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Is the Horizon always straight


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When taking seascapes is the horizon always straight (horizontal)? I use the level in the camera, (3 different cameras)but when processing the horizon is often not straight, especially when the picture was taken looking north or south. 

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For a seascape, the horizon would always be level... water simply won't do anything else but go level. If your horizon consisted of distant hills, there is a little more latitude because land isn't always 'flat'.. in this case, I usually edit for what looks right (normally taking into account verticals in the foreground).

 

If you are using a tool like Lightroom/Photoshop, straightening the horizon is no big deal however... just do as good a job in the camera as you can so that you don't lose too much of your image as a result of straightening/cropping.

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On 8/2/2018 at 17:45, Steve UK said:

Turns out, the world is not flat so from certain viewpoints, the Horizon is not horizontal. 

 

?? Yes the world isn't flat. I think the video demonstrates that, for an observer close to sea level, that a distant ocean horizon will appear to be at eye level and it will appear to be straight (i.e. not curved). By inference, if all of the distant ocean horizon appears to be at eye level then it must also be horizontal.

 

Mark

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1 hour ago, John Morrison said:

So the world isn't flat!?!? Next, you'll be telling me that the earth orbits the sun!!

 

In truth they orbit around each other, although the sun is so massive relative to the earth that the sun barely moves...

 

Mark

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1 hour ago, Allan Bell said:

 

The sun circles the milky way at 486,000 miles per hour.

 

Allan

 

 

 

 

And our whole galaxy is probably moving too, or is it all the galaxies that are allegedly moving away from us???

 

Mark

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Enable grid if your camera allows it and that tends to work better than the level indicator. If your viewfinder has a visible focus point array use that.  Failing that align the edge of the viewfinder frame with the horizontal reference as a guide (this way you can find out if you viewfinder is correctly aligned with your sensor).  

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Sometimes the lens can make the horizon seemed slightly curved as well - depends on the lens and zoom etc. If you shoot in raw then apply the lens profile in light room that does sometimes straighten things out a bit.

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Keep in mind that if you’re photographing the horizon on the shore of an ocean or a large lake, you can get perspective distortion that can make the horizon appear to slant even when the camera is level. It’s an issue with reproducing a 3D scene onto a 2D plane.

 

As for the flat earth “The horizon always rises to eye level,” nonsense, I had an opportunity to test that last Thursday evening. I’d volunteered to photograph a networking event for a non-profit I support that was held on the 35th floor of an office building just north of Millennium Park in downtown Chicago. I had my two Lumix GX85s with me and I was marveling at the view of the park and Lake Michigan with some out of towners. I realized that the GX85’s ability to display a 2D level on it’s screen or viewfinder as well as a grid would allow me to take a level shot. So with a 42.5mm (85mm equivalent) lens  attached I used the level to take some shots of the Lake Michigan horizon. Guess what? From 35 floors up which I’m guessing is about 300 meters, you can clearly see that the horizon is noticeably below the horizontal center line of the photos. I’m guessing it’s a fair proportion of the angular size of the sun or moon, which are both about half a degree.

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14 hours ago, TABan said:

 

As for the flat earth “The horizon always rises to eye level,” nonsense, I had an opportunity to test that last Thursday evening. I’d volunteered to photograph a networking event for a non-profit I support that was held on the 35th floor of an office building just north of Millennium Park in downtown Chicago. I had my two Lumix GX85s with me and I was marveling at the view of the park and Lake Michigan with some out of towners. I realized that the GX85’s ability to display a 2D level on it’s screen or viewfinder as well as a grid would allow me to take a level shot. So with a 42.5mm (85mm equivalent) lens  attached I used the level to take some shots of the Lake Michigan horizon. Guess what? From 35 floors up which I’m guessing is about 300 meters, you can clearly see that the horizon is noticeably below the horizontal center line of the photos. I’m guessing it’s a fair proportion of the angular size of the sun or moon, which are both about half a degree.

 

As the camera gets higher the distance to the horizon increases, and it appears lower, partly due to the earth's surface curving away (downwards) and because the camera is also higher.

 

Screen_Shot_2018-08-05_at_20.11.12.png

 

Do you know how accurate/inaccurate your camera's electronic level is? Isn't the accuracy spec of camera levels only around +/-1 degree?

See https://cpn.canon-europe.com/content/education/infobank/digital_camera_features/dual_axis_electronic_level.do

Also the IS function may mess things up slightly.

 

Mark

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15 hours ago, TABan said:

Keep in mind that if you’re photographing the horizon on the shore of an ocean or a large lake, you can get perspective distortion that can make the horizon appear to slant even when the camera is level. It’s an issue with reproducing a 3D scene onto a 2D plane.

 

 

Probably clearer to use the term "shoreline", rather than the "horizon". The shoreline may slant if the distance from the camera to the shoreline changes across the field of view. If the distance is constant, the shoreline will appear horizontal.

 

Mark

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1 hour ago, geogphotos said:

Isn't the point that the camera isn't always straight.

 

Stand on 200 metre high cliff and take a picture looking obliquely down at the cliff base and how can the distant horizon appear to be straight?

 

Obviously if the camera is tipped (rotated about lens axis), the horizon will be tipped. The OP was about what happens with a level camera.

 

Mark

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On 8/2/2018 at 09:52, Steve UK said:

When taking seascapes is the horizon always straight (horizontal)? I use the level in the camera, (3 different cameras)but when processing the horizon is often not straight, especially when the picture was taken looking north or south. 

 

Is the slant maybe always to the same side?

Like the horizon is always higher on the right side?

Then it could be a heavy trigger finger.

 

If it's not, just test your cameras on a tripod. I just lay my phone on top of the hot shoe and use a level app. One with a digital readout is best. I'm still looking for a good one that has an audible signal to level something I cannot reach or see.

My Sony's all have quite a margin before the display goes from level to slanted.

 

wim

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5 hours ago, geogphotos said:

 

Okay. In that case I don't understand the OP's question- and what has north and south got to do with anything? 

 

Looking out to sea the curvature of the Earth is obvious, the horizon line is not straight. 

 

I guess it is much like the tall building perspective conundrum - the image has to look acceptable rather than anything else.

 

No idea why north or south could have any effect.

 

Whether the ocean horizon appears curved or not depends on the focal length of the lens (determines how wide the view of the horizon is) and the elevation above sea level (higher = more visible curvature).

 

I ran some numbers for a wide angle lens with 90 deg horizontal angle of view (e.g. 18mm lens on 35mm film) and calculated the horizon curvature at different camera elevations.

Assuming I got my maths right, here are the results.

 

Screen_Shot_2018-08-06_at_21.40.05.png

 

So horizon curvature appears pretty insignificant when standing at sea level and using a wide angle lens, but becomes quite noticeable as the elevation is increased.

However, I suspect in many cases the horizon curvature seen is more often due to uncorrected barrel distortion in the lens.

 

Hope I haven't made any mistakes.

 

Mark

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