DSLR lenses?

Question

How do you calculate the difference between film lenses,and digital lenses?When it says 18-70mm on a digital camera lens ,what is it's eqivallancy to a regular lens? Thanks

Answer 1

If the digital camera has a full-frame sensor 24mm x 36mm like the 35mm film camera, the lenses see exactly the same. However, depending upon the physical size of the digital sensor, all lenses will have a different view (magnification) of the same scene. Each digital camera manufacturer will state what the magnification ratio is with each of their different digital cameras -- they are all NOT the same. However, all lenses used on a digital 35mm styled SLR are stated in terms of a full frame film camera. If for example the particular digital camera has a 1.6x focal length conversion factor, all the lenses used on this camera will have the equivalent to approximately 1.6x the indicated focal length compared to a 35mm format. A 50mm lens on this camera will produce an image similar to an 80mm lens on a full-frame camera. Your 18mm-70mm lens will give the equivalent to a 28mm-112mm lens on a full-frame camera.

Answer 2

You have to know the sensor size to do it accurately. Olympus 4/3 system has a 2x factor. Different manufacturers and models also have different crop factors. A 18-70 on a canon 30D and a 5D are completely different.. 5D is full frame so 18-70 would be 18-70. The 30D it would be approximately 28-112mm as the 30D has a 1.6 crop factor

Answer 3

I agree with Bob. It depends on the size of the sensor. A tiny sensor will seem to have higher magnification, while a large sensor with the same lense has lower magnification.

Answer 4

Multiply it by 1.5 or 1.6. Thus, the 18-7mm in digital will translate to about 28-110mm in a 35mm film camera.

Answer 5

they're right about the crop factor.... you'd need the size of your sensor x the mm of the lens...

(or go to Adorama's site and look up the particular lens for your camera, in the details it gives you the converted numbers )