WIDE ANGLE DISTORTION Nikon FX

I have both of them, Gary.....

;)

... or are you saying you want somebody else to do the work for you?

:D
 
Seriously though, I don't think you should be worrying about distortion. The key concern here is perspective. The wider the lens, the closer you need to be to your subject in order to frame/compose the picture, and the more exaggeration of features you get. There's a reason that short telephotos (~85mm) are often quoted as ideal for portraits - it's because they force you to be a bit further back and the perspective is more flattering.
 
Seriously though, I don't think you should be worrying about distortion. The key concern here is perspective. The wider the lens, the closer you need to be to your subject in order to frame/compose the picture, and the more exaggeration of features you get. There's a reason that short telephotos (~85mm) are often quoted as ideal for portraits - it's because they force you to be a bit further back and the perspective is more flattering.

Can you replace every instance of distortion, and replace it with perspective? :D Actually what I meant in the first place :)

So perspective, does it differ on normal lenses? I understand you can get tilt / shift, expensive!

G.
 
Well, its not perspective thats the root cause, its the difference in distance. Its not an idividual lens problem, its user error :)

A good explanation/demonstration here:

http://photography-on-the.net/forum/showthread.php?t=672913

I am surprised that you Gary would need to ask this as you are doing pro studio work arent you??
 
Well, its not perspective thats the root cause, its the difference in distance. Its not an idividual lens problem, its user error :)

A good explanation/demonstration here:

http://photography-on-the.net/forum/showthread.php?t=672913

I am surprised that you Gary would need to ask this as you are doing pro studio work arent you??

Indeed. I ran into a problem with a shoot due to a severe limitation on space. Wanting to avoid the same problem going forward.

Gary.
 
Indeed. I ran into a problem with a shoot due to a severe limitation on space. Wanting to avoid the same problem going forward

Ahhh so either a short Nikon PC-E for you or a breaching charge on the wall to make some more distance :D

Who's nose/ears/errrm did you make look enormous then? :lol:
 
Can you replace every instance of distortion, and replace it with perspective? :D Actually what I meant in the first place :)

So perspective, does it differ on normal lenses?
Perspective isn't a function of the lens (except in the case of tilt-shift lenses, obviously). It's a simple function of the distance to the subject. The lens you use won't affect it.

Here's a way of visualising it.

Suppose you want to take a head-and-shoulders portrait of someone. With a 24mm lens (FX) you'll want to be about 1m away to frame it nicely; with a 100mm lens you'll want to be about 4m away to achieve the same composition. OK so far?

Now, the issue is that the subject's nose sticks out from the front of his/her face. Say the nose is 15cm in front of the ears. With the 24mm lens, the nose is 15% closer than the ears, so the nose will look 15% larger than the ears. That will be pretty obvious, and unflattering. With the 100mm lens, the nose is only 4% closer than the ears, so it will only look 4% larger, which is negligible.

OK? It's not about the lens. It's only about the distance.
 
It was a family of 14 and as a result, "my space" was invaded so to speak. Not by a huge amount, but enough to make a small difference. The PC-E might be on the cards, but there are other considerations first.

Gary.
 
Ahhh so either a short Nikon PC-E for you ...

The PC-E might be on the cards

Won't help though. You can do wacky things with a PC-E, but you can't make the nose seem closer to the ears.

Here's another thought experiment.

Stand a long way back from your subject and take a photo of them with an 800mm lens. (Obviously you can't do this indoors.) Now, without moving the subject or the camera, switch to a 14mm lens and take another photo. Look at the two photos side by side, the full frame of the 800mm photo and the central portion of the 14mm photo so the compositions are the same.

What's the difference? (Apart from image degradation because you've had to enlarge the 14mm photo by a huge amount?) NONE.
 
PC-E won't help? Ok, my bad then - have never seen it used on people, but assumed it would be the answer...
 
Perspective isn't a function of the lens (except in the case of tilt-shift lenses, obviously). It's a simple function of the distance to the subject. The lens you use won't affect it.

Here's a way of visualising it.

Suppose you want to take a head-and-shoulders portrait of someone. With a 24mm lens (FX) you'll want to be about 1m away to frame it nicely; with a 100mm lens you'll want to be about 4m away to achieve the same composition. OK so far?

Now, the issue is that the subject's nose sticks out from the front of his/her face. Say the nose is 15cm in front of the ears. With the 24mm lens, the nose is 15% closer than the ears, so the nose will look 15% larger than the ears. That will be pretty obvious, and unflattering. With the 100mm lens, the nose is only 4% closer than the ears, so it will only look 4% larger, which is negligible.

OK? It's not about the lens. It's only about the distance.

Great explanation and personally very helpful. Thanks :thumbs:
 
I have another booking in the not too distant future, 14 people...

I will need to think about how best to shoot it. It just removes the little bit of play I have with the current space.

G.

Based on what Stewart has said, you could ask them all to remove their noses prior to the shoot. Might be complicated though :shrug:
 
Based on what Stewart has said, you could ask them all to remove their noses prior to the shoot. Might be complicated though :shrug:
Removing the noses might be undesirable. However it is not the existence of the noses that is the problem; it is the fact that they protrude in front of the other facial features.

Hence my solution. Install a large plate of glass in front of where the victims subjects will be. Get them to press their faces right up against the glass - hard - before you take the photo. This will reduce the front-to-back distance which causes the problem, and the results will be much more flattering.
 
Removing the noses might be undesirable. However it is not the existence of the noses that is the problem; it is the fact that they protrude in front of the other facial features.

Hence my solution. Install a large plate of glass in front of where the victims subjects will be. Get them to press their faces right up against the glass - hard - before you take the photo. This will reduce the front-to-back distance which causes the problem, and the results will be much more flattering.

:D
 
There's lots of kinds of distortion and I think there might be some talking at cross purposes here.

The one that usually claims general use of the term is geometric distortion, which is where straight lines towards the edges of the picture appear curved. It's a lens defect and can be barrel or pin-cushion shaped, and either a smooth curve or a wiggly curve (moustache distortion). Easily corrected in post processing, though moustache is more tricky. (Canon has custom corrections for this that can be automatically applied in their [free] Raw processor DPP. Don't Nikon have this too? :D )

Perspective distortion, where objects closer to the camera appear relatively larger, is purely a function of shooting distance, as described above. A tilt/shift lens won't help with this in the situation described. I prefer to call this exagerated perspective, if only for differentiation. With the more distant shooting position using longer lenses, the opposite applies and perspective is flattened/reduced/compressed.

Then there is the stretching distortion you get at the edges and corners of images shot with a wide-angle lens, where things get pulled out of shape - badly out of shape with super-wides. Don't use one for group photos, or at least keep important areas of the subject away from the edges. I've got a feeling this might be Gary's problem? It's an unfortunate side-effect of rectilinear correction - basically if the lens is properly corrected for geometric distortion, things get stretched. So again, not really a lens defect and all wide-angles do it the same at similar focal lengths

The other thing to mention in the context of perspective distortion is that when you move close with a wide-angle, the field of view gets much bigger. Even though the main subject might be normal size in the frame, there will be a lot more background visible behind than if you'd stood back with a longer lens. This is the main reason why longer lenses tend to give better subject isolation and subjects stand out better from the background - better bokeh. Most people think it's a depth of field effect but since DoF remains the same if the subject framing remains constant, that's not it. It's a bit of an optical illusion maybe but, depending on how much detail there is in the background, it looks real enough.

Edit: Just a note: the 'natural' imaging state of a lens is generally spherical and a lot of these issues are to do with the way this is corrected in lens design. Basically an uncorrected lens will produce a fish-eye type image, with strong barrel distortion. The subject field of sharpest focus will also be curved, and so will the image projected on the sensor. Rectilinear design corrects geometric distortion by pulling out the corners of the image to make them straight. The same thing has to happen on the imaging side because the sensor (film) is flat.

A lot of lens design effort goes in to sorting out these things and it is an interesting prospect to consider what might be possible if we had a curved sensor (basically saucer shaped) and geometric distortion was corrected in software. Actually, the latter is already happening in some compacts without our knowing as the only image we see is the processed JPEG shown on the LCD - we never see the actual optical image projected by the lens. I think we are going to see more of this with ILC cameras (interchangeable lens compacts like the Panasonic GF1 and Olympus E-P1) which could result in sharper, simpler, cheaper, smaller, lighter lenses with greater zoom range and lower f/numbers - or at least some of those things.
 
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