The Dynamic Range of the Fuji S3 pro

Fuji's new Super CCD SR II sensor is touted to have an expanded dynamic range because it contains two pixel types. Is this true? How is it different from a standard sensor? (The Luminous Landscape has a "first look" review.)

I tested the dynamic range of the FujiFilm S3 pro digital SLR in two ways:

Right at the top, let me offer you two pictures that you can use to compare the Standard and the Wide dynamic ranges of the S3. See if you can tell the diffence before you read this. Then, after you understand what the camera does technically, see if you can then pick up the differences. Yes, they are subtle. Oh, and lest you doubt: the pictures were taken identically except for changing the dynamic range of the camera; in-camera 6MP jpeg images were written and no other post-processing was done.

Comparison of the Standard Dynamic Range and Wide Dynamic Range of the FujiFilm S3 pro digital SLR

Click on the word "Standard" or "Wide" to load a full-size image file.
Click on "Detail" to see a 500KB selection from each image that shows nicely the difference in hightlight detail between the standard and wide dynamic ranges.
I'd suggest that you download each into a separate tab for easy reference.

Standard Dynamic Range (Detail)

Wide Dynamic Range (Detail)

Characteristic curves of the F3

I re-shot the test a week after I first posted this page, using half-stop exposure increments (the smallest this camera is capable of) to show more clearly what this dual-pixel sensor does in the high values. Note that there is abrupt pixel saturation using the standard dynamic range, and a nice, film-like rounded shoulder using the Wide2 dynamic range.
Wdr = Wide2 Dynamic Range ("400%"); Sdr = Standard Dynamic Range
EI100 = ISO 100, this camera's slowest setting.
EI1600 = ISO 1600, this camera's highest setting.

Click for half-size or quarter-size images.

Comparison of the S3 with an ordinary sensor

Next, here's a graph of the results of my testing of the S3's dynamic range versus itself and the A2: There are three curves:

Note two things:

Table of image intensity values (range 0 - 255):
The numbers below are the mean pixel intensities resulting from each exposure. If you open the image table in another window, you can view the test images, and measure them yourself as well. The test target is actually the left or darker panel; the right or lighter panel is one zone brighter. It is there to allow you to see whether a one-stop difference in subject brightness is detectable at any given exposure.
Zone S3 Wide DR S3 Std DR DiMage A2
-V 2
-IV 4 3 3
-III 6 4 4
-II 9 7 6
-I 13 10 8
O 19 15 15
I 29 22 28
II 44 33 49
III 66 51 71
IV 96 77 103
V 134 111 129
VI 177 160 179
VII 224 211 236
VIII 243 254 253
IX 255 251 255
X 255 251 255
XI 255 251 255

Let's look at the "toe" of these curves in more detail. This shows that when using the Wide Dynamic Range setting of the S3, that image brightness or intensity gain is almost equivalent to the image brightness of a target one stop brighter than when using the Standard Dynamic Range. The A2 tracks the Wide DR brightness down to Zone O, then joins the Standard DR line. This produces somewhat less muddy shadows in A2 images through higher shadow contrast; conversely the S3 Wide dynamic range preserves information (texture) further into the shadows.

Summary:These curves show that the S3 gains about 2 stops of dynamic range over the A2 and over its own "standard" dynamic range. The image processing algorithm puts one extra stop at the top of the curve, diminishing or postponing "blocking" of highlights, and one at the toe of the curve, preserving shadow detail.

But will this be noticeable in photographs?

Well, that's going to depend on the subject brightness range and your exposure technique:

What about that long, long "toe" on this curve?

Zone Zero is the subject value that traditionally was assigned to the deepest black that photographic paper could produce. The fact that both of these cameras record detail 3 to 4 stops below this value means two things:

Let's look at the characteristic curve again for one more lesson:

What's the best way to calculate exposure with a digital camera?

First, remember that exposure calculations are standardized on middle gray, and that the algorithms of these cameras place this middle tone quite near the pixel-saturation value. (They do this to keep the bright values "snappy" but the cost is muddy shadows.)

Second, remember that pixel saturation and loss of image texture occur in these digital cameras three stops (A2 or S3 std. dynamic range) or four stops (S3 Wide DR) above middle gray.

Third, at the lower ISO settings, there's a long "toe" that preserves detail. This is a safety reserve that you can use.

These things mean that you can "underexpose" images by one or two stops (three if the brightness range of the subject is small) in order to guarantee against highlights blocking up. The price of doing so is more work in post-processing; all your images may print too dark unless manipulated. The advantage is that it's much easier to create a terrific print if you leave yourself room on both ends of the characteristic curve.

Text and images, except for the photo of the CCD sensor, Copyright 2005, Daniel L. Johnson. All rights reserved. Permission is hereby given for non-commercial use of these words and images as long as they are distributed without charge and without alteration.