Even so, I suspect that a lot of one colour in the image may cause
variations. Grass is supposed to be 18% grey, like caucasian skin but
an unusual image with a lot of red or a portrait of a very dark skin
face might confuse the ISO response? I've got no idea - just
speculating.
But DxO claims to test in Studio/Portrait, Sports/Action and
Landscape situations - while DPReview tend to nip out and photograph
Tower Bridge! Which sounds more objective?
Andrew Fildes
afildes@xxxxxxxxxxxxx
On 30/01/2009, at 2:46 PM, C.H.Ling wrote:
> There should be a standard to measure the ISO for digital cameras,
> I believe
> it check the grey rendering. For example, the grey card should read
> 128 (?)
> if properly exposed. But they have to first make sure the accuracy
> of the
> grey card and their external meter. Either or both must be wrong if
> DXO and
> DPreview are different. For the maufacturer, they always not follow
> the rule
> for some marketing reasons, like a F2 lens could be F2.1, a 35-80mm
> lens
> just a 36-76mm...
--
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