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Mark M
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Posts: n/a
 
      10-09-2004

<(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> In message <(E-Mail Removed)>,
> "George E. Cawthon" <(E-Mail Removed)> wrote:



> There are two problems with your theory:
>
> 1) Digital sensors are not film. Film receives its optimum exposure in
> the middle zones, and it is usually best to expose things centered
> around 18% reflectance. Digital cameras give their best performance
> when exposure is just short of clipping the data.


My shooting results, and the experience of others I've read here on this
forum fully support/agree with the above correction. Sunny 16 really
becomes more like "sunny 11" with my 10D...even in full, high
sunlight--without visible haze or atmospheric obstructions, etc. Other
digitals have tended to also need more light in general to their ISO film
"equals."

Add to this that the 10D's RAW files are amazingly able to recover from a
bit of over-exposure in processing, and you're in good shape.


 
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George E. Cawthon
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Posts: n/a
 
      10-09-2004


Roger Halstead wrote:
>
> On Fri, 08 Oct 2004 02:43:59 GMT, "George E. Cawthon"
> <(E-Mail Removed)> wrote:
>
> >
> >
> >Roger Halstead wrote:
> >>
> >> On Thu, 07 Oct 2004 00:36:49 GMT, http://www.velocityreviews.com/forums/(E-Mail Removed) wrote:
> >>
> >> >In message <Vag6d.35627$(E-Mail Removed)>,
> >> >Phil Wheeler <(E-Mail Removed)> wrote:
> >> >
> >> >>Moon is far too bright for 10 sec exposure.
> >>
> >> Even then 10 seconds should be enough to show the surface on the unlit
> >> portion of a half moon.
> >> >
> >> >Not when it is orange.
> >>
> >> At ASA 100 I'd still expect 1/25 to1/60 or so which is still far too
> >> slow for a telephoto of that size except on a tripod.
> >>
> >> Nor would I expect an inexpensive zoom of that range to be tack sharp
> >> through its whole range. The wide range can be very handy, but even
> >> in expensive lenses the quality would suffer at that wide a range.
> >>
> >> The AF Nikor 75 to 300 f4.5-5.6 is a relatively inexpensive lens in
> >> the $300 range. It gives quite good results and focuses very fast on
> >> the D-70 *unless* it has to go through the whole range from close
> >> focus to infinity.
> >>
> >> When spending $1000 for a camera body I'd try to give it the lenses to
> >> do it justice. However I have seen the D-70 advertised as low as in
> >> the $700 range.
> >>
> >> Roger Halstead (K8RI & ARRL life member)
> >> (N833R, S# CD-2 Worlds oldest Debonair)
> >> www.rogerhalstead.com

> >
> >Good Grief, doesn't everybody know that the moon recieves the same
> >light as the earth. Thus the correct exposure is 1/ASA at f16. For
> >and ASA of 100 that is 1/100 at f16 or 1/200 at f11, etc. The only

>
> Yup and with that lens and a 3X telextender he's looking at roughly at
> f16. Take into account the haze when just above the horizon and you
> get 1/25 - 1/60 At least out here in the farm country with summer
> haze from the vegetation you get a good 2 f stops when close to the
> horizon. Were you out in the Boulder CO area I doubt it'd even be one
> stop on most evenings. Of course that'd still leave him with a soft
> lens and a 3X telextender to make it even softer. I seriously doubt
> he's using a really high quality telextender as they are quite
> expensive so in addition it's going to be soft as well.
>
> >correction you need is for a lousy atmosphere due to smoke, haze etc.
> >which is likely to be less than 2 f stops (otherwise get the hell in
> >doors and quit breathing that crap). Which means that at f5.6 1/800
> >sec is normal and 2 stops more would be 1/200 second. So what is all
> >this talk about 1/25 second? The moon through dense fog? a forest
> >fire? Mount St. Helens ash? your sun glasses?

>
> Typical visibility here is 10 to 15 miles in the summer. On good days
> it'll be a bit over 20 to 30 and on very rare days it may push 50.
> Compare that to the Western states where 75 is typical and 125 is not
> unheard of. I've spent over 1300 hours flying over much of the
> country East of the Rockies in the last 10 years. Nearly all was under
> 10,000 feet Visibility varies widely, but a normal day here in
> central Michigan would be considered terrible in Colorado. <)
>
> It's not uncommon to find mornings and evenings here where you can
> look directly at the sun with no eye protection.
>
> Roger Halstead (K8RI & ARRL life member)
> (N833R, S# CD-2 Worlds oldest Debonair)
> www.rogerhalstead.com


I didn't comment on the lens or the extender because I can imagine
using a 3x teleextender with a zoom lens and especially a wide range
zoom. All I can say is YUK if you can look at the sun without eye
protection. No one mentioned light polution, but that is another
atmospheric condition that will play havoc with (or enhance depending
on the artistic merit) moon images.
 
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George E. Cawthon
Guest
Posts: n/a
 
      10-09-2004


(E-Mail Removed) wrote:
>
> In message <(E-Mail Removed)>,
> "George E. Cawthon" <(E-Mail Removed)> wrote:
>
> >
> >
> >Roger Halstead wrote:
> >>
> >> On Thu, 07 Oct 2004 00:36:49 GMT, (E-Mail Removed) wrote:
> >>
> >> >In message <Vag6d.35627$(E-Mail Removed)>,
> >> >Phil Wheeler <(E-Mail Removed)> wrote:
> >> >
> >> >>Moon is far too bright for 10 sec exposure.
> >>
> >> Even then 10 seconds should be enough to show the surface on the unlit
> >> portion of a half moon.
> >> >
> >> >Not when it is orange.
> >>
> >> At ASA 100 I'd still expect 1/25 to1/60 or so which is still far too
> >> slow for a telephoto of that size except on a tripod.
> >>
> >> Nor would I expect an inexpensive zoom of that range to be tack sharp
> >> through its whole range. The wide range can be very handy, but even
> >> in expensive lenses the quality would suffer at that wide a range.
> >>
> >> The AF Nikor 75 to 300 f4.5-5.6 is a relatively inexpensive lens in
> >> the $300 range. It gives quite good results and focuses very fast on
> >> the D-70 *unless* it has to go through the whole range from close
> >> focus to infinity.
> >>
> >> When spending $1000 for a camera body I'd try to give it the lenses to
> >> do it justice. However I have seen the D-70 advertised as low as in
> >> the $700 range.
> >>
> >> Roger Halstead (K8RI & ARRL life member)
> >> (N833R, S# CD-2 Worlds oldest Debonair)
> >> www.rogerhalstead.com

> >
> >Good Grief, doesn't everybody know that the moon recieves the same
> >light as the earth.

>
> The sun shines with equal intensity on both bodies. However, when the
> moon is on the horizon, its reflected sunlight has to pass through much
> more atmosphere than when it is high in the sky. The amount of
> atmosphere between moonrise and moonset would chart something like this:
>
> * *
> * *
> * *
> ** **
> ** **
> *** ***
> ***********************


True. Do you suppose that was one of the reasons I said you needed to
correct for the atmosphere?
>
> >Thus the correct exposure is 1/ASA at f16. For
> >and ASA of 100 that is 1/100 at f16 or 1/200 at f11, etc. The only
> >correction you need is for a lousy atmosphere due to smoke, haze etc.
> >which is likely to be less than 2 f stops (otherwise get the hell in
> >doors and quit breathing that crap). Which means that at f5.6 1/800
> >sec is normal and 2 stops more would be 1/200 second. So what is all
> >this talk about 1/25 second? The moon through dense fog? a forest
> >fire? Mount St. Helens ash? your sun glasses?

>
> Your assumptions are incorrect. On my Canon 10D, even on nights when
> the stars are visible, sunny f16 results in a way-underexposed moon,
> even if the sun is high in the sky.


I'm not sure that is true. Most images I have seen of the moon are
way over exposed and appear as a ball of light with little or no
differentiation of tones.

>
> There are two problems with your theory:
>
> 1) Digital sensors are not film. Film receives its optimum exposure in
> the middle zones, and it is usually best to expose things centered
> around 18% reflectance. Digital cameras give their best performance
> when exposure is just short of clipping the data. The moon is mainly
> grey, not white, so there is room to pull the exposure for the moon.
> Also, many digital camera are really metering for lower-than-stated
> ISOs, by film standards.


For all I know, you are correct about the digital sensors, but that
doesn't change the fact that "sunny 16 is a fact." If manufacturers
don't meter for the correct ISO, that's a manufacturing problem. If
someone brings out a film and exposure are substantially underexposed
when using "sunny 16" on nearby subjects, that doesn't invalidate the
"sunny 16" rule, it just means the manufacture gave the film an
incorrect ASA rating. BTW, "metering for lower than stated ISOs"
would result in more exposure not less.

>
> 2) The moon loses a bit of light to the atmosphere, even under
> relatively clear conditions. When you look through the atmosphere at
> distant objects during the day, you lose light from each of your
> subjects, but you regain a lot of that light anyway, as it hits the film
> or sensor at some other angle, causing a loss of contrast. The moon
> does not have "neighbor" subjects to swap light with. It can only lose
> light, as the rest of the sky has little light to contribute.
> --


Humbug! What ARE you talking about? Perhaps you are mixing in the
well known pre exposure effect on silver halide emulsions, but
subjects swap light? But that would do the opposite of what you are
claiming.

>
> <>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
> John P Sheehy <(E-Mail Removed)>
> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

 
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JPS@no.komm
Guest
Posts: n/a
 
      10-09-2004
In message <i0K9d.18934$a85.16184@fed1read04>,
"Mark M" <(E-Mail Removed)> wrote:

>Add to this that the 10D's RAW files are amazingly able to recover from a
>bit of over-exposure in processing, and you're in good shape.


I like to think of it as "over-JPEG-exposing", not "over-exposing". The
JPEGs at normal contrast simply toss a stop of green and blue
highlights, and a stop-and-a-half of red highlights into the trash bin.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <(E-Mail Removed)>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

 
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JPS@no.komm
Guest
Posts: n/a
 
      10-09-2004
In message <(E-Mail Removed)>,
"George E. Cawthon" <(E-Mail Removed)> wrote:

>(E-Mail Removed) wrote:


>> The sun shines with equal intensity on both bodies. However, when the
>> moon is on the horizon, its reflected sunlight has to pass through much
>> more atmosphere than when it is high in the sky. The amount of
>> atmosphere between moonrise and moonset would chart something like this:
>>
>> * *
>> * *
>> * *
>> ** **
>> ** **
>> *** ***
>> ***********************


>True. Do you suppose that was one of the reasons I said you needed to
>correct for the atmosphere?


Yes, but you made it sound like the correction was always small. When
the moon is orange and on the horizon, it is almost impossible to
photograph at a low ISO without a tracking mount, because it moves
significantly in the time needed for exposure. The best bet would
probably be to take multiple under-exposures, and then stack them with a
program that aligns such images at a sub-pixel level (if it doesn't, you
can upsample them before-hand yourself).

>> >Thus the correct exposure is 1/ASA at f16. For
>> >and ASA of 100 that is 1/100 at f16 or 1/200 at f11, etc. The only
>> >correction you need is for a lousy atmosphere due to smoke, haze etc.
>> >which is likely to be less than 2 f stops (otherwise get the hell in
>> >doors and quit breathing that crap). Which means that at f5.6 1/800
>> >sec is normal and 2 stops more would be 1/200 second. So what is all
>> >this talk about 1/25 second? The moon through dense fog? a forest
>> >fire? Mount St. Helens ash? your sun glasses?


>> Your assumptions are incorrect. On my Canon 10D, even on nights when
>> the stars are visible, sunny f16 results in a way-underexposed moon,
>> even if the sun is high in the sky.


>I'm not sure that is true. Most images I have seen of the moon are
>way over exposed and appear as a ball of light with little or no
>differentiation of tones.


That is automatic exposure where the moon is a small part of the frame.

>> There are two problems with your theory:


>> 1) Digital sensors are not film. Film receives its optimum exposure in
>> the middle zones, and it is usually best to expose things centered
>> around 18% reflectance. Digital cameras give their best performance
>> when exposure is just short of clipping the data. The moon is mainly
>> grey, not white, so there is room to pull the exposure for the moon.
>> Also, many digital camera are really metering for lower-than-stated
>> ISOs, by film standards.


>For all I know, you are correct about the digital sensors, but that
>doesn't change the fact that "sunny 16 is a fact." If manufacturers
>don't meter for the correct ISO, that's a manufacturing problem. If
>someone brings out a film and exposure are substantially underexposed
>when using "sunny 16" on nearby subjects, that doesn't invalidate the
>"sunny 16" rule, it just means the manufacture gave the film an
>incorrect ASA rating. BTW, "metering for lower than stated ISOs"
>would result in more exposure not less.


Perhaps; what I should have said is that when the camera automatically
exposes a scene, it may use aperture and shutter values that a light
meter would give you for a lower ISO setting than the one the digital
camera claims to be using.

With the Canon 10D, for example, if I use "sunny f16" literally, using
the ISO value the camera claims to be using, on a day with deep blue
skies at noon, even sunlit white objects may be a half a stop or more
below the JPEG clipping point (a stop and a half below the RAW clipping
point, or more). I am talking about scenes where conventional wisdom
would tell you to set the EC to -1. I have taken numerous pictures at
sunny f16 when the conditions warrant it, and they are all dark,
resulting in an effective multiplication of ISO and loss of bit depth.
The only exception is when there are large vertical structures,
reflecting extra light into the scene, like sky-scraper areas with light
colored bricks or lots of windows.

>> 2) The moon loses a bit of light to the atmosphere, even under
>> relatively clear conditions. When you look through the atmosphere at
>> distant objects during the day, you lose light from each of your
>> subjects, but you regain a lot of that light anyway, as it hits the film
>> or sensor at some other angle, causing a loss of contrast. The moon
>> does not have "neighbor" subjects to swap light with. It can only lose
>> light, as the rest of the sky has little light to contribute.


>Humbug! What ARE you talking about? Perhaps you are mixing in the
>well known pre exposure effect on silver halide emulsions, but
>subjects swap light? But that would do the opposite of what you are
>claiming.


Let me try stating this another way; the moon loses light in the
atmosphere to diffusion (it goes in another direction, instead of your
lens). If there were 64 moons in the sky, in an 8*8 grid, all touching
each other, light that refected of any given moon would come towards the
lens, but some of it is scattered and comes from the moon to the lens
from an angle that is not within the disc it came from. In this sens,
each disc loses light to the atmosphere, which lowers the contrast by
placing light outside of its disc on the focal plane. this darkens the
disk itself, *but*, the disks around it do the same thing, so the lost
light is made up, just like viewing a mountain range 5 miles away
through the atmosphere. Take away 63 of those moons, and you have one
moon losing light in its disc but *NOT* gaininga any light in the disc
area from adjacent disks.

Now do you understand what I'm saying? Sunny f16 works for distant
mountain ranges, because light is diffused but the total effect is not a
net loss. A sole moon in the sky loses light from its disk, and regains
nothing from adjacent subjects. Clear now?
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <(E-Mail Removed)>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

 
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George E. Cawthon
Guest
Posts: n/a
 
      10-10-2004


(E-Mail Removed) wrote:
>
> In message <(E-Mail Removed)>,
> "George E. Cawthon" <(E-Mail Removed)> wrote:
>
> >(E-Mail Removed) wrote:

>
> >> The sun shines with equal intensity on both bodies. However, when the
> >> moon is on the horizon, its reflected sunlight has to pass through much
> >> more atmosphere than when it is high in the sky. The amount of
> >> atmosphere between moonrise and moonset would chart something like this:
> >>
> >> * *
> >> * *
> >> * *
> >> ** **
> >> ** **
> >> *** ***
> >> ***********************

>
> >True. Do you suppose that was one of the reasons I said you needed to
> >correct for the atmosphere?

>
> Yes, but you made it sound like the correction was always small. When
> the moon is orange and on the horizon, it is almost impossible to
> photograph at a low ISO without a tracking mount, because it moves
> significantly in the time needed for exposure. The best bet would
> probably be to take multiple under-exposures, and then stack them with a
> program that aligns such images at a sub-pixel level (if it doesn't, you
> can upsample them before-hand yourself).
>
> >> >Thus the correct exposure is 1/ASA at f16. For
> >> >and ASA of 100 that is 1/100 at f16 or 1/200 at f11, etc. The only
> >> >correction you need is for a lousy atmosphere due to smoke, haze etc.
> >> >which is likely to be less than 2 f stops (otherwise get the hell in
> >> >doors and quit breathing that crap). Which means that at f5.6 1/800
> >> >sec is normal and 2 stops more would be 1/200 second. So what is all
> >> >this talk about 1/25 second? The moon through dense fog? a forest
> >> >fire? Mount St. Helens ash? your sun glasses?

>
> >> Your assumptions are incorrect. On my Canon 10D, even on nights when
> >> the stars are visible, sunny f16 results in a way-underexposed moon,
> >> even if the sun is high in the sky.

>
> >I'm not sure that is true. Most images I have seen of the moon are
> >way over exposed and appear as a ball of light with little or no
> >differentiation of tones.

>
> That is automatic exposure where the moon is a small part of the frame.
>
> >> There are two problems with your theory:

>
> >> 1) Digital sensors are not film. Film receives its optimum exposure in
> >> the middle zones, and it is usually best to expose things centered
> >> around 18% reflectance. Digital cameras give their best performance
> >> when exposure is just short of clipping the data. The moon is mainly
> >> grey, not white, so there is room to pull the exposure for the moon.
> >> Also, many digital camera are really metering for lower-than-stated
> >> ISOs, by film standards.

>
> >For all I know, you are correct about the digital sensors, but that
> >doesn't change the fact that "sunny 16 is a fact." If manufacturers
> >don't meter for the correct ISO, that's a manufacturing problem. If
> >someone brings out a film and exposure are substantially underexposed
> >when using "sunny 16" on nearby subjects, that doesn't invalidate the
> >"sunny 16" rule, it just means the manufacture gave the film an
> >incorrect ASA rating. BTW, "metering for lower than stated ISOs"
> >would result in more exposure not less.

>
> Perhaps; what I should have said is that when the camera automatically
> exposes a scene, it may use aperture and shutter values that a light
> meter would give you for a lower ISO setting than the one the digital
> camera claims to be using.
>
> With the Canon 10D, for example, if I use "sunny f16" literally, using
> the ISO value the camera claims to be using, on a day with deep blue
> skies at noon, even sunlit white objects may be a half a stop or more
> below the JPEG clipping point (a stop and a half below the RAW clipping
> point, or more). I am talking about scenes where conventional wisdom
> would tell you to set the EC to -1. I have taken numerous pictures at
> sunny f16 when the conditions warrant it, and they are all dark,
> resulting in an effective multiplication of ISO and loss of bit depth.
> The only exception is when there are large vertical structures,
> reflecting extra light into the scene, like sky-scraper areas with light
> colored bricks or lots of windows.
>
> >> 2) The moon loses a bit of light to the atmosphere, even under
> >> relatively clear conditions. When you look through the atmosphere at
> >> distant objects during the day, you lose light from each of your
> >> subjects, but you regain a lot of that light anyway, as it hits the film
> >> or sensor at some other angle, causing a loss of contrast. The moon
> >> does not have "neighbor" subjects to swap light with. It can only lose
> >> light, as the rest of the sky has little light to contribute.

>
> >Humbug! What ARE you talking about? Perhaps you are mixing in the
> >well known pre exposure effect on silver halide emulsions, but
> >subjects swap light? But that would do the opposite of what you are
> >claiming.

>
> Let me try stating this another way; the moon loses light in the
> atmosphere to diffusion (it goes in another direction, instead of your
> lens). If there were 64 moons in the sky, in an 8*8 grid, all touching
> each other, light that refected of any given moon would come towards the
> lens, but some of it is scattered and comes from the moon to the lens
> from an angle that is not within the disc it came from. In this sens,
> each disc loses light to the atmosphere, which lowers the contrast by
> placing light outside of its disc on the focal plane. this darkens the
> disk itself, *but*, the disks around it do the same thing, so the lost
> light is made up, just like viewing a mountain range 5 miles away
> through the atmosphere. Take away 63 of those moons, and you have one
> moon losing light in its disc but *NOT* gaininga any light in the disc
> area from adjacent disks.
>
> Now do you understand what I'm saying? Sunny f16 works for distant
> mountain ranges, because light is diffused but the total effect is not a
> net loss. A sole moon in the sky loses light from its disk, and regains
> nothing from adjacent subjects. Clear now?
> --
>
> <>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
> John P Sheehy <(E-Mail Removed)>
> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><


1. By low ISO you mean 100? If so, thousands of moon shots are
succesfully taken on low ISO film, people just don't use very long
focal lengths. A 400 mm work well.

2. Automatic exposure when the moon is a smal part of the frame?
Who's talking about that? No, the subject is taking pictures of the
moon with a telephoto. So if one doesn't know enough to expose for
the moon, one should study photography for a few hours.

3. Of course what you are saying is clear, it just doesn't make any
sense. Enuf said, if it works for you go with it.
 
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