How to Get Sharper Footage With the DJI X5 Professional Camera
It has been weeks, months even, since I bought the DJI X5 Professional camera for my Inspire 1. I have been desperately trying to justify the cost with sharp, usable footage. I needed to find the best camera settings for the X5 from DJI.
Many people, including myself, were keen to test the X5 against the fabulous Panasonic GH4. This is because it also has a M43 (micro four thirds) camera but in all honesty, that is pretty futile. For one, the GH4 has a higher bit rate of 100mbps at 4K and 200mbps at 1080p. Secondly, Panasonic have been making cameras for a lot longer than DJI.
To further my quest, I bought the Olympus Zuiko 12mm lens for the X5. This is a high quality piece of glass and works a treat on the Panny. Still, as you can see in the video below, I still wasn't getting sharp enough footage from the Inspire and X5 straight out of camera.
Click to play
After much reading and practicing, I re-calibrated the lens and started messing with the settings a little. I decided to also try filming at 29.97p (NTSC) to get smoother footage.
I also had a bit of an epiphany with regards to the aperture setting…
Aperture on the DJI X5
For years I have gone on about apertures and setting them too small (i.e. f22/f32 etc). It is common to think that by using the principle of "smaller aperture = more depth of field (more in focus)". Surely using the smallest possible aperture would produce incredibly sharp images and footage?
Not the case. Meet diffraction.
When you set an aperture that is too small, the light literally starts to disperse or diffract meaning it loses it's clarity. As the aperture gets smaller, the light hitting each pixel disperses more and more. This happens until it starts to overlap the pixels, like "bleeding", and therefore hinders the sharpness or quality.
When choosing a lens for M43 cameras, you need to multiply the focal length by 2x to get the 35mm equivalent. So, the Olympus Zuiko 12mm lens effectively becomes a 24mm lens on the X5.
What many people don't realise is that you need to do the same for the aperture. This is why all M43 lens companies promoting apertures such as f2.8 or f2 are a little misleading.
You also need to double these apertures to get the equivalent 35mm aperture and this may well affect the diffraction ruling.
Diffraction in detail
On the following page, about half way down, there is an excellent visual representation of this entitled VISUAL EXAMPLE: APERTURE VS. PIXEL SIZE.
Lens Diffraction at Cambridge in Colour
Choose a camera with a small sensor (similar to the X5) such as the Canon Powershot G1X. Then play with the apertures. You will see that whilst f4 (f8 35mm equivalent) still gives quality images as the light is kept within the boundaries of the pixels. When you move to f5.6 (f11 35mm equivalent), that light starts to bleed into the adjacent pixels.
Go to f16 or f22 and you could start to see problems.
Holy Grail of Apertures
It is said that f5.6 is the best all round aperture for photography. It gives fairly good depth of field for lenses in the wide to short telephoto range and when used on wide angle lenses, you get great depth of field and high quality sharpness.
I guess it is the same for video.
Therefore, to get close to the equivalent of f5.6 on the Olympus Zuiko 12mm lens, I set the aperture to either f2.8 or f3.2. The results were night and day compared to the video above.
When shooting aerial footage, you are essentially "flattening" the landscape by having no foreground objects to affect focus and depth of field. We also tend to use wide angle lenses in the sky. So, to get good depth of field and everything in focus, you don't need a small aperture of f8, f11 etc.
Setting the aperture to f2.8 or f3.2…or even f4 will suffice for most shoots. After all, did we not all get super sharp footage from our X3 cameras on the Inspire 1 which only shoots with an aperture of f2.8?
Start to set smaller apertures on the DJI X5 professional and you will more than likely start to get "mushier", less sharp footage.
Potential Problems
One of the reasons I was looking forward to the X5 was the ability to set smaller apertures thinking:
- 1It would make for sharper footage due to depth of field
- 2It would make it easier to set slower shutter speeds due to less light hitting the sensor
For best footage quality and smoothness, you should aim to set the shutter speed to roughly double that of the frame rate. Therefore, when shooting in 25p, you should aim for a shutter speed of 1/50th sec. For 60p, look at around 1/125th sec.
However, when using an aperture of f2.8 or f3.2 in bright sunshine, you are going to struggle to get slow shutter speeds. Even at ISO 100, therefore you will need to add an ND filter (I just ordered one for the X5). To bring the shutter speed down 6 stops.
Camera Settings for the X5 Camera
I was using a basic 3-stop ND filter for the video below. Because of this, I struggled to get shutter speeds below 320th/sec or even 640th/sec. My settings for the following video clips were:
In a perfect world, I would like to get to:
To do this, I think I am going to need a stronger ND filter. I look forward to testing more and seeing other people's settings and results. The following is a selection of clips taken yesterday using the settings I mentioned earlier…
Dust
One last thing worth mentioning is dust. If you take your lens off the X5 regularly, you may start to get a build up of fine dust particles on the sensor which can cause spots to appear on your footage.
With a full frame DSLR, these spots only tend to show up with apertures smaller than f5.6. So shoot at f16 with a dirty sensor and it looks like an invasion of flies have entered your shot.
Luckily, when shooting with wide apertures (f2.8-f4), dust doesn't tend to show. Whilst cleaning dust spots from still images is easy, cleaning them from footage can take a fair bit of skill and time.
Focus
For most situations where you are a fair distance away from your subject, always make sure you have focus set to infinity for best and sharpest results.
Caveat: All of the above is just my findings and not necessarily the best solution. If you would like to share your own findings and camera settings, please leave your Facebook comments below.
Clips below have only had minor levels/brightness/contrast tweaked and a tiny bit of sharpening made.
Click to play
Note: There is some banding in the sky due to a little "over-processing" and YT compression…
Sample X5 Images
