Fuji- Thank you! EXR....

Started Feb 4, 2009 | Discussions thread
MrClick Senior Member • Posts: 1,886
How the EXR sensor really works

Kim Letkeman wrote:

Ehrik wrote:

How is the reduced sensitivity achieved?

Half the pixels are read early. This is probably built into their
pixel-binning technology, which means that they'll either average
them and bin them for a 6mp image, or average adjacent pixels for a
12 megapixel image. Either way, I think you'll see information more
on the lines of 6mp ... but that's enough.

No. That is not how it is done. There is no 'reading early' thingy going on. Either all readouts HAVE TO be done at the same time ...or... multiple readouts have to be done from the SAME data if the readouts are done one after the other. There is no other way.

Anyone who has a good understanding of both electronics and photography would understand straight away why this has to be so. Do not believe at face value whatever you read in the media or the marketing drivel spouted by the marketing departments of consumer companies.

Thanks for the link, but I had read that. It states that it takes a
high-sensitivity [with half the pixels] and a low-sensitivity [with
the other half] shot at the same time, but not how the low
sensitivity is achieved.

Early readout.

At the engineering level (electronics), there is more than one way to achieve what Fujifilm claims they do with their EXR sensor. An early readout implies that there is another readout subsequently (i.e. a second delayed readout.) This method would result in technically a 'double exposure'... similar to having two film exposures shot consecutively one after the other in high-speed burst and then superimposed on each other... and quirks can show up as a result

The EXR sensor has a special pixel layout to achieve what it does... according to what Fuji claims. But that is only half of the story. The other half of the story is that the camera with the EXR sensor has special circuitry too i.e. the data from half the number of pixels is processed differently from the other half... but both halves at the same time.

The data from the first half set of pixels is read at base ISO. The data from the other half set of pixels is amplified to a slightly higher level (i.e. slight gain up.) After this, the data from both sets of pixels is then combined to form one single image.

All this fancy technical explanation boils down to simply nothing but what is actually an in-camera HDR process.

For those who are HDR gurus, it is evident that an EXR sensor is not really necessary to obtain similar results... especially if they have access to any camera that offers a feature called ISO-bracketing. The same result (actually even better) can easily be achieved in post processing.

But, then again,there are many of us (I'm included in this group) who hate dealing with PP and would love to avoid it if we can. Hence, a compact camera such as the F200 is most welcome if it does all this processing automatically in-camera in the first place.

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