Dual Pixel RAW is one headline feature of the EOS 5D Mark IV that has gone rather quiet since launch. Initially we all hoped for a lot of focus adjustment, but in reality – there’s not that much.
Dual Pixel RAW
Dual Pixel RAW is only found on the EOS 5D Mark IV and you may be wondering how useful the capability is? Firstly it’s really useful if you want to make memory cards fill up quickly. A dual pixel RAW is around 60MB compared to a standard RAW at 30MB. It also slows the camera down and some camera features are not possible while dual pixel RAW is active.
Those huge dual pixel RAW files can only have dual pixel processing with Canon Digital Photo Professional software. I have found that Adobe Lightroom will process the files, but it treats them like a regular RAW – just slower.
Dual Pixel RAW gives the option of one of three post processing steps;
- Image micro adjustment
- Bokeh shift
- Ghosting reduction
How much focus shift can you actually expect?
Apparently we all have those days where the subject moves fractionally, or we get bumped in to and the focus in our pictures is not right where we’d like it. It always happens more so when wide aperture prime lenses are being used wide open. EF 85mm f/1.2L II USM and EF 135mm f/2L USM folks, you know this to be so.
I took my EF 135mm f/2L USM and set up a focus test chart, the Datacolor Spyder Lenscal. I put the camera on a good solid tripod and positioned the Lenscal 3 meters from the camera. With the aperture wide open at f/2 depth of field is minimal. So the resulting RAW should show what is possible.
So then I process the file in DPP, here’s a crop in to 100% on the RAWfor no shift, full back and full front shift.
No image micro adjustment
Maximum back micro adjustment
Maximum front micro adjustment
To my eye, there’s not much difference between all three. Yes I can see a shift in sharpness but it’s about the same as the shift from an eyelash to the eye, not from the nose to the eye at this distance. Certainly macro photographers will not see much different at close distance. Canon’s folks told me that as the lenses get longer, more than 200mm the effect is reduced too. So wildlife photographers hoping to shift the focus on to a birds eye photographed with a 500mm lens are stuck too.
Super model Ed
Time for Ed, my super model – he doesn’t move, is super quick in make-up and is mostly “clothes-optional”. Fortunately Ed’s rugged skin texture also helps to show any effect. Ed was told to go and stand still next the Spyder lenscal some 3 meters from the camera. There’s only one problem, Ed is a one-trick pony, he only understands a request to ‘stay there and don’t move’.
Ed – with no shift
Ed with maximum back shift
Ed with maximum front shift
What I have found is that dual pixel RAW bokeh shift is more interesting… but i’ll save that for another post.