Originally posted by sany Hi Chex, I am not following what you mentioned there in the first sentence,about that number 1.52,can you elaborate on this please..thanks
As Ismael has already mentioned earlier, its a crop factor. Lets keep things simple
Film Camera: They are full frame cameras, dimension of the sensor are 36 x 24mm. Nikon D700 is an example of that.
APS-C Camera: Camera sensors are small as compared to full frame sensor. For Pentax k-r, its 23.6 x 15.8 mm. So basically the sensors are cropped by a factor of 1.5
35mm Equivalent: So if you use any lens on Digital sensor, the image circle wont match and the whole image will be cropped by the cropping factor i.e. 1.5 in all APS-C cameras
This implies to all lenses, so if you use Pentax-A 50mm F2 on your Pentax K-r, the 35mm equivalent focal length will 50mm x 1.5 = 75mm
That means if you used a 75mm lens on full frame camera and used 50mm lens on APS-C camera, both will have same field of view.
Read this to know more:
Crop factor - Wikipedia, the free encyclopedia