Let's do some math, how many megapixel is enough

RedSox · August 28, 2006

Not considering digital noise etc. Just from the lens resolution perspective, how many Megapixel is enough?

I found this formula for 35 MM film camera

(24 X # lpmm res. X 2 pixels/lpmm) X (36 X # lpmm res. X 2 pixels/lpmm) = res. in pixels

So, a 22x15 1.6 crop 8.2 MP sensor from 20D/30D/XT(close to 20D and 30D) can resolve 79 lpmm and 36x24 FF 12.8 MP sensor from 5D can resolve 61 lpmm.

I know that excellent lenses rarely can make 110 lpmm in the center and the resolution goes down at the edge. Usually good professional lens has 65-80 lpmm resolution power. if above are true. Are we having enough sensor megapixel yet or at least very close? :rolleyes

Eric

pathfinder · August 28, 2006

Without getting into math calculations, it is genereally agreed that the 16Mpxl 1DsMkll is frequently limited by the resolution of the optics available for it - that is to say, the best optics that Canon sells commercially as L glass.

The interest in the Zeiss and Olympus ultra wide angle lenses is a manifestation of this fact - curent wide angles tend to demonstrate softness in the corners that was not really noticeable with film, but is quite apparent with a full frame CMOS sensor. Andy has posted several threads about his pursuits of sharpness in the corners with Zeiss lenses.

I frequently prefer to use an 8Mpxl camera simply because the files are so much easier to process and handle than the larger 16Mpxl files. Unless I know I will need the larger file for large prints.

The rumors of 22-24 Mpxl cameras to come in 35mm format, are interesting, but really unnecessary for most of us. JMO YMMV

:

The good news is tha DSLRs have left 35mm film quality in the dust.

My prints from 10Ds,20Ds, 1Series cameras are far superior to what I ever saw with Kodachrome ( which I still like ) or Ektachrome or color negative film. My prints from my Epson 4000 are far superior to my 16x20 Cibachrome prints from years gone by.

The best is yet to come I suspect.

RedSox · August 28, 2006

Well, if the formula is correct and professional Lens resolution is between 65-80 lpmm that will translate to 14.6-22.12 megapixel so the ID MarkII N with 16 MP sounds is in the range and bump the MP to 22-24 MP range make sense.

Just wondering how much sense does it make with those 7MP p&s DC with the sensor size less than the size of my finger nail and crapy lens?

Eric

ziggy53 · August 28, 2006

RedSox wrote:

... Just wondering how much sense does it make with those 7MP p&s DC with the sensor size less than the size of my finger nail and crapy lens?

Eric

It makes sense to the manufacturers as long as they can market the cameras successfully. It makes sense to the general buying public as long as they believe they are getting extra "something" for their money.

Since the general public equates image quality with the number of pixels, it could be some time before some other factor changes their mind.

Some unsuspecting public still believe in "interpolated" resolution.

Is it factual that most folks need the extra pixels? No, of course not.

Is it factual that the average consumer digicam lens can support high-resolution? I think in many cases the answer is a simple no.

I have a perfectly great 8"x10" image of my kids that even my ex-wife likes, shot with a 3 MPix Kodak digicam. (I was very careful about lighting and the image needed a fair amount of post work to eliminate the background, but it is still a pretty good shot.) Most of the time, I'm happy to get a 5MP crop from an 8MP camera to do an 8"x10".

Then again, the general buying public is fixated on the processer speed of a computer, when many factors have as much or more influence on overall throughput.

... And just how much horsepower is required for an automobile to go 65 MPH? ... And how often do people really need an SUV?

Ah, Marketing makes the world go 'round. Perception "is" reality.

BTW, would a 24 MPixel professional 24x36mm FF dSLR sell? Probably so, even though it probably is not justified by any current lens technology. People would buy it just for "bragging rights" and the hope that someday lenses might catch up. I know some folks with more money than they could ever spend who purchase that way.

ziggy53

pathfinder · August 28, 2006

I was intrigued that the new Canon 400D Canon recently announced has a 10Mpxl sensor. I think I would have rather had a better AF mechanism with the standard 20D 8Mpxl sensor. Probably it is cheaper to update the sensor chip than include a higher grade AF mechanism.

The biggest difference I see daily between the 20D, 30D, 5D and the 1 series cameras is not the sensor, but the speed and accuracy of the AF mechanisms. There the difference is real and palpable, and usable.

But that may be a harder thing to market than MORE PIXELS

cmason · August 28, 2006

pathfinder wrote:

I think I would have rather had a better AF mechanism with the standard 20D 8Mpxl sensor. Probably it is cheaper to update the sensor chip than include a higher grade AF mechanism.

Didn't the 400XTi get a better AF? (better than 350XT?) it got the same one in the 20D/30D. Now of course those models need an upgrade

:

pathfinder · August 28, 2006

It is listed as a 9 point AF - But it is not the number of points really, but the speed of aquisition that really matters. Not trying to hijack this thread, but there are so many other ways to improve a 20D or a 30D besides more pixels. A bigger, brighter viewfinder for instance. A split image range finder reticle perhaps. Single button mirror lockup. These would be real, useful, significant improvements.

10Mpxls is nice, but at the end of the day, not something to write home about.

claudermilk · August 29, 2006

I'm on board with ziggy here.

IMHO, we have plenty of pixels now, in some cases too many--does a 4x crop P&S really need 10MP? I would rather see the other aspects addressed more: lower noise floor, better detail, etc.

As ziggy said, people are fixated on MP for cameras. Just like HP for cars, Watts/channel for home theater, GHz for PCs; one easy to quantify and easy to market spec that has been addressed already & is now a small part of the overall package. More MUST be better even if it distorts the rest of the performance envelope.

For 35mm format, I don't see that the current pixel counts really need to move much. 8MP for my 20D works just fine, my buddy's 16MP 1DS Mk II just gives him bigger files more than anything else using the same lenses. I've printed 8x10, even 8x42 6-frame panos off a 3.3MP Nikon P&S that look fantastic. Honestly, I don't think I *want* a 22MP DSLR. Now if I do mvoe to MF--and could actually afford a digital back (and monkeys might fly out of my butt)--I can see value in that kind of pixel count; we have a print from a Kodak back that's 6 1/2' tall by 3' wide that is dead sharp even putting your nose to it. A 1/2" tall calibration label is readable! But that's an unusual case.

Justiceiro · August 31, 2006

I remember once that Leica advertised themselves as having a 22 megapixel camera; that is to say, that 35mm film was equal to 22 megapixels. This was back when they were still attempting to pretend that digital didn't exist, say, 2003 or 2004. Is 35mm film really equal to 22mp, or were they just pulling that number out of the air?

Regardless, my 8mp camera (20d) does just fine, and can hold its own against the top level of Canon or Nikon, when the light is right and I'm at f8 with my 50mm f1.8. I really think its the lens at this point. And at some point we have to ask ourselves how often we need to go above 16"x20" enlagements. I don't think I ever will, but then I try to peddle my stuff at art fairs, I don't do advertising or billboard shots, maybe its a different story there.

colourbox · August 31, 2006

Justiceiro wrote:

Is 35mm film really equal to 22mp, or were they just pulling that number out of the air?

I thought I saw a Kodak study or something a few years ago to that effect, but the conditions under which you'd reach it would be rather extreme. You'd have to have the best lens, the best slow-speed fine-grain film, a tripod, a high shutter speed, and no wind or vibration of any kind.

A quick Google search shows a lot of people think 35mm film is worth about 10-13 megapixels. Put consumer lenses, handholding, and moderate shutter speed into the mix and it sure looks like no matter how many megapixels your camera has, shooting conditions and equipment limitations could limit the actual achieved resolution to maybe 6-10 megapixels of real resolution. Which is a number that I'm pulling out of the air.

Justiceiro · August 31, 2006

ziggy53 wrote:

People would buy it just for "bragging rights" and the hope that someday lenses might catch up. I know some folks with more money than they could ever spend who purchase that way.

ziggy53

don't those folks disdain digital, and buy only Leica?

pathfinder · August 31, 2006

I remember when the 10D came on the scene several years ago, only 6Mpxls.

There were folks everywhere saying it could not begin to compare to 35mm film.

Well, I have 16x20 Tri-X B&W images I printed myself 25 years ago, as well as 16x20 CIbachrome prints shot with Ektachrome 64 or Kodachrome 64, and none of those prints ever came close to the accutance and color and lack of grain from shots made with my 10D. And I was shooting jpgs, and just beginning to learn better post processing of digital images then. I could do much better with them today.

So I took an EOS 3 with color slide film to Bosque del Apache along with my 10D, and shot them side by side. I still have the images from the 10D, but the slides I disposed of. They weren't even close.

I sold my film cameras shortly after that.

We consider a 10D a less than state of the art digital camera today. A very good camera that can create great images. But it certainly is not the equal of a 20D, or a 1DsMkll or a D200.

I hope the market for 35mm films does not disappear, but the experience with color printing paper and other films is not encouraging.

There were articles saying 2 or 3 years ago, that to equal 35mm film would require 35-40Mpxls. Well, today the are medium format backs with 30-45Mpixel images, and they are being compared to 4x5 film, not 35mm or even 6x7 cm medium format. 4x5 film - that is saying something. Some folks think the P45 back is beginng to step on the toes of 8x10 view cameras.

In the end, the image is what counts - I really don't care how it gets there. If you use film and get a great image, that's fantastic.

Justiceiro · August 31, 2006

pathfinder wrote:

In the end, the image is what counts - I really don't care how it gets there. If you use film and get a great image, that's fantastic.

You're right, but there is something to be said for playing around with gear. It's fun- like owning a dodge dart.

mercphoto · August 31, 2006

pathfinder wrote:

The biggest difference I see daily between the 20D, 30D, 5D and the 1 series cameras is not the sensor, but the speed and accuracy of the AF mechanisms. There the difference is real and palpable, and usable.

But that may be a harder thing to market than MORE PIXELS

Yes, it is harder to market than pixels. And yes the difference is real, palpable, and usable. The reason it is hard to market is because it is hard to quantify. And if you can't attach a number to it it is hard to market and make the public understand. And if they can't understand it, then it won't make them want to buy it.

colourbox · August 31, 2006

Some point out that especially on a small sensor, raising the megapixels can actually lower the image quality, because a greater proportion of the finite sensor area is given over to the necessary gaps between each photosite. You have more pixels, so you have more gaps, so you use more pixels to capture less of the actual scene, and you have more noise.

It looks like if you really want more megapixels to result in higher-resolution images, paying attention to the actual design of the sensor is as important as how many megapixels it produces.

For example, I found this interesting reading in the Canon Rebel XTi White Paper:

"First, the spacing between the on-chip microlenses is now about half of the Digital Rebel XT’s. This new configuration gathers light much more effectively, loses less light between the microlenses, and improves light convergence. Second, a higher percentage of each pixel’s surface area is sensitive to light. Third, the output amplifiers have been optimized, lowering noise. Last, the second-generation, on-chip noise reduction circuit minimizes random noise and removes fixed-pattern noise. As a result, the XT and the XTi have the same signal-to-noise ratio and equivalent dynamic ranges despite the smaller pixels of the XTi."

ziggy53 · September 1, 2006

colourbox wrote:

Some point out that especially on a small sensor, raising the megapixels can actually lower the image quality, because a greater proportion of the finite sensor area is given over to the necessary gaps between each photosite. You have more pixels, so you have more gaps, so you use more pixels to capture less of the actual scene, and you have more noise.

It looks like if you really want more megapixels to result in higher-resolution images, paying attention to the actual design of the sensor is as important as how many megapixels it produces.

For example, I found this interesting reading in the Canon Rebel XTi White Paper:

"First, the spacing between the on-chip microlenses is now about half of the Digital Rebel XT’s. This new configuration gathers light much more effectively, loses less light between the microlenses, and improves light convergence. Second, a higher percentage of each pixel’s surface area is sensitive to light. Third, the output amplifiers have been optimized, lowering noise. Last, the second-generation, on-chip noise reduction circuit minimizes random noise and removes fixed-pattern noise. As a result, the XT and the XTi have the same signal-to-noise ratio and equivalent dynamic ranges despite the smaller pixels of the XTi."

That is encouraging, but I would like to see proof in comparative reviews of the two cameras, side-by-side. (I worked in and with "Marketing" for 31 years. Need I say more?

)

ziggy53

Let's do some math, how many megapixel is enough

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