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Maximizing the size of the moon as it rises


bob_bill

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Although the shot I will be taking will involve a portrait, I expect the landscape folks are experts on this question. I will be shooting a lit subject standing on a hill top and the rising moon behind her. I want to make the moon as large as possible, larger than my subject if possible. I believe there is an illusion that makes the moon look bigger when it is close to the horizon and that is perfect for the shot. Anyone have any thought on how well a 600 or 1000 mm equivalent lens will make the moon? I expect I want to use a 1.7 teleconverter on the 400 mm lens on a nikon crop camera to get the maximum possible distance from my subject. My light triggers should work up to 300 feet. I am guessing the further I am from my subject, the larger the moon will appear and using as long a glass as possible would help. I can control my strobe power from camera to dial it in for the first shot then adjust in the changing light. Will initially do a silhouette or 2 then turn on the lights. The sun will be setting behind me as the moon rises. Tonight the moon was about in the perfect position at 6 to 6:30 pm. Any thought if it will rise earlier or later tomorrow night. I don't think my sun seeker program gives that info. Any suggestions are appreciated.
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The “Moon illusion” doesn’t work in a photograph. But you’re right that a long lens and large subject distance will make the Moon large in comparison with the subject. The Moon’s angular diameter will be about 0.56°; with a 400 mm lens and a 1.7× converter (is there such a thing?), the diagonal FoV with a 1.5 crop camera will be about 2.4°. Changing subject distance will change the size of the subject but will have no effect on the size of the Moon. I’d set the distance to make your subject the desired size; the Moon will be as it will be. If 300 ft (or whatever) isn’t enough, you’ll need to crop the image.

 

You didn’t say where you will be shooting, so it’s tough to give you specifics. In San Francisco, the Moon will rise about 51 minutes later tomorrow night; at 36 minutes after sunset, it’s going to be mighty dark, so the foreground lighting will be provided almost entirely by your lights (perhaps that’s what you want). You can get better information from any of a number of mobile apps, including The Photographer’s Ephemeris, PlanIt! for Photographers (Pro version), and PhotoPills. If you want to work on a computer, there is The Photographer’s Ephemeris web app and the Sun/Moon Calculator.

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Thanks Jeff. I figured out how to get moon rise on my sun surveyor but need to figure out how to find the path as it rises. I am in Clearwater FL. Yes, I use the 400 on a crop taking it to 600 mm effective and still 2.8. Using the 1.7 tc takes it to 1020 mm but cuts my speed to f/4.8, no problem as my lights will take care of the subject and I want plenty of dof and I can use the shutter speed to control sky/ moon tone. Will the 2.4 degrees be a portion of the angle of view of the lens degrees. I am guessing 1000 mm has less than a 3 degree angle of view. Edited by bob_bill
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Maths is your friend.

If you want a standing subject of around 5.5ft high to appear the same height as the moon diameter, then they need to be 600ft away from the camera. That's regardless of the lens used. Proportionally less for half-length, etc.

 

With a 680mm lens (400x1.7) both the moon and 5ft 6" figure at 600ft will be approximately 3/8ths of the horizontal frame height. I.e having a height/diameter of about 6mm on the sensor image.

 

Having pointed a 1000mm Reflex-Nikkor at the moon attached to a D7200, I can tell you that you still don't get an awful amount of frame filled by the moon, even with that combo. But good luck, and good 'seeing' on the night!

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In Clearwater on Dec. 2, the Moon’s altitude was about 10° at 6 PM and about 16.3° at 6:30 PM. These seem mighty high; are these indeed the correct times? In any event, tonight the Moon will be at 10° at about 6:55 PM and at 16.2° at about 7:25 PM. At 6:55, the Moon’s path will make an angle of about 64° with the horizon, and at 7:25, the angle will be about 65°—essentially the same. You can get the path angle from the Sun/Moon Calculator.

 

At 80 and 110 minutes after sunset, it’s going be very, very dark—I estimate almost a 24-step difference between the Moon and the sky. So aside from your lights, it will indeed be a silhouette. I estimate the Moon’s luminance at about EV 13.7 for ISO 100; this is of course a mid-tone placement; I’d probably give a step or two additional exposure.

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An inexpensive smart phone program called "Photopills" will give you the exact azimuth and altitude of the moon (or sun) on any date and time. Also given is the time of moonrise and moonset, all based on your GPS position. I presume theses values are based on the local geoid of reference, and local topography will affect the horizon.
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Joe, I am a photographer, not a math guy so I really appreciate your calculations. Last night I had a huge moon at the distance I was standing from the location so hopefully can capture it. My triggers say good to 400 feet. It being later means no light from the sun, if any, so I will probably be closing down quite a bit, but then, I want a large dof to get both subject and moon in focus so closing down shouldn't be a problem and I have plenty powerful studio strobes. I haven't shot the moon in a couple of years but will check my metadata for those settings as a starting point.

Thanks everyone.

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"On shooting with big lenses the general rule of thumb is that the moon will be 1mm for each 100mm focal length on a 35mm or equivalent film size."

 

- It'll be the same size whatever film or sensor area is used!

 

Actually it's very slightly over 0.9mm per 100mm of focal length. The full moon subtends an angle of 0.52 degrees from Earth, and the tangent of 0.52 is 0.009076. Meaning a 100mm lens gives an image diameter of ~ 0.908mm, a 500mm lens gives an image 5 times bigger, and a 1000mm lens gives an image ~ 9.08mm across, etc. It doesn't matter what the frame size is.

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If by your “sun surveyor,” you mean the Sun Surveyor app, you have many ways to get the Moon’s position vs. time. Dragging the time slider with the Moon in the info panel will adjust the values, and if desired you can show the path on the display (most useful with the map). The videos do a pretty good job of showing how to do this. You can also use the “augmented reality” feature, but you need to be on site—preferably before it gets so dark that you can’t see anything.
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Thanks everyone. Just finished editing a project and will post an example of the size of the moon soon. It is about 10-11 mm tall in the 24 mm tall frame. Joe, I admire your math. I ended up shooting 150 feet from my subject with the 1020 mm. A far cry from my usual portrait distance of about 10 feet. My light triggers performed flawlessly at that distance. Jeff, I will have to check the instructions for the Sun Survey or app as I couldn't get the moon path. I just need it to show where it will rise because I need to set my lights up, dial them in and start shooting as it comes up. Taking the easier route, composite.
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  • 3 weeks later...

2126398644_supermoonsunrises.thumb.jpg.56fc121aa5f018fbfa06bf0f7bfae9ce.jpg

 

If you want to photograph the moon when it actually looks larger than normal, wait for the"supermoon" on January 31. A supermoon occurs when a full moon is at perigee, the closest approach of the moon with the earth. A supermoon appears 14% larger in diameter than the moon at apogee, when the moon is furthest away from the earth. The last supermoon just occurred on January 1, making the supermoon on January 31 a "blue moon", which is when two full moons occur in the same month. Not only that, but the there will be a total eclipse of the moon early the next morning. This will be a Super Blue Blood-Moon! If you are in the Mountain Time Zone or west of it, you should be able to see it in the early morning hours. See' First Blue Moon Total Lunar Eclipse in 150 Years Coming This Month.

 

Here is a composite photo of the previous supermoon setting, taken on the morning of January 2. The pink band is the "Belt of Venus", which is caused by atmospheric backscattering of the reddish dawn light. The photo was taken with a Canon 5D IV with a 24-105mm lens set at 105mm. One photo was taken exposed for the moon plus sky, and one photo was taken for the foreground and mountain range.

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As said, the easiest way to get a big moon is to shoot it separately with a telephoto and then combine it with a landscape. In fact, that approach goes back to the dawn years of photography. Articles about how to do it were common in the pre- and immediate post- war photo magazines, long before Photoshop was dreamed of.
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  • 4 weeks later...
As said, the easiest way to get a big moon is to shoot it separately with a telephoto and then combine it with a landscape. In fact, that approach goes back to the dawn years of photography. Articles about how to do it were common in the pre- and immediate post- war photo magazines, long before Photoshop was dreamed of.

 

I did a negative sandwich in my photo class at the local JC, doing exactly that.

You just had to plan the landscape shot in advance, so that you had a clear sky to put the moon into.

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