A website for people who are passionate about image quality.

Discussion of all digital SLR cameras under the Minolta and Konica Minolta brands
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bfitzgerald
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Re: A website for people who are passionate about image quality.

Unread post by bfitzgerald »

Interesting link.

So why is Alain Briot there then? lol ;-)

No disrespect intended, something odd about his shots, not composition..I mean he never seems to have shadows in his shots, I find that very off putting and strange. Plus, go visit his site, his print prices are shocking! Granted, I expect to pay for the art a bit, but honestly...ouch!
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bakubo
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Re: A website for people who are passionate about image quality.

Unread post by bakubo »

Sonolta wrote:Pretty fair amount of positive press DxOMark has been getting...
I haven't seen any mention of DxOMark on the dpreview news page. Strange.
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bfitzgerald
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Re: A website for people who are passionate about image quality.

Unread post by bfitzgerald »

I don't know about the DXo numbers, maybe they are accurate.

From their site..
"Sensitivity is the ability of a sensor to provide a defined response for a given level of lighting. This information is used by photographers to determine the nominal exposure conditions. If the actual ISO sensitivity of a digital camera’s sensor is lower than the sensitivity set by the user, the image is underexposed; if the sensitivity is greater, the image is overexposed. To be easily understood by photographers, the ISO sensitivity of digital cameras has been defined such that it is similar to the ISO sensitivity of photographic film cameras, thus lower sensitivities require longer exposure for the same luminance to produce the same result. However, just as very sensitive films are known to be very grainy, parallels can be drawn for digital cameras, since high sensitivities are related to high gain and noise amplification."

"The intrinsic sensitivity of a digital camera is determined by the silicon structure of the sensor itself and cannot be changed, but the ISO of the camera can be artificially increased to arbitrary values by applying a gain to the signal. The price to pay is a proportionate increase of noise and eventually, a decrease of SNR for a given output value (see Explaining Noise Characteristics). The only trick is that the gain is applied before analog/digital conversion so as to avoid quantization effects. So the fact that a camera attains ISO 10000 is not a warranty of image quality; the noise level at this ISO has to be reported as well"



I can only comment on real world use. I don't think they have the A200 up there, last time I looked.

But, I know I get faster shutter speeds with the A200 at high ISO than the KM5d. BUT...the 5d is showing a good bit more shadow details..so my conclusion would be, that it's actual ISO rating at higher levels is more accurate/higher than the A200. No doubt some makers do play about with the processing in camera, and rate ISO levels that are not correct. As above it might be to have some headroom, makes sense for lower ISO levels, works against you at high ISO.

The A200 overall is pretty cautious exposure wise, so I am sure most of the differences are the sensor/processing..whilst the metering readings are not always the same, I put that down to different real ratings for ISO. The KM has no fear with showing great shadow details, the A200 is very different in this regards. Whilst I am a bit cautious about their DR figures (erm no mention of image quality with the DR), maybe the ISO ones are near the truth.

Have to disagree with their remarks on down sampling though. It's really not that simple..


A few odd things on DXo stick out pretty strongly..

Panasonic LX-3 has the same DR as the KM7d? Huh???

7d rated higher for high ISO than the 5d..

Fz 28 has a DR of 10.1....

Erm yeah right!!!

Not saying all their numbers are junk, but I have a hard time thinking a compact can match the DR of a 6mp DSLR..really, note a hope in hell..
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