Digital camera glitch

[David H]

What is the inherent design fault that makes so many digital photos of parallel lines bend? I've never seen it on a film camera but so many digital buildings bend to one side. Can it be avoided or is it just poor quality equipment?

[almcd007]

I suspect it has nothing to do with quality - it's to do with the the very wide angle lenses that the manufacturers install on the phones. The wide angle throws the buildings out of perspective, "bending" long straight lines.

Its very similar to this effect with a fish eye lens but not as drastic.

http://en.wikipedia.org/wiki/Fish_eye_lens

Or see here for a technical explanation of Wide Angle.

http://en.wikipedia.org/wiki/Wide-angle_lens

Normal vision is about 50 mm and alot of these lenses are 35mm or less.

[almcd007]

As a post script - you can see the same effect on non digital cameras - but the lenses are not generally as wide angle as the modern digital lenses. They were very expensive on older cameras.

[David H]

I haven't got a phonecam, but sometimes get bent walls with a reasonable Olympus. But some in the albums do look really distorted which may be with phones.
I also discovered if you move when you take a digital photo it bends rather than blurs.
I think I'll make a few tests with the tripod to see, and if it really makes a difference may hold out for an slr.

[almcd007]

Which camera do you have ? If you have a look at the lens it will say something like 35mm - 75mm what are these figures on your camera ?

the principle is the same - the wide angle persepective - you could try zooming slightly to the 50 mm actual sight area and see if this makes a difference. I've never experienced the bending rather than blurring issue though.

[David H]

Olympus fe4400, 5.8-17.4mm

Actually I don't get this too often or I'd have changed cameras by now, but it does happen sometimes and far worse on other people's. I'd never seen it before as fisheye distortion curves lines in an arc, this just bends them randomly. I bet the manufacturers know exactly what it is and would rather we didn't.

[almcd007]

It's difficult to understand without seeing it and I haven't seen anything like you are describing in 25 years of photography. I can say that 17.4mm is extremely wide and will distort lines and objects in many ways it lends my mind to think that there's something the matter with the camera. I'd suggest going into somewhere like Jessops and showing them the results and one of their reps advising whether it be camera or just a trait.

Good Luck

Have you seen and examples of the effects you describe on the net ?

[David H]

I've seen many far worse than mine, gice me a while and I'll link one or two here.

[kempie]

5.8 � 17.4mm for a DC lens is equivalent to 35 � 105mm lens in 35mm format.

[David H]

OK, here's one, http://www.flickr.com/photos/lavendel/57426375 5/in/pool-92575895@N00/

notice how the house leans to the right but the railings on the rest are leaning to the left.

This suffers from a very similar problem
http://www.flickr.com/photos/liverpoolsuburbia /561335160/]

and here's one of mine that looks like it was taken underwater.
http://www.flickr.com/photos/satguru/494935792 /in/set-1483219/
The buildings on the left look like they're falling over.

Any clues as to the causes? I've seen far worse than these but hope they give you an idea.

[almcd007]

I can't find anything "wrong" in the photos - just a case of "perspective" bending the lines.

http://en.wikipedia.org/wiki/Perspective_%28vi sual%29

If you were to adjust the zoom on your camera slightly to 50-55mm (by zooming very slightly) and you were able to still fit the subject into the frame - the "perspective bending" will diminish. The 1st photo - the railings are appearing quite normal and I can see the bend on the left hand edge of the building - however that is further away and you will find bend occurs to the outer edges of the photo as oppposed to the middle of the shot.

I cant see the second but the third of Ashbourne Parade - is a typical example or bending. The buildings look like they're on a tilt. Again If it's posisble to zoom slightly, move back and still be able to fit it all in then it will diminish.

Unfortunately I'm sure it's something quite normal with the 35mm equivelent lens you have on your camera.

[David H]

Thanks for that, luckily it seems to only affect a few pictures and I may need to test some with a tripod and zoom settings to see if I can eliminate most of it, as I use some photos in books and can't if they look crooked.

[David H]

Now here is a classic example http://www.flickr.com/photos/dgbalancesrocks/1 28932578/
The taker has since photoshopped it and is all straight, but this effect cannot be reproduced by a film camera. Wide angle lenses distort lines in a circle from the centre, digital do it randomly (apparently). It shouldn't be possible to sell technology capable of ruining such efforts.

[kempie]

The effect of perspective causing lines to converge affects all types of cameras.

When you tilt the camera upwards to photograph a building the roof is further away from the lens than the base (the difference being proportionally greater when using wide angle lenses) and since more distant objects appear smaller (as you would expect) vertical lines at the edge of the frame converge towards the middle or the vanishing point. This is similar to the effect of photographing along a railway track, the amount of tilt governs the severity of convergence... Pic 1 & Pic 2

[kempie]

As an example I have quickly corrected the photo of the Ashbourne Parade building, with the effect of removing a 5� clockwise twist and tilting the viewpoint downwards as if it was taken horizontally and at eye-level. The vertical edges appear parallel and do not exhibit any of the barrel or pincushion distortion associated with zoom lenses at their extreme settings.

[David H]

I was told this was possible but never seen it done before. Was that with photoshop or something cheaper? And do you need to have a maths degree to know what to do first?

I just saw a house advertised with the worst bending I've ever seen, each vertical wall faced a different angle, left and right depending where they were. I can't ever remember seeing that with film cameras though.