Just like there is no absolute when looking at the exposure of an image, so is true about Distortions in an image.
There are two main categories of image distortion.
1. Caused by Equipment
2. Caused by improper use of equipment
2. Caused by improper use of equipment
1.0 Distortion Caused by the Equipment
We all have seen a photograph of a person or group of people taken using a Fish-eye Lens. A Fish-eye lens is a lens found in the Ultra Wide Angle Lens group. Normally it is between 8-16mm with distortion on the edges. This distortion can also be removed by software but we use it to capture large group shots or special shots say of the bride entering the church. We try to take at least 10 shots per wedding with the Fish-eye Lens. These normally are very High Quality Lenses costing around $1000 per so not everyone has one to use.
I will divide the Lenses into 7 groups for ease of discussion:
1. Normal view on a 35mm Full Frame Camera with a 50mm Lens. This is what a person would normally see with their eyes.
2. Telephoto Lenses- Any lens above 50mm that will magnify the image. This can go from a 50-100mm portrait type lens all the way up to and over 500mm.
2. Telephoto Lenses- Any lens above 50mm that will magnify the image. This can go from a 50-100mm portrait type lens all the way up to and over 500mm.
3.0 Wide Angle Lenses - 24-50 mm ie below 50mm focal length
4.0 Ultra Wide Angle Lenses 12-24 mm (Architectural and wedding photography to capture more of the scene).
5.0 Fish-eye Lenses 8-16mm typical
6.0 Macro Lenses (for up close and personal - flowers and insects or anything small)
7.0 Tilt-shift Lenses (Architectural)
The types of distortion that we will find built into Camera Lenses and equipment are both Optical and Geometrical distortions.
A. Optical Distortions cover: Lens distortion, Vignetting, color fringing, lens softness (lens blur). Lens distortion covers barrel and pin cushioning, complex distortion, circular Fish-eye distortion
B. Geometrical distortions- Volume anamorphosis (people - objects get distorted at the outer edge of an image when using a Wide Angle Lens), key stoning/ horizon - objects do not appear straight or the horizon is curved.
2. Caused by improper use of equipment and angle taken of the image relative to the subject.
This type of problem can be prevented in the most part. We were at one of our Custom Labs yesterday and Irene and I both love to look at other photographers albums and work. We are very critical of our own work so that we can bring our customers the best quality that we can. Irene pointed out to me, "look at the mother of the bride" in this 3 person shot in their living room. The person taking this must of been standing on a chair and shooting down! To both of us, we grinched our teeth and said "and this is their wedding album". Standing of a chair can be an excellent way to shoot some photos. It is NOT the way to shoot group shoots - the people were terribly distorted IMHO.
Think that you are standing on a set of Rail Road tracks looking into the distance. This is called perspective. The tracks appear to be converging but we know that they are always equal distance apart. That is what happened here. The head and shoulders were large and the body and legs looked short. Not at all flattering to anyone. Is is an example of a highly specialized photographic technique used in the wrong manor. Used correctly with the right lens and F-Stop, you can get wonderful pictures, normally close-up head shots only.
For group shots, the camera should be positioned about chest height of the subjects, so as NOT to add too much distortion. A 50mm lens should be used. Lighting is also an important part of this image and directional lighting should be employed to show the bride in the most flattering manor. The sensor frame plane and the plane that your subject's body must be the same. Think of a large sheet of plywood behind the subject and the camera. Both must be parallel to each other. The photographer must always be aware of these planes when taking images of people.
Here is another example of shooting large groups of people. We have a long line of say of 15-20 people. What do people do? Pull out the Wide Angle lens and shoot away. Perhaps the photographer couldn't move back any further. Result is poor aunt Martha has been stretched out looking like she was run over by a cement truck. Uncle Fred on the other hand was too close to the camera and looks a bit like a giant compared to what he should look like. The problem is the wrong lens for the type of shot or not enough room to take it correctly. All of this type of geometric distortion is called volume anamorphosis and it can ruin a shot that people wanted to have in their album if NOT corrected during post processing.
Most professional wedding photographers will have the 70-200 mm telephoto lens as part of their kit. Telephoto lenses should be Image Stabilized or they will need to be mounted on a tripod. The rule of thumb is that your shutter speed should be the reciprocal of the focal length. Therefore for a 200mm lens, you should shoot at a shutter speed of 1/200th of a second or the Flash Syc speed of the Canon 5 D Mark II. Now add IS and you can drop up to 3 to 4 stops or 1/100, 1/50, 1/25, 1/15. For people photography, one should try to never shoot below 1/30 or 1/60 because people move. One should be very careful not to push IS beyond say 2 stops, but that is person dependent. The result will be camera motion blur in the image and another lost image for the day.
How to prevent or Correct these common Distortions in your Photographs?
It is the responsibility of the Professional Photographer to know in advance about the equipment limitations and limitations when taking a photograph. Sometimes your equipment will not focus properly. We try to take 3 shots of each image to cover us on this one. People also move their eyes and are easily distracted on a wedding day.
We know that even the best EOS Cameras from Canon, has these built in limitations and as soon as we finish shooting your wedding we load your memories on to our computer hard drive and store them in a RAID 1 system to ensure 100% file backup in case a hard drive fails. We do NOT open these files to look at them but first process them all though a specialized Computer software to not only correct the above mentioned problems but to correct exposure, white balance, lens softness, add expanding the dynamic range of your images, remove any noise or deal with dust on the sensor. Our sensors have dust cleaning built into them these days, but that was not the case 4 or so years ago. It can take over 24 hours to process the 1000-2000 images that we took. All of our cameras have dust removing sensors and most of our lenses above 50mm have Image Stabilization built in.
The good news is that you only see the images after this correction and are not handed images taken directly from the camera. IMHO this is a MUST DO step in processing of your wedding images. Again, when I speak with most other photographers, they never heard of this software? This has more importance as you try to print larger prints than 4x6 in images.
This is not the end of the line in our work flow, but rather the being. It is then on to another software program called Lighroom and another called Photoshop. Now the images are ready to burn to a disk for customer viewing. All of this processing will take much more time and effort than some one who says, hey, I will give you the files from the camera. I have seen images taken by top professional photographers before and after processing and the difference is day and night. Top photographers seldom give away their images for obvious reasons.
I will be posting things on a daily or so basis, so if you are a camera buff or a prospective customer who wants to know a bit more about photography link up to us and enjoy the articles. As a former Microsoft Technical Trainer, with an excellent student rating, you might find these articles interesting. It is my way of twittering. Enjoy and suggest any topics that you might want me to cover in the up and coming months.
Kirk is owner and operator of KW Masters Photography Windsor, Ontario, Canada and is a Professional Wedding and Portrait Photographer in Windsor Ontario
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