F/Stop and the Moon

[winn]

I have been trying to capture the moon with a Canon 400D and their EF70-300mm

f/4-5.6 IS USM lens at the 300mm zoom. The image is not filling the frame and I

heavily crop the photo to get what I want. Since I am only using the center of

the frame, should I be setting the f/stop at the lowest setting (f5.6)to get

the faster shutter speed and/or lower ISO setting?

[awahlster]

The moon is a front lit object in full sun. if your camera has a metering pattern that only uses the center of the frame select that but basically you should shoot at f11-f16 at the shutter speed your ISo is set at.

 

so try an Iso setting of 100 shutter speed of 1/125th and f11 use a good steady tripod and have fun.

[walang_pangalan]

You'll never get a good image of the Moon through a 300mm lens. Things only begin to get interesting at about 700-1000mm:

 

http://www.photo.net/photo/2745849

 

Even then, you'll still be cropping. As for exposure and such, just play around. The constraint you are working against is the rotation of the Earth, and atmospheric turbulence, not your optics. Bias towards high ISO, short exposures. Collect multiple frames and stack.

[SCL]

And don't forget that since you have a digital camera you can shoot and chimp so that you can make instant adjustments. I typically used to shoot at a minimum of 500mm with modest cropping. The critical component for me was to ensure the lens was rock steady which meant sturdy tripod, cable release, and, of course, a perfectly clear night with absolutely minimum atmospheric interference (generally late fall or early winter where I live).

[alex_lofquist]

The moon has a low albedo (reflectance) and using the "sunny 16" rule it will look rather grey in the final image. Many people feel that a "sunny 11" rule should apply here. That is to set your aperture to f/11 and expose for the same fraction of a second as the ISO film speed, or the equivalent. The diameter of the image on the film, or semsor, will be approximately equal to the focal length of the lens divided by 100. e.g. a 500mm lens would give the moon a diameter of about 5mm on the sensor. To really fill the frame, you would need the equivalent of a 1700mm lens!

[greg s]

I always shoot in manual mode and bracket for exposure for moon photos. The tricky part is obtaining optimal focus.

[alan_birnbaum]

Remember, while the moon often LOOKS large, particularly when it is near the horizon, its actual angular size is about half a degree. A "normal" lens for 35 mm covers 45 degrees, so to fill a 3:2 ratio frame you'd need one about 0.9 degrees, a bit more than that really for framing. With that, you see where the earlier advisory for 1500 to 2000 mm 35 mm EFL comes, such divided by the 1.6X multiplier effect of your DSLR, i.e., you'd need a lens with a native true focal length of around 1000 mm. That's....TELESCOPE territory!

[winn]

I'll try shooting the moon at f/11 with the ISO setting matching the shutter speed and adjust from there. I've been having better luck in the past with the ISO setting at 200 or 400 with my set up, (including my not so steady tripod). I'll start playing around with stacking lenses and the exposures (that will be new ground for me). As for the 500mm and beyond lenses, that will have to wait until I recover from my initial camera purchases. I don't know what it takes to "piggyback" on to a telescope.

 

Thanks again....

[kelly_flanigan1]

A swag is the moon or sun is roughly 1/100 your focal length in diameter on the film or sensor. Thus my 6" f8 reflector's image of the moon is close to 1/2 inch in diameter. With a 300mm point off 2 places so a rough guess is 3 mm.

[kerry_grim]

After reading these answers, I would get the impression it is not worth the effort to try photographing the moon.

 

This is not the case. During the next full moon, please check weatherunderground.com where people submit their photos of anything supposedly weather related. I have seen excellent moon photos there with a minimum of equipment including ones taken with a 300mm lens. Surely they are cropped and sharpened, but some are incredibly sharp as well.

[winn]

I've been excited with my captures of the Moon; at the same time, I realize they are not near the level of Walang's above image. I plan on trying the f11-16 settings suggested above. However, I still don't understand why the lower apeature setting isn't better in this case. Since the Moon is not filling the frame, isn't it being captured by the "sweet spot" (center) of the lens? And because of the background and distance, is the DOF in this situation not an issue? (I've had my camera for about 6 weeks and I think I've now learned enough to be dangerous!) Thanks...

[tommyyearginjr]

Maybe this will help:<br><br>

 

<a href=-"http://www.photo.net/learn/nature/sunmoon">http://www.photo.net/learn/nature/sunmoon</a><br><br>Hope that helps!<br><br>Tommy Yeargin