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Dawg Pics

Senior Member
@hark Rayleigh scattering of light through the atmosphere causes the red color. The sky is blue for the same reason. There is more atmosphere for the light to pass through from horizon, so the moon looks redder and then gets lighter as it gets higher up. If you can catch a rising orange/red moon, it is pretty spectacular and pretty cool to watch it change color. I can't explain the physics of it all, something about particles, wavelenghts, etc, etc. :p
 
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hark

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@hark Rayleigh scattering of light through the atmosphere causes the red color. The sky is blue for the same reason. There is more atmosphere for the light to pass through from horizon, so the moon looks redder and then gets lighter as it gets higher up. If you can catch a rising orange/red moon, it is pretty spectacular and pretty cool to watch it change color. I can't explain the physics of it all, something about particles, wavelenghts, etc, etc. :p

Thanks for the explanation! :cool: I had no idea.
 

Peter7100

Senior Member
Gee, I think we found the next Carl Sagan! :cheerful:

That would be a great addition to have to the forum :cool:, particulary as @Dawgpics reply has got me thinking about something and I can't find a way to calculate the following:

If you take any point in the World, lets say San Francisco and you were able to extend say a ruler straight above you, how high would it have to go before someone, lets say in New York to was able to view it (assuming they could see that far). Obviously the curvature of the Earth x the distance between the two points will determine the answer. Anyone know if there is such a calculation as I assume one must exist somewhere :confused:
I'm sure the following is probably involved in part of the calculation, where the average 6ft person can see approximately 3 miles to the end of the horizon and if you are say 1 mile up a mountain you could then see out to approximately 350 miles out to the horizon line.
This is @hark 's fault as she got me thinking when she mentioned fires out west affecting colours:playful:
 

Dawg Pics

Senior Member
Gee, I think we found the next Carl Sagan! :cheerful:

;) Hardly. I barely passed high school physics. When you start talking in detail about things like "Rayleigh scattering", "Root Mean Square" and "Nyquist Frequency." I bow-out of the conversation. Other than I know that light scatters into different colors. Any other information, and I would refer you to articles about it. :D

Astronomy is my other hobby (kinda). Haven't used my scope much in a long time, but starting to get back into it.
 

Dawg Pics

Senior Member
That would be a great addition to have to the forum :cool:, particulary as @Dawgpics reply has got me thinking about something and I can't find a way to calculate the following:

If you take any point in the World, lets say San Francisco and you were able to extend say a ruler straight above you, how high would it have to go before someone, lets say in New York to was able to view it (assuming they could see that far). Obviously the curvature of the Earth x the distance between the two points will determine the answer. Anyone know if there is such a calculation as I assume one must exist somewhere :confused:
I'm sure the following is probably involved in part of the calculation, where the average 6ft person can see approximately 3 miles to the end of the horizon and if you are say 1 mile up a mountain you could then see out to approximately 350 miles out to the horizon line.
This is @hark 's fault as she got me thinking when she mentioned fires out west affecting colours:playful:
I just heard an explanation regarding weather radar for windspeed. The meteorologist was explaining why the values in the periphery would be off due to the curvature. You get upper air currents not ground currents farther away, and it wasn't all that far. You might want to start another off-topic thread for science stuff.
 
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West

New member
New walk around pocket cam.
Fuji X100V (3).jpg
 

Whiskeyman

Senior Member
;) Hardly. I barely passed high school physics. When you start talking in detail about things like "Rayleigh scattering", "Root Mean Square" and "Nyquist Frequency." I bow-out of the conversation. Other than I know that light scatters into different colors. Any other information, and I would refer you to articles about it. :D

Astronomy is my other hobby (kinda). Haven't used my scope much in a long time, but starting to get back into it.

At least you took high school physics. I once read that well over 95% of high school graduates/attendees never took a class in physics. The same for advanced math.

That you know of the term Rayleigh Scattering is a complimentary comment to your educational achievements.

The reason that illuminated celestial bodies appear redder at and near the horizon has to do with the wavelengths of light rays passing through the Earth's atmosphere and the size of the molecules making up the atmosphere. The atmosphere's molecules are of a size that they scatter/reflect the shorter wavelength light rays that appear blue and violet to us more than those which are longer wavelengths and appear as red. As the light rays must travel through much more atmosphere when the image is at or near the horizon than when the image is higher in the sky, more of the shorter wavelength photons are scattered and don't reach our eyes or camera sensors. The red appearing wavelengths are less affected and more of these photons reach us, causing the image of the object to appear even more red. When there is small particulate suspension in the sky, often even more blue light is scattered. Although more red may be scattered and reflected, it is still to a lesser extent, causing even more of the sky to appear in a reddish hue.

And to keep at the theme of this thread, I recently added the following equipment to my stable of accessories: Mag Mod Widlife Kit.
Screen Shot 2021-08-30 at 8.55.20 PM.jpg

Now I must figure how to store and travel with it and also keep it away from my storage media since it's got a set of fairly strong magnets associated with it. It won't do much good to have well-illuminated subjects in my photos if the photos are damaged by magnetic fields from the Mag Mod!

WM
 
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hark

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I am really interested in compositing, but it's more than just pasting images onto a background. The lighting and color temperature have to match along with the correct perspective. After watching a number of videos by Ben Shirk, Joel Grimes, Matt Kloskowski, Phlearn, and others to really grasp an understanding of the process, I purchased a preowned copy of this book.

https://www.amazon.com/Photoshop-Co...stic+Composites&qid=1630701013&s=books&sr=1-1

516z9aHuR6L._SX258_BO1,204,203,200_.jpg
 

bluzman

Senior Member
Since wildlife photography has become my favorite genre, particularly critters in motion, I decided that I had to have a D500. My D7500 has been my go to camera for this type of shooting up until now and it's no slouch. That said, things like the continuous shooting speed and buffer depth of the D500 make it irresistible to me.

I have several cameras and I try use all of them regularly - easier said than done :). Adding another makes it that much harder so something had to go. When I compare how often I've used the various bodies, my D750 gets used the least by a big margin.

Long story short, I traded my D750 and several full frame lenses for a lightly used D500 body (~9K shutter count) and more than ample cash to fund a proper set of relevant accessories. In addition, I already have a couple of telephoto lenses - Nikon AF-P FX 70-300mm f/4.5-5.6E ED VR and Sigma 100-400mm f/5.0-6.3 DG OS HSM Contemporary - that I've used and like.

I'm hoping to have the D500 in hand by the end of next week...woohoo!!
 

Peter7100

Senior Member
Since wildlife photography has become my favorite genre, particularly critters in motion, I decided that I had to have a D500. My D7500 has been my go to camera for this type of shooting up until now and it's no slouch. That said, things like the continuous shooting speed and buffer depth of the D500 make it irresistible to me.

I have several cameras and I try use all of them regularly - easier said than done :). Adding another makes it that much harder so something had to go. When I compare how often I've used the various bodies, my D750 gets used the least by a big margin.

Long story short, I traded my D750 and several full frame lenses for a lightly used D500 body (~9K shutter count) and more than ample cash to fund a proper set of relevant accessories. In addition, I already have a couple of telephoto lenses - Nikon AF-P FX 70-300mm f/4.5-5.6E ED VR and Sigma 100-400mm f/5.0-6.3 DG OS HSM Contemporary - that I've used and like.

I'm hoping to have the D500 in hand by the end of next week...woohoo!!

Congrats and I'm sure you will love your D500!
 

hark

Administrator
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Super Mod
Contributor
I've been agonizing over an arca swiss ballhead - although I'm not a big arca swiss fan, there are reasons why one would be beneficial. So after spending a lot of time comparing brands and reading reviews, I settled on the Desmond Demon DB-44 ballhead. Eventually I might swap out the clamp and replace it with a locking lever clamp - either by 3 Legged Thing or Really Right Stuff. The ratings indicate it's pretty solid with many excellent Amazon reviews (as well as on B&H).

https://www.amazon.com/Desmond-Demo...ball+head&qid=1631906370&s=electronics&sr=1-4
81N7K5n2UdL._AC_SL1500_.jpg
 

bluzman

Senior Member
I am sure you will love the D500 for critters. However, I would have kept the D750 and and unloaded the redundent D7500.


Thanks for the comment. I thought about that scenario. I may be branded as a heretic :eek: but I've never been all in on the D750 as its comparatively infrequent use by me can attest. In the end I decided that keeping the D7500 was a better choice for what I do. YMMV
 
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Bikerbrent_RIP

Senior Member
Since I didn't get credit for this posting, I will try again! :mad:

[h=5]09-18-2021[/h] 11:32 AM Bikerbrent has earned 5352 Total points for posts points 11:32 AM Bikerbrent has earned 522 Total points for misc points 11:32 AM Bikerbrent has earned 3939 Total points for user points 11:32 AM Bikerbrent has earned 2244 Total points for threads points

What does this mean? I still did not get any credits for 11:19 AM 09/18/2021. :confused:
 
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