[wim]

Thanks for quick replay Brightcolour.

See my comments bellow

Ooops you aleredy make an assumption and forget for the second one.

 

The second assumtions is - How do you get the saturation point? 

 

My point is that above metioned absolute Fstops are meaningless unless you specify the conditions. 

This values can be used only to compare two cameras - same as photozone's LW/PH for lenses

 

Some test methodes defines DR fot low quality Normal quality and high quality and the difference is between 2.....5stops

 

PS: My personal taste is 2 stops lower than Dxo

 

Do you mean to say you overexpose by 2 stops? Lose two stops? How? Where?

 

As to comparing cameras: you can't, unless you have specialised equipement to measure such stuff. DxO uses a specific noise floor to measure DR. The funny thing is that Nikon and Sony manipulate Raw (I'd have to find the scientific article again), artificially lowering the noise floor by blacking out (parts of) the noise at certain low DR levels. This allows them to reach the minimum level at a lower point in the measured DR range, because the remaining noise on average remains below the DxO noise floor a bit longer.

 

There is in itself nothing wrong with this, other than that it potentially throws away information. Canon does not do this, resulting in more noise at higher DR levels, and hence also retaining more info. However, it is not easy to extract the information which others effectively throw away.

In practice, the lower DR levels are so low that it is almost impossible to see anything but black anyway, so it is a bit of a moot point whether a camera with advanced preprocessing prior to saving the Raw and hence getting a higher DR range than another which doesn't, is better than the other. It is a matter of preference.

 

In the past, with film, black was black, the lower part of the tonal range did not show any detail at all, whereas there still was some detail in the high ranges. With digital it is the opposite. Info is lost when overexposure happens, but more can be obtained from the lower tonal ranges than ever was the case with film.

 

Generally, I like contrasty images when processing my own stuff, and therefore I will lose the lowest and/or highest end of an original tonal scale anyway. Funnily enough it does not make a difference in that case whether a DR is 12 or 14 stops; I only need 8 to 10 at the most, and with proper exposure I generally do not need much if any leeway. I am quite capable of processing a jpeg to the exact view I want and had previsualized without even bothering with Raw;  I happen to be capable of ending up with the same end result in most cases - when viewed on screen or in print .

 

Kind regards, Wim