December 18, 2017, 08:07:26 AM

Author Topic: Further Confirmation of the PowerShot G1 X Mark III  (Read 6162 times)

docsmith

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Re: Further Confirmation of the PowerShot G1 X Mark III
« Reply #15 on: September 29, 2017, 09:03:33 AM »
The only advantage would be if the 1" sensor and lens combo was cheaper than the APS-C or full-frame versions.

At the risk of pointing out the obvious, the main advantage of APS-C over a smaller sensor is the larger size of the individual sensor pixels (assuming equivalent megapixels) meaning greater sensitivity and less noise.

The main DISADVANTAGE is that a f/3.1-4.8 zoom isn't as marketable as a f/1.8-2.8 zoom even if they are, as you say, identical.
Doesn't matter, the amount of light is still the same.

That's all good in theory, but in practice no it's not. For example, there are gaps between the pixel sensors where the transistors live, etc. So on larger sensors you're maximising the space for actual sensor as opposed to overheads. THe smaller your pixel pitch, the more light you lose 'through the gaps'.
Micro lenses when a long way to addressing the gaps between pixels.  I have not seen results on how effective they are, but I have seen some references years ago looking at sensors before and after and the sensors did make a significant improvement.  This is most evident in sensor efficiency that has been quantified and bottom line is that all sensors are getting pretty efficient in capture all the light that comes their way.

http://sensorgen.info/

There is absolutely something to the total amount of light gathered argument.  That is a reason I own the G7X II.  It has a f/1.8-2.8 lens.  It can gather a good amount of light to offset the size of the APS-C sensor especially considering M series lenses are pretty slow.

However, there is still a "quality" of pixel argument.  The best discussion I have seen on it was clarkvision, but the bottom line is that pixels can and do get small enough that "waves" of light enter the pixels less efficiently.

Also, I do fall back on my pragmatic experience.  I believe in using wider apertures on a smaller sensor to help compensate for light gathering ability, but bottom line, I prefer the images coming off my M3 (and 5DIII).  The G7XII is really very good.  But there are improvements with larger sensors.
« Last Edit: September 29, 2017, 09:27:23 AM by docsmith »

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Re: Further Confirmation of the PowerShot G1 X Mark III
« Reply #15 on: September 29, 2017, 09:03:33 AM »

traveller

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Re: Further Confirmation of the PowerShot G1 X Mark III
« Reply #16 on: September 29, 2017, 09:46:32 AM »
Sorry, but I'm not buying into the subjective "quality of pixels" argument. You can either measure it, or you can't: if you can't measure it then it isn't real. Sensor performance scales pretty well with area down to quite small pixel sizes and 1" sensor fall within this range:

https://www.dxomark.com/Cameras/Compare/Side-by-side/Canon-EOS-80D-versus-Sony-A6300-versus-Canon-PowerShot-G7-X___1076_1072_978

I've chosen a comparison between the G7X (the Sony RX100 V is very similar in performance) and the best performing APS-C sensors from Canon and Sony. The difference in the SNR should be about 1.66-1.76 stops, based upon the difference in sensor area and this is more or less exactly what we see in the graphs (click on the 'Measurements' tab).  There is an advantage for the larger sensors in terms of dynamic range where light levels are not a limiting factor (i.e. you can use low ISO and narrow apertures), but this is unfortunately offset by the fact that the current Canon 24MP APS-C sensor underperforms compared to Sony sensors in this respect by between 0.5-1 stop.

docsmith

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Re: Further Confirmation of the PowerShot G1 X Mark III
« Reply #17 on: September 29, 2017, 11:09:01 AM »
Sorry, but I'm not buying into the subjective "quality of pixels" argument. You can either measure it, or you can't: if you can't measure it then it isn't real. Sensor performance scales pretty well with area down to quite small pixel sizes and 1" sensor fall within this range:

https://www.dxomark.com/Cameras/Compare/Side-by-side/Canon-EOS-80D-versus-Sony-A6300-versus-Canon-PowerShot-G7-X___1076_1072_978

I've chosen a comparison between the G7X (the Sony RX100 V is very similar in performance) and the best performing APS-C sensors from Canon and Sony. The difference in the SNR should be about 1.66-1.76 stops, based upon the difference in sensor area and this is more or less exactly what we see in the graphs (click on the 'Measurements' tab).  There is an advantage for the larger sensors in terms of dynamic range where light levels are not a limiting factor (i.e. you can use low ISO and narrow apertures), but this is unfortunately offset by the fact that the current Canon 24MP APS-C sensor underperforms compared to Sony sensors in this respect by between 0.5-1 stop.
There is a lot going on, of course, but a higher density of pixels means more information moving through smaller spaces which has heat build up faster.  The actual pixel size we are talking about with many high density sensors is actually approaching the size of the wavelength of certain bands of light.  Pixels that can fit an entire wavelength are more efficient.  Pixels that don't, are less.  Microlenses are not perfectly efficient.  Then there is the size of the bucket argument.  If you have a 1 gal bucket and a 5 gal bucket, there is no difference if you are measuring 0.5 gals of water.  They are both great.  But try to measure 3 gal of water, the water overflows from the smaller bucket, but can still be quantified by the larger bucket.

Taking a step back, I actually agree with most of what you are saying.  To a very large extent, aperture can be used to offset sensor size and smaller sensor cameras can have faster lenses.  This is literally one of the reasons why I bought the G7X II.  This is actually supported by these articles.  As I said earlier, I think Clarkvision has some of the more interesting write ups on this subject.  You might like these:
http://clarkvision.com/articles/does.pixel.size.matter/
and he continues it here:
http://clarkvision.com/articles/does.pixel.size.matter2/
Basically, the sensors on these two (abeit older) cameras are different sizes but give very similar S/N ratios once normalized to size.  So, they test out similarly (hence the DXO test results).  Yet the smaller sensor was visibly nosier results.  Why?  If you read, it is actually because of the smaller lens having a smaller aperture diameters which, when set to the same aperture, is actually letting in less overall light.

So, another way to state this is if you set an aperture diameter to be the same, and if the sensor behaves ideally, then sensor size becomes irrelevant. 

But to think that sensors behave ideally or even the same is incorrect.  There are minor differences.  The one I see most often when going through photos is I simply have less headroom with the G7X II.  I attribute that to the "bucket" size being exceeded with smaller pixels.  But in midtones, I see very similar results.





ElBerryKM13

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Re: Further Confirmation of the PowerShot G1 X Mark III
« Reply #18 on: September 29, 2017, 01:16:13 PM »
Who is this camera really targeted to? Whatever it does it might be on par to an iphone 8 or any latest phone.
Wish canon focused more on the pro market and release more 4k cameras or a new 80d with 4k.

traveller

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Re: Further Confirmation of the PowerShot G1 X Mark III
« Reply #19 on: September 29, 2017, 01:49:06 PM »
There is a lot going on, of course, but a higher density of pixels means more information moving through smaller spaces which has heat build up faster.  The actual pixel size we are talking about with many high density sensors is actually approaching the size of the wavelength of certain bands of light.  Pixels that can fit an entire wavelength are more efficient.  Pixels that don't, are less.  Microlenses are not perfectly efficient.  Then there is the size of the bucket argument.  If you have a 1 gal bucket and a 5 gal bucket, there is no difference if you are measuring 0.5 gals of water.  They are both great.  But try to measure 3 gal of water, the water overflows from the smaller bucket, but can still be quantified by the larger bucket.

Taking a step back, I actually agree with most of what you are saying.  To a very large extent, aperture can be used to offset sensor size and smaller sensor cameras can have faster lenses.  This is literally one of the reasons why I bought the G7X II.  This is actually supported by these articles.  As I said earlier, I think Clarkvision has some of the more interesting write ups on this subject.  You might like these:
http://clarkvision.com/articles/does.pixel.size.matter/
and he continues it here:
http://clarkvision.com/articles/does.pixel.size.matter2/
Basically, the sensors on these two (abeit older) cameras are different sizes but give very similar S/N ratios once normalized to size.  So, they test out similarly (hence the DXO test results).  Yet the smaller sensor was visibly nosier results.  Why?  If you read, it is actually because of the smaller lens having a smaller aperture diameters which, when set to the same aperture, is actually letting in less overall light.

So, another way to state this is if you set an aperture diameter to be the same, and if the sensor behaves ideally, then sensor size becomes irrelevant. 

But to think that sensors behave ideally or even the same is incorrect.  There are minor differences.  The one I see most often when going through photos is I simply have less headroom with the G7X II.  I attribute that to the "bucket" size being exceeded with smaller pixels.  But in midtones, I see very similar results.
You should be careful when you compare different cameras because there is a lot going on behind the scenes in the RAW converter software. Unless you are comparing in a program like Rawdigger (https://www.rawdigger.com/main), it is quite dangerous to draw conclusions, especially about things like "headroom": are you really getting more headroom with camera A vs camera B, or is the manufacturer playing games with their ISO ratings and tone curves? 

okaro

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Re: Further Confirmation of the PowerShot G1 X Mark III
« Reply #20 on: September 29, 2017, 02:00:09 PM »
Who is this camera really targeted to? Whatever it does it might be on par to an iphone 8 or any latest phone.
Wish canon focused more on the pro market and release more 4k cameras or a new 80d with 4k.

Come in, I phone has some 7 mm sensor. APS-C sensor is way superior. Sure it may lack some gimmicks like artificial background blurring but in basic photography there is no comparison.

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Re: Further Confirmation of the PowerShot G1 X Mark III
« Reply #20 on: September 29, 2017, 02:00:09 PM »