JW S

Most of us have either experienced or at least seen the effects of shooting a person too close and too wide. The results are terrible, with the wide nose and odd shaped cheek bones.

I've recently started shooting a Canon crop body camera and I am wondering if the distortion is less than it is with a full frame?

Lens opening / Crop Body Equivalent
16mm -------/ -----25.6
24mm ------ / ------38.4
35mm ----- / ------56
50mm ----- / ------80

If I had a full frame and a crop body both, I could test this myself, but since I don't, I'm reaching our for thoughts??

Thanks!

selmslie Loc: Fernandina Beach, FL, USA

When you are using a wide angle lens you will be tempted to get too close to the subject.

The distortion is caused by the camera to subject distance, not by the focal length.

There is a lot less distortion if the subject is between 7 and 15 feet from the camera. The subject will look smaller. To correct that, use a longer focal length.

A full frame focal length of about 80mm to 120mm (50mm to 75mm for a 1.6x crop) will let you stand back from the subject.

Blair Shaw Jr Loc: Dunnellon,Florida

out4life2016 Loc: Bellingham, Washington

I havnt seen any portrait studio or wedding photographer using a crop sensor body so I’m sure there is good reasoning for them to be using full frame

SuperflyTNT Loc: Manassas VA

With modern technology there’s really no reason they couldn’t, just traditionally what they’ve used. Probably not so much the sensor size as the build quality. There aren’t really any crop sensor cameras that are built like a D5.

uhaas2009

Lens distortion applies to every lens. It’s better to learn and use it.

dpullum Loc: Tampa Florida

Consider for simplicity...portrait of a person pointing at the camera. A wide angle lens on a FF camera is used, the result is a large foreshortening distortion of the hand and forearm. If the photo is cropped in post-processing the distortion remains the same, such cropping is the same as trimming the edges off of the FF sensor to be equal to a smaller "cropped" sensor. The distortion is a product of the lens, not the sensor.

The foreshortening-distortion is well discussed in the following:
https://www.cambridgeincolour.com/tutorials/wide-angle-lenses.htm

Tomfl101 Loc: Mount Airy, MD

👍👍👍

CHG_CANON Loc: the Windy City

The focal length of the lens remains unchanged no matter what type of camera where the lens is mounted. Don't get confused by the crop factor. Here's 16mm and a good looking elongated nose.

Boeing KC-135 Stratotanker by Paul Sager, on Flickr

speters Loc: Grangeville/Idaho

You don't need any testing! You allready know you'll get different field of views either way by using the same lenses!

JW S

Thanks so much for the responses. .... I don't know why I struggled with this ...
..... Wide Angle Distortion is Wide Angle Distortion ...

Thanks.... case closed!

ELNikkor

Not just distortion, but there is less of a "bokeh" with the wide-angle lenses.

CatMarley Loc: North Carolina

On a crop body, the virtual focal length is not as wide as on a full frame. An F2 lens will give you the angle of a 2.8. Assuming you are using a lens manufactured for FF, the distortion will be less as well, since distortion is usually max at the edges and a crop sensor is cropping those off.

amfoto1 Loc: San Jose, Calif. USA

This is correct.

And it helps explain why a 50mm lens... a "normal" or "standard" lens on full frame... But the same 50mm works so well as a "short portrait telephoto" on a crop sensor camera. (On an APS-C camera 50mm "acts like 75 to 80mm on full frame", while on a Micro 4/3 camera the same 50mm "acts like 100mm on FF").

The image below was shot with full frame camera, 24-70mm lens at 63mm... slightly telephoto, but the close distance leads to a lot of perspective exaggeration. Obviously, the horse's head isn't larger than it's body!



The effect can be used humorously, as I tried to do with the above shot. But most people won't appreciate being photographed in a way that makes their nose look big and their ears look tiny, so keep your distance and choose the appropriate lens for the purpose.

50mm on full frame (~30mm on APS-C or 25mm on M4/3) can be used for full length portraits of individuals or couples standing or for wider "environmental" shots that show a lot of their surroundings.

Anamorphic distortion is another effect that occurs with wide angle lenses that also needs to be considered. Parts of the subject close to the edges and corners of the image will be "stretched" and look deformed. Compare the two shots of this car, for example...



Both were shot with the same zoom lens on an APS-C camera... The lefthand image was shot with a 12mm focal length setting, while the righthand image was shot with 20mm. Positioning the car to the far left side of the horizontal images causes it to appear quite distorted... notice the size of the tires in relation to each other and the grill in relation to the rest of the car.

This effect looks even worse when people are placed near the edge of the frame, especially on the "long side" of the image... it causes effects sometimes referred to as "elephant legs" or "Hellboy arm".

Depth of field is another subject entirely, although it can be important for portraiture.

DoF is actually doesn't change with sensor format alone. If you use the same aperture, the same lens focal length and shoot the subject from the same distance, DoF will be identical regardless of the sensor size. However, because the framing of the subject in the image area will be quite different with the change in format, you would almost never do that. Instead, when you switch from crop to FF, in order to frame the subject the same way you either need to move closer to your subject or you need to use a longer focal length... or a little bit of both.

DoF does change when focal length or distance or both change. The result of the changes in focal length and/or distance is that at any given aperture FF "seems like" it's able to render about one stop shallower depth of field than APS-C, and about two stops larger than M4/3. This is also why it's very difficult to get shallow DoF effects with digital cameras that use really tiny sensors like 1/2.3". (Plus, this is nothing new to digital... same happened with film formats. When the same stop is used, but distance and/or focal lengths are changed, medium format film camera images look about a stop shallower DoF than 35mm film cameras. Larger format film cameras could render even shallower DoF effects. Conversely, small film formats like APS-C, 126, 110, disk, etc. have difficulty rendering shallow DoF.)

kymarto Loc: Portland OR and Milan Italy

FF allows for shallower DOF at the same viewing angle and maximum aperture, and this is an effect--isolating the subject from the background--that can be used to great effect with portraits and weddings.