The P4P Camera – An attempt to establish The Facts

Mine is very different to that and with a little work the corner detail is possible to recover so it's certainly being recorded - I've used this image before but it gives a decent illustrationView attachment 86410

I don't doubt that you have data recorded in the corners, but your lens is well centred and the image I believe "just get's there". If your lens was a little off centre you would most likely see the edge of the image circle as I do. Even with that, abrupt vignetting as we see here is not the traditional gradual lens vignetting that ventures towards the middle with wide open apertures.... this is very much a corner issue that varies only marginally with aperture and IMO evidence of image circle falloff. :(
 
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the red line roughly shows what the crop is (about 14.5mp) but (if you'd seen the other threads) that is only a small part of the story

View attachment 86413

The embedded profile also adjusts the white balance, boosts highlights, corrects the barrel distortion, supposedly corrects any chromatic aberration then re-scales the image back up to 20mp. These are 'destructive' edits if you use Adobe Camera Raw as there is no way you can reverse the process.

Here's what Adobe Camera Raw sees (all sliders set to zero). As you can see the shadows are way too black, whites and highlights are blown, reds way over saturated, contrast has been boosted and edge detail is much softer than in the raw file viewed in Rawtherapee. This is not what you expect of a raw file.

A quick look at the Adobe raw should tell you that there is a lot wrong - The length of the shadows suggest it was taken early morning (or late evening) so the light should be 'soft' and have a golden hue to it - exactly how it looks in the original unaltered raw. In this version it looks like midday and that's hopeless.

View attachment 86414

It doesn't matter what it compares to and how much of a bargain it is (strawman/fanboy argument) what matters is that it's not outputting what the specifications say and to some of us that matters. I can't say for sure but it's possible that if I had been aware of this issue I would have probably looked at a more expensive alternative platform - every single image being a compromise is not what I call a 'professional' piece of kit.

I said in one of the other threads that publishers and print houses don't want/refuse interpolated images so without a lot more work than should be required the P4Pro struggles to produce the kind of images that it should be capable of and that we were led to believe when we bought the product before this 'cheat' was known
If you picked me as a DJI Fanboy, as you put it, I'm well outside that cohort. I am hoping other manufacturers will produce competing product. I don't aspire to the claim often made that DJI as the jump on technology. The OA is Movidius/Intel, the microprocessors and other critical SOC are all buy ins. Lightbridge is a great name for the wifi standards enabled wifibroadcast protocol. Batteries are manufactured by at least two third party suppliers, likely cameras also- even the so called tuned propulsion system is seemingly nothing more than the factory application note implementation of Texas Instruments three phase motor driver SOC, power mosfets and all. They have market penetration that's for sure, no question. There is still opportunity for completion though it seems.

I asked the question as to what the seemingly usable image size was as I was looking for a correlation to the often stated 15mp number.

I understand your gripe- it would be like buying a reflector telescope and finding that the objective lens assembly only used 75% of the mirror.

My point is simply for the AC (regardless of who the supplier company might be) to carry a lens of equivalent focal length and acceptable sensor coverage would sell at a significantly higher price. Notwithstanding the expectation that the image processing employed in the P4P should have been disclosed in the specifications and marketing is, in my view, reasonable.
 
My reason for starting this thread, which has been described as a waste of time by two contibutors who, I'm pleased to say, keep contributing, was twofold. Firstly to collate the information spread over various threads, much diluted by opinion and counter-opinion, and secondly to discuss the P4P camera performance as factually as possible, with suggestions based on direct observation, detailed knowledge of the subject, or preferably both!. And no, I don't expect it's likely to actually solve anything, but you never know. The more aware that DJI are about people's concerns, and the more that this information filters through to the people who are deciding which drone to buy next, the better!

Moving on.
It's really good to see Andy's pictures reproduced here as they represent facts.

Talking about the vignetting again - there are 3 kinds and the first two are easily identifyable.

mechanical - a restriction in front of the lens system, becomes more abrupt as you stop down the lens (has anyone tried removing the filter, and holding something (soft!) close to the front element so see when it starts to vignette, and what the shadow looks like at different apertures? (I don't have a P4P)

optical, caused within the lens and is usually reduced when you stop down.

pixel - a function of the acute angle of the rays at the corners of the sensor. I think it will also be a function of the back focal distance of the lens, so lens design will infuence it. I read that some sensors have compensation built in. I havn't seen this sensor's datasheet.
There is also comment eleswhere (Wiki) that some cameras have compensation built in - so much for RAW images!

[Note - "stopping down" - making the f/no (number) bigger, like moving from f/32 to f/64]
 
Here's an example from me. Picture taken in 3:2 , 2.8 aperture.

Viewed in Rawtherapee. I have darkened what is gone if opened in Adobe Camera Raw.
Skärmavbild 2017-08-08 kl. 15.24.10.png
And in Camera Raw, un edited:
Skärmavbild 2017-08-08 kl. 15.24.47.png

After the crop the picture is (roughly) 4870x3350, equals to 16.3 MP. Almost 4 MP gone, that is about 18% of the sensor that's evidently unusable. How about that for 20 MP effective pixels..

This bother me a lot actually.

If I apply -0.300 distortion correction in Rawtherapee, the picture is starting to look a lot like how it does in Adobe Camera Raw. See here:

Skärmavbild 2017-08-08 kl. 15.38.39.png

Notice the MP amount is still 19.9. Can this mean the DJI profile actually does not crop and upscale, but only applies distortion correction? That still means the same amount of sensor is unusable but it would still be better. One less destructive save. I actually think this is the case. The file opens so fast, I don't think my PC can handle that much corrections, crop and upscale so fast. It might be just a dist correction. Hopefully.
 
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a few comments -

If you look at the Adobe 'raw' look how blown the highlights in the window are - they have been boosted way above what they should be - having to start off every edit in ACR by trying to rescue highlights is ridiculous.

You have lots more detail and content around the edge of the Rawtherapee version than the Adobe version even after your edits - space below the chair leg at the bottom, candle on top of the speaker etc.

As far as I can tell, the embedded profile does the following....
Uses distortion correction to remove the curvature created by the lens - you can easily duplicate the effect using the warp transform in Photoshop
Crops to take out the edges - it's nearer to 15mp in my experience
Corrects/adjust colour imbalance (very clumsily) to remove chromatic aberration and other stuff DJI/sony don't want us to see
Enlarges back to 20mp.

It's not exactly processor heavy and will be applied as the file is viewed

If images don't really matter (web/phone viewing etc) then the profile is no issue but scaled/interpolated images are too much of a compromise in some circumstances.
 
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a few comments -

If you look at the Adobe 'raw' look how blown the highlights in the window are - they have been boosted way above what they should be - having to start off every edit in ACR by trying to rescue highlights is ridiculous.

You have lots more detail and content around the edge of the Rawtherapee version than the Adobe version even after your edits - space below the chair leg at the bottom, candle on top of the speaker etc.

As far as I can tell, the embedded profile does the following....
Uses distortion correction to remove the curvature created by the lens - you can easily duplicate the effect using the warp transform in Photoshop
Crops to take out the edges - it's nearer to 15mp in my experience
Corrects/adjust colour imbalance (very clumsily) to remove chromatic aberration and other stuff DJI/sony don't want us to see
Enlarges back to 20mp.

It's not exactly processor heavy and will be applied as the file is viewed

If images don't really matter (web/phone viewing etc) then the profile is no issue but scaled/interpolated images are too much of a compromise in some circumstances.
Notice the heavy magenta effect on my highlights in Rawtherapee. How do you suggest I work these away?
 
Notice the heavy magenta effect on my highlights in Rawtherapee. How do you suggest I work these away?
Use the Chromatic aberration tools. Start with auto and then fine tune. you can also use curves to pull those magentas down as well
 
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Use the Chromatic aberration tools. Start with auto and then fine tune. you can also use curves to pull those magentas down as well
I don't have time for this crap. (no offense to you!). I will use the standard DJI profile.

I agree it's shitty work of them but I rather fix any quirks made by their crap auto-profile when I'm posting it anyways in PSP, than work from the start in unfamiliar software.

But, maybe there's a silver way. Can I use any software to delete the camera profile from the .DNG, so when Adobe Camera Raw opens it it will won't auto apply these corrections?
 
I don't have time for this crap. (no offense to you!). I will use the standard DJI profile.

I agree it's shitty work of them but I rather fix any quirks made by their crap auto-profile when I'm posting it anyways in PSP, than work from the start in unfamiliar software.

But, maybe there's a silver way. Can I use any software to delete the camera profile from the .DNG, so when Adobe Camera Raw opens it it will won't auto apply these corrections?


To a degree yes...... set Photoshop as your external editor - open the image in Rawtherapee and click 'ctrl +E' or use the little palette icon (bottom left of the main screen) It will open as an uncompressed Tiff

Here's the wiki manual showing the options depending on O/S

Preferences - RawPedia
 
To a degree yes...... set Photoshop as your external editor - open the image in Rawtherapee and click 'ctrl +E' or use the little palette icon (bottom left of the main screen) It will open as an uncompressed Tiff

Here's the wiki manual showing the options depending on O/S

Preferences - RawPedia
Bah for crying out loud. Do they have to do this.

It makes no sense for them to boost highlights and crush blacks. If they absolutely have to do something, do the opposite!

They don't trust us to know the professional tools. I wonder, is it the same for the X4S camera? They have got to trust the customers of the Inspire 2 with such settings.

I might sell mine, what if it is updated in P5?
 
Bah for crying out loud. Do they have to do this.

It makes no sense for them to boost highlights and crush blacks. If they absolutely have to do something, do the opposite!

They don't trust us to know the professional tools. I wonder, is it the same for the X4S camera? They have got to trust the customers of the Inspire 2 with such settings.

I might sell mine, what if it is updated in P5?


It's easy to boost/blow the highlights - as you've found out, that's a quick and dirty way of losing fringing and aberration. My pics of the cliffs earlier show what they do to the blacks as well - as you say, it's not nice!

I don't think that it's about not trusting us, I think it's about using the cheapest lens they could get away with and playing 'top trumps' with megapixels to impress buyers - it clearly works.

One of the first 'pre-release' reviews I read mentioned that DJI would most likely be updating the camera firmware at some stage as the image quality whilst very good was nowhere near what the sensor was capable of in other applications.

Now that I have a reasonable compromise, I'm less worried by it's shortcomings. a genuine 15mp image is much better for me than an interpolated/re-sampled 20mp one and I tailor my work flow depending on the planned use of the image.
 
It's easy to boost/blow the highlights - as you've found out, that's a quick and dirty way of losing fringing and aberration. My pics of the cliffs earlier show what they do to the blacks as well - as you say, it's not nice!

I don't think that it's about not trusting us, I think it's about using the cheapest lens they could get away with and playing 'top trumps' with megapixels to impress buyers - it clearly works.

One of the first 'pre-release' reviews I read mentioned that DJI would most likely be updating the camera firmware at some stage as the image quality whilst very good was nowhere near what the sensor was capable of in other applications.

Now that I have a reasonable compromise, I'm less worried by it's shortcomings. a genuine 15mp image is much better for me than an interpolated/re-sampled 20mp one and I tailor my work flow depending on the planned use of the image.
Agreed!

Could you please be so kind and describe your entire workflow in RawTherapee for a DJI P4P .DNG?? If possible, upload a preset. I saw you could make them yourself, maybe you have one?
 
I don't have a preset as such because I use RT when an image needs 'bespoke' treatment - however, I'll try and put something together tomorrow if I have a bit of spare time - the weather forecast has forced me to cancel a job in the afternoon so I should have some free time then
 
I would greatly appreciate that! Many thanks if you find the time.
 
I would greatly appreciate that! Many thanks if you find the time.
Edit:

What if I crop away the distorted area in Rawtherapee and open in PSP as usual.. maybe it wont apply the profile then and I can work with controls I'm familiar with? I tried to mess with the metadata earlier to make it not load the profile, but no luck.
 
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Edit:

What if I crop away the distorted area in Rawtherapee and open in PSP as usual.. maybe it wont apply the profile then and I can work with controls I'm familiar with? I tried to mess with the metadata earlier to make it not load the profile, but no luck.

I hope this works. This would be the easiest possible workflow... although it doesn't address the chromatic aberration issues.
 
Edit:

What if I crop away the distorted area in Rawtherapee and open in PSP as usual.. maybe it wont apply the profile then and I can work with controls I'm familiar with? I tried to mess with the metadata earlier to make it not load the profile, but no luck.

no reason not to do that - as I said in the earlier post - export as an uncompressed tiff to retain the maximum data. Adobe Camera Raw/Bridge can be used to (batch) save them back to DNGs if you want to keep them in that format for any reason - it doesn't allow the camera data to be accessed but at least it keeps your future edits as non destructive from that point :)

You can batch process in RT as well - details in the Wiki
 
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I hope this works. This would be the easiest possible workflow... although it doesn't address the chromatic aberration issues.

I firmly believe the easiest workflow comes with CaptureOne (although it comes at a cost). CaptureOne is a professional level RAW processing application that far exceeds LR and ACR for output quality.... and it of course provides a simple menu selection to avoid the DJI profile, while providing all the usual RAW adjustments inc. chromatic aberration.
 
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Ian, how certain are you this is the sensor model?

The IMX183 was identified by tapping into debug instrumentation on the Ambarella SoC. The sensor is 5440 x 3648 which is 19.8MP which is roughly a 1.49 aspect ratio.
 
The IMX183 was identified by tapping into debug instrumentation on the Ambarella SoC. The sensor is 5440 x 3648 which is 19.8MP which is roughly a 1.49 aspect ratio.

The sensor records raw files of 5464 x 3640 which is nearer to 19.9mp
 

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