Auto or manual exposure for the upcoming solar eclipse

[jayeldee]

I will take my mini 4 pro to the April solar eclipse. I plan on launching it about 6 min before totality, pointing it facing SSW and catching the approaching shadow, then bringing it down when the shadow had gone...so probably an inflight time of about 15 min total.
I will not be using it to shoot the sun, just the shadow coming at me at about 1000mph. I'll have two other cameras set up for that.
If I use auto exposure on the Mini, the camera will compensate for the lower light during the eclipse and brighten things up, maybe not that big of a deal if I can catch the shadow approaching and departing.
If I use manual exposure, it will require someone at the controller to manually adjust things (thus missing some of the "experience") unless I leave the exposure at the daylight exposure and trust that during totality some detail will still be captured.
Which way would you go on this?

Also, is there a calculator that shows how many gB of data will be captured during that 15 min whether I use 12 or 48MP?

Thanks in advance and would appreciate any advice on this.

 

[MotoSavy]

That would be great to be there for such a great event. I have never had to opportunity to witness such a great spectacle.

Can't tell you off the top of my head how much space you would need for each size. I have big cards on both of my drones. I have a 1TB on one and a 512GB on the other. And also big cards on my DSLRs.

One thing I do recommend, is to offload your card of all images before the event and format it in the drone. I have followed this rule for years on all my cameras and have never had any corruption of Memory Cards.

Some people don't follow this practice and have never had problems. Sometimes if you offload with the card directly connected to your PC, it could write something to the FAT, that the camera or drone may not like and cause corruption.

And that is why I always format a card in camera or drone after using it on my PC.

 

[LeeB]

Perhaps using the AEB (Automatic Exposure Bracketing) setting for your camera would help. You should be able to get 3 or 5 exposures of each image (normal, over, under). Then you can pick the best one or combine them using HDR software to blend them.

 

[Robert Prior]

Which way would you go on this?

You're effectively going from day to night and back again. I don't think the sensor has enough dynamic range to handle that without some form of changing exposure.

I'd be inclined to shoot it as a time exposure (hyperlapse) rather than a video, saving the raw files to allow me more options to change exposure/cropping in post. I'd pick the shortest time interval between shots for this. I'd shoot in auto-exposure because there are apps that can compensate for that by adjusting each image so they have the same exposure before stitching them into a video.

 

[Illuminata Photo]

First, this is a great idea! I’m planning on photographing the eclipse, so will also be thinking about this.

I’m a photographer, too, and my current inclination would be to use something like 4K video set to an auto capture. I’ll be too busy with my still cameras in the ground to worry about the drone video capture. Set it and forget it. Whatever I capture with the drone video I’d clean up in post-processing.

I took several videos a week ago with my Air 3. The longest was about two minutes and the file size was ~1 Gb. I don’t recall if it was 4K or what. Anyway, it’s very easy to run your own experiment and figure out your file storage requirements.

Thanks for the idea! Something else to keep me busy!

 

[jayeldee]

to respond and many thanks for the input

yes, I am going to test beforehand. I will just left the Mini hover—extended battery—at 4k and see how long it lasts...if it lasts anything over 16 min, I think that part is good and will likely shoot 4k.

My main focus will be a two camera setup, one stationary to create a composite, one on a clock drive for detail work—and bracketing, so that will make me pretty busy, too busy to play with the controller during totality. I am using the drone solely to catch the shadow approaching and departing and the 360 degree horizon which will likely be orange. My son will handle drone duties. We will shoot at first toward SSW, during totality will pan 360 degrees, then point NNW for the shadow departing, then land. The shadow travels at somewhere between 1500 and 3000 mph depending on location—prob the lower end where we will be in Texas.

My concern is exactly as expressed by Robert Prior, ie exposing for daylight then let the shadow fall where it may, and that is why I was thinking about just using auto. Concern there is that auto in totality may brighten things too much and the viewer would lose the sense of "darkness" (which during totality is more like a moderately deep twilight, ie NOT night-time).
Thanks for the responses! Clear skies!
@Illuminata Photo
Yes, I saw someone mention this on CloudyNights.com and I thought it sounded like a great idea also, as if I won't have enough to do during those 288 seconds! The stationary camera will be automated, taking a shot every 5 minutes from 1st contact to 4th. The camera on the clock drive will be for more detail work (1200mm focal length). It is not a well regarded telescope—Bausch and Lomb 4000, but I think I have a decent copy and have used it on previous eclipses with acceptable results, for me.

 

[Illuminata Photo]

So, will you use a star tracker with your camera setup? I hadn't thought of this before, but it makes a lot of sense! I have one and just realized that I could use it for the eclipse. Wow, my head is exploding with everything that you're making me think about!

 

[reedyjt]

I took video of the eclipse in 2017 with my Phantom 3 pro. It turned out decently in auto exposure mode. I could post it here if there's enough interest.

A couple of things to keep in mind: 1. Be sure to cover up all the lights on your drone if you are going to be flying in an area with other people around watching the event. You don't want to be "that guy" that ruins someone else's one in a lifetime experience. 2. Don't expect to see a sharp shadow traveling across the landscape even from 400 feet up. It just didn't happen that way for me and it was a fairly clear day.

Good luck!! I plan to use my lessons learned from last time to hopefully get even better footage this time around with my Mavic 2 pro.

 

[jayeldee]

@Illuminata Photo
My telescope has a clock drive and I will run that through an inverter from my car battery. I did that for the annular eclipse in October and it worked well enough. It did require fine tuning often enough, but probably because I didn't have it polar aligned well enough...but it worked far better than nothing. Sorry to make your head explode, LOL. I know how that feels! To polar align you point the "fork" of the mount toward the north. I used the compass on my phone to do that, but I surely could have done it better. Also, it is important to tilt the fork of the telescope mount to your viewing latitude, and that was a very coarse adjustment on the mount, but I think it was pretty close
@reedyjt very good point on the lights! I did not think of that and I really don't want to be THAT guy. I suspect I will be on the side of a farm road somewhere in the Texas boonies, so there may not be many people around at all...though we do generally clot together.
I'm hoping to see the shadow, but would not expect it to be "sharp", more of a sense of darkness approaching. You used auto exposure before in 2017; do you think it would have been better had you used manual exposure and take your chances on landscape detail during totality? As Robert Prior says above the camera may not have that much dynamic range to capture usable images from both before/after and during totality. IOW if the exposure is set for daylight can it capture the landscape during totality, will there be enough light?

 

[MS Coast]

IOW if the exposure is set for daylight can it capture the landscape during totality, will there be enough light?

You might get a good approximation by setting the exposure for daylight and then capturing images with the same setting during the night under a light level (time after sunset, cloud cover, moon phase) similar to what you expect during totality?

Then again, do you really need that much detail during totality? Things are supposed to go dark then.

 

[jayeldee]

All good points, MS Coast, but I would like to have some shadow detail and not just a black screen. I was thinking about performing the exact experiment you suggest, ie get a manual exposure on a sunny day at around 1pm, then, using the same setting see what it looks like just after sunset.
I tested the drone today. I used a fully charged extended battery and just hovered in my house. The charge lasted about 25mn. I was running 4K video for about 24 mn and then it did a forced landing because of low battery. IOW plenty of time for what I want to do.
I was looking at my card tonight and it captured the video in 5m26sec chunks, each 3.76gB, so card real estate is not a problem.
I can stitch them together in post, but is there a setting to make a continuous video and not chunks?

 

[MS Coast]

All good points, MS Coast, but I would like to have some shadow detail and not just a black screen. I was thinking about performing the exact experiment you suggest, ie get a manual exposure on a sunny day at around 1pm, then, using the same setting see what it looks like just after sunset.
I tested the drone today. I used a fully charged extended battery and just hovered in my house. The charge lasted about 25mn. I was running 4K video for about 24 mn and then it did a forced landing because of low battery. IOW plenty of time for what I want to do.
I was looking at my card tonight and it captured the video in 5m26sec chunks, each 3.76gB, so card real estate is not a problem.
I can stitch them together in post, but is there a setting to make a continuous video and not chunks?

The video file size maximum is an unavoidable, but minor, limitation of the drone's video system. Just stack the files on the time line in the video editor and all appears seamless.

 

[EyesWideShut]

Sounds like you've got your plan figured out. Hope you post the results! Now to pray for clear skies...

 

[Zbip57]

I took video of the eclipse in 2017 with my Phantom 3 pro. It turned out decently in auto exposure mode. I could post it here if there's enough interest.

Please, do post it.

 

[Droning on and on...]

1,500 mph is 2,200 ft/s. While it will make file sizes much bigger, I'd shoot this at 4K/100 or FHD/120 which the Mini 4P is capable of.

In 4k/30 you'll have like 3-5 frames of the shadow passing by, which won't be too exciting.

As far as overexposure in auto, stop the EV down, maybe -1, shoot dlog, and color correct in post to bring out the detail in the shadow.

 

[jayeldee]

Thanks ^
>1,500 mph is 2,200 ft/s. While it will make file sizes much bigger, I'd shoot this at 4K/100 or FHD/120 which the Mini 4P is capable of.<
So, higher is better for a longer view. Any suggestions how high that should be? right now I am set to 300 ish feet.
>In 4k/30 you'll have like 3-5 frames of the shadow passing by, which won't be too exciting.<
good point

>As far as overexposure in auto, stop the EV down, maybe -1, shoot dlog, and color correct in post to bring out the detail in the shadow.<
But wouldn't that really underexpose during totality. Don't understand.

 

[Droning on and on...]

>As far as overexposure in auto, stop the EV down, maybe -1, shoot dlog, and color correct in post to bring out the detail in the shadow.<
But wouldn't that really underexpose during totality. Don't understand.

That's a real risk, part of what dlog is supposed to help with by extending dynamic range at the low light end.

Best strategy would be to go out and shoot at night, experiment with Auto, Pro, EV settings, and get to know what you're working with before the event.

It's easier to recover some image data at the low end with Dlog than it is to try and restore blown out highlights.

Also keep in mind that 100/120fps are special slo-mo modes, so you have to select that rather than regular video and setting the resolution and framerate the usual way.

Then in post, you'll need to adjust the playback framerate in your editor to 100/120 to get real-time playback.

 

[jayeldee]

Thanks again,
That's a real risk, part of what dlog is supposed to help with by extending dynamic range at the low light end.

Got it; would that, dlog, setting tend to overexpose the daylight setting and that is why you suggest -1 exposure compensation?

Best strategy would be to go out and shoot at night, experiment with Auto, Pro, EV settings, and get to know what you're working with before the event.

Yes, I completely agree and when it stops raining, I am going to do that...it could be that there is a Goldilocks exposure setting that would satisfy both pre/post and totality close enough. Maybe even AUTO would work, just don't know now

It's easier to recover some image data at the low end with Dlog than it is to try and restore blown out highlights.

Right, if something is blown out, it's gone. Shadows may have some room to open up.

Also keep in mind that 100/120fps are special slo-mo modes, so you have to select that rather than regular video and setting the resolution and framerate the usual way.

Then in post, you'll need to adjust the playback framerate in your editor to 100/120 to get real-time playback.
Or watch it in slow motion and considering the speed of the shadow's advance and departure, that may be a better option

 

[reedyjt]

All good points, MS Coast, but I would like to have some shadow detail and not just a black screen. I was thinking about performing the exact experiment you suggest, ie get a manual exposure on a sunny day at around 1pm, then, using the same setting see what it looks like just after sunset.
I tested the drone today. I used a fully charged extended battery and just hovered in my house. The charge lasted about 25mn. I was running 4K video for about 24 mn and then it did a forced landing because of low battery. IOW plenty of time for what I want to do.
I was looking at my card tonight and it captured the video in 5m26sec chunks, each 3.76gB, so card real estate is not a problem.
I can stitch them together in post, but is there a setting to make a continuous video and not chunks?

Please, do post it.

The file is "too big" to post according to this sites policies. Ideas???

 

[Zbip57]

The file is "too big" to post according to this sites policies. Ideas???

Upload to YouTube, then post the link here.

Here's an interesting video using a 360° spherical camera, allowing you to click-and-drag the view to any angle as the shadow passes overhead, starting at about 4:20. It shows how much the lighting changes.

This guy (his videos are great) made a free app, "Solar Eclipse Timer", which based on your GPS location announces the timing of things to watch for. The app is free, but the actual data pertaining to this eclipse has to be purchased and downloaded for a mere $3.

www.youtube.com/watch?v=WzC4aGE6heI