Luminous Landscape Forum

Equipment & Techniques => Landscape & Nature Photography => Topic started by: gwarrellow on February 08, 2004, 11:25:37 am

Title: Shooting the Moon
Post by: gwarrellow on February 08, 2004, 11:25:37 am
Quote
The exposure's going to depend on the magnification.
Ray,

I know this is counter-intuitive but I believe the magnification doesn't affect the exposure when photographing an object that is illuminated by reflected light, such as the moon.  Imagine a terrestrial object such as a brick wall, then the correct exposure for the wall is say, 1/250 sec f8, whether you use a 50 mm lens or a 1000 mm lens, or you move 10x closer to the wall, for example.

The dimming effect you see in a telescope when viewing at higher magnifications is due to other effects of the optical system.

It's curious I know!
Regards,
Graham
Title: Shooting the Moon
Post by: Bill on February 08, 2004, 06:37:48 pm
A great time of year to shoot the moon (at least I found) is during the fall full moon (I imagine there is a correpsonding time in the spring too).  

More precisely, for reference, was the full moon around October 12th, 2003.

At that time of year the moon rises just after the sun sets.  There is still ample light being reflected in the atmosphere.  The moon is also bright.
Title: Shooting the Moon
Post by: gwarrellow on February 16, 2004, 06:38:20 am
Quote
Oh! I forgot to add, if it's just the moon you're after, this is one of those occasions when both the 10D and SD10 will outperform the 1Ds. Just thought I'd slip that one in, to clear the waters.  
What makes you think that!  Just curious  
Title: Shooting the Moon
Post by: Ray on February 18, 2004, 01:16:06 am
Quote
Hmnn. Here we go again on pixel sizes... People keep forgetting that at the end of the day it's always the lens quality that matters, not really the pixels, especially when it comes to tele capabilities. You can always add tele-extenders (or for the astro-buffs eyepiece projection) to magnify the lens' image such that all its limitations become patently obvious. Let me explain. Any Canon supertele will have its job stretched quite beyond its "razor-sharp" capabilities if we use stacked 2x + 1.4x converters, on both the 10D or the 1Ds. Were this not the case then Canon would have offered us 3x or 4x extenders...
Well, I've not forgotten this.  :D . I think your bringing in other issues here; diffraction and the Rayleigh's limit.

I'm talking about ordinary (but expensive) telephoto lenses which are used at apertures well above the Rayleigh's limit, not astronomical telescopes

Of course, at the end of the day it's always the lens quality that matters. My comparison of the three cameras are in relation to the same lens. If the lens is lousy enough, you probably won't notice much difference. If the lens is absolutely superb, the 1Ds might have the edge with a 2x converter. The Canon 1200mm, which costs as much as a house, might just trump the SD10 if used with a converter, but I'm not certain, and I don't expect anyone to show me some comparisons.  :D
Title: Shooting the Moon
Post by: Ray on February 20, 2004, 07:05:53 am
Okay! I'm glad we sorted that  . As a matter of interest, running the eyedropper over default TIF conversions of the moon at various exposures and 100 ISO, and checking the info palette in PS, I get the following.

(1) F8 and 1/90th, maximum highlight value 240.

(2) F8 and 1/125th, maximum value 230.

(3) F8 and 1/180th, maximum value 209.
Title: Shooting the Moon
Post by: Howard Smith on March 10, 2004, 01:59:34 pm
Scott, when you say f/8, was that f/8 on the lens setting or f/8 after adding a stop for the extender?

The image looks pretty good.  It is lkely just a personal perference, but I would like a stop or so less exposure to make the seas a darker and reduce the highlights to less than white with detail.
Title: Shooting the Moon
Post by: Exegeter on February 07, 2004, 11:34:01 pm
When I saw the clouds creeping in front of the moon on my way home tonight I almost ran a stop sign trying to get home.  I ran to my tripod leaning by the door and set everything up on the roof.  One last look with my light to make sure everything was level, a few shakes to see if I'd be shopping for a new body and lens, and I was off...  

A missed opportunity but a learning experience none the less.  I learned a lot about setting up on the roof and got a few ideas to try implimenting before next time.  

How do you shoot the moon?  How do you pick up all the gradients  and contrasts?  All the craters?  And still pick the clouds up?  

(http://exegeter.com/images/webmoonOne.jpg)

(http://exegeter.com/images/webMoonThree.jpg)
Title: Shooting the Moon
Post by: Exegeter on February 08, 2004, 12:01:33 pm
Thanks a lot!  I'll be using a 70-200 2.8 on a Sigma SD9.  

It's disapointing that I need to essentially choose between moon and clouds.  I'm not sure how I'd blend them very well with the composition I'm after.
Title: Shooting the Moon
Post by: b.e.wilson on February 08, 2004, 05:18:13 pm
Quote
The exposure's going to depend on the magnification.
Ray,

You are quite correct, exposure does depend on magnification, especially if you use some external exposure rule instead of in-camera metering.

For example, using a 2x extender means you must increase the exposure two stops more than the rule dictates. This is because the extender is taking only one-fourth of the full image circle and making that 25% the new image circle.

The principle involved is the lens-to-film distance. The farther away the lens is, the wider the image circle it will project on the film. If the film is a fixed size, then it will 'capture' a smaller amount of the total light. Macro photographers (who use extention tubes or bellows to increase magnification) know this rule all to well. So do kids burning leaves with a magnifying glass. The farther you get from the lens the less heat you project onto the leaf.

This effect is seen in consumer zoom lenses also. I have a Canon 75-300 lens that is f/4 at 75mm, but only f/5.6 at 300mm, even though the iris is completely out of the light path. As the magnification increases, the passage of light through the lens decreases. Gives you a clue why constant-f-stop lenses (like the Canon 'L' line) are so expensive.
Title: Shooting the Moon
Post by: Ray on February 16, 2004, 08:34:34 am
Assuming one is using a camera telephoto lens and not a telescope.  :)
Title: Shooting the Moon
Post by: samirkharusi on February 18, 2004, 12:21:23 am
Hmnn. Here we go again on pixel sizes... People keep forgetting that at the end of the day it's always the lens quality that matters, not really the pixels, especially when it comes to tele capabilities. You can always add tele-extenders (or for the astro-buffs eyepiece projection) to magnify the lens' image such that all its limitations become patently obvious. Let me explain. Any Canon supertele will have its job stretched quite beyond its "razor-sharp" capabilities if we use stacked 2x + 1.4x converters, on both the 10D or the 1Ds. Were this not the case then Canon would have offered us 3x or 4x extenders... With stacked extenders it becomes a moot point, IMHO, as to whether you use 7.5 or 8.8micron pixels. Both images will look "stretched" as on a balloon. I did some calculations recently, plus some field testing, to educate myself (one does get distracted into irrelevancies by web noise)  to verify whether there's any merit in "extending" a diffraction-limited scope well beyond its theoretical diffraction limit. Here are my results, showing graphically what the various definitions of diffraction limit mean, what happens when you sample the intensity profiles at Nyquist or otherwise, and finally shooting Saturn at 4600mm f23 and 10,000mm f50 with 5.6micron pixels:
http://www.geocities.com/ultimaoptix/sampling_saturn.html (http://www.geocities.com/ultimaoptix/sampling_saturn.html)
For the field testing I used a 2x and a 5x extender and then resized the images to an identical size to compare them.
Title: Shooting the Moon
Post by: Howard Smith on February 19, 2004, 06:18:04 pm
An error.  Adding 1 1/3 stops would give about f/11 @ 1/50, not 1/80.  So that is about a stop more exposure than BJL suggested and 2 stops more than sunny-16.
Title: Shooting the Moon
Post by: scott kirkpatrick on March 10, 2004, 04:19:58 pm
f/8 after correcting for the one stop increase in focal length due to the extender.  The E-1 is really pretty smart about this stuff.  As far as it is concerned, you may have set f/5.6 before, but you're at f/8 now, so that is what it displays, and what the EXIF shows.  To check that this is happening, you notice that the largest opening available is one stop less bright after installing the 1.4X extender.  

I'll go back and check the darker shots to see what I can get from them after developing the RAW files in Viewer or PS-CS.

scott
Title: Shooting the Moon
Post by: b.e.wilson on February 08, 2004, 12:35:21 am
The moon is about 25% reflective, and it's illuminated by the sun. The Sunny-16 rule usually works (f/16 and 1/ISO for the shutter speed).
Title: Shooting the Moon
Post by: Ray on February 08, 2004, 09:11:32 am
Last time I shot the moon, I used my 100-400 IS zoom with 1.4x extender attached to my D60 producing an effective 35mm focal length of about 900mm. (Just wanted to see how sharp I could get those craters  ). I tried a number of exposures, but the one that brought out the most detail was something like 1/125th at F11 and ISO 100.

The exposure's going to depend on the magnification. If you want some foreground as well, and/or visible clouds, you'll need to take 2 exposures and blend them.
Title: Shooting the Moon
Post by: Ray on February 08, 2004, 03:35:02 pm
Quote
I know this is counter-intuitive but I believe the magnification doesn't affect the exposure when photographing an object that is illuminated by reflected light, such as the moon.
Quite right!  :)  Whether the object is big or small within the frame, it needs the same exposure to bring out the detail. What was I thinking of!  ???
Title: Shooting the Moon
Post by: gwarrellow on February 09, 2004, 12:17:03 pm
Quote
Quote
The exposure's going to depend on the magnification.
Ray,

You are quite correct, exposure does depend on magnification, especially if you use some external exposure rule instead of in-camera metering.

For example, using a 2x extender means you must increase the exposure two stops more than the rule dictates. This is because the extender is taking only one-fourth of the full image circle and making that 25% the new image circle.

The principle involved is the lens-to-film distance. The farther away the lens is, the wider the image circle it will project on the film. If the film is a fixed size, then it will 'capture' a smaller amount of the total light. Macro photographers (who use extention tubes or bellows to increase magnification) know this rule all to well. So do kids burning leaves with a magnifying glass. The farther you get from the lens the less heat you project onto the leaf.

This effect is seen in consumer zoom lenses also. I have a Canon 75-300 lens that is f/4 at 75mm, but only f/5.6 at 300mm, even though the iris is completely out of the light path. As the magnification increases, the passage of light through the lens decreases. Gives you a clue why constant-f-stop lenses (like the Canon 'L' line) are so expensive.
Bruce,

I think we may be talking about different things here.  If there is no change in the f-ratio of your optical system (e.g. by adding an extender or reducer) then for an object illuminated by reflected light (e.g.) moon) then there is no change in exposure.

In the examples you cited you are either changing the effective f-ratio (adding extension tubes) or using a source (the Sun) of light that is not a point source (as you have with e.g. a star).

I told you it was counter-intuitive!
regards,
Graham
Title: Shooting the Moon
Post by: gwarrellow on February 09, 2004, 05:41:17 pm
Quote
I have been out in to the cold the last two full moons and taken a number of shots

<snip>

Minus 32 C ???
Minus 32 C!  Minus 32 C! That's not cold, that's brass monkey weather  

Where on earth do you live?

BTW Nice full moon with plenty of detail.
Regards,
Graham
Title: Shooting the Moon
Post by: b.e.wilson on February 09, 2004, 06:34:01 pm
Quote
Re you getting "bellows extension factor" mixed up with magnification by focal length?
Is there a difference?

M = image height/subject height

M = (lens-to-film distance - focal length/focal length)

M = focal length/(lens-to-subject - focal length)

In macro shots, where the bellows factor is significant, the magnification is high enough to matter to the exposure. With the "magnification by focal length" I presume we are speaking of distant large objects where the magnification is extremely low, low enough not to affect the exposure.

Except when extension lenses are used. That's changing the focal length without changing the aperture, and that changes the f-stop (f-stop = focal length/aperture).

It's been fun going through the old equations again.
Title: Shooting the Moon
Post by: Ray on February 15, 2004, 05:02:50 pm
I've just been checking the actual exposures I used for my moon shots. From memory I think I wrote F11 at 1/125 with 1.4x extender. I see this is not correct. I did take some underexposed shots at f8 and 1/125th without extender, but the best exposure was 1/90th at f8 and 100 ISO (400mm without extender) of a full moon. This was a very slight underexposure with the histogram about 1/3 of a stop away from the right.

On a different night I shot a 3/4 moon using the 1.4x extender with the 100-400 zoom. Best exposure was 1/30th at f11 with histogram just touching the right.

I'd say it's more like a sunny F8 rule that would apply.  :D

What I did find surprising was the noticeable improvement I got with the 1.4x extender; slightly more detail and slightly contrastier detail with the craters appearing more 3-dimensional. Well, you might say, this is to be expected. However, previous experience with this combination of 100-400 IS zoom and 1.4x extender had led me to believe there was no advantage when the subject was at or close to infinity - something I'd puzzled over and attributed to dust in the atmosphere blocking out or reducing the contrast of all fine detail, and the fact that only the best lenses produce useful results with converters.
Title: Shooting the Moon
Post by: gwarrellow on February 17, 2004, 12:20:40 pm
Quote
Assuming one is using a camera telephoto lens and not a telescope.  
I'm sorry Ray I don't understand.  Your initial comment indicated that the other cameras would "outperform" the 1Ds but I have the impression that your talking about image scale rather than quality.  Is that right?  Remember the 1Ds has significantly more pixels to play with so much more opportunity for cropping.
Regards,
Graham
Title: Shooting the Moon
Post by: Howard Smith on February 19, 2004, 02:19:21 pm
If you use Adams' "Exposure Formula,"  then the "sunny 16" would be 1/16 @ 1/250.  His key f/stop is the square root of the film speed.   16 squared is 256 (or 250 to photographers).  So f/16 @ 1/250 using ISO 250 would put his moon in Zone V.  Give it 2 stops more exposure to put the moon in Zone VII, you get f/16 @ 1/60.  Add about 1 1/3 stops to go to ISO 100, f/11 @ 1/80.  That's well within a third stop of BJL's f/11 @ 1/100 for ISO 100 setting.  The sunny-16 would give a stop less exposure (f/16 @ /100) which is likely adequate and would give a much more pleasing result than the washed out white disc.

Ray, I don't think you have missed anything except Zone VIII pushing over exposed.  I don't know the dynamic range of your digital camera, but on chrome film, the moon would be getting prety close to blown out.  For slide film with a small dynamic range, maybe f/11 @ 1/ISO would be pretty good.

In his discussion of "Moon and Half Dome," Adams says that for moon exposures at night (not late evening which is the time the above dicussion is about), his exposures range between Zone IV thru Zone VIII and the details will be "subdues or exaggerated as desired."  But again, Adams is talking about black and white film with maybe 10 or 11 stops of latitde as apposed slide film with 5ish stops.  So Zone VIII is getting pretty far up for color film.  "as desired" says there is some latitude in personal taste.
Title: Shooting the Moon
Post by: Howard Smith on February 18, 2004, 02:29:12 pm
The photo is "Moonrise" over Hernandez.  It is detailed in "Examples, The Making of 40 Photographs."

Adams said he knew the moon had a liminance of 250 c/ft2.  He used this and the Exposure Formula to determine his exposure.

The Exposure Formula is discussed in "The Negative" by Adams.  It says that the key f/stop is the square root of the film speed.  The shutter speed is the reciprical of the luminance in c/ft2.  This will place the subject in Zone V.  He exposed the moon for Zone VII, which he claims is ideal.  (The modern problem is not many meters read in c/ft2.)

In the discussion of "Moon and Half Dome," Adams provides some information on selecting the exposure for the moon in the evening and in the dark.
Title: Shooting the Moon
Post by: Howard Smith on February 20, 2004, 10:12:54 am
What I was trying to say was:

Adams exposed for the moon and let the landscape fall where ever.  He then tried to salage the landscape as much as possible while developing the negative.  He still had a difficult to print negative.  He even itensified the lower part of the negative later to help.

More commonly, photographer expose for the landscape and let the moon fall where ever, usually over exposed.  Not much can be done to help an over exposed moon during processing or printing.  No detail is no detail.
Title: Shooting the Moon
Post by: Howard Smith on March 12, 2004, 10:56:27 am
Scott, Ansel Adams' exposure formula would give f/14 @ 1/250.  That is about 1 2/3 stops less than your image.  I would have given about a stop less exposure.

With film, it is my experience that the ISO isn't as fast as the manufactorer claims in order to suit my tastes.  Most filmsI find are about 2/3s of a stop slower.  Do you know if digital camera subject to the same "over rating?"
Title: Shooting the Moon
Post by: scott kirkpatrick on March 13, 2004, 05:16:16 pm
I think I got it rightside up, so that the darker areas look like a rabbit (the Chinese interpretation).  I've seen it come up the other way when you use a good telescope and view with the camera's lens through the telescope objective, as in this very impressive shot:

http://www.dpreview.com/forums/read.asp?fo...message=3094625 (http://www.dpreview.com/forums/read.asp?forum=1007&message=3094625)

Or perhaps you are right and things look different from Oz.

scott
Title: Shooting the Moon
Post by: Richard Dawson on February 08, 2004, 01:24:43 am
You might find this article useful.

 http://www.u-net.com/ph/mas/observe/lunar-p/lunar-p.htm (http://www.u-net.com/ph/mas/observe/lunar-p/lunar-p.htm)

Richard
Title: Shooting the Moon
Post by: b.e.wilson on February 08, 2004, 10:40:06 am
Since moon exposures are about the same as you'd use for a bright day, typical exposures of the moon at night will include no detail of the sky or the foreground at all.

Many images of the moon in its surroundings are faked by taking a shot of a night scene (exposed properly for a night scene) and dropping in a properly-exposed image of the moon. If the moon is added close to its original size, position, and orientation, it doesn't look too bad. It's tricky to do if you want the interaction of moonlight and clouds near the moon, however, and maybe a three-stop ND grad could help. Shame nobody produces a spot ND that would bring the moon brightness down to match the surrounding brightness. That'd be fun to play with.
Title: Shooting the Moon
Post by: gwarrellow on February 08, 2004, 01:04:44 pm
Exegeter,

Let me suggest you stop your lens down to f4 or f5.6 and try shooting the moon in twilight.  You may have more chance of correctly exposing both the moon and any clouds but you will need to experiment.  

If you are looking for a good lunar photo opportunity then there are two nice ones coming up this month.  On Feb 23 the crescent moon and Venus will be close together and on Feb 25th the crescent moon and Mars are very close at dusk.

I have downloaded the Michael Oates exposure calculator from the website Richard mentioned earlier and printed it onto photo quality paper.  It's nice and simple to put together.  Using the calculator it seems that an exposure of around f5.6, 1/30, ASA100 should do the trick for the Venus and Mars conjunctions I mentioned above.

Graham
Title: Shooting the Moon
Post by: DMcLarty on February 08, 2004, 10:07:02 pm
I have been out in to the cold the last two full moons and taken a number of shots

here a couple of examples of my results. This one was taken later at night after the moon had risen past the lower clouds and atmospheric gasses

(http://www.kivalliq.com/NSPhoto/NS2003moon02.jpg)
Setting for this one were
Date/Time: 2003:12:09 20:58:36 Minus 32 C ???
Shutter speed: 1/125 sec
Aperture: 14.0
Exposure mode: Manual
Self-timer: 10 secs & Mirror locked up to allow the canera and lens to stop vibrating.
ISO: 200
Lens: 500.0 mm plus 1.4 x
AF mode: Manual Focus
Tripod etc.

The second a combination of two images taken just before the moon set at 09:30 am is more likely what needs to be done to get clouds and moon all in one image. I used PS to blend the two images together. Micheals Tutorial is great for this.

(http://www.kivalliq.com/NSPhoto/NS2004MorningMoon01.jpg)

The first shot settings was at
Shutter speed: 1/30 sec the second shot for the land exsposure was 1/20 sec
Aperture: 11.0
Exposure mode: Manual
Self-timer: 2 secs Mirror locked up
ISO: 200
Lens: 500.0 mm

To get both the clouds and moon as you want in the samples you pretty well need blend two images together. Expose one for the moon and then one for the clouds. You will notice the moon does move quickly at higher magnifications so if you have a land mark in the image you may find blending will be harder.
Title: Shooting the Moon
Post by: Howard Smith on February 09, 2004, 04:40:17 pm
Re you getting"bellows extension factor" mixed up with magnification by focal length?
Title: Shooting the Moon
Post by: Howard Smith on February 10, 2004, 10:59:00 am
OK.   The moon is on the order of 15 BILLION inches away.  So, M is about 6x10(-11).  Even if you assume the moon is 3000 miles away, M would be about 5x10(-9).  I have never thought of that as a "correction factor" considering the accuracy and repeatability of the shutter speed,  f/stop, meter reading (or rule of thumb), effects of the atmosphere and film speed, and the practicality that exposure within a quarter stop is plenty close enough.  No exposure correction is needed - even as a matter of degree or because you used the sunny-16 rule instead of any light meter.  Besides, you just cannot physically do it.

The error in correctly exposing the moon using a TTL, even a fairly small spot, is large because the meter will be reading a lot of black.  The calculated exposure will try to make that gray, so the moon will be over exposed.

The exposure guideline given above by Graham is sunny-16 plus 4 2/3 stops.  The conclusion would be that sunny-16 doesn't work all that well all the time.  There are a lot of variables to deal with (magnification not being one of them).

The two samples given by DMcLarty I would judge to be over exposed, maybe a stop and a half for the first, maybe more for the morning moon.
Title: Shooting the Moon
Post by: Ray on February 15, 2004, 07:42:08 pm
Oh! I forgot to add, if it's just the moon you're after, this is one of those occasions when both the 10D and SD10 will outperform the 1Ds. Just thought I'd slip that one in, to clear the waters.  :D
Title: Shooting the Moon
Post by: Ray on February 17, 2004, 07:26:44 pm
Okay! Here's my reasoning. I hope I'm not falling into one of those counter-intuitive traps, so you'll have to check my maths.  :D

The data I used for the basis of these calculations I got from the Dpreview site, ie. the D60 sensor has 135 pixels per mm, the 1Ds sensor 113.5 pixels per mm and the SD9/10 sensor 109.5 pixels per mm. (I'm referring here to full pixels containing red, green and blue elements whether interpolated or not.)

Measuring the diameter of the moon on my shot with D60/400mm combination, I find it's 3.78mm on the sensor, which translates to 510 pixels in diameter on the D60, 429 pixels on the 1Ds and 414 pixels on the SD10 sensor (using the correct terminology describing the SD10 as a 3.43MP camera).

Since it's been established that the SD9 outresolves the D60 by a noticeable margin, we can make the satement that one SD9/10 pixel has the value of two D60 pixels for any given area of sensor.

Since it's been established, on this forum at great length, that the Canon 10D does indeed exhibit higher resolution than the 1Ds when using identical lenses on both cameras, I think it's a fair assumption to make that one SD10 pixel is also worth two 1Ds pixels.

To normalise the figures for all three cameras, we get 510 pixels across the moon diameter with the D60, 429 pixels with the 1Ds and 414 x (square root of 2) = 580 pixels with the SD10.

Now I'm sure everyone would be prepared to accept that a moon that's 580 pixels wide will have significantly higher resolution that the same moon that's only 429 pixels wide.

Okay! 400mm is not particularly long. I believe the longest lens that would fit all three cameras would be the Sigma 800mm. The moon now becomes 7.56mm in diameter on all three sensors. Let's add a 2x extender. It becomes 15.12mm in diameter. Oops! The SD10 is now cropping the image and the D60 is borderline. (However, if it isn't a full moon, you'd probably still fit it in the frame  :D ).

Even if we compare the 1Ds/800mm/2x combination with the SD10/800mm/1.4x combination, we're comparing 1427 SD10 pixels with 1716 1Ds pixels. The images might be on a par, but it's doubtful. A 1.4x extender at best offers a marginal improvement. A 2x extender is even more marginal. Those extra pixels in the 1Ds image would not be doing much.

I rest my case. Thanks for giving me the opportunity to exercise my mind with some basic maths, and I'm sure you'll point out any errors in my reasoning  :D .
Title: Shooting the Moon
Post by: BJL on February 18, 2004, 01:15:15 pm
Ansel Adams produced one of the most famous moon photographs; I forget the title, but I mean the one in New Mexico with gravestones in the foreground lit by the last of the setting sun and some details in clouds too. Adams has written a detailed discussion of his exposure decisions (with no light meter available!) that kept detail in all the main elements, and it has been reproduced in various books, both his own, and volume 1 of the "Ansel Adams" books by Schaeffer. I will try to dig up a detailed reference.
Title: Shooting the Moon
Post by: BJL on February 19, 2004, 09:54:17 am
Quote
A full moon on a clear night, about half way between the horizon and the mid point in the sky, required a 90th sec at F8 and ISO 100. With this exposure, the histogram was not quite fully to the right.
I think we are dealing with two different but legitimate approaches; roughly, mine is for "JPEG, ready to print" while yours is for "raw with optimal information, but needing post-processing".
 
   Putting the histogram all the way to the right in this situation will have a spike for the moon at the right edge, between three and four stops above middle gray, or in the old currency, between Zones 8 and 9. On a straight print, I would expect that to give the washed out white disc that Ansel Adams comments disparagingly about in his discussion of "Moonrise", and which relates to his lower placement at about Zone 7. Indeed, your "expose to the right" exposure levels are one or two stops higher than the f/11 I suggested, so the numbers all match up.

  That sort of "overexposure" is not necessarily wrong in the digital world, since you can then compensate down by a stop or two in post-processing, and maybe that is a better approach for retaining shadow detail in a high contrast subject like this one; the option I described was based instead on the old fashioned idea of getting the exposure of the moon right "straight out of the camera", as I would think is still needed when using JPEG recording instead of raw.
Title: Shooting the Moon
Post by: scott kirkpatrick on March 12, 2004, 05:09:19 pm
The moonshot that I posted looks sharper than the ones taken at 1/500 and f/8 or f/11, I believe, because the craters on the upper right edge of the moon were more clearly resolved with a little overexposure of the main surface of the moon.  So that does not conflict with the Ansel Adams rule, it's just because the important part of the image is facing nearly at right angles to the camera.

scott
Title: Shooting the Moon
Post by: Ray on March 13, 2004, 11:07:45 am
The image can be darkened to taste with 'levles'. The main concern is to avoid blowing out any highlights. The D60 at 100 ISO is actually 125 (according to dpreview). My exposure at 1/90th at f8 and 100 ISO is really 125 ISO or about 1/125th at 100 ISO or 1/250th at ISO 200, which is the identical exposure that Scott has used.

My moon looks very similar to Scott's (hope you haven't infringed my copyright Scott  :D ), except the white crater, lower right, that looks like a pole, is upper left on my shot.

Could this be because I'm in Australia, or has one of us inadvertently processed the image upside down  ???  :D
Title: Shooting the Moon
Post by: scott kirkpatrick on March 10, 2004, 12:53:07 pm
Well, another full moon has gone by, so here's my contribution to this thread:

http://www.pbase.com/image/26739799.jpg (http://www.pbase.com/image/26739799.jpg)

Olympus E-1 with 50-200 (at 200) plus 1.4X extender, tripod, 3 sec delay after the mirror goes up, plus viewfinder blackout.  I shot it raw at 1/250 at f/8 ISO 200, and used Olympus Viewer to make a JPG.  I took two more bracketed images each one stop further down, but this one was best.  The histogram was totally uninformative, since there are so few moon pixels in the frame, but I think this was exposed to the right, and the slight push to ISO 200 spreads it out a bit.
Title: Shooting the Moon
Post by: Exegeter on February 08, 2004, 02:23:48 am
Thank you very much.  so f16 @ 50 seconds for iso 100?
Title: Shooting the Moon
Post by: b.e.wilson on February 09, 2004, 01:58:24 pm
Yeah, it's pretty clear we are arguing degree. I looked it up again:

f-stop = metered f-stop * (magnification + 1)

for a symmetric lens (where the iris appears the same diameter from the front or the back of the lens).

For the moon, where magnification is incredibly small (3000? miles down to less than an inch), the term (M + 1) equals 1.

For the extender, it seems silly to argue something so easy to test: meter a wall with your lens, add the extender, and meter it again. I'm pretty sure the lens opens up, but it's been a long time since I played with 35mm and I'm just not certain.
Title: Shooting the Moon
Post by: samirkharusi on February 14, 2004, 06:40:54 am
OK, my 2 bits. IMHO the sunny 16 rule turns out to be more like a sunny 11 rule for the full moon. It's not beach-sand-white, more like charcoal grey. Some minor bracketing is often necessary. That said, double the exposure for half moon, quadruple for quarter moon, and go even further for a crescent. Here's an example of both a crescent moon and earthshine:
http://www.geocities.com/samirkharusi/earthshine.html (http://www.geocities.com/samirkharusi/earthshine.html)
And then it all depends on what effect one is looking for. A "natural" looking moon or one showing intricate details? The latter, if done at full moon, requires a lot of contrast stretching:
http://www.geocities.com/samirkharusi/apollo.html (http://www.geocities.com/samirkharusi/apollo.html)
Title: Shooting the Moon
Post by: Ray on February 18, 2004, 06:40:12 pm
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Putting these together suggests that the moon needs about 1 to 1 1/2 stop more than "sunny 16 exposure", or about f/9 to f/11 at 1/ISO; this matches nicely with someone's suggestion of f/11 at 1/ISO!
BJL,
If your deductions are correct, my D60 light meter must be out by a mile.  :D

A full moon on a clear night, about half way between the horizon and the mid point in the sky, required a 90th sec at F8 and ISO 100. With this exposure, the histogram was not quite fully to the right. I could probably have used 1/60th without blowing highlights. On another occasion I used 1/30th at f11 with extender, with good results.

As I recall, during discussions on the accuracy of the Sony F828 ISO settings, it came out that ISO 100 on the D60 is actually about 125. (I hope I haven't got this the wrong way round). Using the reciprocal of the real ISO, my exposure would then be 1/125th at f5.6. In other words, a sunny F5.6 rule.

I don't know what the dynamic range of the film used by Ansel Adams was, but modern B&W film has considerably greater latitude than any DSLR. If I were using B&W film instead of the D60, I think I could probably use 1/125th at f2.8 without blowing out highlights.

If we use the figures Howard has quoted, ie. the f stop is the square root of the ISO when the shutter speed is the reciprocal of the luminance in c/ft2, we get 1/250th at F10 and 100 ISO, which places the moon in zone 5. Moving it to zone 7, gives us 1/60th at f10 and in zone 8, 1/30th at f10 which is pretty close to my exposure of 1/30th at f11 at a 'real' ISO of 125.

What am I missing?
Title: Shooting the Moon
Post by: BJL on February 20, 2004, 09:17:20 am
One more comment on "Moonrise"; I looked at the photo again, and it really is striking how dark and contrasty the moon is compared to most moon photos, far darker than the clouds below it. That could in part be his printing choices of course, but clearly Adams aimed for a quite different tonality than is common in moon photographs, even though he knew he would then have to struggle to maintain detail in the shadowy foreground with special development procedures.
Title: Shooting the Moon
Post by: BJL on March 12, 2004, 05:38:31 pm
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With film, it is my experience that the ISO isn't as fast as the manufactorer claims in order to suit my tastes. ... Do you know if digital camera subject to the same "over rating?"
  In one sense it is far worse with digital cameras. Bearing in mind that there is absolutely no ISO speed/sensitivity standard for electronic sensors corresponding to the ISO/ASA/DIN ones for film speed, digital cameras seem to be all over the place in their exposure index scales.
   On the other hand, the good news is that as far as shadow handling, DSLR's generally compare favouably to film of speed significantly higher than the minimum speed setting of the DSLR. In other words, the minimum speed settings of most DSLR's seem to be significantly "under-rated", so are like "push processing" speeds.

P.S. The base ISO standard for digital sensors measures the highest exposure level (lowest exposure index) for which one has adequate highlight headroom; it has nothing to do with the film speed concept of determining the lowest exposure level (highest exposure index) for which one gets adequate handling of shadow regions.
Title: Shooting the Moon
Post by: Lin Evans on April 11, 2004, 01:49:20 am
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Ansel Adams produced one of the most famous moon photographs; I forget the title, but I mean the one in New Mexico with gravestones in the foreground lit by the last of the setting sun and some details in clouds too. Adams has written a detailed discussion of his exposure decisions (with no light meter available!) that kept detail in all the main elements, and it has been reproduced in various books, both his own, and volume 1 of the "Ansel Adams" books by Schaeffer. I will try to dig up a detailed reference.

Actually, the correct title was "Moonrise"  Hernandez, New Mexico"

Hernandez is a very poor rural district just north of Espanola, NM and the shot was made in the late afternoon while it was still daylight from just off the shoulder of the road. The sun was low on the horizon and beautifully illuminating the white crosses in the cemetary. He exposed for the moon with an "estimate" because he couldn't find his Weston meter and the light was rapidly changing. He was shooting with a Wratten (G) filter, ASA 64 film and shot it at 1 second at F/32. Later, Ansel said that he should have given 50 percent more exposure (a half zone) because of the "low value" of the foreground which would have made the foreground slightly more dense. He had lots of difficulty with the print and several years later used Kodak IN-5 intensifier on the lower part of the image. He did lots of selective burning to get the effect he wanted and said on numerous occasions that no two prints were exactly alike.

Officially, the date and time of the shot were established by Dr. David Elmore of the High Altitude Observatory at Boulder, Colorado as 4:05 pm, October 31, 1941. Ansel never kept good notes about the time and day of his photos :-)

Today, the old church still stands north of Espanola. The bell has fallen from the bell tower and the roof has a different pitch. It's no longer possible to get a similar shot from the highway and the entire area has given way to junked autos, trashy travel trailers and such. The back of the church has debris and chain link fencing piled against it, but it still makes a nice shot from the front. It's in bad need of repair - hopefully the state of New Mexico will eventually contribute toward its preservation. Here's what the front looks like today:

Lin

(http://www.lin-evans.com/southwest/k_moonrise.jpg)
Title: Shooting the Moon
Post by: gwarrellow on February 08, 2004, 06:02:12 am
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Thank you very much.  so f16 @ 50 seconds for iso 100?
Exegeter, definitely not the exposure time you have suggested!  If you go to the website Richard suggested you will see a link to Michael Oates' "exposure calculator".  Make this device and it will guide you well.  I don't have the calculator myself but I would guess that for a full moon at f16 you would need around 1/125 sec at ASA100.  The secret is to bracket and keep notes (if you don't shoot digital).

There is actually no point in shooting at f16 as the moon is essentially at infinity in photographic terms.  A wider aperture will allow a shorter exposure with less chance of blurring due to the earth's rotation.  This effect will be dependent on the f.l. of your system; in my telescope I need to engage the motor drive even for relatively short exposures.

Other things to watch out for are precise focusing, use a tripod and cable-release, and mirror lock up if you have it.  Precise focusing is more difficult than it sounds and is a particular problem with longer focal length lenses or when shooting through a telescope.

What type of equipment are you using?  You will find that it is very difficult to obtain an exposure that is able to reveal lunar details and cloud features/colours and is dependent on the lunar phase and whether you are shooting in the "twilight zone" or at night.  Some people resort to shooting more than one exposure: one for the moon and the other for the other feature and then combine in something like Photoshop.

Taking good lunar pictures is not as easy as it seems.  If you venture further into astrophotography you will find another world again.

Good luck!
Graham
Title: Shooting the Moon
Post by: Howard Smith on February 14, 2004, 02:27:03 pm
Your examples look good, so I think you have it.  What looks "normal" is probably over-exposed on film since your eye opens up for the night sky and is blown out by a very bright moon.  The guide lines you give are simple to remember too.

As for the "sunny-16" rule, I have always found with my particular camera/film combinations, it is more like 16 1/2.
Title: Shooting the Moon
Post by: Howard Smith on February 09, 2004, 01:45:00 pm
The moon has about the same eflectivity as the earth.  The sunny 16 rule works fine.  Remember to increa exposure to account for overcast, haze and other atmospheric things.

Be careful with your TTL meter.  It will be reading ots os black and trying to make it gray.  Hence, overexpose the moon.

"Magnification"maens nothing.  f/16 @ 1/125 is the same for any focal length.  Remember, when using an extender, you are hanging the foal length, so f/16 isn't f/16 anymore.   The diameter of the diaphragm hasn't changed, but the focal length got longer.  The effect is a reduced f/stop.  You will need to open up or increase exposure time.
Title: Shooting the Moon
Post by: BJL on February 18, 2004, 03:19:09 pm
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The photo is "Moonrise" over Hernandez.  It is detailed in "Examples, The Making of 40 Photographs."

Adams said he knew the moon had a liminance of 250 c/ft2.  He used this and the Exposure Formula to determine his exposure.

The Exposure Formula is discussed in "The Negative" by Adams.  It says that the key f/stop is the square root of the film speed.  The shutter speed is the reciprical of the luminance in c/ft2.  This will place the subject in Zone V.  He exposed the moon for Zone VII, which he claims is ideal.  (The modern problem is not many meters read in c/ft2.)

In the discussion of "Moon and Half Dome," Adams provides some information on selecting the exposure for the moon in the evening and in the dark.
Howard,
  thanks for the details.

  Probably the most useful piece of information is the idea of placing the moon on Zone VII, or two stops above "middle gray", combined with someone else's mention that it reflectance is about 25%, or about 1/2 to 1 stop above the 13% to 18% variously quoted for light meter calibration. Putting these together suggests that the moon needs about 1 to 1 1/2 stop more than "sunny 16 exposure", or about f/9 to f/11 at 1/ISO; this matches nicely with someone's suggestion of f/11 at 1/ISO!
Title: Shooting the Moon
Post by: Howard Smith on February 20, 2004, 10:04:46 am
Perhaps it is in the printing.  But the clouds are white and the moon isn't.  Quite different reflectivity with about the same illumination.  The moon may even have less illumination because the light path psses through all of the earth's atmosphere twice (the moon is near the horizon and full).  The clouds are quite near, so the light passes through about half of the earth's atmospere once and a very short distance back to the camera.

It is my opinion that many landscape images that include the moon over expose the moon - approach or achieve the washed out white disc Adams wanted to avoid.  That may be why his moon appears darker than is common.  Getting shadow detail at eveni requires more exposure to capture shadow detail and risks over exposing the moon.  The range of luminance is huge, and common TTLs will have trouble.  The moon is a small bright spot with little effect on overall exposure, so it gets lost.
Title: Shooting the Moon
Post by: Howard Smith on March 12, 2004, 06:12:57 pm
Thanks for the info.  I was thinking to compare exposures of film and my digicam to find an equivalent digital ISO.  Maybe that won't work?

As for the moon image, the "right" exposure is the one that works for you.  A sharper mage may be more important than merely a darker image and a bit of highlight detail.
Title: Shooting the Moon
Post by: BJL on March 14, 2004, 12:16:46 pm
Quote
Or perhaps you are right and things look different from Oz.
Indeed the moon looks the other way up Australia; I had never seen the "man in the moon" until I got to the Northern Hemisphere!