what part used to level?

[Top_Gun]

I knew these were going to be a problem when I was editing them. I want to see what you would use as a reference. For the first pic, I used the side of the hanger where the camera is and it looks pretty vertical.



On the second one, I believe I used the wall below the I in AIR. Should I use the top of the hanger for both to keep them level?


appreciate any insight on these 2 images.

[wwshack]

Keep in mind the lens distortion at wide angles. It may be worth running the Photoshop, Transform, perspective function on the images to compensate. I would choose a vertical as near the centre of the image as I can find.
Here are a couple of quick and dirty edits with transformation, perspective.

I don't like the way the right hand side has turned out

[seahawk]

Simple rule, if possible use a reference in the middle of the pic, it is the least distorted

[Top_Gun]

Simple rule, if possible use a reference in the middle of the pic, it is the least distorted

but should I use the one's that go up and down or across?

I used the one's that were vertical but obviously it didn't work out, are horizontal lines the preferred?

[seahawk]

verticals. In the first I would use the outer edge of the Guard-hangar, in the second use the edge of hangar under the word "Air". So in fact you did it right the first time, although I think there is an error in leveling in the second pic. Does not seem leveled against the reference correctly.

[wwshack]

Verticals first. The horizontals can be distorted by perspective, eg. if you stood well to the side of the shed, the horizontal roof line would be seen to slope away from you, a vertical in the centre is always a vertical irrespective of perspective.

I would encourage paying attention to the perspective especially so in wide angle shots, otherwise it's sloppy photography.

At the end of the day you have to produce a photo that is acceptable to the screener and sometimes one has to change the physical reality of an airport to suit - runways are always flat and horizontal unless there is a vertical reference point.

[Top_Gun]

thanks guys, I'll have another go at the original.

[brianw999]

runways are always flat and horizontal unless there is a vertical reference point.

Sorry Wallace, I would have to disagree with that statement. (and yes, I did see your smilie ) Two examples spring immediately to mind.

The Greek island of Skiathos has a very noticeable curving uphill slope that could almost be likened to a Harrier takeoff jump !!

Biggin Hill in the UK has such a large hump that if you stand at one end of the runway you won't see a reasonable sized airliner lined up at the other end.

Out of interest I once took a spirit level to a hangar corner upright and found it not to be vertical !!

My last set of uploads to JPnet included some with a clear sea horizon. No arguing with unlevel horizon there.....but take a look at this one....http://www.jetphotos.net/viewphoto.php?id=5837662

Yes, it's level, you can see that immediately by the horizon....but now cover up the background so that you can't see the horizon, close your eyes for a few seconds and then take another look. Does it look like it could do with some CW rotation now ?

As others have said already, use a vertical close to the centre of the image if you can to avoid perspective problems.....but sometimes you have to make it "look" right and not necessarily "is" right.

[seahawk]

I nthe exampel I see no useable refenrence except the horizon. And we generaly do accept pics, if we are not sure it is unlevel or if it does not look absolutely strange. (had some interesting take-off shots recently)

If there is reference that can be used, we do use it. I can only recommend to add a few words to teh screeners if judging the correct alignement can be difficult in the pic. For exampel if a struture is not level, let us know.

[wwshack]

I can see your point Brian, it is the perspective line that deceives the eye in your DC9 photo.

I have a similar problem with photos taken on the apron at Scone, which has an impressive slope to it and I would like to add in a non-sycophantic way the JP screeners have been very understanding, other screeners elsewhere have not been to understanding....
There is a 2.6 degree difference between two reference points in this picture http://www.jetphotos.net/viewphoto.php?id=5796856

[brianw999]

Jeez, that Scone apron has some slope to it !!

Out of interest I levelled your Scone pic using the centres of the prop spinners. The aircraft is now, without a doubt, level as far as a spirit level would be concerned......but look at the buildings in the background !!!

http://img131.imageshack.us/img131/6...0613ediih2.jpg


I actually found myself leaning to the left with my eyes constantly flitting back and forth between the aircraft and buildings. That doesn't happen with your database picture....which only goes to prove that the human brain is an amazing thing when sorting out what is and isn't right, by using averages to produce an acceptable view.....because I couldn't find a pair of verticals or horizontals in your database pic that produced an identical off-level number with the measure tool. That pic has got to be the best ever example of what "looks level" but isn't necessarily so. Nice pic.