not perform nearly as well as NEX sensors and would not carry the same advantage over RX100 as NEX. Even NEX-7 which packs more pixels onto the sensor would not carry the same advantage as NEX-5R sensor. Just think about the sensor scores on the DXOmark RX100 scores close to 400 on the ISO while NEX-5R almost 1000. Again not just the sensor size that matters here.

My math was not pointless, but it was a gross over-simplification as a comparison as it was only dealing with the light-gathering capabilities of the RX100 vs NEX with kit lens, not sensor performance.

Which brings us to your third misconception about assigning a static value to the sensor advantage.    ISO performance is not necessarily linear if you look at DXO graphs as such the stop advantage could become even larger as the two sensors continue to push up the ISO scale. And the number you quantified is definitely meaningless because you based it on the size rather then actual sensor performance.

Theoretically speaking the small sensors of tomorrow may outperform the large sensors of today. Of course their larger counterparts will still keep the lead but my point here that ultimately its sensor performance that matters not sensor size which may or may not be a factor depending on which sensors are being compared.

I wasn't talking about sensor size - I was talking about the light gathering capabilities of each system, which will be a huge factor in determining image quality. And as my math showed a small sensor with fast lens (at least wide on the RX100) can be at an advantage over a large sensor with a slow lens.

Of course it doesn't take into account lens quality and sensor performance, but it's a worthwhile exercise to see how much light each sensor has to work with.

Even though my math was an over-simplification, it's interesting to note it essentially agrees with your first post on this thread:

"I'd say even comparing kit for kit NEX-6 wins overall, IMO...unless we are talking specifically at their lowest focal lengths at which RX100 has a slight lead."

For example the RX100 may already outperform or come extremely close to some of the significantly larger m43 sensors from previous generations.

Reply   Reply with quote   Complain
Keyboard shortcuts:
FForum MMy threads