Question About Shooting the Next Lunar Eclipse

[astrostu]

We have a total lunar eclipse coming in just under two weeks. The thing is, I've "done" lunar eclipses now and grown jaded with the up-close moon-fills-the-frame thing and very, very, VERY slowly (over 5-6 hrs) seeing it change colors/shades/brightness. And dealing with mounts that track the moon that, if off by a teeny bit, result in smearing because I'm using a 1280 equivalent lens.

What I really like these days is the shots that show the stars, partly because a total lunar eclipse is the only time you can photograph a moon and stars in the same shot with the same exposure. And, I have a fairly good landscape near me, the moon will arc over a valley, start eclipsing maybe half-way through, and then set while still partially eclipsed over some mountains (assuming I have my geometry right, I need to watch the path the day before).

The question is, how should I do this? Ideally, I'd have two cameras. But, I bought a 14mm f/2.8L this year which shot (ha!) my camera budget, and I decided awhile ago that my 7D will have to do until the 5D MkIV comes out.

My intent is to do a timelapse. In the past, when using the super-dooper-closeup lenses, I've done it once every 5 minutes. If I want to show the moon's motion over the landscape, I'll probably need to shoot at least once a minute to make it smooth. With a 5hr 15min event, once every minute = 315 frames = only 10.5 seconds at 30fps, so I'd probably want at least every 30 seconds. To do slow-moving clouds, you need once every 10 seconds. I should probably experiment the night before ...

My 14mm will almost get the whole field of view, but not quite. I'll need to check exactly how much the morning before. But, the moon's a tiny spec in a 14mm lens. My 24-70 gets a much narrower view, so I'd have to move it and I don't think can get the foreground and moon in the same shot when the moon is highest. But it would allow me to zoom in, and do a quick-swap between shots to the 70-200 to get even closer. Thoughts on focal length / lens(es), keeping in mind I want a cohesive and smooth timelapse?

What about exposure and post-processing? Many of us know and politely remind others that the moon is really bright and night is really dark. You need a maximum of 1/60-sec for a full moon, usually closer to 1/250 depending on atmosphere and f/# (and ISO). But during the total eclipse, it dims by a factor of around 50,000 (last lunar eclipse, I calculated a dimming of closer to 62,500x). And, I want to get the landscape. The vision in my head is a movie showing a brightly lit landscape with a glowing moon where you can just barely make out detail, and then the landscape dims as the moon turns red and travels through the stars for an hour, to start to emerge just as it sets. Beautiful movie in my head, but I have no idea how to pull it off when I'll need to somehow combine 1/250-sec with a 5-10-sec shot, and a few hours later be pulling 10-second shots at ISO 800 so the moon doesn't move in the frame. And if I'm using 70 or 200mm at that point, I actually probably can't go longer than 5 seconds without seeing trails. Thoughts?

 

[TreeofLifeStairs]

Sounds like you have things pretty thought out. You may want to test things before the actual occurrence. Go out to that spot on a new moon or when the moon isn't visible in the sky (I don't know if this is possible before the eclipse) to test out what the settings are to get the stars exposed properly. That way you're not shuffling when it's fully eclipsed and on a time table.

You still may have to do a composite for the foreground; I don't know.

 

[astrostu]

My standard go-to star exposure these days with my 14mm is 15 sec, f/2.8, ISO 1600. With my camera body, the moon should move around 2 pixels in that time, so indistinguishable. But at 200mm, I have 1 second before it moves 2 pixels, at 70mm I have about 3 seconds.

 

[Rick50]

Thanks for posting this. I would have missed it as it hasn't shown up on any news feeds yet. In any case I'm going to try shooting it using a 300mm lens and tripod. My only hope will be a high ISO. Seems anything less than 300mm will not produce any good resolution. A tracking telescope might be the only answer here.

 

[astrostu]

If you're shooting at 300mm, then anything longer than a second or so is going to show motion blur, so yes, you'll have to use as wide an aperture as possible and then just bump up ISO during totality. Last eclipse I was shooting for 15 seconds at f/8 (400mm f/4 +2x extender) at ISO 800 to get a reasonable exposure.

 

[NancyMoranG]

Don't want to hijack, but can we also include how to photo the moon in different positions and make it 1 photo ?
We see photos of the moon 'across the sky' in same photo...
Or moderator can delete..
Nancy

 

[Rick50]

I'll have to play. I have a 1.4x and a 2.0x extender but don't want the light loss. My 300 is an F/4 and I have shot as high as ISO 12,800 so hopefully 1 second or less will work. Will be a long night as I intend to get a full moon setting at 6:30am. Sun rise is 6:45am so there should be enough light to include some foreground objects. I'm using a Canon 5D3 camera which is pretty good at high ISO.

 

[Rick50]

Nancy,
I think I can find a reference for you. The answer is yes, you can combine multiple photo's of the Moon into one photo.

 

[astrostu]

This is definitely going to be difficult. A test tonight showed a 14EV difference between the moon being reasonably exposed and the landscape. My thinking at the moment is that I can use levels to set the background to cap out at ~200 (using 8-bit numbers even though I'm editing in 16-bit), set my moon to use 0-55 levels, and set the moon to a Linear Dodge. Use curves to darken the maria on the moon a bit.

This should work in principle, but on s 20-second exposure, the moon has a glow in the frame that's around 3x its actual extent. If that glow were 3x smaller, I think this solution would be perfect. But because it's so large, it looks ridiculously fake. I suppose I could just increase the moon size.

 

[Rick50]

Nancy,
Here's a reference video. You can also search 'Combining images' in YouTube.


stu,
If you can pull that off your way above me. I have not figured out how to get rid of the moon glow without just replacing the moon. I have resorted to only shooting the moon with foreground objects to the twilight hour around sunset or sunrise. Then there is enough light in the sky. Then there is always 'Black Magic'.

In this pic I set the exposure for the moon (to reduce that glow) and used flash for the foreground.

Then I thought Well why not just replace the moon.

This one is real but I can do a lot better with the timing. Here the sun was way to high. I used focus stacking on this.

Here the timing was right but I was slightly off in my focus.

 

[astrostu]

The problem with just replacing the moon in such a long exposure is that it really tends to look fake. In this case, the actual glow is a large gradient that extends maybe 10x from the moon, while just the center 3x is what's completely saturated. So I'd be replacing a large chunk of the sky, and you run into issues where it really just looks like it was simply plopped down in there, which is something I'm trying to avoid.

 

[astrostu]

I've thought a bit more about this in terms of processing, and there's some theory and then putting that into practice.

Exposure, Moon: For the full moon, the longest exposure I can do is about 1/125-sec, f/2.8, ISO 100.

Exposure, Moon, Eclipsed: The shortest exposure I can do is about 4-sec, f/2.8, ISO 100. Longer would be better.

Exposure, Stars: The shortest exposure I can do (without boosting the EV in post-processing) is about 15 seconds, f/2.8, ISO 100. Longer is better, but >20 sec at 14mm gives star trails, >15 sec at 24mm gives star trails.

Exposure, Landscape: Longer the better. At least 20 seconds, but can compensate in post-processing.

Shooting Frequency for Time-lapse: Once every 20 seconds is preferable. I haven't tried once every 30 or 40 seconds, but I've done a lot of stars time-lapse with 20 seconds and it is smooth when merging to 30fps.

Theory Behind HDR: The theory here is you have a dynamic range that is too large to be captured by a detector with one exposure setting. So, you can take multiple exposures and combine them. To make the numbers simple, you take a 1-second exposure and record light from 10 to 100 (the max of your detector), and you take a 0.5-second exposure and record light from 0 to 75. If you had basic image arithmetic software, you would multiply the values in your 0.5-second exposure by 2, and for anything >100 in the 1-second, you replace it with the value in the 2x0.5-second. That way, you get around the fact your detector can only record 0-100, and get a final image that can span 0-150 (but spans 10-150 because 10 was the minimum in the 1-second exposure). Seems simple enough.

But for this case, we're talking about a difference of something like 12-14EV between the moon and the landscape/stars (for the uneclipsed part). How do you represent that in an 8-bit JPG (-> movie frame), and how do you put that into practice?

Attempted Steps: (1) Bring the background image into Photoshop. (2) Apply a clipping mask Curves layer and set the brightest point instead of at (255, 255) to around (255, 180). This means that the bright white saturated moon, with a brightness of 255, will be mapped to about 180. (3) Bring in your moon image as a new layer. (4) Set blending mode to Linear Dodge (Add). (5) Apply a clipping mask Curves layer and set the brightest point at (255, 75). [Even though I'll be editing in 16-bit, Photoshop still uses 8-bit numbers for curves key points.]

What this does is attempt to put theory into practice by adding those unsaturated (short exposure) moon pixels onto a scaled-down saturated (long exposure) moon.

A problem putting that into practice is scattered light from the moon that makes the saturated area practically 3x the actual size of the moon. So, I increased the moon's size by 3x. Here's a rather large (HD frame size) attempt at doing that with a 30-sec and 1/125-sec exposure.

I think it looks fake, but I'm not sure how to improve it. Thoughts? Also, there are some star trails and I was walking on the deck so they're jiggly, but that's because it was 24mm at 30 sec rather than 15 sec.

Focal Length: Sometimes I wish I bought cheaper lenses, for a 14-300mm would be nice for this application. Last night, the moon was about 35° above my horizon, and my 14mm lens easily captured that. On the night of the eclipse, altitude gets up to around 50°. The field of view of my 14mm lens on my 1.6x crop 7D body is roughly 52° by 78°. Meanwhile, the moon's azimuth will change by around 70° from eclipse start to moonset. So ... a 14mm will almost work, but then the moon will be about 34 pixels across. At 24mm, it's about 52 pixels across. At 70mm, it's about 140 pixels across. And all of these would be x3 if the above method is what I'm using to combine images.

Changing Lenses: My 24mm won't capture the mountains and moon at the beginning of the eclipse. It won't until the moon is totally eclipsed, around 2 hrs into the event, when the moon will be about 30° above the horizon. A problem is that I don't have a 14-24mm, and changing lenses while going for that "HDR" effect will not be seamless because the apertures of the lenses are different and so the glow/glare/flare will be different.

Possibly Playbook (times are MDT):

- 2:00 - Use 400mm +2x to get several shots of the moon, pre-eclipsed, to use in case I decide to really fake things.

- 2:00 - Use 14mm to get several shots to stitch into a panorama of the landscape (stars and moon being PS'ed out).

- 2:00 - Put 24mm lens on and ensure focus is correct.

- 2:10 - Set everything up with 14 mm on camera, timer set for 40 second interval shooting. Moon should be in upper-left corner.

- 2:15 - P1 contact. Start shooting every 40 seconds, taking 1/125-sec immediately followed by 20-sec shots. Adjust intervalometer timing if absolutely necessary.

~ 3:00 - U1 contact in +15 min. Shots have probably increased at this point to 1/60-sec or so. Also need to take 1-sec shots with the 1/60 and 20 to properly expose umbral part of eclipsed moon.

- In post-processing, will start to zoom into the moon at this point.

~ 4:10 - U2 contact in +15 min. Shots will be ~5 sec and 20 sec, MIGHT be able to get away with only 20-sec shots and still properly expose eclipsed moon.

~ 4:15 - Switch to 24mm lens. If the movie will be 30 fps, then zooming entire way to 70mm should be done over the course of no less than 100 minutes -> 5 seconds in time-lapse (150 frames). Alternative way is every 15 frames (10 min), increase focal length by ~5mm which will get me to 70mm after 135 frames -> 4.5 seconds time-lapse. In post-processing, each cluster will be a separate move clip and will need to zoom in smoothly in the animation software via careful key framing. As focal length increases, shutter speed must decrease so ISO must increase to get the same exposure. By 70mm, can only be taking ~1-2 second shots, so ISO must be ~10,000-20,000 to get the same EV.

[4:56 - Greatest Eclipse]

[5:24 - U3 contact]

~ 5:45 - Should be done zooming to 70mm focal length. Throughout this time, will also need to actually TRACK the moon, as well.

~ 5:45 - With U3 at -20 minutes, will need to return to 20-sec, 5-sec, and 1/60-sec exposures.

[5:47 - Moon at 15° elevation]

~ 6:00 - Twilight will be beginning, so likely will be able to decrease the 20-sec shots, but unknown by how much.

[6:28 - Moon at 7.5° elevation, and sky brightening.]

[6:34 - U4 contact]

[6:42 - Moon at 5° elevation]

[7:11-7:14 - Moonset at 0° horizon line, my horizon line is probably around 5° (will need to check night before).]

[7:33 - P4 contact]

 

[Rick50]

Well, you sure have thought it through.
From the little experience I have had with stars:
I have used 2 lens for the Milky Way. 35mm, 1.4 and a 16-35mm, 2.8. Both on Canon 5D3 (full frame).
35mm, 10 sec at 1.4 = No star trails.
35mm, 15 sec at 1.4 = Start to see star trails 2-3 pixels.
16mm, 15 sec at 2.8 = No star trails.
16mm, 20 sec at 2.8 = Start to see star trails, 2-3 pixels.
16mm, 30 sec at 2.8 = Stars look like footballs close up.

Here is the ISO 12,800 photo. It's begging for a better edit but the ISO didn't seem to hurt. This is on 5D3.

I have a 10mm lens for cropped sensor and a 16mm lens for full frame. Both about the same FOV.
My 16mm would reach at the moons highest point.

I once tried to HDR that range and gave up. Photomatix did not like it. The only thing I know that may help the fake look of compositing is how the edges get feathered. I have not perfected it by any means.

In any case I will try my 300mm to see what I can do with the moon eclipse. If all works out I may buy a small telescope
to get a larger image on my sensor. I was looking at a 127mm Cassegrain with a 1540mm focal length. At that length the moon would fill my sensor enough.

 

[NancyMoranG]

Thank you Rick50 for that link!
AstroStu, that's a lot of info! Thanks,
Nancy