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Phantom 4 PRO lens "sweet spot" test
8812 33 2016-12-28
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Madebyvadim
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Hi everyone, just wanted to share my test with you regarding the "sweet spot" of the new Phantom 4 Pro 1" sensor 20 Mb lens.
Sweet spot is refering to F-stop in a lens that produce sharpest or "most focused" picture outcome.
As you can see from the fist picture I did a test with all f-stops that this lens can do both in automatic focus and manual focus mode.
Typically in traditional photography with DSLR or mirrorless camera lenses the sweet spot it somewhere around F8-9 or close to that points, where lowesr and biggest f-stops are the softest, BUT...
if you look that the chart I made, f2.8 is not the softest one, but rather to my suprise I can't see real difference in sharpness from f2.8 up till f6.3 then at f7.1 focus get softer and at f11 is the softest.
Also on the second picture you can see that I belive is a app's UI mistake in icons. The designer must mixed up macro and infinity icons, because typically you get the sharpest results in infinity manual lens focus setting, but here it's vise versa.
Ok see for your self and I hope this small test will help you in your video or photo productions.
Let me know what do you think.
Fly safe
P.S. Full chart jpeg is here - http://madebyvadim.d.pr/fSzb

Full chart.jpg Focus UI error.jpg
2016-12-28
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Zatx
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So which f-stop do you see as the sharpest?
2016-12-28
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Ange1walk
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Well typically F-Stops don't matter so much in Aerial Photography, but f8.0 is imo the sharpest one.
2016-12-28
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Madebyvadim
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Zatx Posted at 2016-12-28 04:54
So which f-stop do you see as the sharpest?

I would suggest anything form f2.8 to f5.6
2016-12-29
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Madebyvadim
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Ange1walk Posted at 2016-12-28 05:54
Well typically F-Stops don't matter so much in Aerial Photography, but f8.0 is imo the sharpest one.

It actually does now ,before we have fixed f-stops for Phantoms and Mavic hence focus on eternity, but now we have ability to change the f-stop on new P4Pro so we have to be careful not to go over certain f-stops to have the sharpest image possible.
I would say that f8 is on the softer side. I would say f2.8 to f5.6 is the safe choice
2016-12-29
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epicjib
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Madebyvadim Posted at 2016-12-29 08:29
It actually does now ,before we have fixed f-stops for Phantoms and Mavic hence focus on eternity, but now we have ability to change the f-stop on new P4Pro so we have to be careful not to go over certain f-stops to have the sharpest image possible.
I would say that f8 is on the softer side. I would say f2.8 to f5.6 is the safe choice

I find that the manual focus adjustment is not consistent and changes with time. I tested this in the studio with a backfocus chart. Initially if you go all the way to infinity it's out of focus, 25 minutes later it's almost all the way to the infinity mark, It is not consistent with the dial indicator. This will make focusing at night nearly impossible and unreliable, if we can't get the scale to be accurate all the time. I have had my P4P for almost a month and have never flown it and within hours of testing it indoors, I am finding all sorts of bugs and problems, how do the DJI engineers not see all these issues? The beta community can find these within hours of owning these units.
2016-12-29
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CineView Media
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epicjib Posted at 2016-12-29 20:06
I find that the manual focus adjustment is not consistent and changes with time. I tested this in the studio with a backfocus chart. Initially if you go all the way to infinity it's out of focus, 25 minutes later it's almost all the way to the infinity mark, It is not consistent with the dial indicator. This will make focusing at night nearly impossible and unreliable, if we can't get the scale to be accurate all the time. I have had my P4P for almost a month and have never flown it and within hours of testing it indoors, I am finding all sorts of bugs and problems, how do the DJI engineers not see all these issues? The beta community can find these within hours of owning these units.

The focus system on this camera is horrible, and very inconsistent and inaccurate.

Unless youre closer than 30m to the object, adjusting focus is just waste of time, it only makes the whole picture go in and out of focus and doesnt move the focal point back and forth like any quality prime lens does.
My advice, keep it in manual and infinity at all times, then you cant go wrong.

In regards to aperture, in my 10 years experience with aerial photography and EF lenses, i found that Aperture 9-11 is the best area, especially if you photograph horizontally and see "far away" then the distant areas would loose details at larger apertures closer to 2.8
Also remember this is a cheap plastic lens, and cannot be compared to even the cheapest EF lens.
2016-12-30
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Madebyvadim
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CineView Media Posted at 2016-12-30 01:51
The focus system on this camera is horrible, and very inconsistent and inaccurate.

Unless youre closer than 30m to the object, adjusting focus is just waste of time, it only makes the whole picture go in and out of focus and doesnt move the focal point back and forth like any quality prime lens does.

I get that about manual, I almost 99% of time using it with my traditional photography.
The fully thing with the P4P is that it's has error with macro and infinity icon (As I am previously stated in post with pictures attached(, so unfortunately however you are right , at this time its best to keep manual focus at macro all the time.

Also what about focusing at any object more then 30 meters aways, technically its the same as manual focus to infinity?
2017-1-1
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CineView Media
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Madebyvadim Posted at 2017-1-1 11:57
I get that about manual, I almost 99% of time using it with my traditional photography.
The fully thing with the P4P is that it's has error with macro and infinity icon (As I am previously stated in post with pictures attached(, so unfortunately however you are right , at this time its best to keep manual focus at macro all the time.

Yes, im having problems myself with this camera/lens, it appears that focus doesnt work properly, just made another thread about it 5 mins ago you can read.
Unless its a tele lens, i dont think you would see much difference in DOF with this lens from 30m and further.
Also it depends on the distance to the object in the background.
If my camera has a failure, i cannot conclude and say anything for sure, but at the moment, i can barely see any differences at all whe focusing manually from macro to infinity, i can only see the element moving, i might have to compare with another craft to see.
2017-1-1
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gt3rs
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F4-5.6 seems about right for sweet spot, above that on a 1 inch 20mpx sensor diffractions comes in making the picture blurrier. On a 1 inch sensor with an equivalent 24mm lens at f4 focusing at 14m you will get a dof from 7m to infinity.
2017-1-1
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Todka
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When changing F-Stop, which functions did you change t maintain exposure?
If you increased ISO as your stepped up the fstop, it may be sensor noise we are seeing at higher F-stops.
If you decreased shutter speed, it may be motion blur is becoming exhibited.
If you add ISO and Shutter speed to the chart the picture will become clearer, so to speak.  ;)
Nice job doing this test. Much appreciated. I'm keen to know best settings for sharpest images.
Cheers.
2017-1-2
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Madebyvadim
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gt3rs Posted at 2017-1-1 12:30
F4-5.6 seems about right for sweet spot, above that on a 1 inch 20mpx sensor diffractions comes in making the picture blurrier. On a 1 inch sensor with an equivalent 24mm lens at f4 focusing at 14m you will get a dof from 7m to infinity.

Its seems for me too. But really could not find any significant differences in f2.8-f5.6 for landscape shoot * meaning infinity focus as main).
2017-1-5
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Madebyvadim
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Todka Posted at 2017-1-2 02:49
When changing F-Stop, which functions did you change t maintain exposure?
If you increased ISO as your stepped up the fstop, it may be sensor noise we are seeing at higher F-stops.
If you decreased shutter speed, it may be motion blur is becoming exhibited.

99% of the time I shoot at ISO 100 so for me the crucial point of this tae was how short if the f-stop (sort to say( and how far can I go without softening the picture. I was thinking it in practical way to determine I really need ND filters for video.

As for the shutter speed. Drone was stationary on the table all the time so in combination with gimbal system motion blur form shutter speed was 0%

So I did not add this values to the chart as they are not relevant to the test. I should mention it saw ISO 100, just to be thorough.
2017-1-5
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canadagoose
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I can't believe they have the infinity and the macro symbols reversed....even Homer Simpson could figure that one out lol
2017-1-7
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Satureyes
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Actually they did the same with the Osmo and the focus wheel. It's the opposite to how the whole film industry use a focus wheel. There is a setting to reverse it in the DJI go app but not in the drone app. So we have to go in and set it to 'reverse' which is actually the normal way around.

God bless DJI.
2017-1-8
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Madebyvadim
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canadagoose Posted at 2017-1-7 16:21
I can't believe they have the infinity and the macro symbols reversed....even Homer Simpson could figure that one out lol

HA HA! D'oh!
2017-1-8
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Madebyvadim
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Satureyes Posted at 2017-1-8 03:14
Actually they did the same with the Osmo and the focus wheel. It's the opposite to how the whole film industry use a focus wheel. There is a setting to reverse it in the DJI go app but not in the drone app. So we have to go in and set it to 'reverse' which is actually the normal way around.

God bless DJI.

OMG! Indeed God bless DJI!!
2017-1-8
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liningiv
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ERROR. Sorry.
2017-2-9
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Rob8888
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I thought that the icons were back to front several months back, but now I think the design interface is just different to how I expect it to run (the background slides, not the foreground as expected). Either way it's not intuitive and I've given up on it.
2017-2-16
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24ctDrone
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Looks like f 4-6 to me.  
2017-2-16
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Eric13
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Interesting thread, thanks to Mr. Madebyvadim!
Infinity and macro are not reversed. Slide your finger down towards infinity and the camera will focus accordingly.
Slide up and the camera focuses to nearby.
We could argue about the makro being at top and infinity at bottom.
That just doesn't feel right...
2017-4-20
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JoiCam
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I have been in film making for 21 years and my experience tells me the sweet spot for my taste is around and as closest to 5,6 as possible, and i always aim for 5.6 using ND and PL filters to help me out.
It is not only the sharpness I care about, it is also the dept of field (DOF) and dynamic range of videos and pictures.
F stop from f4 to f8 is what I mostly use but I prefer the f5,6 over other F stops.
Of course If I am going for shallow dept of field I use up to f2,8 on the phantom and bigger like f1,2 or f1,4 on other cameras when needed.
ISO settings I use depends on the character and dynamic range I am looking for in the shot and also it depends on light conditions like if the sun is giving me to much of contrast I use higher ISO.
Shutter speed I use is 1/50 for 25fps and 1/100 for 50fps. Always use shutter speed twice the frame rate for video, no more and no less then twice on the Phantom 4 pro camera, Like if you go higher then twice the frame rate you get over sharpen image in the video an you will end up with bad artifacts. The Phantom camera does not have the same rule like many other cameras. Like one for 25fps: 1/160, 1/320, 1/640 etc, and other rules.
2017-4-20
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0mGGhMTKTk2U
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Thanks very much... nice work.. I appreciate your research!
2017-4-27
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Dingoz
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Eric13 Posted at 2017-4-20 02:46
Interesting thread, thanks to Mr. Madebyvadim!
Infinity and macro are not reversed. Slide your finger down towards infinity and the camera will focus accordingly.
Slide up and the camera focuses to nearby.

Manual focus slider is definitely not intuitive and at first I too found out the hard way the icons IMO are reversed.  Immediate perception of this control is the wheel itself is the meter. But as you put it the direction is the meter. Its just plain confusing.

DJI get rid of the fancy scroll wheel (which often leads me to miss hit and enter full screen mode anyway), and just have a flat slide like the gimbal slider. Move the marker towards macro for close focus and visa versa.
2017-9-21
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ribjig
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f8 rule = full frame (full sensor) cameras
this camera is 1" sensor;
so f8 equivalent is f3.5-4?
that said, I am permanently at f4.5 for little extra depth of field insurance...

related: IME, having had (2) P4P+ lenses replaced due to poor diffraction away from center,
there are tremendous differences between lenses in image quality moving away from center towards all edges...
request replacement before warranty runs out if your edges are unacceptably blurry...
2017-10-14
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AntDX316
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I ran my own test and saw f/6.3 as the sharpest.
6-18 08:32
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Madebyvadim
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AntDX316 Posted at 6-18 08:32
I ran my own test and saw f/6.3 as the sharpest.

Good for you
7-8 00:07
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fansdb6ff1f7
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Madebyvadim Posted at 2016-12-29 08:27
I would suggest anything form f2.8 to f5.6

Thanks for the test. That's good information. I've always worked with f5 - f8. I'll try going a bit wider.
7-8 02:20
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Madebyvadim
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fansdb6ff1f7 Posted at 7-8 02:20
Thanks for the test. That's good information. I've always worked with f5 - f8. I'll try going a bit wider.

Glad it helps!
7-8 02:34
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A J
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Great examples - I aways aim for f4.0
7-8 02:45
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Madebyvadim
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A J Posted at 7-8 02:45
Great examples - I aways aim for f4.0

Yep. f4 is nice. Anything below 7 create a nice result
7-8 03:35
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A J
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Madebyvadim Posted at 7-8 03:35
Yep. f4 is nice. Anything below 7 create a nice result

Great advice.
7-8 03:40
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allyssongemelli
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Maybe f/4 or f/5.6 could be the sweet spot?
9-17 11:09
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Madebyvadim
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allyssongemelli Posted at 9-17 11:09
Maybe f/4 or f/5.6 could be the sweet spot?

I guess so.
9-18 07:06
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