Photographing a solar eclipse with a smartphone (safely)

[Andy Resnick]

I've been getting a lot of questions (at work and home, etc.) about using a smartphone to photograph the eclipse. I don't own one, so I thought I'd check in the group here about 2 items:

1) I have been telling people if they place a (ISO 12312-2) solar viewer over the smartphone lens, everything should be fine- is that correct? I ask because the ISO IR transmittance maximum is 3% (OD 1.5), which seems borderline unsafe for the hardware- but since the lens is small, I figured it's fine. Comments?

2) I recall a discussion about an app that gives smartphone users increased control over their camera settings- setting the exposure time, f/#, ISO.... does such a thing exist, and if so, what app?

Thanks in advance!

 

[berkeman]

@davenn

 

[russ_watters]

1) I have been telling people if they place a (ISO 12312-2) solar viewer over the smartphone lens, everything should be fine- is that correct? I ask because the ISO IR transmittance maximum is 3% (OD 1.5), which seems borderline unsafe for the hardware- but since the lens is small, I figured it's fine. Comments?

I'd never looked into it before(googles) -- 3% is just for IR. Doesn't glass (the lens on the camera) stop IR? I use that material on telescopes though, so I'd say the answer is it'll be fine. My main concern would be having enough magnification. My phone is limited to 3x optical.

2) I recall a discussion about an app that gives smartphone users increased control over their camera settings- setting the exposure time, f/#, ISO.... does such a thing exist, and if so, what app?

I'm sure there are lots of pro mode apps for smartphones. I got one that's made for my steadi-cam mount called AOCHUAN which can be used without the mount, just for the camera pro mode.

I guess people don't use real cameras anymore? Even a zoom point and shoot would be much better than a cell phone.

 

[Andy Resnick]

I'd never looked into it before(googles) -- 3% is just for IR. Doesn't glass (the lens on the camera) stop IR? I use that material on telescopes though, so I'd say the answer is it'll be fine. My main concern would be having enough magnification. My phone is limited to 3x optical.

I'm sure there are lots of pro mode apps for smartphones. I got one that's made for my steadi-cam mount called AOCHUAN which can be used without the mount, just for the camera pro mode.

I guess people don't use real cameras anymore? Even a zoom point and shoot would be much better than a cell phone.

Thanks!

Regarding the IR stuff: it matters if the IR cut filters (and the specific glass and/or plastic lens materials) are absorptive or reflective. I just don't know. Since I've yet to see a complaint or discussion about melted/discolored parts, I also assume it's fine. Getting a second opinion, is all :)

Spent some time getting to know my solar filter (Spectrum Telescope, a black polymer film) and I'm glad I did- the OD is higher than I expected (close to OD 6, I think), and I also needed to adjust the white balance settings- the best setting (for me) is a 2500K blackbody, auto expose and auto WB totally failed.

 

[Vanadium 50]

Hmmm.....

Having seen a total eclipse, I suspect a cell phone picture will be disappointing. The outer corona is a dim, wispy thing, probably better served by longer exposures. The inner corona is brighter, so you want a shorter exposure - and therein lies the problem. It is probably impossible to get the beautiful pictures you see with a single exposure, especially with a cell phone camera.

A filter makes this worse.

You also probably have the wrong focal length. The sun is small - half a degree of arc. Most of the picture will be background.

 

[russ_watters]

ving seen a total eclipse, I suspect a cell phone picture will be disappointing. The outer corona is a dim, wispy thing, probably better served by longer exposures. The inner corona is brighter, so you want a shorter exposure - and therein lies the problem. It is probably impossible to get the beautiful pictures you see with a single exposure, especially with a cell phone camera.

A filter makes this worse.

Just to be clear (and it isn't clear if the original question got this): the filter is for the partial phases. Totality is shot without filters.

 

[Vanadium 50]

Totality is shot without filters.

I didn't want to say this, as people may take this as advice as to what is safe to do with their irreplaceable eyeballs. But it also means you are fiddling around with the configuration during the few minutes of totality.

One can improve on this with a tripod and maybe some other things, but once you start down that path you need to ask yourself "do I really want to use a camera optimized for cat videos"?

 

[sophiecentaur]

You can forget fancy results with a smarphone. The 'standard lens ' is far too wide for useful results. you can predict the sort of solar image you can expect by trying to image the Moon on almost any night. You'd be lucky to see any detail but it's a test that will cost you nothing. The shapes of the partial solar eclipse phases will be similar (different actual shapes of course) to the lunar phases. You can decide on whether it's worth while for a solar eclipse.

Incidentally, if you are hoping to use equipment around totality, you will need a red head light to see what you are doing in the dark. A friend of mine was hugely disappointed by missing his one-off chance when he couldn't drive his system.

On an entirely different tack, you can image the sun very well by projecting the Sun's image with a binocular onto a good quality matt white card. You can get an image of several cm diameter which the phone camera can do justice to. Sun spots are easily visible by this method. You need a firm, movable mount for the system but preparation is everything in astrophotography. There's no such thing as a lucky snapshot when magnification is involved.

 

[russ_watters]

I didn't want to say this, as people may take this as advice as to what is safe to do with their irreplaceable eyeballs.

Eyeball damage isn't instantaneous and in any case if you follow the guidance there is no damage. Everyone looks at a total eclipse, regardless of the guidance anyway.

But it also means you are fiddling around with the configuration during the few minutes of totality.

One can improve on this with a tripod and maybe some other things, but once you start down that path you need to ask yourself "do I really want to use a camera optimized for cat videos"?

Yeah, the big upside of using a real camera is that you can script the exposures so you don't even have to do anything with it during totality. You just watch totality with your eyeballs.

 

[Vanadium 50]

Eyeball damage

I'm not going there. I'm also not going to say what I did or didn't do when I last saw a total eclipse.

 

[russ_watters]

I'm not going there. I'm also not going to say what I did or didn't do when I last saw a total eclipse.

I mean, when I was a kid I was fascinated by the heavens and I stared at stars a lot.

 

[sophiecentaur]

Everyone looks at a total eclipse, regardless of the guidance anyway.

Not when I'm around.

I mean, when I was a kid I was fascinated by the heavens and I stared at stars a lot.

You could stare directly at Sirius all night. How much energy would that represent, compared with a few seconds of direct Sun-gazing? There are people who spent / spend hours and hours at loud music concerts and who operate loud machinery. They end up DEAF.

These issues should not be trivialised.

Eyeball damage isn't instantaneous and in any case if you follow the guidance there is no damage. Everyone looks at a total eclipse, regardless of the guidance anyway.

This just has to have been posted ironically. 'Everyone' used to smoke, too (including King George VI - and we know what happened to him).

 

[russ_watters]

Not when I'm around.

These issues should not be trivialised.

This just has to have been posted ironically. 'Everyone' used to smoke, too (including King George VI - and we know what happened to him).

Ok, without the bit of sarcasm, to be clear:

1. You must wear eclipse glasses or equivalent during partial phases (or use an indirect/pinhole viewer). Do not look through a telescope/camera/binoculars/etc with eclipse glasses on (they require their own filters on the objective).
2. You must take the eclipse glasses off during totality, otherwise you will see nothing.
3. Putting the eclipse glasses back on the moment you see the sun exiting totality is sufficient to avoid eye damage.
4. If significant/permanent eye damage occurred due to brief, incidental viewing of the sun, everyone would already be blind. Yes, we shouldn't trivialize the risk, but we also should not overblow it.

NASA on eclipse viewing safety: https://science.nasa.gov/eclipses/safety/

Regarding pinhole viewers: they are for the partial phases. They will not show much if anything during totality.

 

[Andy Resnick]

One can improve on this with a tripod and maybe some other things, but once you start down that path you need to ask yourself "do I really want to use a camera optimized for cat videos"?

I guess people don't use real cameras anymore? Even a zoom point and shoot would be much better than a cell phone.

Having seen a total eclipse, I suspect a cell phone picture will be disappointing. [...] It is probably impossible to get the beautiful pictures you see with a single exposure, especially with a cell phone camera.

One can improve on this with a tripod and maybe some other things, but once you start down that path you need to ask yourself "do I really want to use a camera optimized for cat videos"?

You can forget fancy results with a smarphone. The 'standard lens ' is far too wide for useful results.

Just to be clear here- the majority of people asking (and attending my upcoming talk) are going to use their smartphone because that's all they have. And there are lots of interesting ways to shoot the eclipse wide-angle- a google image search is proof enough of that.

When someone asks me about using their smartphone to take photos during the eclipse, I don't think a helpful response is "Don't bother because your photos will suck".

 

[russ_watters]

When someone asks me about using their smartphone to take photos during the eclipse, I don't think a helpful response is "Don't bother because your photos will suck".

That's fine but it's also reasonable to ask what kind of photos they hope to capture and steer them in a direction that might produce better results.

 

[Vanadium 50]

I think managing expectations is important.

If someone said they have a "1000x telescope" they bought for $45 at Wal-mart and were going to use this to see, I dunno, Phobos, what would you tell them?

I would bet dollars to doughnuts that the pictures they are looking at and thinking they will be taking themselves are composites. The inner corona is quite bright and the outer corona is not. Getting them both requires actual expertise.

 

[sophiecentaur]

I don't think a helpful response is "Don't bother because your photos will suck".

To be fair, I gave an alternative which would actually produce something identifiable. And when people have no idea what to expect they can be disappointed when reality kicks in. That's why I suggested trying lunar images to calibrate their hopes.

I would bet dollars to doughnuts that the pictures they are looking at and thinking they will be taking themselves are composites.

Advertisers are liars.

 

[Vanadium 50]

FWIW, I thought taking a picture of the moon would be a good calibration of expectations.

People think this is what the pictures will look like:

They won't.

 

[russ_watters]

I think managing expectations is important.

If someone said they have a "1000x telescope" they bought for $45 at Wal-mart and were going to use this to see, I dunno, Phobos, what would you tell them?

I recently had dinner at a friend's house, where he had gotten one of those telescopes for his little daughters for Chanukah a few months ago. It didn't work? Well, at least until I pointed it at Jupiter and focused it for them. Meanwhile, @jtbell took this picture during the 2017 eclipse(I don't think from a cell phone though). It's in a collage on the wall in front of me.

 

[DennisN]

2) I recall a discussion about an app that gives smartphone users increased control over their camera settings- setting the exposure time, f/#, ISO.... does such a thing exist, and if so, what app?

Thanks in advance!

I'm answering regarding Android:

There are quite a few such apps, and my favorite is OpenCamera:
https://play.google.com/store/apps/details?id=net.sourceforge.opencamera&hl=en&gl=US

(though, if memory serves me you may have to check a few things in the settings in the app to go "fully" manual)

Also, it is my understanding that many new smartphones have a manual option in their default camera app.

 

[jtbell]

(I don't think from a cell phone though)

No, it's from my Nikon D7000 DSLR. I had to adjust the brightness levels very strongly in Photoshop, using the RAW file from the camera. Here's the JPEG that the camera saved at the same time, unmodified except for image size.

I took some pics with my iPhone 5S, of the crowd (not the sun itself) as totality approached. The phone's autoexposure boosted the overall brightness so much that at first glance they might have been taken during full sunlight. However, the colors and shading are somewhat unnatural. The concrete sidewalk has a definite yellowish cast which is not normal.

 

[Vanadium 50]

I think @jtbell took an excellent picture (pre-Photoshop), and it should be made clear that that is an absolute upper limit on what can be expected.

As far as colors and shading beingunnatural, the world looks (to the eye) very blueish. I believe taht is because we are used to seeing this level of light at dawn and disk, when the illumination is quite red, and we have subconsiously learned to compensate.

If you use a cell phone,

• The sun will be small
• The large dynamic range of the corona will be hard to capture
• It will take a lot of post-processing to get even close to the pictures everyone sees on the web.

People should be aware of this. Maybe they are OK with this, maybe they want to bring a real camera, maybe they just want to use their eyeballs. Futzing with a camera for the few minutes of totality to try and get a picture that will never happen might not be the best use of their time.

 

[sophiecentaur]

Futzing with a camera for the few minutes of totality to try and get a picture that will never happen might not be the best use of their time.

Absolutely. The only way to get the best out of whatever gear you have is to practice practice practice in the light and use the Moon as a doppleganger when you're operating in night conditions.

All this is the same sort of advice for any proposed photography session. Other advice could be to remember to wear your wedding and engagement rings if you ever want a picture published and to take a lot of care with photoshopping. This advice may be wasted on non-UK readers.

 

[OmCheeto]

Anyone have any idea how reliable NASA is regarding experiments?
It looks as though they are requesting a million participants point their unshielded smart phones at the sun during the eclipse to take photos.


Further reading: https://science.nasa.gov/citizen-science/sunsketcher/

 

[Vanadium 50]

It's not NASA; it's Western Kentucky University. NASA is just footing the bill and taking the credit - the Medici's have nothing on them. I spent a few minutes trying to find the exact proposal as the description they offer the public "measuring the shape of the sun" makes no sense. The sun is behind the moon during an eclipse.

Further the sun covers a few hundred pixels, so individual measurements are good to maybe 1000 miles. The sun's diameter is known to 80 miles.

I'm sure they are measuring something useful. But it seems like the story has been oversimplified to homeopathic levels.

 

[OmCheeto]

It's not NASA; it's Western Kentucky University. NASA is just footing the bill and taking the credit - the Medici's have nothing on them. I spent a few minutes trying to find the exact proposal as the description they offer the public "measuring the shape of the sun" makes no sense. The sun is behind the moon during an eclipse.

Further the sun covers a few hundred pixels, so individual measurements are good to maybe 1000 miles. The sun's diameter is known to 80 miles.

I'm sure they are measuring something useful. But it seems like the story has been oversimplified to homeopathic levels.

Actually, my post was in response to Andy's first question in the OP regarding filters. According to their equipment list:

"Equipment: An Android or Apple smartphone running the free SunSketcher app and a tripod or material to position your phone to face the Sun."

I don't see mention of any filter.

From my experience photographing the 2017 eclipse with my not a smartphone camera where I accidentally just kept filming the sun even after totality with no regards to my camera sensors future livelihood with zero degradation was kind of proof that filters are not necessary for smart phones during an eclipse.

Perhaps someone should take some smartphone photos of the sun during the day to test this.