Megapixel discussion - why limited to 6 ?

Hi Group,
I just read that Pentax Digital SLR's sensor has only 6 megapixels. The standard seems to be 8MP, some Pro-DSLRs have 11 MP. Some picture agencies don't accept pictures under 8 MP.
I don't have DSLR yet but a lot of Pentax film SLRs and lenses so my choice would probably Pentax. My compact Digicam already has 5 MP, is an old model and has just a zoom lens but it fills that chip at full details! (Casio with a f/2-3 7-21mm Canon lens)
To my understanding the compact digicams don't use 8 MP resolution fully but DSLRs with their much better lenses should do so! Or I got something wrong?
An excellent 35mm film negative covers about an equivalent to 13-16. So my feeling is even my worst Takumar lenses will be able to show more details, colors and contrast than the current DSLR chip is able to fix!
So question: why no Pentax DSLR with at least 8 MP ? Diskspace is cheap these days... sorry if this was discussed already.

cheers, Frank
http://www.taunusreiter.de/Cameras

Mega pixels aren't the whole story...

Forget compact digicams. They don't compare. The sensor for compacts is miniscule, and consequently the pixel zone is minute. Noise becomes a serious problem. For example, the *ist-D at 1600ISO has less noise than some compacts at 400ISO.

As regards the agencies - it doesn't matter. Just upsize the image from the camera. The *ist-D at 6mega pixels will give you fine art quality at 18x12", given the right workflow. By that I mean - work in RAW, convert well (Capture One being my personal favourite). Capture One Pro, and Adobe Camera Raw in Photoshop CS/CS2 will upsize to 4x, and the resolution is absolutely stunning.

Of course, you have to have half way decent lenses

In fact, since going RAW and improving my workflow I've had to upgrade all my lenses (that I used happily with the MZ5 & Z1 film cameras) because I have become much more critical

Yes, more mega pixels would help.
Pentax are producing a medium format digital camera which should be superb, and who knows? Maybe they are developing a higher resolution DSLR too?

It's true, Pentax are a little way behind the other brand names, but you certainly get a full featured product (things like true spot-metering for example are often not available on other entry level products). And the compatibility with older lenses is second to none

Matt

A lot of other DSLRs are 6mp. e.g. Minolta 5D, Nikon D50, D70.

OK Canon has 8mp, and professional level DSLRs have more megapixels, but I'd say the standard amongst amateur level DSLRs is still 6, though no doubt they'll all start putting 8mp sensors in to compete with Canon.

Not that I think it makes a huge difference. As long as quality is acceptable, its the picture that counts. A 6mp DSLR will beat any 8mp compact with a tiny sensor hands down, and is the sensible choice.

If you have pentax lenses buy and pentax DSLR. I don't see any point in switching systems and having to spend lots of money reinvesting in new lenses.

Are you sure sensor size counts most? Some of the newer 8MP-Digicams really challange DSLRs, much less noise than the prior generation although their small sensor. Their weak part now seems to be their lenses (far too long slow zooms which cannot be corrected so good as DSLR lenses).
Some time ago I started to doubt about the "big size chip" theory (waited too long for the full format sensor). Maybe the future is in short focal length lenses (for small chips): easier to design, less weight for same complexity, or level of optical correction (and heaper)? If they will come down from their 12x zoom hype - "eierlegende Wollmichsau" - down to reasonable, maybe 2-3x zooms of high speed (f/2) or even fix focal lengths? Just a thought!

cheers, Frank

I think the thread in which this appeared at dpreview was an interesting discussion on megapixels. The author of that particular posting is/used to be the principal designer at a very well respected chip design company and seems to know exactly what she is talking about - and a Pentax user to boot.

Be sure to read her (and other's) comments on that thread, then be content with your meagre 6.1 million pixels for just a little bit longer.

I wondered the same thing about Pentax opting for 6mp. Without the technical mumbo jumbo...please give me some insight as to why the 6mp is better/worse than say an 8mp.

Thanks.

I think Sophie was saying that given the current sensor size and the fact you can't do much to change the wave length of light then anything much above 6 megapixels is going to cause a trade off in another area.

But don't ask me I know no more than I have read in that thread and a similar one I wasn't able to locate.

Basically, she thinks that 6Mp sensors are about as good as they are likely to get. If you cram more pixels onto the same size sensor, you'll get more noise (so 8Mp may give you worse quality, and it's not significantly bigger).

If you want more quality, you'll have to go for a bigger sensor. However, bigger sensors have their own problems (they are much more difficult to manufacture, and therefore much more expensive).

6Mp sensors already offer quality equivalent to 35mm film, and 35mm film became the most popular format because the ratio of quality to price and weight was right for most people (including many pros).

By the time full-frame sensors (ie: the same size as 35mm film) become "affordable", the price of a 6 or 8Mp sensor will have dropped so much that a camera like the *ist DS will cost about £200/$275 (things cost less in the USA). So, many people will still opt for an APS-C sized sensor, and the small lenses will be much lighter and cheaper than full-frame ones.

G

The difference between 6.1 megapixels and 8 megapixels is not enough to even think about. To double the "resolution", you'd need four times the pixels!

Not long ago 4 or 5 megapixel cameras were good enough for double-page spreads in magazines, so why are the six megapixel cameras suddenly not up to snuff?

Kodak has a sensor out that's pretty much full-frame 645, and it has to be that big to squeeze 31 megapixels in withoug turning into a noise factory!

You could always shoot RAW and render the file at 12 or 14 megapixels. But what do you need all those megapixels for? Generally you're eventually outputting to a four color offset press that can't even provide the detail that a four megapixel camera is capable of.

By the time you get to 5 or 6 megapixels, you're at the 35mm film level of quality. What counts is the quality of those megapixels, and the sensor.

Those 8 megapixel digicams with the tiny sensors were a disaster! There's an upper limit to what current tehnology is capable, and the 6 megapixel sensor is pushing the ceiling.

They could squeeze 8 or 10 megapixels into a full-frame sensor (preferrably not with a 2:3 aspect raio but something more like 3:4 or 4:5) but even there you run into a limit. Hence the medium format backs.

And another thing! No lens available today can out-resolve a 6Mp APS-C sensor . So more pixels won't give you sharper pictures; sharpness is limited by the lens, not the sensor.

People who think they would benefit from more pixels are generally ignorant victims of cynical marketing.

It's interesting that (almost) all the new "digital" lenses are reckoned to be very sharp. You wouldn't know they were so sharp if the sensor wasn't sharper (by which I mean, capable of resolving all the detail provided by the lens).

G

Yes, we're into the realms of discernable differences and we've achieved near perfect results with sensible file sizes from user-friendly equipment.
There always has to be a trade-off somewhere but I think Pentax have found the right balance.
It's a bit like hifi systems, even if you are lucky enough to have 20:20 hearing (20Hz to 20.000Hz), if you think that a £1000 system 'sounds' better than a good system (with the same speakers) costing half as much then frankly you're kidding yourself.
There'll always be some people that are taken in by the hype and undoubtedly some other manufacturers will produce equipment that is better suited to certain applications but as a general purpose tool for the photographic enthusiast, the current Pentax range takes some beating and even satisfies most professional uses.

If a Rolls Royce, Mercedes, Ferrari and a BMW were all travelling from Coventry to London at 70mph and I joined them in a Mondeo or Vectra, we'd all get there at the same time in relative comfort, so irrespective of price and prestige, is any one of those cars 'better' than any of the others?

Oh dear – the hifi analogy yet again and sorry, the comparison with the cars shows you have completely lost the plot. A comfortable Ferrari now that is something to look forward to!

"comfortable Ferrari" is an oxymoron. Fast, yes, flashy, yes, but comfortable? Keep dreaming!

I did use the word 'relative'

Comfort isn't a priority for Ferrari owners, as speed isn't for drivers of Rollers, my analogy was purely to show that a car (short for carriage) is for carrying people from A to B and they are all equally capable of doing that despite the differences in specification and price.
You don't NEED a luxurious limo to travel in comfort, you don't NEED a car capable of 150mph+ to drive at 70mph, you don't NEED the most expensive hifi for perfect sound and you don't NEED more than 6.1megapixels for perfectly good digital images!

............unless you do, in which case you're perfectly welcome to pay for it

all completely irrellevant of course

the only reason that pentax/minolta/nikon et al have a 6 mp sensor is because thats the only sensor available to them in the right format at a reasonable cost - until sony and the other sensor manufacturers have a replacement with a higher mp count they are essentially stuck with that

canon make their own dslr sensors
oly are the only major to use the kodak 4/3 sensor
sigma use foveon
fiji also make their own sensor

all the others currently use sony...that may change with some of the new deals on the table - ie pentax and samsung...