Focus on DJI Air 2s

[marcushartelt]

Hello,

I switched from the Mavic Air 2 to the Air 2s and wanted to ask how you focus best.

I have so far received different statements on how to be sure that everything is in focus.

I have a shooting coming up where I'm accompanying a rowing club so I want to be sure everything is in focus even in fast shoots.



Do you use tap focus before each shoot? Or do you just let the auto focus do its thing without tapping? Or should i learn using the Manual focus?



How does that compare for shoots of objects like: cars and boats versus landscapes? Any things I have to keep in mind for Revealing shots, for example?

 

[brett8883]

Hello,

I switched from the Mavic Air 2 to the Air 2s and wanted to ask how you focus best.

I have so far received different statements on how to be sure that everything is in focus.

I have a shooting coming up where I'm accompanying a rowing club so I want to be sure everything is in focus even in fast shoots.



Do you use tap focus before each shoot? Or do you just let the auto focus do its thing without tapping? Or should i learn using the Manual focus?



How does that compare for shoots of objects like: cars and boats versus landscapes? Any things I have to keep in mind for Revealing shots, for example?

So I’d be happy to explain to you why this works and the technical aspects of it but I don’t want to bore you or overwhelm you with information unless it’s requested.

If you tap to focus on something about 30 feet away (this is totally ballpark don’t worry about it being exact) and then switch to manual focus to lock this in. Now you won’t need to refocus the lens. Everything will always be in focus unless it’s really close to the lens (like less than 5 feet.)

This works for all shots, it doesn’t matter what the subject is.

 

[marcushartelt]

Thank you very much!

 

[brett8883]

Thank you for the tip! I'll try it out right away. Does this also work at night or at sunset?
And also with photgraphs?

I would also like to know more about it technically, because I also tried it again yesterday to film and photograph with tap focus and likewise without tap focus in AF and saw no difference, what is the reason?

It has to do with depth of field, hyperfocal distance and the optics of the lens. This works for anything and everything on that camera because it’s a fixed lens with a fixed aperture. Photographs, video, night, day, etc. It is the physical characteristic of the lens itself and doesn’t change.

And just to be clear none of this is my opinion and this isn’t some controversial fringe theory. This is science based fact that every professional photographer will understand. This concept works for all cameras but the values will be different depending on the lens. We’ll focus just on the Air 2s lens.

The depth of field describes how much of the photo or video will be in sharp focus. When you tap to focus on something that sets your focus distance. If you tap to focus on something 30 feet away that means your focus distance is 30 feet.

Now it’s not just things that are exactly 30 feet away that will be in focus when you do that. Depending on some other factors things that are a certain distance in front of and back of your 30 foot focus distance will also be in focus. Your focus distance, lens focal length, aperture, and sensor size will determine how much is in focus. There is a formula for this but so have a handy dandy calculator on my phone to compute it.

The focal length of the lens is 7mm and this is fixed it never changes.

The aperture of this lens is 2.8 and this is fixed it never changes.

We know the sensor size is 1” type which isn’t actually 1 inch of anything contrary to popular belief and from here we can determine the circle of confusion is 11 nanometers. You’ll just have to take my word on this. There could be an entire conversation dedicated to what this means and how I got there but for now you don’t need to know what it means as long as we know what value we need to put it into the calculator

So I put those know and constant values into the calculator and then find the focus distance value that would give you the most depth of field


If you focus the camera to 30’ 1” everything that is 4’ 8” away from you all the way to infinity will be in focus. That is enough so that we can say everything will be in focus if you set you focus distance (tap to focus on something about 30 feet away). Even if you focus at 20 feet or 50 feet you get about the same values so like I said it doesn’t have to be exactly 30 feet that just seems like a good sweet spot. This is called the hyperfocal distance, the focus distance that gives you the most depth of field. Some people call this infinity focus even though that’s technically not the correct name for it. Using this how drones like the Mini 2 doesn’t even have adjustable focus. It’s just has the lens mechanically locked at the hyperfocal distance.

I know there’s a lot there to unpack but if you look up videos on depth of field and hyperfocal distance you can learn more. Basically it comes down to the Air 2s having a really wide 7mm lens and a small sensor (compared to 35mm cameras) that make it able to do this.

 

[marcushartelt]

Wow, thanks for the detailed explanation.

Sorry for a dump question, Whats about Shots where i cant get a focus point which is 30 feet away, the nearest is 100m, so i set the Focus on this and the whole Image is also Sharp?

Thanks again and have a nice day!

 

[brett8883]

Wow, thanks for the detailed explanation.

Sorry for a dump question, Whats about Shots where i cant get a focus point which is 30 feet away, the nearest is 100m, so i set the Focus on this and the whole Image is also Sharp?

Thanks again and have a nice day!

That would work on this lens because because it’s so flexible to get a lot of depth of field.

You see that when I plug in 300’ for the focus distance the depth of field is from 5’ 5” to infinity. So it is a little less depth of field than if you focus at 10 meters but it is a tiny difference.

However, what most people do is set the focus at the beginning of the flight so as you take off fly some 10 meters away and then turn the camera back at you and tap to focus on yourself to set the focus. Then switch it to manual focus mode so you lock in that focus distance.

You may at this point wonder if you can just focus at any distance to achieve hyperfocus so let me show you an example of a focus distance where this doesn’t work.

If you were to set your focus distance to 3’ 9” your depth of field would only be from 2’ 3” to 11’ 4”. Everything that is more than 11’ 4” would be blurry. Having said that the it’s not like something at 11’ 4” will be in sharp focus and at 11’ 5” it will be completely blurry and unrecognizable. It is a gradual fall off of sharpness. So the further things are from that 11’ 4” mark the more blurry they will be.

 

[marcushartelt]

Wow, Thanks again mate! The tipp with flying the drone 10m away focus me is very Good and Perfect for all Situation!
I Appreciate your help!

 

[brett8883]

Wow, Thanks again mate! The tipp with flying the drone 10m away focus me is very Good and Perfect for all Situation!
I Appreciate your help!

No problem happy to help

 

[MS Coast]

It has to do with depth of field, hyperfocal distance and the optics of the lens. This works for anything and everything on that camera because it’s a fixed lens with a fixed aperture. Photographs, video, night, day, etc. It is the physical characteristic of the lens itself and doesn’t change.

And just to be clear none of this is my opinion and this isn’t some controversial fringe theory. This is science based fact that every professional photographer will understand. This concept works for all cameras but the values will be different depending on the lens. We’ll focus just on the Air 2s lens.

The depth of field describes how much of the photo or video will be in sharp focus. When you tap to focus on something that sets your focus distance. If you tap to focus on something 30 feet away that means your focus distance is 30 feet.

Now it’s not just things that are exactly 30 feet away that will be in focus when you do that. Depending on some other factors things that are a certain distance in front of and back of your 30 foot focus distance will also be in focus. Your focus distance, lens focal length, aperture, and sensor size will determine how much is in focus. There is a formula for this but so have a handy dandy calculator on my phone to compute it.

The focal length of the lens is 7mm and this is fixed it never changes.

The aperture of this lens is 2.8 and this is fixed it never changes.

We know the sensor size is 1” type which isn’t actually 1 inch of anything contrary to popular belief and from here we can determine the circle of confusion is 11 nanometers. You’ll just have to take my word on this. There could be an entire conversation dedicated to what this means and how I got there but for now you don’t need to know what it means as long as we know what value we need to put it into the calculator

So I put those know and constant values into the calculator and then find the focus distance value that would give you the most depth of field

View attachment 131411
If you focus the camera to 30’ 1” everything that is 4’ 8” away from you all the way to infinity will be in focus. That is enough so that we can say everything will be in focus if you set you focus distance (tap to focus on something about 30 feet away). Even if you focus at 20 feet or 50 feet you get about the same values so like I said it doesn’t have to be exactly 30 feet that just seems like a good sweet spot. This is called the hyperfocal distance, the focus distance that gives you the most depth of field. Some people call this infinity focus even though that’s technically not the correct name for it. Using this how drones like the Mini 2 doesn’t even have adjustable focus. It’s just has the lens mechanically locked at the hyperfocal distance.

I know there’s a lot there to unpack but if you look up videos on depth of field and hyperfocal distance you can learn more. Basically it comes down to the Air 2s having a really wide 7mm lens and a small sensor (compared to 35mm cameras) that make it able to do this.

Thanks for your post; it's particularly useful information for pilots of most drones.

Instead of manually focusing on an object at approximately 30 distance, might it be easier to set the focus to a particular position on the on-screen manual focus slider? The scale isn't graduated by distance, but a little tinkering should reveal the "sweet spot."

 

[marcushartelt]

Thanks for your post; it's particularly useful information for pilots of most drones.

Instead of manually focusing on an object at approximately 30 distance, would be easier to set the focus to a particular position on the on-screen manual focus slider? The scale isn't graduated by distance, but a little tinkering should reveal the "sweet spot."

I use this method for all my shots, whether for photos or videos and it has always worked 100% for me, it's physics after all. It don't has to be exact 30 feet, I also improvise sometimes, because the environment does not always allow 30 feet.
You can only look and try what fits best to your workflow. Good luck with it!

 

[MS Coast]

I use this method for all my shots, whether for photos or videos and it has always worked 100% for me, it's physics after all. It don't has to be exact 30 feet, I also improvise sometimes, because the environment does not always allow 30 feet.
You can only look and try what fits best to your workflow. Good luck with it!

I'm not questioning the physics at all. The objective is to set the focus to a certain approximate distance, near 30 feet. I'm just suggesting an alternative way to set it that might be more convenient for some folks. @brett8833. any thoughts?

 

[brett8883]

I'm not questioning the physics at all. The objective is to set the focus to a certain approximate distance, near 30 feet. I'm just suggesting an alternative way to set it that might be more convenient for some folks. @brett8833. any thoughts?

Whatever method you use to get to about a 30 foot focus distance doesn’t really matter. If you prefer that method it should work especially with how approximate we are talking. However, I personally don’t really trust manual focus by wire to reliably focus at the same focus distance consistently just generally speaking. Again in this case it’s so approximate it would be fine even if it was off by a large margin. Just my preference to use tap to focus.

I don’t have an Air2s but on the DJI drones I do have the focus distance doesn’t get reset between power cycles so assuming the Air2s is the same way you only have to do this once and it should stay locked in. I tend to do redo it frequently but when I am in situations where I can’t rely on the tap to focus method (such as flying at night) I just let it be and have never had an issue.

 

[Jeanb]

It has to do with depth of field, hyperfocal distance and the optics of the lens. This works for anything and everything on that camera because it’s a fixed lens with a fixed aperture. Photographs, video, night, day, etc. It is the physical characteristic of the lens itself and doesn’t change.

And just to be clear none of this is my opinion and this isn’t some controversial fringe theory. This is science based fact that every professional photographer will understand. This concept works for all cameras but the values will be different depending on the lens. We’ll focus just on the Air 2s lens.

The depth of field describes how much of the photo or video will be in sharp focus. When you tap to focus on something that sets your focus distance. If you tap to focus on something 30 feet away that means your focus distance is 30 feet.

Now it’s not just things that are exactly 30 feet away that will be in focus when you do that. Depending on some other factors things that are a certain distance in front of and back of your 30 foot focus distance will also be in focus. Your focus distance, lens focal length, aperture, and sensor size will determine how much is in focus. There is a formula for this but so have a handy dandy calculator on my phone to compute it.

The focal length of the lens is 7mm and this is fixed it never changes.

The aperture of this lens is 2.8 and this is fixed it never changes.

We know the sensor size is 1” type which isn’t actually 1 inch of anything contrary to popular belief and from here we can determine the circle of confusion is 11 nanometers. You’ll just have to take my word on this. There could be an entire conversation dedicated to what this means and how I got there but for now you don’t need to know what it means as long as we know what value we need to put it into the calculator

So I put those know and constant values into the calculator and then find the focus distance value that would give you the most depth of field

View attachment 131411
If you focus the camera to 30’ 1” everything that is 4’ 8” away from you all the way to infinity will be in focus. That is enough so that we can say everything will be in focus if you set you focus distance (tap to focus on something about 30 feet away). Even if you focus at 20 feet or 50 feet you get about the same values so like I said it doesn’t have to be exactly 30 feet that just seems like a good sweet spot. This is called the hyperfocal distance, the focus distance that gives you the most depth of field. Some people call this infinity focus even though that’s technically not the correct name for it. Using this how drones like the Mini 2 doesn’t even have adjustable focus. It’s just has the lens mechanically locked at the hyperfocal distance.

I know there’s a lot there to unpack but if you look up videos on depth of field and hyperfocal distance you can learn more. Basically it comes down to the Air 2s having a really wide 7mm lens and a small sensor (compared to 35mm cameras) that make it able to do this.

Why do you refers to 7mm focal length? DJI doc indicates 22mm.

 

[brett8883]

Why do you refers to 7mm focal length? DJI doc indicates 22mm.

DJI documentation indicates the field of view is equivalent to a 22mm lens on a 35mm (full frame) camera. It doesn’t say the focal length is 22mm lens.

Manufacturers use this terminology to try to portray the field of view in terms people will understand. I’m a professional photographer and even so, if you tell me the field of 88 degrees I generally know that’s pretty wide but I don’t have a sense of exactly how wide that is. Tell me it’s like what you would see looking through a 22mm lens on a full frame camera and now I know exactly what that means.

The smaller the sensor on the camera the more it crops the image from the lens. See photo below.
The smaller the sensor the wider the lens you need to get the same field of view. The Air2S has a 1” sensor which has a 3x crop factor compared to 35mm (full frame) sensor so to get a 22mm equivalent field of view on a 1” sensor requires a 7mm lens.

 

[Jeanb]

DJI documentation indicates the field of view is equivalent to a 22mm lens on a 35mm (full frame) camera. It doesn’t say the focal length is 22mm lens.
View attachment 139854
Manufacturers use this terminology to try to portray the field of view in terms people will understand. I’m a professional photographer and even so, if you tell me the field of 88 degrees I generally know that’s pretty wide but I don’t have a sense of exactly how wide that is. Tell me it’s like what you would see looking through a 22mm lens on a full frame camera and now I know exactly what that means.

The smaller the sensor on the camera the more it crops the image from the lens. See photo below. View attachment 139855
The smaller the sensor the wider the lens you need to get the same field of view. The Air2S has a 1” sensor which has a 3x crop factor compared to 35mm (full frame) sensor so 22mm equivalent on a 1” sensor is a 7mm lens.

DJI documentation indicates the field of view is equivalent to a 22mm lens on a 35mm (full frame) camera. It doesn’t say the focal length is 22mm lens.
View attachment 139854
Manufacturers use this terminology to try to portray the field of view in terms people will understand. I’m a professional photographer and even so, if you tell me the field of 88 degrees I generally know that’s pretty wide but I don’t have a sense of exactly how wide that is. Tell me it’s like what you would see looking through a 22mm lens on a full frame camera and now I know exactly what that means.

The smaller the sensor on the camera the more it crops the image from the lens. See photo below. View attachment 139855
The smaller the sensor the wider the lens you need to get the same field of view. The Air2S has a 1” sensor which has a 3x crop factor compared to 35mm (full frame) sensor so 22mm equivalent on a 1” sensor is a 7mm lens.

Got it ! thanks a lot for clarifying. Not a professional photographer but your answer makes sense to me as a mathematician

 

[PCDroneGuy.com]

Has anyone found a way to lock the focus on infinity or to get MF off the Air 2S screen? Yes, MF can give you a little flexibility, as long as you maintain the predetermined distance. However, that is unlikely since I'm always moving around. To me this flexibility is really just another opportunity to come home with poor video. I prefer the simplicity and reliability of the Air 2 in this regard for sure.