Megapixel theory

most people who see my portfolio are looking at 12x18's, usually in a coffee shop or office, (not a gallery) and are holding the prints up to thier face. Most of these clients will be ordering 16x20 to 20x30. (sometimes a video done a digital projector in hi-def). note cropping an image to a 16x20 aspect ratio involves throwing out a good chunk of image realestate...

I'll often take one image file and use a Ken Burns styled pan and zoom to create a video clip.... it's nice when a wide angle shot from a church can be panned this way and people in the image are recognizable. I do multimedia... photo and video in hi-def off the same files!

I believe you can see it in cropped images. I wouldn't always be able to use a longer lens instead.

Also you could see it if you looked closely at an uncropped large print - which you might want to do to study small details in a landscape, for example.

And it will be good in future when the resolution of monitors increase - to produce more naturalistic results.

(I may post some hopefully-convincing evidence next time I come accross some, but for the moment this is just casual chat on the matter from me. I have no scientific proof!).

And the final argument for larger pixel counts is this:
Many people thinking that if they buy a "Better" camera they can get images as good as the pro's. this results in development of better cameras being sold in larger numbers, and lower prices. When the marketing guys do thier thing, we all win.

Was only a few years ago that a camera producing images like the k20 would've cost more than a starter house.

What would hockey be like if guys like Wayne Gretzky couldn't afford to buy skates?
Can just anybody with a good pair of skates play like Wayne Gretzky?

it's all good!

I was always told that the optimum distance for viewing a print depended on the focal length of the lens it was taken with as well as the amount of enlargement.

eg a wide angle lens used for frontal facial portraits will give your sitter a big nose but move in closer and the perspective becomes normal. Likewise a print of telephoto lens picture will look more natural if viewed from further away.

I believe the formula is
viewing distance = focal length * print width / sensor width
obviously adjust 'sensor width' acording to how much you are croping.

This could mean that if doing a photo exhibition and you anticipate folk will view from 1m as they walk past then appropriate sizes of print can be calculated. Of course if you want Uncle Fred to have a big nose then reduce the size of the print below the optimum, or increase the size to enhance a telephoto effect.

all of that is rather different from the effect of the number of pixels in the image.

You can make a A3 print from a 6Mp camera without signs of pixelation.
But a higher Mp camera is likely to have greater detail in the shadows, and will slower to show pixelation with greater wenlargement.

I have also entered competions where they want A4 prints and images on disk stored at 300dpi - if you have a 6Mp camera then you have to increase the number of pixels in your image.
High quality 300dpi printing needs 10Mp for A4 or 14Mp for A3 if you are going to print without interporating pixels with a photoshop enlargement.

Buying a new camera just for mega pixels is a fools game as there will be more pixels next week and even more the week after.

But more pixels
= bigger prints (at same quality)
= greater ability to crop
= more detail in picture
= less photoshop enlargement

if you just want 6x4 inch prints to show your gran buy a 2Mp point and shoot. If you want A2 or enven A1 buy a K20D with as much DA* glass as you can afford.
It horses for courses and the favorite changes depending on whats wanted as a final result.

Bob

To a certain extent, this is true. Certainly it has contributed mightily to the fact that most members of this forum have a *istDL or better to play with. When I first started taking photography a little more seriously back in 2002 no one I knew had even SEEN a DSLR, let alone owned one.

However, the argument eventually breaks down. Because Joe Bloggs doesn't really know what a "Better" camera is, he chases Megapixels. To stay competitive, the manufacturer must squeeze more and more megapixels (and recently, higher and higher ISO ratings) out of their cameras. 12800 ISO and 20Megapixels will gain them more stupid customers than it looses intelegent ones, so these market forces end up making good cameras unsaleable.

Eventually you end up back where you started, the ~20MP DSLR (I'm talking in a few years time here) becomes a niche item valued only by the true photographers who value image quality above all else. The entry level models all have 45MP so they sell like hot cakes, but they take terrible photos.


Our only hope is that what happened in the P4 vs Athlon battle will happen in photography. At some point, the situation will change so that the top flight cameras no longer have more megapixels than the base models, and may even have less. If you look at the Canon lineup you can already see this starting to take hold. People will always want to have the same equipment as the pros, and when they realise that the K2D, Canon 1DS MkIV, Nikon D4 and whatever actually have rather fewer pixels than the compact in their pockets they will start to ask why. At that point, and not before, the megapixel race will be over for good.

I'm really not trying to catch anyone out - I'm genuinely keen to learn here.

Can you explain why a higher MP camera will have greater detail particularly in the shadows? Does it have greater detail elsewhere too?

OK at this point I'd like to check the mathematics so I can be sure I understand the nature of the beast.

Let's compare 10 MP with 6 MP.

In overall terms the 10 MP has 10/6 more pixels = 1.667 times more.

That's the figure for the rectangle. The increase in horizontal or vertical resolution is therefore the root of 1.667 = 1.29.

So for each row/column of 10 pixels on the 6 MP camera, the 10 MP camera has 12.9 pixels.

Is that right?

mongoose...the flipside of that argument is this:
for years pro's balked at af, built in flashes and ttl flash metering.
left to thier own devices, pros would impede development of better cameras, it's the amateurs that drive development.

we're in a catch 22. We need to produce images amauers don't, so we need better equipment, and sometimes we demand more from manufacturers. some areas we have to pioneer to stay ahead of the game, however, we tend to buy the technology, AFTER it's matured, more often than not.

so an outrageous ff, 40 mp sensor hits the market, the well heeled pros get the first batch at prices that recoup r&d costs for the manfacturer. The amatures demand it, it goes to mass production...the amatuers find out it's noisy, more r&d goes into fixing that because amatuers won't buy expensive pro lighting gear, they find a way to fix it, and it winds up in a prosumer, or pro model we can live with.

end result? they say the k20 has less noise than the k10. the k10 has more noise than the ds2.
k20=ds2? (for noise) + higher resolution + more pro features, weatherproofing etc....
bottom line for me?
next year the k20 will sell for equal or less money than I paid for my ds2 when it was new.
so why complain?

I've talked to one or two pros of the creative type and they love AF, AE etc. They say it lets them concentrate on the subject not the technology.

true today...wasn't always so. the technologies matured in the "wild" on amateur models before gaining acceptance with pros.

Don, You raise good points, but I would argue that your premiss is flawed. The general public don't demand better cameras, they don't have the knowledge or interest in the technology to even know what a better camera is. What they demand is higher specifications.

AF and AE as we know them were introduced on consumer grade SLRs. At that time the general public didn't buy SLRs, it was the amateur photographers who drove the development and widespread adoption of that technology.

In a world where only photographers bought cameras, your argument would be totally valid, but in this world most of the money is made by selling in large volume to fools who'll buy anything as long as it has bragging rights.

I'd be willing to bet that half (or more) of the D-SLR's sold in the last 5 years were sold to users that have never changed a lens, have never switched the camera off of "Green" mode, and have never printed anything bigger than 4 X 6 - if they print at all...
It's just a honkin' big P&S that makes better pics (sometimes - despite the user) because of the "advanced" on-board processing, and makes all the other snap-shooters go "Oooohhh, Ahhhh" Is it any wonder that they think more MP is better? The image out of todays 10MP compacts is better than the image out of a 4 or 5 year old 6MP camera, and since they care nothing for advances in on-board hardware or software, the only really quantifiable difference is the MP count.

There are valid reasons for a higher MP count (assuming other things advance as well - like noise suppression and dynamic range) as others have stated earlier - and it's kind of sad that the masses think they can get the same images as a Pro or enthusiast just by buying similar equipment.

(I must confess to catching myself thinking this way too sometimes - if only I had that Ltd or * lens, I could shoot pictures like [insert name of forum member who posted a shot you would have been proud to make here]...)

Is there any one on the forum who, if money wasn't an issue, wouldn't pick up a K20D ? (if they haven't already )

If money wasn't an issue I probably would buy one on the basis that it's the (presumably) best and latest offering from Pentax.

However, if I could only just about afford it I think I might think twice and maybe consider spending the money on some decent lenses instead - I think if I had to choose between upgrading from 10 MP to 14 MP or perhaps buying a fast, top quality lens that the lens might win the day.

I'm going to have to disagree with you there. From what I have seen 6MP is roughly optimal for a compact. The higher MP sensors seem to require so much inbuilt noise reduction that you loose detail almost from ISO 64.

I just haven't seen a compact past 6MP I would be happy to buy on IQ grounds, and certainly not one I would consider an upgrade from my 5MP Panasonic.

Otherwise I agree with you, most base level DSLRs are just glorified P&S cameras bought by people who believe that throwing money at photography will make their holiday snaps into masterpieces.


Although, perhaps we should consider this: The Pentax ME, MV, MG and A3 all have no manual mode at all. They are as fully automatic as cameras of their time could be. The K100D by comparison is extremely pro-orientated.

Can anyone explain to me why noise becomes more of a problem with higher pixel chips please?