JPEG puzzle

[Justinr]

I have just acquired a used Pentax K10 for events and website shots as the Pentax ist I was using could lack a little in resolution when printing at A4 especially if cropped.

In my simple minded way I thought that a 10 million pixel camera would produce jpegs 1.6 times as big as a 6 million pixel camera especially since they were from the same stable. But no, this is not the case as when switched to full size and quality on both camera the jpeg file size is pretty much the same at 2.5 - 3 mb for each and I have tested with the same subject/lens/light combination. OK, some of the K20's can be larger but not by much and not that often.

Pentax in the manual for the K10 tell me that I should get around 200 jpegs to a 1GB card or approx 5mb each so what is going on? Will a 3mb jpeg from a 10mp camera produce a more detailed image than a 3mb jpeg from a 6 million pixel camera as Pentax have sort of told me?

The proof of the pudding is in the eating and I should do some prints but it all seems a bit odd. I like the camera otherwise though and I also appreciate the superiority of RAW.

[fredjeang]

I have just acquired a used Pentax K10 for events and website shots as the Pentax ist I was using could lack a little in resolution when printing at A4 especially if cropped.

In my simple minded way I thought that a 10 million pixel camera would produce jpegs 1.6 times as big as a 6 million pixel camera especially since they were from the same stable. But no, this is not the case as when switched to full size and quality on both camera the jpeg file size is pretty much the same at 2.5 - 3 mb for each and I have tested with the same subject/lens/light combination. OK, some of the K20's can be larger but not by much and not that often.

Pentax in the manual for the K10 tell me that I should get around 200 jpegs to a 1GB card or approx 5mb each so what is going on? Will a 3mb jpeg from a 10mp camera produce a more detailed image than a 3mb jpeg from a 6 million pixel camera as Pentax have sort of told me?

The proof of the pudding is in the eating and I should do some prints but it all seems a bit odd. I like the camera otherwise though and I also appreciate the superiority of RAW.

In raw Justin, in raw.
That's why I was surprised when compared my jpegs from the now vintage 5.5MP Olympus E1 and their capacity to handle up-sampling sometimes better than the current 12MP cameras ??!!  even being a Four-third sensor...but the E1 had, if I remember, it's native res at 240ppp in jpeg.
So? The Marketing genius arrived fast in the play to confuse us with very apetizings claims. I really regret my E1, honestly.
Raw is the answer.

Fred.

[PeterAit]

In raw Justin, in raw.
That's why I was surprised when compared my jpegs from the now vintage 5.5MP Olympus E1 and their capacity to handle up-sampling sometimes better than the current 12MP cameras ??!!  even being a Four-third sensor...but the E1 had, if I remember, it's native res at 240ppp in jpeg.
So? The Marketing genius arrived fast in the play to confuse us with very apetizings claims. I really regret my E1, honestly.
Raw is the answer.

Fred.

It may be that the new camera is using a lower jpeg quality for its "high" quality output than the old camera, hence the smaller than expected files.

You don't always need RAW despite what some people say. Yes, RAW always gives you more room for adjustments and the potential for a better image, but you may not need that. Why put in all the extra time and effort for RAW processing if the jpegs your camera produces meet your needs?

[Justinr]

In raw Justin, in raw.
That's why I was surprised when compared my jpegs from the now vintage 5.5MP Olympus E1 and their capacity to handle up-sampling sometimes better than the current 12MP cameras ??!!  even being a Four-third sensor...but the E1 had, if I remember, it's native res at 240ppp in jpeg.
So? The Marketing genius arrived fast in the play to confuse us with very apetizings claims. I really regret my E1, honestly.
Raw is the answer.

Fred.

I know what you are saying about RAW and I was trying to avoid bringing it up for the arguments are well rehearsed. From my point of view I see it as horses for courses. RAW files no only consume memory but processing time as well and since more and more of my stuff will be appearing on the www where jpegs are the file of choice and browser/screen/OS combinations will totally bugger up the finer points of any photograph, going straight to jpeg makes a lot of sense. But for events where well over 200 shots may be taken I also need to produce a decent print up to A4, hence I need a good jpeg.

It was put to me elsewhere that jpeg algorithms have become more efficient at packing in information over the years, an argument which I feel has flaws but I can't quite put my finger on them. I'm in complete agreement about the boys from marketing screwing everything up though, I pity the poor guys designing and developing cameras for they probably do a good and conscientious job knowing full well that once it passes into the hands of the sales department their hard work will be totally disregarded in favour of shifting boxes, which is the name of the game I suppose.

Justin.

[Justinr]

It may be that the new camera is using a lower jpeg quality for its "high" quality output than the old camera, hence the smaller than expected files.

You don't always need RAW despite what some people say. Yes, RAW always gives you more room for adjustments and the potential for a better image, but you may not need that. Why put in all the extra time and effort for RAW processing if the jpegs your camera produces meet your needs?

I think you have it there Peter. The K10 has three quality options whilst the K20 has four and I wonder if the same wasn't planned for the smaller camera but pulled at the last moment to leave a little more space between the two models, or they decided to increase the compression for the same reason. I feel it's a marketing decision rather than a technical one and Pentax themselves seem somewhat reluctant to discuss the issue in as much detail as I would like. Trouble is that I now have an otherwise perfectly competent camera that only fails in the very area that I bought it for.

Just to muddy the waters a little I printed an A4 portrait today from a 2.5mb jpeg but originally taken as a RAW. It looked pretty good so I thought I'd chance the same file at A3 and that worked fine as well. There was a lot of the black backcloth in it though which would have helped but it does go to underline the fact that life is not as straightforward as we would wish at times.

Justin.

[fredjeang]

I think you have it there Peter. The K10 has three quality options whilst the K20 has four and I wonder if the same wasn't planned for the smaller camera but pulled at the last moment to leave a little more space between the two models, or they decided to increase the compression for the same reason. I feel it's a marketing decision rather than a technical one and Pentax themselves seem somewhat reluctant to discuss the issue in as much detail as I would like. Trouble is that I now have an otherwise perfectly competent camera that only fails in the very area that I bought it for.

Just to muddy the waters a little I printed an A4 portrait today from a 2.5mb jpeg but originally taken as a RAW. It looked pretty good so I thought I'd chance the same file at A3 and that worked fine as well. There was a lot of the black backcloth in it though which would have helped but it does go to underline the fact that life is not as straightforward as we would wish at times.

Justin.

Justin,
The Kx also have 3 levels of jpeg. When you are in max quality, what do you see when you open the file in photoshop, pixels and ppp?
The KX max quality right of the box in jpeg is: 4288x2848 at 72ppp wich is 36x24cm at 300ppp for print what they call a 12MP sensor.
Now, the 5.5MP E1 is 2560x1920 at 240ppp wich is 21x16cm at 300ppp...you follow me?
21x16 is not the half of 36x24, so someone is lying there. Looking at the files, the Pentax (and others) is certainly doing some good marketing.
I have some jpeg from Sony Alfa at 6048x4032 at 240ppp so here we are, like with the E1, ok. (beautifull resolution by the way the Sony)
Ahhh...marketing departments  

Fred.