Until now, dual pixels were known only to experts, now it is likely going to change. Canon 5D mark iv has introduced Dual Pixel Raw – a new type of file enabling some really incredible stuff. I was testing the abilities of the new feature, and was really surprised that, yes, photographers can really adjust the shape of bokeh (using Bokeh Shift option) and much more…
I have to admit I am not a big fan of experimental technology – when reviewing cameras I do not really care much about all the geekish details.
But in this case, I was really surprised – during my tests of new Canon 5D mark iv (you can see the review here, in Czech only) I decided to try heavily advertised raw microadjustments, eg saving photos in a special type of raw file – dual pixel raw and playing with it a bit. My expectations were really low, since I was not able to discover any reasonably looking examples of it on web.
But it worked and indeed it is quite interesting – still too early to say if dual pixels can have some real-life impact, but as a “toy”, it is quite impressive.
Just look at the animated gif – you can see two versions of the same picture developed from one dual pixel raw. The difference is quite visible, isn’t it?
Let’s have a more detailed and systematic look…
What is dual pixel raw?
Dual pixel sensor is by no means a new concept – Canon used it in Canon 70D back in 2013, similar system is used by Samsung, for instance, in Samsung Galaxy S7.
And what is it good for? Mainly for very precise autofocusing. Each pixel consists of two parts each of which “sees” slightly different picture. It is quite similar to human eye – people are able to view in 3D thanks to this very simple principle of seeing slightly different picture with both eyes.
This is used in autofocusing systems that are able to estimate distance by comparing two slightly different “views”. Now Canon 5D mark iv gives photographers chance not only to use these signals for focusing, but also possibility to save both pictures separately in one super-raw file (dual pixel raw). And not only saving them but also using them for a new generation of photo adjustments. As you can see from the photos on this page, the changes can in fact be quite significant.
Option 1: Image Microadjustment
How to start? First you need to set Canon 5D mark iv to save photos in dual pixel raw and then to open it with a special Canon’s piece of software called Digital Photo Professional. It can be downloaded from their website (you will need a licence number of your Canon camera to proceed) or just check your camera box with all those long forgotten manuals, cables and CDs… It is on one of them…
Then just go to Tools and activate Start Dual Pixel Raw Optimizer.
There are three major options there. First is Image Microadjustment described by Canon as follows: “When an image isn’t quite sharp enough in a specific area, such as on a subject’s eyes for example, it’s possible to adjust the image and bring sharpness back to a desired area.”
But does it work? I was searching a lot of specialised forums and general view of many Canon fans that, in fact, the effect is very hard to reproduce. That’s certainly true, I was really struggling but after several failures I made it!
So I you carefully view the .gif animations of my daughter’s eye, you can really see that the level of sharpness is moving there and back…
But can this feature be really handy in real-life situations? Frankly, I sort of doubt it… The difference between two levels is very small and would probably disappear after even slight sharpening in Photoshop.
Yes, it is quite interesting but I somehow cannot see dual pixel image microadjustments making it into mass usage…
A different view of the picture…
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This is one of my first experiments, did not really work well…
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Option 2: Bokeh Shift
Bokeh Shift, the second option in Digital Photo Professional, works much better – or I was just luckier during my experiments. Not only it works better, it also made me to write this text, since I was really impressed how different the two “developed” pictures can be…
You can see it on the photo of my wife with significantly changing background. In fact, I somehow cannot believe how the very tiny difference in the view of two small diodes can make so big impact on the overall look of the photo.
Bokeh clearly shifts between two versions of same picture developed from dual pixel raw.
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But it does, although definition from Canon’s pages is rather boring and the example picture not convincing. “With Dual Pixel RAW it is possible to adjust the position of out of focus areas, or ‘bokeh’ to enhance composition, for example moving an out of focus object that is obscuring the subject.”
Yes, it works – and I can really see this tool jumping into real world. It could just be very handy for portrait photographers to be able, for instance, to slightly adjust the shape of what is behind the photographed person.
And maybe it will spread into other branches of photography, but since there are some usage limits (Canon claims best results are achieved with zoom or prime lenses with “long” reach) portraits are likely to be the most probable field.