241
EOS Bodies / Re: The Next 5D on February 27/28, 2012 [CR3]
« on: February 22, 2012, 07:02:49 PM »
Change it to 1.6 crop, f/8 AF sensors, and everything else the same for $1,700 and I might be in. For this, I'll keep my 5D (not II).
June 19, 2013, 12:34:31 AM
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242
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 15, 2012, 10:00:28 PM »Where, pray tell, has it been "confirmed" all over the place that pixel size has nothing to do with ISO noise performance?
Smaller pixels perform better at high-ISO all the way until read noise starts to dominate (which is way, way out there for most sensors). These were shot at the same ISO, same shutter speed, same f-stop, same focal length, both use the same sensor area, both were shot in raw and processed in the same software. The pixel area is different by a factor of 16. The processed images on the far right column tell the story - the smaller pixels preserved more detail with less noise than the bigger pixels did even though they were set at their maximum ISO.
http://photos.imageevent.com/sipphoto/samplepictures/Pixel%20density%20test%20results.jpg
That test is extremely poorly done.
And yet, you have nothing to say what about it was poor except that the answer isn't what you expected it to be. Two cameras, same generation, same f-stop, shutter speed, focal length, ISO, light level, sensor size, capture method and processing. The only significant difference is the pixel size, and it's different by such a large amount (factor of 16) that it swamps out other minor effects.
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The reality of the situation is that generally the more pixels you have, the more noise a camera will have. Not because the pixels somehow cause the noise, but because it reduces the light gathering ability of the camera's sensor. To actually put more pixels on a sensor you have to make the pixel wells themselves smaller.
And there's more of them. The overall effective fill factor is about the same between the 5D and the G12. So I wouldn't hang the hat of your argument on that issue.
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It's like dividing a house up into rooms. A house with just one big room has a lot more space than a house with walls everywhere. On top of that the current generation of sensors has the wiring for the pixels on the front of the sensor, meaning the more pixels you have the more wiring you have which isn't capturing photons.
House rooms don't have microlenses.
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So in general assuming everything is equal more pixels means more noise.
No. It means the pixels have more noise, and the sensor has the same photon capture with more detail.
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The test you posted obviously has the variables skewed to show otherwise likely by comparing a body which isn't very advanced to one that is. Furthermore most camera manufacturers lie about their iso settings to the point where they are inflated by 80% in many cases. So the camera is shooting at iso 900 but it says iso 1600 on the display. So comparing cameras outside a lab setting isn't very useful.
None of that is relevant because f-stop, shutter speed and focal length were the same. Thus, the number of photons that struck the sensor was the same. ISO calibration is irrelevant.
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Anyways I encourage people to read about the quantum efficiency of a sensor:
http://www.sensorgen.info/
Often times a camera will go up from on generation to another both in reducing noise and increasing resolution, like the 1D III to the 1D IV through superior sensor design. Other times you have cases like the D3s and D3x where the D3x has twice as much noise and twice as much resolution than the D3s.
The sensors I tested were of the same generation and of about the same QE.
243
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 15, 2012, 08:51:52 PM »Where, pray tell, has it been "confirmed" all over the place that pixel size has nothing to do with ISO noise performance?
Smaller pixels perform better at high-ISO all the way until read noise starts to dominate (which is way, way out there for most sensors). These were shot at the same ISO, same shutter speed, same f-stop, same focal length, both use the same sensor area, both were shot in raw and processed in the same software. The pixel area is different by a factor of 16. The processed images on the far right column tell the story - the smaller pixels preserved more detail with less noise than the bigger pixels did even though they were set at their maximum ISO.
http://photos.imageevent.com/sipphoto/samplepictures/Pixel%20density%20test%20results.jpg
Ok, let's say this is correct (I'm not buying this as I can point to 1000 other examples of images taken where this is not the result). Can you explain why comparisons of exactly the same RAW images taken with a 5Dmk2 at ISO 3200 are so much cleaner than the 7D?
Because the comparison isn't done correctly. It's not done with the same sensor area used. It's done with both at 100% or both full-frame. Neither is correct if you're talking about pixel density. If you change nothing but pixel density, you have to assume the same amount of sensor area is used. If you do that, you'll find your 7D out-performs your 5DII. The reason the 5DII is better overall is because it has more sensor area.
Incidentally, those images I posted were from the 5D and the Canon S3IS compact. The compact won easily when the 5D didn't have the advantage of it's massively larger sensor.
I'll need some time to wrap my head around what you are saying....been a long day at the office. Let me digest that, but if you can post a use-case as an illustration, that would help.
Just what we're talking about - 1Dx versus D800. Same sensor size, different pixel size.
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One question as a background item: do you know what the SNR is per pixel on say the 5Dmk2 and the 7D? My BSEE head says the smaller pixels (photodiodes) have more leakage (assuming similar generation sensors, not old stuff vs. new stuff) than larger ones and hence more noise.
My MSEE head says leakage is a very, very minor issue on the very large pixels (and not much related to noise anyway). Remember, the state-of-the-art in pixel design is for cell phone cameras - 1-1.5 microns. 4-7 micron pixels like we use in our dSLRs are enormous by comparison.
Since you're an engineer, I can explain very easily why smaller pixels are better, as long as read noise doesn't dominate.
What do large pixels do compared to small ones? Spacial block averaging. Now, which do you think is more effective at preserving detail and removing noise, spacial block averaging or modern noise reduction algorithms? The answer is obvious - no one could sell any noise reduction software if it couldn't beat the daylights out of a simple block average approach, which is close to the lousiest filter you can imagine!
244
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 15, 2012, 07:49:30 PM »Where, pray tell, has it been "confirmed" all over the place that pixel size has nothing to do with ISO noise performance?
Smaller pixels perform better at high-ISO all the way until read noise starts to dominate (which is way, way out there for most sensors). These were shot at the same ISO, same shutter speed, same f-stop, same focal length, both use the same sensor area, both were shot in raw and processed in the same software. The pixel area is different by a factor of 16. The processed images on the far right column tell the story - the smaller pixels preserved more detail with less noise than the bigger pixels did even though they were set at their maximum ISO.
http://photos.imageevent.com/sipphoto/samplepictures/Pixel%20density%20test%20results.jpg
Ok, let's say this is correct (I'm not buying this as I can point to 1000 other examples of images taken where this is not the result). Can you explain why comparisons of exactly the same RAW images taken with a 5Dmk2 at ISO 3200 are so much cleaner than the 7D?
Because the comparison isn't done correctly. It's not done with the same sensor area used. It's done with both at 100% or both full-frame. Neither is correct if you're talking about pixel density. If you change nothing but pixel density, you have to assume the same amount of sensor area is used. If you do that, you'll find your 7D out-performs your 5DII. The reason the 5DII is better overall is because it has more sensor area.
Incidentally, those images I posted were from the 5D and the Canon S3IS compact. The compact won easily when the 5D didn't have the advantage of it's massively larger sensor.
245
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 15, 2012, 06:56:13 PM »Where, pray tell, has it been "confirmed" all over the place that pixel size has nothing to do with ISO noise performance?
Smaller pixels perform better at high-ISO all the way until read noise starts to dominate (which is way, way out there for most sensors). These were shot at the same ISO, same shutter speed, same f-stop, same focal length, both use the same sensor area, both were shot in raw and processed in the same software. The pixel area is different by a factor of 16. The processed images on the far right column tell the story - the smaller pixels preserved more detail with less noise than the bigger pixels did even though they were set at their maximum ISO.
http://photos.imageevent.com/sipphoto/samplepictures/Pixel%20density%20test%20results.jpg
246
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 15, 2012, 09:04:28 AM »Regarding the argument of 22MP not being enough to replace the 7D - because a 1.6x crop would not give enough pixels - Canon will probably argue that users should use a 1.4x TC to get the extra reach. - I am not saying this will get the results people are looking for - just that that is what I would expect Canon to argue.
And if I already use 3 stacked 1.4x TCs (or a 2x stacked with a 1.4x) on my 18MP 1.6-crop camera?
We don't have nearly enough pixel density right now to exploit good optics, especially in the center of the image circle.
The other problem with that argument is that they aren't proving f/8 AF sensor, making the TCs occasionally useless. Added pixel density doesn't have that problem.
247
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 14, 2012, 09:13:23 AM »All the same specs are coming in. 22mp, 61pt af, 6.9fps. It could definitely take the spot of the 7D, if the previous rumor is true.
Sorry - wrong. When I'm focal-length or magnification limited, I want pixel density, not pixel count. At 22MP, it could replace the 20D, but it would need 46MP to replace the 7D and, frankly, I want more pixel density than that, not less. This is why it either needs to be really high in pixel count or they need a 7D replacement too, preferably above 22MP.
248
Lenses / Re: A Lens Roadmap? [CR1]
« on: February 11, 2012, 10:08:49 AM »
For me, I think it no longer matters. I bought the 70-200/2.8L IS II and 2x TC III since I got sick of waiting for a 100-400L replacement. The 24-70/2.8L II has no IS so it's a non-starter to replace my 24-105. My 35L is so good I can't figure out why I'd ever replace it. My Sigma 15mm fisheye is a stop faster than the Canon 8-15 zoom fisheye, and the Sigma is an L-prime optically. The 17-40L and 85/1.8 get very little use but both are pretty solid performers when I need them. The most interesting new lens I'm looking at is a 2,800mm f/10 or a 2032mm f/8, and neither is from Canon.
249
PowerShot / Re: Canon PowerShot D20
« on: February 06, 2012, 08:59:05 PM »
So, 28-140mm equivalent f/3.9-4.8 and a 1/2.3" sensor I'm guessing?
250
PowerShot / Re: Canon PowerShot D20
« on: February 06, 2012, 08:56:00 PM »What was odd about the D10? It seems like a standard P&S in a water-sealed case?
What's with that nipple on the upper left?
http://3.s.img-dpreview.com/products_data/products/canon_d10/shots/canon_d10.jpg?v=1323
And that bulge on the left side?
http://1.s.img-dpreview.com/products_data/products/canon_d10/shots/top.jpg?v=1323
251
PowerShot / Re: Canon PowerShot SX240 HS Spotted
« on: February 03, 2012, 02:12:38 PM »ugh, who cares, just use your iphone. we want the new 5D!
No joke. If I could just get my iphone 4S to shoot in RAW I'd be good. The camera on that thing really is pretty awesome.
If you don't mind fixed focal length, slow performance, awful controls, and virtually no flexibility.
I'll keep my Elph 500HS, thanks.
252
PowerShot / Re: Canon PowerShot SX240 HS Spotted
« on: February 03, 2012, 11:45:07 AM »
f3.5 - f/6.8?
Grrrr.......
This whole "who can have the most x-zoom" race is really taking its toll on lens speeds. These little sensors need lens speed desperately. Heck, at these focal lengths and pixel densities even shooting in direct sun is often going to put you into IS territory if you want pixel-level detail.
Grrrr.......
This whole "who can have the most x-zoom" race is really taking its toll on lens speeds. These little sensors need lens speed desperately. Heck, at these focal lengths and pixel densities even shooting in direct sun is often going to put you into IS territory if you want pixel-level detail.
254
Software & Accessories / Re: Lightroom 4 Beta now available
« on: January 11, 2012, 11:48:23 AM »it does not even put the metadata in the fields for city etc. when you have geotagged an image.
Reverse geotagging will be enabled in the final version.
255
PowerShot Cameras / Re: *UPDATE 3* Canon PowerShot G1X Revealed
« on: January 07, 2012, 05:59:17 PM »But given the f/16 spec...
So...here's a question. Even a very low (<6) MP APS-C sensor is diffraction-limited at f/16.
No, they aren't.
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Why can EF-S lenses be stopped down to at least f/22 and in many cases to f/38?
Because sometimes DOF or correct exposure are more important than preservation of detail.
Note that many planetary astrophotographers use 40D-sized pixels, and shoot at f/30 or so for maximum detail (they get the slow f-numbers by using barlows [teleconverters], not by stopping down - the aperture is always wide open on most telescopes).