Calibrating Lens?

Figbar · Dec 27, 2015

tweaker said:
Its all part of the fun figuring it out......

This forum is invaluable to the above along with a bit of logic,skull muscle and experience!!

I could not agree more that this forum is invaluable to all of us.

But there is absolutely no reason why a billion dollar company can't spend a pittance to produce some simple how-to videos and/or coherent step-by-step instructions for us.

I'm way past the point where figuring this crap out is fun. I've got too much invested in this to chalk it up to fun with the guys.

I mean no disrespect to you...I love doing all of this, but this company absolutely sucks when it comes to providing comprehensive instructions or procedures on so many critical functions.

Figbar · Dec 27, 2015

rilot said:
Why the hell do you have to even do this? No micro four thirds or slr camera I've ever used need lenses calibrating.
Is the autofocus **** or something and can't compensate for different lenses?

Sent from my iPad using Tapatalk

Amen!

tweaker · Dec 28, 2015

X2 Regarding the above.

Same same with rolling the dice on fw updates that need an update on the update on the update 3.5 nano seconds after release!!

Casey Preston · Dec 28, 2015

rilot said:
Why the hell do you have to even do this? No micro four thirds or slr camera I've ever used need lenses calibrating.
Is the autofocus **** or something and can't compensate for different lenses?

Sent from my iPad using Tapatalk

No other camera allows you to set the focus distance from an app, which is why you've never seen this before. The calibration is not needed for AF, although I've found the AF to be rather spotty. The calibration tells the camera the outer limits of the focus required for infinity focus or the hyperfocal distance. Once the camera knows the infinity focus, it can use the lens profile to estimate the focus distance while controlling the focus motor. An autofocus lens can focus past infinity focus. When it does this, the entire image looks out of focus and mushy. I actually think poor calibration is the reason that so much X5 footage looks blurry.

rilot · Dec 30, 2015

I don't understand. Does the camera have no way of determining correct focus by itself using phase detection or contrast edge detection like other cameras?

To me it just sounds like DJI have bolloxed up the AF implementation and have devised a calibration procedure to get around it.

Sent from my Nexus 6P using Tapatalk

Casey Preston · Dec 30, 2015

rilot said:
I don't understand. Does the camera have no way of determining correct focus by itself using phase detection or contrast edge detection like other cameras?

To me it just sounds like DJI have bolloxed up the AF implementation and have devised a calibration procedure to get around it.

Sent from my Nexus 6P using Tapatalk

The camera does have a phase detection AF and that is what the camera has you use to determine infinity focus.

You can use the AF without calibrating the lens, although ice found the AF to be spotty. I actually agree that the lens calibration procedure is poor. Infinity focus can be pretty broad depending on the focal length and aperture. Also, like I said, I think the AF is spotty and don't trust it to actually find focus.

DJI could have included the a pre calibration in the software for each lens since the camera does get focus setting information from the lens. DJI could then have allowed the user to adjust infinity focus when they found it was off. Most professional DSLRs have a similar feature. I would have preferred this method myself, but DJI would have had just as many complaints and blurry videos using this method of calibration.

bluethundr · Dec 30, 2015

Do you have to do this per each lens you want to use. I just got the x5 version with no lens. I have the Olympus M, ZUIKO DIGITAL ED 14-42mm f3.5-5.6 EZ lens I only have this lens at this time. I wonder if I need a non- zoom-able lens to start this calibration off "right"?

Casey Preston · Dec 30, 2015

bluethundr said:
Do you have to do this per each lens you want to use. I just got the x5 version with no lens. I have the Olympus M, ZUIKO DIGITAL ED 14-42mm f3.5-5.6 EZ lens I only have this lens at this time. I wonder if I need a non- zoom-able lens to start this calibration off "right"?

Every lens and every tablet requires its own calibration.

FlyHighUSA · Dec 30, 2015

bluethundr said:
Do you have to do this per each lens you want to use. I just got the x5 version with no lens. I have the Olympus M, ZUIKO DIGITAL ED 14-42mm f3.5-5.6 EZ lens I only have this lens at this time. I wonder if I need a non- zoom-able lens to start this calibration off "right"?

No you can get a good Cali with the 14-42. It's one of mine and works great.

Floaf · Jan 1, 2016

Casey Preston said:
The camera does have a phase detection AF and that is what the camera has you use to determine infinity focus.

You can use the AF without calibrating the lens, although ice found the AF to be spotty. I actually agree that the lens calibration procedure is poor. Infinity focus can be pretty broad depending on the focal length and aperture. Also, like I said, I think the AF is spotty and don't trust it to actually find focus.

DJI could have included the a pre calibration in the software for each lens since the camera does get focus setting information from the lens. DJI could then have allowed the user to adjust infinity focus when they found it was off. Most professional DSLRs have a similar feature. I would have preferred this method myself, but DJI would have had just as many complaints and blurry videos using this method of calibration.

According to Eric Cheng, the focus is contrast based and not phase detection based.

Casey Preston · Jan 1, 2016

Floaf said:
According to Eric Cheng, the focus is contrast based and not phase detection based.

True, and I can't see how having a phase detection based autofocus would help much on a drone. I just wish the contrast detection was more reliable. It doesn't seem like it should be difficult to program a decent contrast AF, but my cameras is really hit and miss.

Floaf · Jan 1, 2016

Exactly, contrast based should be totally fine. It may take a little bit longer to focus but that should not be a problem here. Maybe if they slow down the focusing process, it will not miss focus so often, or something like that.

Casey Preston · Jan 1, 2016

I'm thinking that part of the problem might be that the AF relies on the low res wireless image being sent to the remote. I'm guessing that it is, but I'm not sure.

Floaf · Jan 1, 2016

Casey Preston said:
I'm thinking that part of the problem might be that the AF relies on the low res wireless image being sent to the remote. I'm guessing that it is, but I'm not sure.

That sounds like the worst way ever to handling focusing but who knows

RaptorMan · Jan 12, 2016

So, if the lens calibration data is stored on the tablet and if using a different tablet/phone requires a separate calibration has anyone determined what file(s) are used and can they be copied from one tablet to another?

Brian

Droider · Jan 12, 2016

Hi Brian. its all smoke and blooming mirrors!. I have gone down the Manual focus as we shoot with the olympus 12mm we have for the bigger rigs. Seems to be working ok.

The Editor · Jan 12, 2016

RaptorMan said:
So, if the lens calibration data is stored on the tablet and if using a different tablet/phone requires a separate calibration has anyone determined what file(s) are used and can they be copied from one tablet to another?

Brian

Simply calibrate on each tablet for each lens you use. It isn't exactly time consuming and the lens settings are retained. If you buy a new lens add it to the calibration table for each tablet.
How many tablets do you utilise? You do not have a dual remote setup even so I'm guessing a maximum of two?
It will take you longer to brew a cup of coffee!

Droider · Jan 12, 2016

As we mainly shoot video then I really don't need it but we have 4 iPads. two for pilot and two for cam op so its a bit of a faff.

Casey Preston · Jan 12, 2016

Droider said:
Hi Brian. its all smoke and blooming mirrors!. I have gone down the Manual focus as we shoot with the olympus 12mm we have for the bigger rigs. Seems to be working ok.

Yeah using manual focus on the wide angle Olympus lenses definitely makes the most senses. Just manually set to infinity focus and call it a day. It's a lot easier to find infinity focus by manual adjusting versus using the AF program. I wish that DJI would actually program a method that allows manual fine tuning of the infinity focus rather than just relying on whatever point the AF drive picks out.

RaptorMan · Jan 12, 2016

The Editor said:
Simply calibrate on each tablet for each lens you use. It isn't exactly time consuming and the lens settings are retained. If you buy a new lens add it to the calibration table for each tablet.
How many tablets do you utilise? You do not have a dual remote setup even so I'm guessing a maximum of two?
It will take you longer to brew a cup of coffee!

I have four useable lenses so to calibrate all of them it must be done one at a time. Changing lenses in the field risks getting dirt into the camera and as a photographer I know all to well how undesirable it is to get dirt on the sensor. I'm not saying I won't change lenses in the field just that I'm not looking for new reasons to do so.

I do have two tablets and a smartphone so three potential devices making twelve lens changes. If the data is in a single file as I suspect it is it would be far quicker to copy the file among devices and it wouldn't risk getting crap on the sensor.

But, even if none of that applied, why should I not copy the file?

Brian