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Question: megapixel
5 megapixel - 14 (3.9%)
10 megapixel - 67 (18.8%)
15 megapixel - 91 (25.6%)
20 megapixel - 60 (16.9%)
25 megapixel - 47 (13.2%)
30 megapixel - 18 (5.1%)
35 megapixel - 59 (16.6%)
Total Voters: 29

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Author Topic: megapixel  (Read 26767 times)
williamrohr
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« Reply #60 on: June 12, 2005, 02:47:17 PM »
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The fact of the matter is that film, digital imagining chips and our eyes are all sensors ... imperfect ones at that.  They are all bandwidth limited and therefore only represent an approximation of all the photons being reflected/absorbed from the world around us.  Obviously we are primarily interested in devices which capture and store information that maximally stimulates our sensors (in this case our eyes).  Our retinas are composed of rods (sensitive to black & white or luminance) and cones (sensitive to color).  Even the cones are developed into different regions that have different spectral sensitivities.  Today's dominant technologies (CMOS and CCD) utilize some gymnastics (as in bayer mosaics and blur filters) to enable us to generate our beautiful pictures.  In the process they color/alter the information content, but alas with pleasing results.  Certainly for the vast majority of the populace (that was absolutely happy with Kodak instamatics .... and who were basically interested in storing a memory of an event and displacing it in time) today's technology is "good enough".  The work by the folks at Foveon and Fuji suggest paths for refinement of the current capture medium (note that their technologies tackle the issues of spatial color resolution and luminance) and further suggets a bright future for digital.
    I have a contact print of Ansel Adam's Bridal Veil Falls on my wall ... when a hand-holdable digital camers can match the richness and detail of that print ... I'll be happy, regardless of the pixel count.  
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ddolde
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« Reply #61 on: July 17, 2005, 10:14:42 AM »
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I think it's funny that the highest choice was 35mp and now Phase One has announced 39mp.   39 would certainly be enough for me.
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Jonathan Wienke
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« Reply #62 on: August 31, 2005, 10:23:54 PM »
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Well, I would say you are simply repeating the myth. A printed image will appear the same regarless of size if the ratio of the print size and viewing distance is kept the same. It is a simple geometric problem based on the angular resolution of the eye - which is how circles of confusion and depth of field is calculated as well. That does not mean a low resolution image will not look rough, but its appearance is the same when the ratio of size to distance remains the same.
So what?

It's not a myth that if you take a 3000x2000 pixel image and a 600x400 pixel image and print them both at 16x24 and hang them on a wall side by side, the quality difference will be extremely obvious. And it's not a myth that given the fairly standard hanging-on-the-wall-at-arm's-length home/gallery viewing condition most under which most framed prints are exhibited, prints from a 1Ds or MF back can be printed larger than those from a 6MP camera and still maintain an acceptable level of image quality per unit of print area. Yes, you can get away with a lower print PPI standard as viewing distance increases, but at any given viewing distance, a file with more pixels (all else being equal) is going to make a better-looking print than one with fewer.

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The tests you are refering to do not specify the resolving power of the CCD (or film). Those test show the resolving power of the system - CCD (film), lens, aperture. There are tests to determine the resolving power of film, but no standard that I am aware of has been developed for CCDs or CMOS (although the manufactures must be making some assumptions to design their lenses).

While this is technically true, in practice one can measure the resolution of the sensor if one uses a lens that has a decent MTF at spatial line frequencies higher than the pixel pitch of the sensor. In that case, the sensor (or more precisely the anti-aliasing filter over the sensor, if applicable) will be the primary bottleneck limiting the resolution of the image. As noted previously, the pixel pitch of the sensor imposes a hard limit to the amount of fine detail that can be captured in an image, and this limit can be approached, but not quite reached, due to lens imperfections and the AA filter. But if the lens is good enough, the error it introduces into the measurement process is small enough that it does not significantly compromise the usefulness of the results. How do you think film manufacturers determine the MTF curve for film?
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Joja
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« Reply #63 on: January 03, 2005, 09:11:38 AM »
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i would also prefer a medium back ;-)
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Jack Flesher
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« Reply #64 on: January 03, 2005, 10:01:53 PM »
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Okay.  Call it 50MP on a 6x8 sensor.  With super clean ISO 400. And great battery life.
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Peter Simmons
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« Reply #65 on: January 06, 2005, 10:08:53 PM »
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Check out http://www.pixim.com/technology/technology.phtml for wide dynamic range technology for video cameras.
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Stef_T
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« Reply #66 on: January 18, 2005, 07:08:17 PM »
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lol. I love that book.
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Jonathan Wienke
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« Reply #67 on: February 14, 2005, 09:31:47 PM »
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That's the real butt-kicker there. Even with an 11MP 1Ds, 40,000 RAWs starts taking up some serious storage space..
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BJL
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« Reply #68 on: March 29, 2005, 04:40:00 PM »
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The sensors in the P25 and such have a theoretical maximum dynamic range of about 12 stops, or in other words a maximum S/N ratio of about 4000:1; the range from maximum recordable signal to the dark noise level.

How many stops of that are useful for prints is unclear to me, and seems to depend on how well the use of the sensor is done in a particular MF back. My understanding is that noise is visibly quite nasty once you get within a couple of stops of the noise floor, so maybe at most ten stops would really be useful.

For comparison, the maximum S/N of the sensor in the Olympus E-1 (a cousin of Kodak's MF back sensors, with pixels about 60% as big) is about 2000:1, or 11 stops; just one stop less. So maybe you could look at E-1 images of high subject brightness scenes and add one stop?
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valis
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« Reply #69 on: April 20, 2005, 01:44:20 PM »
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Forget everething about money, the cost of the sensor, memory, hard drives, ram, software, ..
Why? all of those factors factor into cost of ownership, and have to be considered unless you have the unique ability to pull money out of your butt on demand. I'd get a digital MF setup with a 22MP back and all the trimmings to go with it if I had infinite cash. But I don't, so I have a 1Ds.
Exactly...this is a silly question.  All things being equal, of course I would want the most megapixels possible.  I have a Digital Rebel because all things are NOT equal.  They will never be equal (though I don't intend to keep the Rebel forever).

6.1 megapixels are perfectly adequate for what I do.  22 megapixels would not only be adequate for what I do, but would enable me to do much more.  500 megapixels would let me do even more...I don't NEED them, no.  But I wouldn't exactly turn away a supercamera if it were offered to me.
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Bobtrips
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« Reply #70 on: June 12, 2005, 03:00:41 PM »
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Well, you said a lot in the last post without actually saying much of anything about the issue currently under discussion.

That is, is there something about film which doesn't end up on the paper if you tried to do the same thing with digital?

Or put differently - Can we arrive at the same place by two different routes?

We won't know until someone actually does the test.
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KapHn8d
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« Reply #71 on: July 15, 2005, 03:36:05 PM »
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I would trade incredible dynamic range for megapixels anyday.
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Anon E. Mouse
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« Reply #72 on: August 31, 2005, 07:01:32 PM »
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I think there are two myths that seem prevalent in imaging. Pixel resolution (or film format) limits maximum print size. And pixel resolution equils resolving power (either with a digital camera or scanner). Both are false.
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You're off base with your characterization of the first "myth". Pixel dimensions certainly affect how large one can print given a specific viewing condition and minimum acceptable quality standard. When you redefine the viewing condition the largest acceptable print size will change, but whatever the viewing condition, a well-processed 2000x3000 pixel image file will always be able to be printed much larger than a 400x600 pixel image file and still meet the minimum acceptable quality standard for the viewing condition.

Well, I would say you are simply repeating the myth. A printed image will appear the same regarless of size if the ratio of the print size and viewing distance is kept the same. It is a simple geometric problem based on the angular resolution of the eye - which is how circles of confusion and depth of field is calculated as well. That does not mean a low resolution image will not look rough, but its appearance is the same when the ratio of size to distance remains the same.

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While there is no method of determining the resolving power of a CCD, it is not equil to the pixel resolution.

The first part of this statement is demonstrably false. The resolving power of a CCD or CMOS imaging device can be measured the same way resolving power is measured using film. If you doubt this, go to DPReview and read some of the camera reviews.

You are correct that pixel resolution only represents a maximum limit to possible image detail, and digital imagers and scanned film record less than the theoretical maximum. Digital comes closer to the maximum than scanned film, though.

The tests you are refering to do not specify the resolving power of the CCD (or film). Those test show the resolving power of the system - CCD (film), lens, aperture. There are tests to determine the resolving power of film, but no standard that I am aware of has been developed for CCDs or CMOS (although the manufactures must be making some assumptions to design their lenses). While this may not be that important for a scanner as the optics and aperture are fixed, it is important for cameras where the optics can vary greatly as well as the aperture in use.
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Jonathan Wienke
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« Reply #73 on: January 03, 2005, 11:07:43 AM »
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thats exactly what i mean!
one day will come when youll dont have to look as many possible megapixels because all cameras will have more than enough.
Cost is always going to be an issue. Lenses are always going to be part of any camera system, and impose a practical limit on the number of megapixels that are worth putting in a sensor. So even if the digital sensor is as cheap as film, you're still going to have to buy lenses to go with it that will require precision fabrication and alignment and will be expensive if you want good quality.
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Sabercat04
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« Reply #74 on: January 03, 2005, 09:58:53 PM »
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My answer to the poll was based on the assumption of using 35 mm. It appears that in 35 mm, there will be minimal advantage of more pixels with the currently available optics, so what is the point in moving higher the 15. However, if we are talking about MF backs, my answer would be very different. The current MF sensors have twice the size of 35 mm film, so 30 should be plenty (if that is an appropriate extrapolation), but if you move the sensor size up to 60 by 45 mm, that number would be a bit higher.
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Lisa Nikodym
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« Reply #75 on: January 06, 2005, 12:33:32 PM »
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Sfleming Posted on Jan. 04 2005,16:32
My fave aspect is 3/4 or 6x8cm. Mat Board comes 32 x 40. Given a 4" mat one ends up with 24 x 32 prints. 24 x 240ppi =6720. 32 x 240 = 7680. 6720 x 7680 = 51,609,600.

Did I do that right?

One digit off. 24x240(not 280)=5760, total 44,236,800.

Close enough to 50.

Me, I'd be content with 180 ppi at that size => 25 mp.

Guess I'll make do with 6 mp for awhile.

Lisa
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Bobtrips
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« Reply #76 on: January 13, 2005, 02:51:05 PM »
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Why not build in a (selectable) algorithm that stops the exposure at the point where motion is detected?

(Sure, we might have to wait for a future generation of processors....)
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Quentin
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« Reply #77 on: January 19, 2005, 03:15:08 PM »
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I want Dicomed / Betterlight quality, so thats 6,000 x 8000 pixels (of the Foveon variety).  

We have a long way to go to achieve that, but I'm happy enough with the 14mp no AA filter quality from my Kodak 14nx, pretty much medium format quality, so I am hoping some of the more positive Kodak rumours are true and they'll release a 20mp upgrade at PMA.

We can dream  :cool:

Quentin
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djgarcia
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« Reply #78 on: February 15, 2005, 08:51:11 PM »
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To put things in perspective, a 1DsMkII raw file is around 15-16MB. When processed, the working copy saved as a 48-bit-RGB TIFF using Zip compression (usually 20-30% more effective than LZW) takes up 85-100MB. If I do my processing in layers and save it as an Adobe PSD document instead to preserve them (more efficient that a layered TIFF), then the working copy is around 180-230MB. Gee, I could put maybe 3 or 6 in a CD-ROM :laugh:.
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BradSmith
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« Reply #79 on: May 15, 2005, 07:06:41 PM »
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Looking at a couple other ubiquitous advancing technologies might be instructive.   Two examples of advancing technology that have evolved in different directions are Hi-Fi equipment and computers. I think that they've evolved quite differently, and the question is, which path will digital photography travel.

Hi Fi equipment progressed to the point in the large, mass marketing world, until people couldn't detect further improvement, (ie, CD's and inexpensive receivers/players) although the finely tuned ear and test equipment could detect it. So while there are $10,000 pieces of stereo electronics, they are clearly fringe elements. Probably 95% of the receivers sold are for less than $500.

Computers on the other hand, keep getting faster and more capable and we keep buying them. This is because we can perceive the improvement AND it is worthwhile to employ the improvement.  So there is immense volume and price stays constant or actually decreases.

I think that a lot of this thread assumes that we'll have the opportunity to have inexpensive 15 or 30 megapixel cameras. I doubt it. They'll only be inexpensive if they are sold in high volume and I think that will only happen if consumers perceive their value. I doubt that will happen. I think that we're closer to the hi fi trail than the computer trail and have just recently reached the point where the two paths diverge.

It will take a few years to look back and recognize it.

Just my opinion.
Brad
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