The Fujifilm Finepix X10 (FX10) camera has an EXR sensor. This provides a hardware method of expanding dynamic range which is not explained or even mentioned in the owner's manual.

This article is designed to help FX10 owners understand how their EXR system works and how to get best performance from the camera, using the EXR sensor's unique capabilities. The observations and suggesttions which follow are based on my own tests of an FX10 over the last two weeks, involving many hundreds of systematic test exposures.

Point and shoot photographers will manage very nicely with the following settings:

Set EXR on the Mode Dial and EXR Auto in the Shooting Menu.  Just point and shoot. The camera will make a multitude of calculations on the run and deliver a good result most of the time. JPG files only.

For better image quality and more control over the image capture process, expert and enthusiast photographers will want to use RAW capture. My comparison studies have shown that in the majority of cases a well processed RAW file delivers better Image Quality (IQ) than JPG, even using the tedious Silkypix.

Suggested Settings for RAW capture:  Note: These settings apply when RAW+JPG is set in the Setup Menu. If RAW only is set, a different range of options for Image Size and DR is evoked.

On the Mode Dial set P,A,S or M.  In the Shooting Menu, Set Auto ISO (limit 3200), Image Size M (=6MPx), Dynamic Range DR400%, Film Simulation Standard, AF Mode Area.  In the Setup Menu, Set Fn button to ISO, IS Mode 2 Shooting only,  RAW + JPG.

Now to explain why:  Everything from here assumes  RAW + JPG capture.

The internal workings of the FX10 using L (=12MPx) Image Size are fundamentally different from those which operate using M (=6MPx). The difference is much more than just  image size.

There are two separate and distinct systems for Dynamic Range expansion in the FX10.  The Owner's Manual fails to mention this but awareness of the difference is the key to understanding how the camera works.

The first system is DR expansion in software and is the same as that used on many digital cameras from many makers. Basically  it underexposes the scene to protect the highlights then applies a tone correction curve in camera to lift the mid and dark tones. On the FX10 it works in L Image Size. If you set DR400% the minimum ISO permissible is 400. The camera will force ISO 400 even if you set 100.

The second is DR expansion in hardware and is the unique function of the EXR sensor. This will not work using L image size, it requires M image size. ( 6MPx)  It operates at any ISO ( but not at slow shutter speeds)  The pixels on the sensor operate in adjacent pairs. One pixel gets the full exposure time, while the adjacent one gets a fraction of that time, controlled on chip.  Some very clever proprietary Fuji technology combines the two exposures into a single image with higher dynamic range than is possible at ISO 100 using the full 12 MPx. The same process also delivers lower noise at high ISO than is possible using the full 12MPx.

My comments on issues arising:

My tests show that 6MPx delivers resolution only marginally less than 12MPx. In fact in some situations 6MPx does better than 12. For instance if using L image size and DR100% produces blown highlights (and it often will) then highlight definition is actually improved by going to M size and DR400. Another example: On a bright sunny day if you set L image size and DR400, the camera will force ISO 400, and in consequence an aperture of f8 or f9 because the shutter runs out of fast speeds. The optimal lens aperture for the FX10 is about f4, so the higher ISO and smaller f stop both degrade resolution to the point you would have been better off using M image size in the first place with ISO 100, DR400 and f4.  In addition the FX10 lens is a bit soft in the corners wide open and the extent to which this reduces resolution is minimised by using M image size.

Auto ISO: The FX10 seems to set the optimum combination of ISO, shutter speed and aperture most of the time so Auto ISO works well for most situations.

I think that DR 200 is not worth bothering about.  DR 800, 1600 are only available in EXR Mode, DRange Priority, JPG.

The takeaway message: I found very few if any situations where the FX10 delivered better image quality at L image size than M image size. So I use and recommend the settings given above all the time in all situations. Doing so gives reliably good results and certainly simplifies using the camera.

Good luck with your own tests and do enjoy using the clever Fuji X10 camera.

Author's declaration: I am a private, amateur camera user. I have no sponsor and no connection with any maker or vendor of photographic equipment. I bought my Fuji X10 at normal retail price in Australia. I really like figuring out how stuff works and the X10 was a nice challenge.