Full frame equivalence to APS-C

Started Jan 22, 2013 | Discussions thread
corneaboy Contributing Member • Posts: 565
Re: Full frame equivalence to APS-C

The 3 links you refer to are about as confusing as anything I have read on the subject. They all make it seem more complicated than it needs to be. I will look to see if I can find something better.


Think of the smaller sensors as just a full frame sensor in a camera with the outer part cut off. You will be cutting off the outer part of the image, so you lose part of the field of view. Since nothing has changed in the camera you would get the same exposure and hence use the same apeture and shutter speed.

The amoount cut off gives you the ratio of the smaller sensor to the full frame sensor. The reciprocal of that ratio is the crop factor, which is simply how much you need to magnify the smaller sensor to give you the same size image as the full frame. Note that while it gives the same size image they do not have the same field of view. Hence if you were to print images from the two cameras to be the same size then the APS image would have to be magnified.

Other properties of the image, such as DOF and noise, etc will have the effect of whatever magnification is needed for the smaller sensor image to be magnified to to the size of the full frame.

Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow