Originally posted by rparmar Going from 6 to 10MP is not a huge increase... it's marginal. In order "to print an image with twice the area you need to quadruple the pixel count", to quote my own recent article
To Say Nothing Of Megapixels. Even upgrading to the K20D will only get you double the size in a single dimension.
If you really want big posters at the same resolution you will need a FF or medium format camera. But most of us don't really need that.
Unfortunately your math is all wrong in the article, giving a lot of misleading guidance.
In your article you state that to print an image twice the size in any linear dimension you need twice the pixel count, (in a linear dimension) OK I can agree with this as long as you stipulate it is the DPI in a linear dimension, but you don't
You then state that to print twice the area, you need 4 times the pixle count (I am assuming you mean here tht toal MP not linear pixels but again this is not stated)
What is wrong with these 2 statements, in the first statement, twice the linear size is 4 times the area, and the total MP count is quadroupled to achieve the same resolution. and in the second, double the area needs double the pixles to have the same pixles per square unit area and the same resolution, not quadroupled as you state.
Lastly you say inthe article that to do more requires A FF sensor, but unless this sensor has more pixles, you will not get any additional benefit in resolution because that is limited by the total pixel count and some FF cameras are less than 14 MP of the K20D.
If you go back to the question the OP has raised, what is the value of going from 6mp to 10 mp without other benefits, the K100D already has shake reduction, and unless there is a deliberate intent to go with a bunch of HSM lenses, I personallu don't see the change as having much value.
I went from *istD to k10D in one step, the *istD was ourchased within 1 month of product release, and I had it for over 3 years without changing. The reason, I saw no benefits, until the K10D came out. The K100 with shake reduction on its own was not enough, but the K10D with higher resolution, and yes the difference was enough, plus shake reduction, much higher frame rates, faster buffer, and HSM support was enough of a change. The OP needs to figure out for himself if HSM and 10 MP on thier own are enough.
If he really wants 3200 ISO, and I still use the *istD for this, then keep the K100D as a back up, it sounds like the controls are much the same.
I don't see noise as an issue, the K20D works just fine up to 1600, in my opinion.