The X-Pro1: Understanding the Dynamic Range Feature and its Relationship to ISO

Continuing the blog serialisation of my popular X-Pro1 lust/hate/love story:

Part Eleven: Understanding the Dynamic Range Feature and its Relationship to ISO

In the last part (click here) we looked at Jpegs and Raw, the benefits of each, and why (in my opinion) you should shoot both.

This time we’ll take a look at the Dynamic Range (DR) feature and it’s relationship to ISO.

It can be a contentious subject.. Certainly the online forums are full of questions and debate about its function and its value.

Some swear by it, others swear at it.

Am I about to end that debate? Will this article once and for all answer whether or not to use it?

No of course not!

As with everything camera related, it’s about understanding the function, then deciding if it works for you (or not)

Let’s start with a quick explanation of Dynamic Range (DR) This is the easy bit!

DR (within a photographical context) is the amount of light and dark that can be captured before detail is lost.

When the LIGHT detail exceeds the DR abilities of the camera (or film) the image will display only WHITE

When the DARK detail exceeds the DR abilities of the camera (or film) the image will display only BLACK

We’re NOT talking about, ‘oh but I can recover that detail from the RAW file’ – no, in absolutes we’re talking it’s gone, lost forever, you blew it (or blocked it!!), zilch, nada.. GONE FOR GOOD.

Of course, in none absolute terms, this might not matter… perhaps only a tiny part of the scene is lost, and that part is not important to the overall look of the photograph. Perhaps it’s only 0.1% of the shot, a tiny sunlight reflection in a pair of sunglasses, or the shadow in a wheel arch of a car.

However, I think it’s safe to say, that we should aim NOT to lose detail from our photographs, and that having the maximum amount of DR available to us is a good thing.

The more DR at our disposal, the more we can still take photographs in dynamically intense lighting conditions.

So Fujifilm (and most camera manufactures) offer us expanded DR modes.

But how can the camera exceed the PHYSICAL limitations of the light range that the camera can capture, that sounds illogical, right?

It sounds illogical because it is – the camera can’t.

Let’s take a look at some examples, and try to understand how it works, we must also look at the role of ISO in the DR expansion equation.

Fuji offer us 4 settings to chose from in regards to DR

DR100 = OFF
DR200 = 1 STOPs of DR recovery
DR400 = 2 STOPs of DR recovery
DR Auto = The camera will pick for you from options 1, 2 & 3

So let’s take a look and see what effect these settings have on a photograph.

We’ll start by looking at the DEFAULT SOOC Jpegs produced by my X-Pro1.

The standard Fujifilm Jpeg:

STD Colour profile (which is Provia) All highlight/Shadow/Colour/Sharpening/NR settings, set to ZERO (0)
Dynamic Range (DR) set to DR100 (off)

The standard DR200 Fujifilm Jpeg:

STD Colour profile (which is Provia) All highlight/Shadow/Colour/Sharpening/NR settings, set to ZERO (0)
Dynamic Range (DR) set to DR200 (1 Stop)

The standard DR400 Fujifilm Jpeg:

STD Colour profile (which is Provia) All highlight/Shadow/Colour/Sharpening/NR settings, set to ZERO (0)
Dynamic Range (DR) set to DR400 (2 Stop)

As you can see, as we increase the DR mode, we are able to retain slightly more detail in the clouds. Even with SOOC Jpegs, by the time we’re getting to DR400 (max) we’re blocking up the shadows a little, in order to darken the clouds.

But what is the camera actually doing here? As discussed in the RAW/Jpeg page, the camera ALWAYS shoots RAW and processes its own Jpeg. We just chose whether or not to make that RAW data available for our own use after the shot.

So in order to understand how the SOOC Jpeg is created using DR expansion, we must look to the RAW file to see what’s going on.

The UNPROCESSED DR200 Jpeg showing the RAW file:

Dynamic Range (DR) set to DR200 (1 Stop)

The UNPROCESSED DR400 Jpeg showing the RAW file:

Dynamic Range (DR) set to DR400 (2 Stop)

The DR modes work, by UNDEREXSPOSING the shot, then applying a brightening tone curve to the dark parts of the image.

So without the camera’s inbuilt tone brightening, we quickly see DR expansion modes for what they are, 1 or 2 stops of underexposure.

The more you increase the ISO of a digital camera, the more you UNDERexpose the image. “But Adam, don’t be daft, everybody knows when the ISO goes up, it’s because it’s dark, and we need a brighter photograph. ISO brightens a picture, it doesn’t darken it”

It’s not quite that simple! ISO gain DARKENS a shot, because it needs to REDUCE it’s sensitivity to light.

So if your camera is set to base ISO (which is 200 on the X-Pro1) and the automated shutter speed selects 1/30, you may think to yourself ‘Hmmm I don’t fancy handholding this at 1/30’ so you increase the ISO to 400, and you’re rewarded with a automatically selected shutter speed of 1/60

This is because ISO darkens, it tells the camera that we don’t mind losing (in this example) a stop of light during image capture, so needing less light, the camera can select a higher shutter speed.

On the X-Pro1:
ISO / Stops
200 / 0
400 / -1
800 / -2
1600 / -3
3200 / -4
6400 / -5

This underexposure is then dealt with in two ways (depending on the SOOC or the RAW)

The SOOC Jpeg is then ‘artificially’ brightened in the camera, so that it’s not too dark

The fact that the image has been underexposed (in this case a stop) is also hardcoded into the RAW file, so that your PP software of choice knows to brighten it.

Underexposure is GENERALLY a bad idea. When we underexpose we lose dynamic range and details.

But let’s have a little bit of fun!!

It’s a very bright scene, and I’ve deliberated blown it out (by using F1.4) so that we can see how the camera and 3 RAW convertors handle it.

So here’s the Jpeg, that’s SOOC and DR has been set to 400 (2 stops)

EPIC FAIL! Even with DR400 there was far too much light and the shot is ruined

OK, lets try the RAW file from the same shot (NB: NO PP WAS USED, SIMPLY OPENED AND EXPORTED TO JPEG)

First up it’s Light Room CC.

Again, EPIC FAIL! LR has read the imbedded instruction in the RAW file to brighten the shot and the net result is about as lousy as the SOOC Jpeg.

Next up it’s Capture One.

Yup, again, EPIC FAIL! C1 has read the imbedded instruction in the RAW file to brighten the shot and the net result is about as lousy as the SOOC Jpeg.

Lastly we have Photo Ninja.

Now PN can be set to ignore all the instructions embedded in the RAW file. As a general rule of thumb this isn’t a great idea, the camera doesn’t embed info in the RAW file for the fun of it, it’s important stuff! But in this rather forced, contrite example, those 2 stops of underexposure have (give or take) just about saved the image.

So if you’re a PN user, habitually like to over expose images and don’t own an ND filter, this might be of interest to you!!!

Hopefully this article has given a little insight into how digital ISO works, and most importantly how the DR expansion modes work.

Now I realise that I’ve (believe it or not) made this as simplistic as possible. There are many RAW convertors and PP software, and of course each has it’s own abilities to recover highlights and boost shadows.

None of my example shots are designed to do anything other than demonstrate what’s going on, and none of them have had any recovery PP work done on them.

But for me?

I leave DR OFF (which on Fujifilm X cameras means setting DR100)

-The maximum dynamic range is base ISO (remember raising ISO darkens the image and forces us to artificially brighten)
-The maximum resolution is base ISO (when we darken an image, we generally lose detail)
-More often or not I go with the RAW file

If I was 100% a Jpeg shooter, I’d use the DR expansion modes, but I probably wouldn’t automate them (ie I would pick when I wanted to use them, and NOT select DR-Auto) but I’m not (a 100% Jpeg shooter) so I don’t use DR.

I go about highlight and shadow recovery in PP, and do my best to expose the shot as I want it within the camera

Of course, as ever, what works for me, needn’t work for you, so go out and find your own settings. But hopefully this piece helps you with doing that.

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