Images & Specifications for PowerShot SX730 HS Leak Ahead of Launch

hendrik-sg

EOS RP
Apr 21, 2011
247
25
Nininini said:
hendrik-sg said:
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
 
May 19, 2016
6
0
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.
 

Talys

Canon 6DII
CR Pro
Feb 16, 2017
2,063
341
Vancouver, BC
anchorage said:
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

The dark side - I've been there
CR Pro
Nov 7, 2013
3,092
1,200
Germany
hendrik-sg said:
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.

Mt Spokane Photography said:
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
 

Tugela

EOS R
Feb 12, 2014
873
23
Nininini said:
hendrik-sg said:
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

EOS R
CR Pro
Dec 26, 2015
1,346
1,150
Turku, Finland
bedford said:
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

EOS R6
Jun 20, 2013
2,505
147
hendrik-sg said:
Nininini said:
hendrik-sg said:
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

Beware of cats with laser eyes!
Jun 4, 2012
8,265
1,927
Canada
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.....
 

Maximilian

The dark side - I've been there
CR Pro
Nov 7, 2013
3,092
1,200
Germany
Don Haines said:
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