K10D 100 ISO vs K100D 200 ISO

What is the (technical) difference between these two?
Does the 200 ISO setting on both cameras produce the same result?

Yes, if both cameras are set to the same ISO, they should give the same result if the aperture and shutter speed are also the same. A comparison test would need to be in all manual mode to avoid differences in metering.

The ISO range on Pre K10D cameras is 200 - 3200. On the K10D the addition of shake reduction has enabled shooting at ISO 100, and/or slower shutter, and/or smaller aperture etc for low light conditions and still get a sharp image. The sensor design also contributes to Pentax's choice of ISO range on the K10D with its limit of ISO 1600.

Hi there,

Im not technical when it comes to ISO but as you are probably aware this is to do with sensitivity to light. I beleive the difference between 100 and 200 is minimal but it all depends on the light shooting conditions i beleave.

Most likely to the naked eye i dare say you wouldnt see to much difference unless your an expert and know what your looking for.

From what i understand the lower the ISO the less noise and better picture quality but up to ISO 400 you would not notice anything.

Between the K10D and the K100 and cant say as i dont have the K100 only the K10D but i presume as this is the flagship model (K10D) and a superior image engine along with various other advancemnets means you are more than likely to get better results with the K10D.

As i said this is what i understand to be the case but i may be wrong so all you readers dont shout at me im only a novice

Regards Pete
New to DSLR and the K10D

The K10D has the 10.2MP sensor as opposed to the 6.1MP of the K100D. As the CCDs are the same dimensions it's obvious that the K10D pixel sites will be smaller. Therefore they will generate less current and will need more amplification. This is why the 10.2MP sensor will be inherently noisier and therefore a lower speed setting (100 ISO) is provided, and equally well why the 3200 ISO top setting has been dropped.

I was quite happy with the *istDS noise levels at 200 ISO and am also using the K10D at 200 ISO. Noise does not seem to be a problem at this speed.

If you consider that I always used to use fast films with their resultant grain (especially Kodak Tri-X) then I am unlikley to be worried by the low noise levels at moderate ISO speeds. Those who did not use the Panatomic-X (32 ISO) type films in days of yore and who think that digital SLRs have noise problems may have already forgotten how much grain they used to accept as OK!

Digital images are clean and sharp, quite unlike film, until we get to higher ISO settings of maybe 800 or above.

Pete, since you clearly haven't mastered this subject, here is a brief introduction to apertures, shutter speed, and ISO.

The relationship between aperture and shutter speed and the way in which apertures are expressed, are just about the most basic concepts in photography.

It is pretty obvious that when you move from one shutter speed to the next, you are either halving or doubling the amount of time the shutter is open, and therefore halving or doubling the amount of light reaching the film/sensor. (Eg: 1/500 second is obviously twice as long as 1/1000 second).

It is less obvious that when you move from one aperture value to the next, you are doing the same thing. 1:2 is not obviously twice 1:2.8, but in photographic terms it is. 1:2 allows twice as much light to reach the film/sensor as 1:2.8 does.

What this means is that if you go up the aperture scale in one direction, say from 1:5.6 to 1:8, and down the shutter speed scale in the other, say from 1/250 to 1/125, the amount of light reaching the film/sensor is unchanged. Some old-fashioned cameras allowed you to lock the aperture and shutter speed together, so that as one increased, the other decreased, and correct exposure was maintained.

These stages (1:5.6 to 1:8, and 1/125 to 1/250) are called "stops". A stop is a doubling or halving of the light.

The same logic applies to sensitivity (or ISO). Each stage (100, 200, 400, etc) is exactly twice the sensitivity of the one before, and therefore each represents one stop.

So the difference between 100 and 200 is not "minimal but it all depends on the light shooting conditions i beleave", but one stop. No more, no less. It's exactly the same difference as between 1600 and 3200.

And with that one stop comes a reduction in quality. 200 is certainly pretty good, but 100 is better, and (unless you're after some special effect) you should always shoot at the lowest ISO that you can, without compromising DOF or blur.

To claim that "up to ISO 400 you would not notice anything" is to insult the person you are addressing.

Peter, your enthusiasm is commendable, but when you yourself admit that "Im not technical when it comes to ISO" and "i may be wrong so all you readers dont shout at me im only a novice ", then perhaps here is an opportunity for you to keep quiet for once and brush up on your photographic theory (not to mention spelling and grammar).

G