23

Your friend is right that it is actually always a 24mm lens — that is a property of the optics and never changes. But, he's wrong in saying that the crop factor does not apply. That's a property of the sensor size of the camera. From a practical point of view, zoom — changing focal length — and cropping are interchangeable. So, using a camera with a smaller ...


16

That difference is because the angle of view of the APS-C sensor is smaller than the 35mm Full frame sensor. Basically the change of focal length is only considered as a change of angle of view. APS-C sensor has a crop factor of 1.6 of the full frame sensor. ie Anything viewed with the APS-C sensor will be cropped 1.6 times the Full frame sensor.Hence 300x1....


15

You have already chosen your answer but I'd thought I would elaborate a little. Focal Length: Yes, it stays the same! The age of the lens doesn't matter regarding focal length. As long as there is some way of fitting any lens onto a body (generally a bigger format lens on a smaller format body), whether by an adaptor or by physically changing the mount, ...


15

When I started photography, this one took me ages to figure out, because people tend to explain it with a lot of math, or in a way that makes sense once you already grasp the principle but not before. How does crop factor affect perspective? It doesn't. Not at all, in the slightest. The only way you change perspective is to move the camera. Changing ...


14

The problem is there are two factors determined by the aperture - depth of field and exposure. Sensor size affects depth of field but not exposure. With focal length it makes sense to talk equivalents as there is exactly one factor involved, angle of view. To be correct you'd have to say that a 30mm f/1.4 mounted on a 1.5x crop camera had a 45mm equivalent ...


14

When Canon released the first 1D, APS-H was simply the largest sensor they could get away with, economically. They followed it up with the 1Ds which was full frame. However the 1Ds was slower than the 1D, and offered less reach with telephoto lenses, so was less popular with sports and wildlife photographers. For this reason Canon chose to continue offering ...


14

Whether a lens is an EF or an EF-S lens, the actual focal length is always used. There are certain technical reasons why this is so, but the simplest is that a lens' focal length is defined as the distance from the film plane needed when the lens is focused at infinity to cast point light sources as a single point on the film plane. This doesn't change with ...


13

Crop factor has nothing to do with T-stop. T-stop is strictly about light transmission which affects exposure. If a lens could be 100% transmissive the T-stop and f-number of the lens would be the same number, but they would still be measures of different things. T-stop measures how much light is passed through the lens, f-stop measures the size of the ...


12

For digital cameras, it's purely due to historical reasons - 35mm was the dominant size for film cameras and cinematography. As for why film cameras ended up with 35mm, I'd suggest 35 mm film and 135 film on Wikipedia as a good place to start. It's also worth noting that "35mm" is not actually the size of the image, which is 36x24 mm, but the width of the ...


11

Take a look at Can a smaller sensor's "crop factor" be used to calculate the exact increase in depth of field?, where the background is explored in detail. It's also roughly the case that larger sensors allow one to use higher ISOs without as much noise penalty, simply because of the intrinsic physics of having more light-gathering area. And, ...


10

Imagine you have an FX camera (or old film camera) with a 50mm lens, and take a picture. Then in post processing, you crop out the edges. You would still have an image with the same perspective of the 50mm lens, but by cropping you've effectively zoomed in on the subject/middle of your image. This is basically what happens with a cropped sensor. Same ...


10

Perspective is determined by one thing and one thing only: Subject distance. Period. If you took an image using a rectilinear wide angle lens such as 17mm, which yields a diagonal angle of view of 104° on a full frame/35mm camera and cropped the resulting image so that only the center 3.08333° is in view, you would have the exact same perspective as if you ...


10

The aperture size is a property of the lens only and does not depend on the crop factor. It does depend, however, on the actual focal length of the lens (not the "equivalent" focal length). So you need to obtain the actual focal length by dividing by the crop factor. actual-focal-length = equiv-focal-length / crop-factor You can then calculate the size (...


10

Nikon 1.5X APS-C sensors in their current lineup are actually 1.52-1.53X depending on the exact measurements of the various different sensors in different models. Some older, discontinued models in the D3x00 series are slightly smaller at 1.55-1.56X. The difference between 1.52X and 1.53X is 0.65789 percent. The difference between 1.5X and 1.53X is a mere ...


10

Assuming that the quoted 1365mm focal length is in 35mm full frame equivalent terms (because otherwise, it would be huge), then the actual focal length of the lens assembly is around 1365 / 5.6 ~= 244mm. To accomplish an equivalent 1365mm focal length with a 1.6 crop factor, you would need about an 854mm actual focal length lens. I'm not aware of anything ...


9

The minimum focus distance is a property of the lens and the distance to the sensor. The lens-to-sensor distance is the same for all Canon DSLRs hence the minimum focus distance doesn't change when using a cropped sensor body. There are adapters you can get to magnify the viewfinder image, here's a review of an offical Canon product, numerous third party ...


9

How do I calculate the aperture size and area You divide the focal length by the aperture/F-stop value. Infact, that's what the F-stop/aperture value is. It's a divider. Sometimes written as ƒ2.8 (as an example) but a lot of people leave out the vinculum and should be written as ƒ/2.8. Replace the ƒ with the focal length and that's the diameter of the ...


9

I think you should, in fact, use the slightly-smaller value. That's not because I've measured, but because I can resolve the apparent contradiction from exiftool: it's showing you a rounded value. Try giving it the -n flag, to disable what exiftool calls "print conversion": $ exiftool -n -ScaleFactor35efl sample.jpg Scale Factor To 35 mm Equivalent: 0....


8

What is the factor, and how is it derived? The factor (also commonly called a 'crop factor') is a measurement of how much larger a full-frame image sensor is than the sensor in your camera. People say the D3000's crop factor is 1.5 because a full-frame sensor is 1.5x larger than the D3000 sensor. A full-frame sensor is 36mm x 24 mm. The sensor in the Nikon ...


8

Well, the main thing is that crop factor doesn't really affect focal length. It just affects the field of view by making it narrower. So, what you really have is a 400x1.4x => 560mm lens combination on a crop body, which has the same FoV that an 896mm lens would have on a full frame body. So, unless you shoot full frame enough to translate focal lengths to ...


7

That is partly true. You won't actually get a lens with a longer focal length, but you get a lens with the same field of view as a lens with a longer focal length. The actual focal length remains the same, but as you are using a smaller part of the image circle you get a larger magnification, similar to what a longer focal length would give. This way of ...


7

The crop factor applies to all lenses shot on camera with a smaller sensor. They look the same because 70mm is 70mm on both lenses, and they're both cropped in exactly the same way. I think the answers to Is an EF 50mm f/1.4 the same as 50mm with an EF-S lens on a Canon 550D? should help. Also check out my answer to What is Angle of View?, because the ...


7

Because the standard size for film cameras for a long time was 135 film which measures 35mm in width including the perforations and leaves enough space for a 36x24mm negative size. Since the Field of View (FoV) for any particular focal length lens is determined by the size of the film or sensor onto which the image circle is being projected, over time ...


7

Here's the short answer: a wide angle lens on a crop sensor skews the image exactly in the way it does in the center of the frame on a full-frame sensor. In turn, this means that using a wide angle lens (small focal length) on a crop sensor gives the same perspective distortion as using a narrower lens (larger focal length) on a full frame sensor, with the ...


7

Crop factor is expressed as a ratio of the linear measurements of a sensor compared to a 36x24mm 35mm film frame or a full frame sensor. This is because a sensor exactly half as large as another will also provide exactly half the angle of view as the other with a lens of the same focal length. Or conversely, a sensor half as large requires a lens of half the ...


7

The "equivalent" focal length draws from history, namely how it relates to a 35mm film camera, and there should come a time (and I think it is past) when we move on. The focal length IS the focal length. Having a smaller sensor may crop a portion of the field of view, but the focal length is a real and meaningful number. Anyone who is interested in the ...


7

In photography, what is interesting is mostly the angle of view (AOV). The AOV is the angle that a lens offers on a sensor - it can be specified horizontally, diagonally, or vertically. AOV [°] = 2 * arctan ( sensor_height|width|diagonale [mm] / (2 * focal_length [mm]) ) The formula to get from a specified focal length (FL) on a non-full-frame sensor to ...


6

Crop sensors are smaller than full frame sensor. The full frame sensor size came from the old days and has been used as a standard for digital sensors size. From Wikipedia Crop factor is related to the ratio of the dimensions of a camera's imaging area compared to a reference format; most often, this term is applied to digital cameras, relative to 35 mm ...


6

Rather than calculating the crop factor from the diagonal regardless of format, this chart is based on the largest-possible cropped print from the respective sensor. For example, for 3:2 aspect ratio (as in 4×6 prints), the Four Thirds image is cropped along the long edges, while for 4:3 aspect ratio, Four Thirds is uncropped but APS-C or "full-frame" 35mm ...


Only top voted, non community-wiki answers of a minimum length are eligible