FOV differences in cameras? (1 Viewer)

Coming from amateur astronomy, eyepieces are often differentiated by field of view (FOV) criteria. So lenses of the same magnification vary in FOV so some are like looking through straws and others are able to give more expansive views at the same magnification. This is also a consideration in binoculars.

I don't read much about fov for cameras and lenses. Why? Would all approximately 50mm lenses (full format and equivalent lengths in APS-C and m4/3) give the same field of view? Or do some cameras/lenses vary greatly in fov? If their are differences, why aren't they hyped? If their are no differences, that would explain the lack of ad hype.

The field of view is difference with different sized sensors. For Canon their APS-C sensor is considered a 1.6 crop factor meaning the field of view is = 1.6 x focal length of lens. so in your case the FOV of the 50mm on a Canon APS-C sensor is about 80mm. The Nikon crop camera are a 1.5 crop factor so the FOV with 50mm lens is 75mm.

Micro 4/3 is half the width of a full frame the field of view is 2 times the focal length. The 4/3 sensor is called that because the sensor is in a 4 x 3 format as opposed to DSLR that are a 3 x 2 format.

There are certainly differences. Sometimes they are hyped. Those difference can be both positive and negative depending on your situation. Another big factor is pixel density on the sensor. Both the Canon 1DX and the Canon 7D are 18 mega pixels but because the 7D sensor is much smaller the pixels are more densely packed.

Given the same technology more densely packed pixels will show more noise at the same ISO setting. However, if you are shooting something from a fixed position that is small in the frame like a bird on the water then an APC sensor can get you more pixels on the target which is typically an advantage.

I'm sure others will chime in with other factors to consider too.

Doug

OK, so if I am understanding you correctly, the size of the sensor sets the fov. So a full format camera with a 60mm and a Nikon APS-C with 40mm lens and an Olympus m4/3 with a 30mm lens set at the same distance from a tree should give the same surrounding fov regardless of who makes the lenses and their maximum apertures?

What about macro lenses. Do they also work on the same parameters?

That's right.

Macro lenses work the same way. I think they only reason they are called Macro is because they allow such close focus that you can get up to a 1 to 1 ratio of size of subject as size on the sensor. Wikipedia can explain it better.

Thanks.

[Recently I took some pictures of "Trumpeter" swans in the Skagit Valley only to get home and discover every one had a yellow area on the face. I had found a flock of Tundra swans. I didn't know this until I enlarged the facial areas!]

Yes, that's a great area to see lots of Swans in the winter. Sometimes there are swans right in your hometown at Juanita Bay.

The advertised so called field of view (FOV) for a telescope eyepiece is the “apparent field of view”. To get the “actual field of view” it is necessary to divide the apparent field of view of the eyepiece, the secondary, by the magnification. This will vary according to the primary focal length of the telescope.

With respect to full frame and crop frame DSLR cameras, the combination of primary and secondary lenses are combined in the camera lens. A principal design constraint is to produce an image circle adequate to cover a 43.3mm diagonal. Consequently, the magnification of any particular lens will be the same. Any given 50mm lens is typically regarded as 1x, and a 400mm lens as 8x. The actual field of view will vary simply as a factor of the focal length.

When a 400mm lens, of 8x magnification, is used on a full frame or crop frame sensor the FOV of the lens is identical. The image circle produced by the lens is designed to adequately cover the diagonal of the full frame sensor. In the case of the crop frame sensor, the image circle simply splashes over the edges and is wasted. Like an eyepiece capable of an 8mm exit pupil for an iris of your eye which might only open 5mm.

The crop sensor suffers a disadvantage of being a small sensor inside a large image circle. So a 300mm lens on a crop sensor body will provide a narrow FOV similar to that of recorded by a 450mm lens on a full frame body. The crop sensor camera only sees the centre portion of the image circle. At no time do you get the magnification equivalent of a 450mm lens on your crop sensor body. The magnification factor is identical for full frame and crop sensor.

Lenses designed for crop sensor cameras, such as Nikon's DX line or Canon's APS-C line, should produce a smaller image circle to fit a smaller sensor format. This would reduce the image waste, and potentially concentrate the available light on the sensor by about ½ stop. However in my experience I have not seen the extra half stop of exposure advantage, so I suspect that these lenses do not properly produce a significantly smaller image circle.

Also bear in mind that “full frame” varies with the native format of the camera. 4X5” view cameras are full frame with their particular lenses, 6×6 Hasselblads are full frame with their lenses, and 4/3 cameras are full frame with their lenses. Each format has a lens design suited for the diagonal of their format. And each has similar FOV with a different focal length lens.