Is this CA that I'm seeing? (1 Viewer)

[DuckNorris]

I started birding fairly recently with gift Celestron Nature DX (not the ED version) in 8x42. They cost about $135 on Amazon.

I am pretty happy with them, but I was thinking about upgrading now that I am using my bins much more often than I thought I would.

I took my Celestrons into my local REI and compared them to Nikon Monarch M7 8x42.

I was looking out their north-facing store window at the parking lot in mid-afternoon on a sunny day. There was a dove on street light to look at about 100 ft away.

The Nikons looked a little better to me. The main thing I noticed was the FOV was better (8.3 deg vs 7.4).

I didn't see a $450 $350 difference though.

But today I noticed something troubling when I was looking almost straight up at a black vulture.

As it flew with blue sky above/behind it, I could see lots of detail, including the white feathers on the ends of its wings.

But when it flew under a cloud, all I could see was a black silhouette.

Is this CA that I'm seeing?

Would something like the Monarch M7's solve this, or would I have to go up another level or even higher?

 

[dries1]

The Nikon M7 8X42 are not $450 more than the Celestron DX in price, and I would think the Nikon is a better binocular.

 

[DuckNorris]

The Nikon M7 8X42 are not $450 more than the Celestron DX in price, and I would think the Nikon is a better binocular.

Yes, it's really about a $350 difference. I should have proof read for arithmetic errors

If a black vulture, when seen from below with blue sky above/behind it, has lots of detail (can see individual feathers), but then when it flies under a cloud, it turns into a black silhouette (as it does with my Celestron DX), is that effect caused by CA?

And whatever is the cause, would M7's probably fix that? Our would I have to go higher?

 

[dries1]

I would search this forum on what CA chromatic aberration is and what causes it, there is much information on Birdforum, there are no easy answers.

 

[GrampaTom]

Yes, it's really about $350 difference. I should have proof read for arithmetic errors

If a black vulture, when seen from below with blue sky above/behind it, has lots of detail (can see individual feathers), but then when it flies under a cloud, it turns into a black silhouette (as it does with my Celestron DX), is that effect caused by CA?

And whatever is the cause, would M7-level bins probably fix that? Our would I have to go higher?

Welcome to the world of binoculars and one explanation for some of the differences discussed here that're often attributed to the binocular itself. See #455 here, Zeiss SFL 8x40, A Field Review, for some related conversation. Its not though just air quality, but light effected by clouds, trees, time of year/angle of the sun. Is the sun behind, in front or to the side at some angle? All kinds of things effect what you see. One trick if you see something like that is to drop the binos from your eyes and look at what mother nature is doing in front of you. An interesting question becomes is this a natural viewing problem or is the binocular creating this?

 

[Maljunulo]

To try to answer your specific question, my answer is “no”. CA is the result of different colors not coming to the same focus.

It is not Chromatic Aberration, but rather the design of the human eyeball.

The eye can be overwhelmed (flooded or saturated, if you will) by light and it loses its ability to see detail in a relatively small object placed against the strong light. It is a dynamic range sort of thing, I think.

If this is wrong, someone who knows what he is talking about will be along shortly to correct me.

 

[DuckNorris]

The vulture was pretty high up. Without the bins, I could see just a silhouette whether it had sky or cloud above/behind it. So I think looking without bins in this particular case doesn't help.

The sun was to the side of it. I was looking east at it, and it was around 4pm when I saw it.

I understand about dynamic range, but I was confused when it went from "detail with obviously white feathers at the wing ends" to "just a black silhouette" when the background transitioned from blue sky to cloud.

Maybe my eyes got a much stronger dose of back light from the clouds than they did from the blue sky? It wasn't obvious to me, but maybe that is it?

 

[GrampaTom]

Chromatic Aberration is a popular term here. I believe Maljunolo first paragraph describes it correctly. Based on your description of what you saw, my guess is that was more a backlighting type problem, not CA. Bright sun behind even if not directly so, the object your trying to see, will cause it to be blacked out, detail lost.

 

[GrampaTom]

What you describe is a common, in fact daily thing where we bird. Bird details and color fine one moment then obscured, blacked out the next. Where’s the sun, clouds, you, what’s the bird doing? A quick change of relationship to the sun, details lost. At least that’s what it sounds like.

I get what you described, the bird was so far away it looked black, so my advice to look without binos would not be helpful. That idea was more directed at a condition where all of a sudden one day binos you thought super nice and clear, the next day not quite so. If the air is soupy, humidity up, very fine mist, micro particles of pollution, forest fire particles your binos have to see through that stuff. Most of my life has been at sea level. Some time ago I spent time in the mountains of Colorado 5000, 10,000 feet up. The night sky was mind boggling, had no idea there were so many stars to see! The air at sea level especially in urban areas is a filter.

 

[DuckNorris]

What you describe is a common, in fact daily thing where we bird. Bird details and color fine one moment then obscured, blacked out the next. Where’s the sun, clouds, you, what’s the bird doing? A quick change of relationship to the sun, details lost. At least that’s what it sounds like.

I get what you described, the bird was so far away it looked black, so my advice to look without binos would not be helpful. That idea was more directed at a condition where all of a sudden one day binos you thought super nice and clear, the next day not quite so. If the air is soupy, humidity up, very fine mist, micro particles of pollution, forest fire particles your binos have to see through that stuff. Most of my life has been at sea level. Some time ago I spent time in the mountains of Colorado 5000, 10,000 feet up. The night sky was mind boggling, had no idea there were so many stars to see! The air at sea level especially in urban areas is a filter.

I live in Florida

 

[CharleyBird]

"As it flew with blue sky above/behind it, I could see lots of detail, including the white feathers on the ends of its wings.
But when it flew under a cloud, all I could see was a black silhouette."

Contre-jour?

 

[GrampaTom]

"As it flew with blue sky above/behind it, I could see lots of detail, including the white feathers on the ends of its wings.
But when it flew under a cloud, all I could see was a black silhouette."

Contre-jour?

Contre-jour - Wikipedia

en.wikipedia.org

 

[Ted Y.]

As it flew with blue sky above/behind it, I could see lots of detail, including the white feathers on the ends of its wings.

But when it flew under a cloud, all I could see was a black silhouette.

Maybe the bird was in the cloud, or near the cloud, and the humidity changed the visibility?
Humidity or hot air ascending can have such effect.

For my binoculars, the CA appears as a line of green.

 

[Troubador]

The vulture was pretty high up. Without the bins, I could see just a silhouette whether it had sky or cloud above/behind it. So I think looking without bins in this particular case doesn't help.

The sun was to the side of it. I was looking east at it, and it was around 4pm when I saw it.

I understand about dynamic range, but I was confused when it went from "detail with obviously white feathers at the wing ends" to "just a black silhouette" when the background transitioned from blue sky to cloud.

Maybe my eyes got a much stronger dose of back light from the clouds than they did from the blue sky? It wasn't obvious to me, but maybe that is it?

Your question 'was this chromatic aberration'? is a straight-forward one and the answer is No. CA causes the appearance of narrow lines of colour (often purple) at points where there is strong contrast. For example a black pole carrying black cables against a white cloud or a white swan against a background of very dark water.

What you describe sounds to me simply that the extra brightness of the cloud caused your pupils to close down somewhat and you ended up with a silhouette.

Lee

 

[Ted Y.]

Your question 'was this chromatic aberration'? is a straight-forward one and the answer is No. CA causes the appearance of narrow lines of colour (often purple) at points where there is strong contrast. For example a black pole carrying black cables against a white cloud or a white swan against a background of very dark water.

What you describe sounds to me simply that the extra brightness of the cloud caused your pupils to close down somewhat and you ended up with a silhouette.

Lee

Can a cloud have extra brightness compared with the sky without clouds?

 

[Troubador]

Can a cloud have extra brightness compared with the sky without clouds?

I posted in haste and should have mentioned I was assuming the clouds were white and illuminated by sunlight.

Lee

 

[William Lewis]

Definitely not CA That appears at the edges of things when there is a high contrast between 2 areas, you may have seen it on the edges of the vulture against the cloud - usually it fringes visibly from between the edge of the darker areas into the lighter areas and is usually most visible away from the centre of the field of view - even is quite expensive binoculars. We get quite a few egrets round here, I moved away from Leica when I could scarcely make out an egret at a good distance through my trinovids hd's, in this unusual case the lighter area was the bird that instead of being white was a mess of various shades, none of them white!

 

[Rg548]

I didn't see a $450 $350 difference though.

Marginal gains as the price goes up.
Zeiss Conquests are awesome at about £1000..... Zeiss SF's are a bit more awesome at TWICE the price.
Worth it to some, not to others.

 

[DuckNorris]

Can a cloud have extra brightness compared with the sky without clouds?

Today I took a picture of a similar sky around 5pm, and when I use the eye dropper in Photoshop it says the luminance is 97-99% on the clouds and is only 70-72% on the blue sky.

I'm not sure how scientific this is, but it does seem to show the clouds have more brightness than the blue sky.

 

[Maljunulo]

Blue sky is light which has traveled through the atmosphere from the sun, and it is blue because shorter wavelengths are preferentially scattered.

Clouds reflect all wavelengths, that is why they appear to be white.

Two very different phenomena, and there is a difference in intensity between some wavelengths and all wavelengths, hence clouds are indeed “brighter” than empty blue sky.

That‘s my guess, anyway.