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Author Topic: Canon 5D Mark III leaked photos  (Read 7119 times)
BJL
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« Reply #20 on: February 29, 2012, 05:58:37 PM »
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More like f5.6 or f6.3.
If you mean the threshold of some detectable effect on resolution. But that is near one end of the gray zone, sort of like taking the high tide mark as the end of the land and the start of the sea. And likewise, my f/11 might be like low tide, and on recalculating I will retract f/16 in favour of about 3x pixel pitch, or f/13.

[Edit:] The cambridgeincolour calculator http://www.cambridgeincolour.com/tutorials/diffraction-photography.html seems to give reasonable guidance once you check "set circle of confusion based on pixels".
« Last Edit: February 29, 2012, 06:04:55 PM by BJL » Logged
BernardLanguillier
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« Reply #21 on: February 29, 2012, 08:14:24 PM »
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If you mean the threshold of some detectable effect on resolution. But that is near one end of the gray zone, sort of like taking the high tide mark as the end of the land and the start of the sea. And likewise, my f/11 might be like low tide, and on recalculating I will retract f/16 in favour of about 3x pixel pitch, or f/13.

True.

We should compare a 36 mp camera at f11 to a 24mp camera at f6.3... my guess is that the level of detail will be very similar...

So those who intend to keep shooting at f11 will IMHO not see much value with a D800.

Cheers,
Bernard
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A few images online here!
BJL
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« Reply #22 on: February 29, 2012, 10:12:09 PM »
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I would be interested in comparisons at equal f-stop between cameras with sensors of the same size but different resolutions, like 16MP, 24MP vs 36MP for Nikon, and 18MP, 22MP and 45MP or whatever for Canon. Say comparing those several resolution options all at f/5.6, and all at f/8, and all at f/11. That would show which DOF choices can benefit from greater resolution, and by how much, and also at what stage there is little resolution gain (even though there could be other gains, like reduced aliasing and maybe less jaggies). It seems common opinion that there will be little resolution benefit in going beyond 22/24MP when you need f/16 to get your desired DOF, but f/11 and f/8 are controversial.

And if the limit is as low as f/8, when you look close enough to see all the exta detail that the resolution increase delivers, OOF effects will be clear outside a narrower range of subject distances than with standard viewing distance --- for 36MP+, only the same range of distances as with about f/4-5.6 for standard viewing distance.
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Michael West
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« Reply #23 on: February 29, 2012, 11:05:51 PM »
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 from China

http://www.spreecast.com/channels/phototips

8AM EST

amnouncement time

the stage looks pretty impressive.




« Last Edit: February 29, 2012, 11:07:33 PM by Michael West » Logged
uaiomex
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« Reply #24 on: February 29, 2012, 11:38:38 PM »
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Those are huge pictures. Does it mean the 22 mp rumor is wrong? Or they want to prove that 22 or 18 mp's are enough for really big pictures?
Eduardo

 
from China

http://www.spreecast.com/channels/phototips

8AM EST

amnouncement time

the stage looks pretty impressive.





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Michael West
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« Reply #25 on: March 01, 2012, 12:26:30 AM »
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only time will tell.
 
these are the specs posted on a chinese wbesite for the 5D X

http://detail.zol.com.cn

http://tinyurl.com/The-Canon-5D-X
 
Body features: full frame digital SLR
Effective pixels: 45 million
Release date: February 2012
Mode of operation: manual operation
Imaging Processor: DIGIC + DIGIC 4
Focus Points: 61 points

if these specs are real..this could be an interesting announcement

 
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Wayne Fox
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« Reply #26 on: March 01, 2012, 12:37:26 AM »
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yeah, those specs have been there for a while.  Actually at this point, I'd be very surprised if there are two significant versions ..

why would the stage be featuring powershots?  Those have all been refreshed quite recently ...  perhaps this is a stock photo of a previous event?

more rumblings the camera will only be 22mp and focus on enhancements in other areas such as ISO, shooting speed, overall image quality, dynamic range, much improved focusing, built in GPS, perhaps built-in wireless connectivity.  Not much of a "surprise" unless surprise means they have have left the megapixel race, which everyone has harped on this is the camera makers should go, then Nikon goes ahead, and now all the talk about no point in it seems to be cast aside. I've no problem with it, because I'll freely admit I've never been one of those, Personally I'm of the camp that the sensor should have so much resolution that the each lens actually becomes the limiting factor, and dialing out diffraction actually determines the "resolution" of each image. So I would be very disappointed in a 22mp 5D Mark3 ...it be more like a 5D mark 2.1 to me.

not much longer ...
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Michael West
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« Reply #27 on: March 01, 2012, 12:40:21 AM »
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The 5D mark 2.1  seems a possibility.

 
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bill t.
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« Reply #28 on: March 01, 2012, 01:25:12 AM »
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Read the graphics in the photo.  PowerShot A4090 IS.  Woohoo!  Maybe it's got 22mp, ya think?
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Ray
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« Reply #29 on: March 01, 2012, 01:48:00 AM »
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I would be interested in comparisons at equal f-stop between cameras with sensors of the same size but different resolutions, like 16MP, 24MP vs 36MP for Nikon, and 18MP, 22MP and 45MP or whatever for Canon. Say comparing those several resolution options all at f/5.6, and all at f/8, and all at f/11. That would show which DOF choices can benefit from greater resolution, and by how much, and also at what stage there is little resolution gain (even though there could be other gains, like reduced aliasing and maybe less jaggies). It seems common opinion that there will be little resolution benefit in going beyond 22/24MP when you need f/16 to get your desired DOF, but f/11 and f/8 are controversial.

I've already done such comparisons, BJL. A few years ago I made the mistake of jumping in too soon and getting a Canon 40D, not realising of course that Canon would release a significantly upgraded 50D a short time later, which I also couldn't resist buying. The 40D at 10mp is equivalent to a 26mp full-frame, and the 50D at 15mp is equivalent to a 39mp full-frame.

The target I used was an Australian $50 bill taped to a wall, and the lens used was the Canon 50/F1.4. With such tests at relatively close distances, focussing is absolutely critical. That was the main challenge. Both cameras have Live View, but the 40D's LCD screen is lower resolution than the 50D's screen. This fact alone created some doubt as to whether or not focussing was identical with both cameras, which were placed alternately on the same tripod in the same position after attaching the same lens.

To overcome such focussing problems, I simply relied upon moire and aliasing artifacts as my guide for best focus. The $50 bill has similar characteristics to any test target with fine lines. When focussing is 'spot on', there's always a blaze of colorful artifacts that appear in certain parts of the image, when the camera is within a particular range of close distances from the target.

From memory, the results of my tests were:

(1) At F5.6 the 40D was very marginally sharper than the 50D at F8, at extreme pixel-peeping levels of 200% or more on screen.

(2) At F11, the 50D was fully equal in resolution to the 40D at F8. In other words, the 50% increase in pixel-count of the 50D had fully compensated for the increased diffraction at F11.

(3) At F16, the 50D had about the same resolution as the 40D at F11. I say 'about' because the results were not quite as identical as the 50D at F11 compared with the 40D at F8. In other words, at 400% magnification on screen one got the impression that maybe the 40D shot was very, very slightly more detailed.

(4) At F22, the 50D image was noticeably softer than the 40D at F11. At F22 I believe diffraction has fully kicked in and no increase in pixel count could compensate for that, without also an increase in sensor size.

(5) Comparing both cameras at equal F stops, from F5.6 to F16, the 50D image was more detailed to varying degrees. The same should apply to comparisons between 26mp and 39mp full-frames, except at the edges and corners of course.


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Rhossydd
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« Reply #30 on: March 01, 2012, 03:13:29 AM »
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Those are huge pictures.
No they're not. It's just normal big TV screens, as seen at concerts etc. HDTV(2mp) at best.
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Derryck
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« Reply #31 on: March 01, 2012, 07:36:05 AM »
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I'm looking forward to heading down to Nanjing Rd tomorrow and watch Jackie Chan unveil the new 45mp Ixus.

Seriously though I'd be happy with a 5DIII that has 22 super clean megapixels for still images and better video that I don't have to worry about moire or aliasing. I can't remember the last time any of my clients reproduced my images larger than A2.
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BJL
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« Reply #32 on: March 01, 2012, 08:32:20 AM »
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Thanks Ray,
    item (5) is somewhat useful, but I am greedy: I want quantification of the resolution, and examples that I can view myself, all at equal image size. I suspect that in the end this requires printing crops of an equal portion of the comparison images at equal size, or upsizing to equalize output pixel counts before doing any 200% viewing.


(I deleted the rest of this post as it was a bit off-topic relative to what you were saying.)


P. S. To get comparisons that are guaranteed to be in focus, how does this sound: focus at a slight angle to the plane of a highly detailed subject like a brick wall from a distance, so that at worst, the plane of critical focus intersects the subject slightly away from the point where one tried to focus, but there is at least a strip that is precisely in focus.
« Last Edit: March 01, 2012, 08:52:19 AM by BJL » Logged
Ray
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« Reply #33 on: March 01, 2012, 09:11:08 AM »
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Observing that, for example, f/16 give less resolution than f/11 on the same sensor only shows that both diffraction and sensor resolution are limiting the overall resolution at f/16, leaving it very likely that an increase in sensor resolution would still give a worthwhile increase in overall resolution at f/16. My interest is knowing at what level of sensor resolution (MP or whatever) does one stop getting any increase in overall resolution from further increases in sensor resolution, holding f-stop constant.......

Perhaps I wasn't clear on the procedure. I wasn't comparing resolution of the same sensor at different f/stops, but the resolution from different sensors with different pixel densities, at the same and different f/stops.

Extrapolating the sensors in the cropped-format cameras that I used to full-frame size, the results as I recall indicate that at F22 a 39mp full-frame camera will have no resolution advantage over a 26mp full-frame, but at F16 it will. At F16 the 39mp camera delivers about the same resolution from the same lens as a 26mp camera produces at F11.

The test was carried out because at the time of the release of the 15mp 50D there was a lot of talk about such increased pixel density being of no advantage at apertures possibly smaller than F5.6 and definitely smaller than F8 because of the effects of diffraction. This concern proved to be unfounded. However, since I don't currently have access to the results, I can't remember with certainty whether that cut-off point for a 39mp full-frame sensor occurred perhaps 1/3rd of a stop before F22, at say F20. But there's no doubt that at F16 the 39mp sensor continued to deliver more resolution than the 'effective' 26mp sensor.
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BJL
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« Reply #34 on: March 01, 2012, 09:17:39 AM »
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Ray, sorry: I post to soon and then massively rewrote my response, focusing on the part of your post that helps me the most. I initially got of on a tangent about issues like not wanting to deal with comparisons of different cameras at different f-stops.

Extrapolating the sensors in the cropped-format cameras that I used to full-frame size, the results as I recall indicate that at F22 a 39mp full-frame camera will have no resolution advantage over a 26mp full-frame, but at F16 it will. At F16 the 39mp camera delivers about the same resolution from the same lens as a 26mp camera produces at F11.
Yes: the f/22 result is no surprise; it is already quite noticeably affected by diffraction limited in normal viewing of prints from film. At f/16, I hope to soon see for myself how much the advantage is of the latest round of sensor resolution increases.
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BJL
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« Reply #35 on: March 02, 2012, 07:02:47 AM »
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I would be really surprised if none of the announced cameras goes significantly beyond 24MP ...
So I have to confess: I am now officially really surprised!

My new guess is that Canon has decided to play to its strengths (video, action, low light?), fix the weaknesses that it easily can (AF, VF, body ruggedness vs the previous 5D models), and avoid areas where Sony and Nikon hold a solid lead right now (per pixel quality and processing speed with high resolution sensors).
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