Focal lengths: full frame vs crop

[Patrick in Oregon]

Weird question. Lets say I'm looking at Flickr or something and the exif tells me a picture was taken at a focal length of 10mm on a DSLR. Is the 10mm the full-frame equivalent or is it 10mm after being cropped?

In other words, if I were to use a full-frame camera to make the exact same picture, would I need a 10mm or a 16mm (assuming original is APS-C sensor)?

 

[HPS3]

The number is the FL of the lens, you have to adjust for the sensor size. If it says 10mm than it has to be mulitiplied by the crop factor.

 

[mikegood2]

The good old full frame crop sensor explanations that are always more difficult to explain than they should be.

The 10mm should be is 10mm. If it was shot on a full-frame it would be 10mm and if it was shot at 10mm on a cropped sensor it is equivalent to the modifier. So Canons are 10 x 1.6 or equivalent to 16mm, Nikon 10 x 1.5 or 15mm and other brands based on their modifier.

 

[photo_chick]

It's listed in the actual focal length.

Cropped sensors means just that. Cropped. There is no actual change to the focal length when you put a lens on a crop body and the lens doesn't magically magnify 1.6 times more. The crop sensor just crops in on the image which changes your field of view of what is captured on the sensor.

 

[wbeem]

Weird question. Lets say I'm looking at Flickr or something and the exif tells me a picture was taken at a focal length of 10mm on a DSLR. Is the 10mm the full-frame equivalent or is it 10mm after being cropped?

In other words, if I were to use a full-frame camera to make the exact same picture, would I need a 10mm or a 16mm (assuming original is APS-C sensor)?

The focal length is the focal length, no matter which sensor you're using. If you stand in the same spot and look at the same subject using a crop-sensor and a full-frame camera at identical focal lengths, the subject will not appear any farther or closer in either camera.

Instead, what you see is that there is more width to the frame on the full-frame camera. On the crop-sensor, the sides are literally cropped off.

Now, that gives you more pixel density of your subject on the final image if both cameras are shooting at the same megapixels per image. However, shoot with your 12 MP crop sensor compared to my 36 MP D800, and I have much more pixel density even after I crop the image to look like the crop-sensor image.

In any case, you don't have additional reach with a crop-sensor camera. That's a misnomer that's grown legs, but it misrepresents the truth.

 

[Patrick in Oregon]

Thanks for the help ya'll