Trouble shooting the moon tonight

[Creeker5]

Hello all this is my first post.

I would consider myself a beginner / hobby photographer. I took a couple photography classes in school (with a film cameras). I currently own a Canon T2i I purchased a few years ago.

Anyway I primarily enjoy shooting wildlife. I was using a canon 70-200mm f4 for most of my shots. I purchased a used Canon 200-400mm f/4.5-5.6L IS. I took it out for a test drive yesterday and I was impressed with the images I got. The lens seems to work fine with no issues.

Tonight I noticed how bright the moon was and wanted to go see how the lens performed photographing the moon. I set my camera up on my tripod with a remote shutter release. At first I left auto-focus on, the moon was bright enough that auto-focus had no trouble bringing the moon into focus. I fired off a couple shots and noticed that they were coming out horrible. I turned off AF and manually focused through the viewfinder. I still got the same results. The pictures have a ghosting effect and are way to washed out.

The temperature outside tonight is 18 and my hands were freezing. I am wondering if the temp has something to do with my results, going from indoor temps to the cold outdoors. I did look at the lens and internal mirror to see if they were fogged up and they were not. Any suggestions on what caused this would be appreciated. I am uploading a picture that may give a clearer picture of what is happening.

Thanks in advanced!

 

[snowbear]

The moon is a sun lit object and really bright; you are picking up flare (shooting directly into a light source). Try 1/125 and about f/11 or so, and see what that does for you.

 

[Creeker5]

Thank You so much Snowbear!!! Ran outside and snapped a couple pictures with your suggestion. Much better!

Even with the the moon being so high in the sky I am impressed the detail this lens captures. Thanks again!

 

[wfooshee]

The thing to watch out for is trying to auto-expose the moon. You generally can't. The camera meter won't read it correctly because it's such a small portion of the frame.

You might get it right with spot metering, but in your first image, the moon's not in the center, so spot metering would have tried to expose the black sky. The duplication of the moon as a ghost image is from reflections inside the lens, light bouncing off the surfaces of the glass elements.

When you said your turned off AF and manually focused, be aware that focus has nothing to do with exposure. In your first image, the moon is seriously overexposed. Also keep in mind that a 400mm lens is enough to detect the moon's motion. You get set up, everything's perfect, and your phone rings. You look down, decide not to answer, and now not only is your night vision ruined, but the moon's moved in the frame and you have to start over.

 

[KmH]

Since the Moon is 250,000 or so miles away it is effectively at infinity.
Consequently you don't need an aperture as small as f/11 to have a deep depth-of-field and can use a faster shutter than 1/125 to compensate for a wider lens aperture.
F/5.6 is 2 stops of lens aperture larger than f/11, and 2 stops faster shutter speed is 1/1000.
In other words f/5.6 and 1/1000 will give you the same exposure as f/11 and 1/125 as long as ISO remains unchanged.

F/5.6 is likely to give you a somewhat sharper image than f/11 for 2 reasons:
1. Less diffraction - which causes focus softness.
2. A faster shutter speed - which makes focus softness from mirror slap and shutter vibration less likely.

Another trick for eliminating camera shake is to put a weight bag on top of the camera to also help eliminate camera movement from mirror slap and shutter actuation.

FWIW. The Moon is about as reflective as a lump of coal and has an average albedo of about 11%.
There is a lot of dynamic range between the young, bright crater ejecta and the old dark lava flows that are the Mare (seas).
The young crater Tycho (near the bottom center of your photo) and it's rays of ejecta are a lot younger than the Mare.

 

[snowbear]

Much, much better.
I suggested f/11 to keep from being wide open (f/4.5-5.6) but use wherever the "sweet spot" is, usually one or two stops down, and adjust the speed accordingly. Yes, spot meter is much better than matrix (or the Canon equivalent) or center-weighted.

 

[TCampbell]

Whenever you photograph the moon, you can use the "Loony 11" rule as a baseline. You don't have to use that exposure -- but it's easy rule to remember and you can play the exposure trading-game from there.

Here's the rule:

You can get a correct image of the moon at f/11 by setting the shutter speed to the inverse of the ISO setting.

That means if you are using ISO 100 and f/11, then you'd set a shutter speed of 1/100th and get an accurate exposure. If you set the ISO to 200, then you would use 1/200th.

This relationship where the shutter speed is the inverse of the ISO only works at f/11. But you don't have to use f/11 if you understand how to trade one part of the exposure triangle for another.

Sometimes I might be shooting through, say, an f/8 telescope... that's one stop faster than f/11. So I'll consider the "Loony 11" rule in my head (at ISO 100 use 1/100th assuming f/11) but realizing that I'm "one stop faster" than f/11, I'll speed up the shutter by a stop to compensate. So at ISO 100 and f/8 I'd want to use 1/200th.

Last summer during one of our astronomy "Beginner's Nights" (really an excuse for us to just get out as a group and observe), someone asked me how to get a photograph of the moon and I shared the above info with them. But since I happened to have my camera with me, I went ahead and connected it to the telescope for a demonstration. Here's how that worked out:

I was using my TeleVue NP101is refractor (a quad-element apochromatic refractor with a 101mm aperture and a 540mm focal length -- making this an f/5.4 telescope). I attached my camera nosepiece with a TeleVue 2x "PowerMate" (think of this as a 2x extender for a lens - except it's designed for astronomy use with telescopes). That gives me an f/10.8 focal ratio on my telescope (close enough to f/11). I dialed in ISO 100 and 1/100th sec shutter speed.

I took ONLY ONE shot (no guessing at the exposure). This is that shot:


Gibbous Moon by Tim Campbell1, on Flickr

If you remember the Loony 11 rule, you'll nail the exposure on the moon every time.

BTW, a bit about why this works. Technically when you are shooting a daylight exposure (e.g. middle of the afternoon on a sunny day) you can use the "Sunny 16" rule (at f/16 you can set the shutter speed to the inverse of the ISO and nail the exposure -- again, this is for "full sun" (not shade, overcast, etc.)) The moon is exposed to full sun... no clouds, no shade... so why would you use f/16 to get the exposure right? It turns out you can... and you'd get a more accurate exposure... but it'll look bad. The moon has extremely poor "surface albedo". It actually is charcoal toned and about as reflective as the black sidewall of a tire. When "properly" exposed using the Sunny 16 rule, it will look under-exposed. So the Loony 11 rule opens up the aperture by a stop to make a much more appealing image.

 

[Creeker5]

Thanks everyone for all of your replies. You were all very informative and I learned more than I could have asked for from asking such a simple question. I look forward to spending more time on this forum and learning from all of you. Hopefully I can take the little knowledge I have on photography and share it with others.