December 15, 2017, 01:59:53 AM

Author Topic: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch  (Read 12588 times)

Nininini

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #15 on: April 04, 2017, 05:00:19 PM »

Would it (in theory) be possible to use deconvolution to (partly) compensate for diffraction?

There's more and more processing power in digital cameras available, so why not use it?

Oliver

Don't see why not. They used to think the human eye was the most detail one could ever resolve with electronics, it was assumed human eyes were diffraction limited and our eyes were perfect.

Until a biologist invented a trick to test how much detail birds were resolving. He used 2 panels, one with a grating and one without, and switched them around. The one with the grating had food behind it. The grating was made 5 times smaller than a human eye could see, yet the bird still managed to choose the grated panel with the food behind it, proving some birds can resolve 5 times more detail than human eyes. This test has become quite popular, there are most likely birds who can resolve 20x times what humans can. We are not even close to that with current sensors.

Birds can see things from miles away, yet they don't have a telephoto lens, they just resolve an enormous amount of detail and manage to overcome any diffraction limits.
« Last Edit: April 04, 2017, 05:08:06 PM by Nininini »

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #15 on: April 04, 2017, 05:00:19 PM »

IglooEater

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #16 on: April 04, 2017, 05:06:01 PM »
I have owned a number of these little jewels. People can say they will not get you great images. But IMHO they are still a heck of a lot better then the latest smart phone/camera on the market. And smartphones are what are taking over the market these days..

I would not dislike to have one of these.  Something more versatile than a cellphone but still fits in my pocket. 

photonius

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #17 on: April 04, 2017, 05:18:31 PM »
Sadly, the new SX PowerShot camera we told you was coming isn’t a replacement for the PowerShot SX60 HS, and a lot of people are going to wish it was.</p>
<p>Instead we get the PowerShot SX730 HS, a compact 40x zoom camera. There is something pretty cool about a 1000mm equivalent camera that will fit in your coat pocket.</p>
<p><span class="goog-text-highlight">PowerShot SX 730 HS Specifications (Google Translated0</span></p>
<ul>
<li><span class="goog-text-highlight">Number of effective </span><span class="goog-text-highlight">pixels: </span><span class="goog-text-highlight">approximately 20.3 </span><span class="goog-text-highlight">million pixels </span></li>
<li><span class="goog-text-highlight">Focal length: 4.3-172.0mm (24-</span><span class="goog-text-highlight">960mm in terms of 35 mm)</span></li>
<li><span class="goog-text-highlight">Lens Speed: F3.3 – </span><span class="goog-text-highlight">6.9</span></li>
<li><span class="goog-text-highlight">Color: Black / Silver</span></li>
</ul>

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<span id="pty_trigger"></span>

probably again no GPS.  These cameras are made for light travel/hiking, where GPS could be useful (sometimes no obvious landmarks). No, don't want to use the phone gps hooked up to camera, save it's batteries for other things.

anchorage

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #18 on: April 04, 2017, 09:14:18 PM »
If the given specifications for the SX 730 are correct, then I don’t understand the reasoning behind them:

From the numbers shown, and assuming a 4:3 aspect ratio, we can conclude that the camera’s sensor is approximately 6.5 mm wide with 5200 pixels across.  This means the size of the pixels is 1.3 µm.  With an aperture of f/3.3 to f/6.9 at the short and long ends of the zoom range diffraction prevents the lens from resolving details smaller than 2.2 to 3.6 µm, or 1.7 to 3.3 pixels.  The effective image resolution will be on the order of 4 Mpixels for wide-angle and 1.5 Mpixels for telephoto shots.

Image processing might improve the resolution somewhat, but with pixels as small as in this device photon shot noise will make recovering real detail very difficult except in situations with very bright light.  Aggressive edge enhancement can make photos look sharper, but the apparent detail will be an illusion.

Note that high end cellphones such as the Google Pixel or the iPhone 7 have sensors as large as the one in the SX 730, but with fewer pixels, and the phones have lenses with an aperture around f/2 in order to make the optical resolution of the device match the sensor resolution.

Unless you really need that superzoom, you will most likely get better images with a cellphone.  Even a 2x digital zoom picture on a 12 MPixel cellphone camera is close to the resolution you’ll get out from an equivalent SX 730 shot.

Talys

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #19 on: April 05, 2017, 12:04:45 AM »
If the given specifications for the SX 730 are correct, then I don’t understand the reasoning behind them:

From the numbers shown, and assuming a 4:3 aspect ratio, we can conclude that the camera’s sensor is approximately 6.5 mm wide with 5200 pixels across.  This means the size of the pixels is 1.3 µm.  With an aperture of f/3.3 to f/6.9 at the short and long ends of the zoom range diffraction prevents the lens from resolving details smaller than 2.2 to 3.6 µm, or 1.7 to 3.3 pixels.  The effective image resolution will be on the order of 4 Mpixels for wide-angle and 1.5 Mpixels for telephoto shots.

Image processing might improve the resolution somewhat, but with pixels as small as in this device photon shot noise will make recovering real detail very difficult except in situations with very bright light.  Aggressive edge enhancement can make photos look sharper, but the apparent detail will be an illusion.

Note that high end cellphones such as the Google Pixel or the iPhone 7 have sensors as large as the one in the SX 730, but with fewer pixels, and the phones have lenses with an aperture around f/2 in order to make the optical resolution of the device match the sensor resolution.

Unless you really need that superzoom, you will most likely get better images with a cellphone.  Even a 2x digital zoom picture on a 12 MPixel cellphone camera is close to the resolution you’ll get out from an equivalent SX 730 shot.

The SX720 has similar specs: f/3.3-6.9, 5184x3888, 4.3-172mm (35 mm equivalent: 24-960mm), and it takes WAY better pictures than an iPhone 6 or Galaxy S7 when you compare it in a variety of situations.

The most obvious is zoom.  You can't have a wide focal range without having moving glass elements, and you can't have great magnification if you can't put separation between the lenses.  So even if you don't need the full superzoom, at most levels of magnification, you're just going to get better IQ out of larger lenses.  It's just way easier to do.

The second is the size of the sensor.  Just like a FF camera takes much better pictures at low ISO than an APS-C, smartphones get stomped on low light.  Pretty much all low light shots have to be taken with the phone camera flash, which is joke if you want to get a good picture beyond happy memories.  There is no way to remedy this on a smartphone, other than build a bigger sensor, and that's not going to happen for all sorts of reasons.

So, if you're taking pictures on a boat while sipping margaritas, yeah, the smartphone will take as good a photo as anything.  But if you're trying to take photos in darker conditions or catch your kid closer up during a soccer game, the SX is going to win out every time.

Having goofed around with the current model, the SX720 -- I think it's a pretty nice point and shoot.  I prefer the Sxxx because it's a little smaller and easier on the pocket (especially in the summer, when I don't have a coat on), but if I didn't so often have a DSLR within grabbing range, I'd consider an SXxxx.  Either way... I'll take the camera with the lenses that extend a few inches to give me a better shot over my cell phone.

hendrik-sg

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #20 on: April 05, 2017, 12:58:16 AM »
For this pixed density the system is clearly diffraction limited, which means it has no possibility to take sharp pics even with a really good lens.

You don't understand how diffraction works in the real world.

The amount of detail you gain from adding more pixels more than makes up for the small detail you lose due to diffraction.

It reminds me of those people who complain that "lenses can't resolve that amount of pixels". These people don't understand that even the worst lens in the world will be able to capture more detail, regardless how bad the lens you put in front of the sensor is.

Thanks for your friendly judgement. I understand difraction quite well, in oposite to most others i could calulate with it and understand the physical basics. From what you want to say (beside qualifying my statement) you are mostly right, but you did not understand my point.

At the diffraction limit you have the same loss from diffraction and from limited sensor resolution (and the bayer filter reduces the sensor resolution even more. This means with a pixel density higher than the diffraction limit the system resolution converges towards the diffraction limit, below the diffraction limit it converges to the sensor resolution. this means every stop of sensor resolution gives less benefit than the last one. a sensor this dense may have a diff limit around 2.8. having a lens with opening 40 this sensor is definitively overkill.

A less long lens with a brighter opening 500mm with f20 equiv than 1000mm with f40 will resolve the same detail but be much less prone to camera shake. As as most people do not have a 1200mm FF lens few owners of 1200mm superzoom camera will have a high end tripod, they will hand hold the camera. At home they may be faszinated of the tight framing (which maybe not contains the intended target) or be frustrated about blurred images.

i remember a friend who (as a beginner) went on safaro with a 24MP APSC camera and a stabilized 300mm F5.6 lens, he did not bring home even one sharp 300mm shot

anchorage

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #21 on: April 05, 2017, 01:25:01 AM »
Talys, there's no doubt that the SX 730 camera will be able to take beautiful pictures, and the zoom is certainly extremely useful.  It's just interesting that the sensor has 20 million pixels when the lens doesn't appear to have a matching level of resolution.

Regarding low light, if the specifications (4.3 mm focal length being equivalent to 24 mm on a full-frame DSLR) are accurate, then the sensor in the SX 730 is no larger than what you'll find in a good cellphone camera, so it is not clear how it could perform better in a dim environment, especially since phone lenses typically have a larger aperture.
« Last Edit: April 05, 2017, 02:23:22 AM by anchorage »

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #21 on: April 05, 2017, 01:25:01 AM »

Talys

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #22 on: April 05, 2017, 02:45:21 AM »
Talys, there's no doubt that the SX 730 camera will be able to take beautiful pictures, and the zoom is certainly extremely useful.  It's just interesting that the sensor has 20 million pixels when the lens doesn't appear to have a matching level of resolution.

Regarding low light, if the specifications (4.3 mm focal length being equivalent to 24 mm on a full-frame DSLR) are accurate, then the sensor in the SX 730 is no larger than what you'll find in a good cellphone camera, so it is not clear how it could perform better in a dim environment, especially since phone lenses typically have a larger aperture.

This is different from my understanding of lens being diffraction-limited (not to say that this one isn't), but I'm no expert on it, so I'm certainly not going to argue the point.  I did not think that diffraction limits would be an issue at f/4-ish numbers even with that sensor size.

I think the SX has a sensor size of 1/2.5" or 1/2.3", whereas the iPhone 6 has a 1/3".  Keep in mind the SX720 is about $350 (way less than the iPhone 6), and something that the average person will see a significantly longer useful lifespan for than any cellphone.

Of course, you make a perfectly valid point, that has turned into greatly reduced compact camera sales:  If zoom isn't important, and you generally snap pictures in reasonable conditions, and you have a flagship smartphone, you probably don't need a compact camera from anyone.  Those are 3 pretty big ifs, but they're also not very uncommon ones, and even if you don't have a flagship smartphone, or you care a little bit about zoom, the smartphone camera, for example, on the $150 Motorola G4 might be just fine.

It's also inarguable that smartphone cameras have really narrowed the gap with compact cameras: they've gotten a lot better, while compact cameras haven't improved *nearly* as much, as we can see in the SX730, which seems pretty similar to the SX720. 

Maximilian

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #23 on: April 05, 2017, 03:02:50 AM »
so maybe this has a 1/2.3 sensor is my guess, is 20MP and has a 6.9 lens at the long end.
...
When you take a look at the technical data of the PowerShot SX720 HS you'll see that this new camera has per datasheet the same sensor (1/2.3") and the same lens. (4.3 – 172.0 mm/f3.3–6.9)

Maybe there is also some optical improvement in sensor and lens. But except for the tilting screen I'd expect most changes in the electronic part.

Its a entry level super zoom and sells very well.  If you are going to produce a camera the masses want for the price they want, there will be compromises.  I'm sure that most who buy one will be very happy.  Those who want a $20,000 rig for a few hundred --???
+1
« Last Edit: April 05, 2017, 03:04:56 AM by Maximilian »
sometimes you have to close your eyes to see properly.

Tugela

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #24 on: April 05, 2017, 05:00:13 AM »
For this pixed density the system is clearly diffraction limited, which means it has no possibility to take sharp pics even with a really good lens.

You don't understand how diffraction works in the real world.

The amount of detail you gain from adding more pixels more than makes up for the small detail you lose due to diffraction.

It reminds me of those people who complain that "lenses can't resolve that amount of pixels". These people don't understand that even the worst lens in the world will be able to capture more detail, regardless how bad the lens you put in front of the sensor is.

High density sensors suffer from light scattering on the beyer filter, resulting in purple fringing around highlights. Small sensors will always have poor IQ as a result of that, no matter how good the lens on the camera is.

Sharlin

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #25 on: April 05, 2017, 07:14:58 AM »
Would it (in theory) be possible to use deconvolution to (partly) compensate for diffraction?

There's more and more processing power in digital cameras available, so why not use it?

Canon is already ahead of you ;) Diffraction correction using embedded point spread functions is available as a part of the DLO (Digital Lens Optimization) feature, included in some new cameras such as the 5D4 and also in Canon DPP. It's still quite slow though so don't expect to see it in consumer compacts any time soon.

rrcphoto

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #26 on: April 05, 2017, 01:09:46 PM »
For this pixed density the system is clearly diffraction limited, which means it has no possibility to take sharp pics even with a really good lens.

You don't understand how diffraction works in the real world.

The amount of detail you gain from adding more pixels more than makes up for the small detail you lose due to diffraction.

It reminds me of those people who complain that "lenses can't resolve that amount of pixels". These people don't understand that even the worst lens in the world will be able to capture more detail, regardless how bad the lens you put in front of the sensor is.

Thanks for your friendly judgement. I understand difraction quite well, in oposite to most others i could calulate with it and understand the physical basics. From what you want to say (beside qualifying my statement) you are mostly right, but you did not understand my point.

it's not really on a pixel pitch or mp's but it depends on the size of the resultant image, and the observer distance.  so for most use cases on a pocket camera, which is facebook, instagram,etc it's not diffraction limited and perfectly fine.


Don Haines

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #27 on: April 05, 2017, 04:54:23 PM »
Wasn't it DXO that came up with the idea of measuring lens sharpness in megapixels? That alone should tell you that it a useless and misleading metric.....

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #27 on: April 05, 2017, 04:54:23 PM »

Maximilian

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #28 on: April 06, 2017, 02:44:12 AM »
Wasn't it DXO that came up with the idea of measuring lens sharpness in megapixels? That alone should tell you that it a useless and misleading metric.....
*lol* that made my day  ;D
sometimes you have to close your eyes to see properly.

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Re: Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch
« Reply #28 on: April 06, 2017, 02:44:12 AM »