Lens focal length question at DVinfo.net

Ian Stark · July 8th, 2012, 02:01 PM

Please excuse what might be a very naive question!

I am looking at the possibility of buying either a Panasonic AF100 or a Sony FS100 (or even, possibly, the FS700). This will be my first foray into the world of interchangeable lenses. (Actually, not strictly true as I used to own and love an XL2, but just with the stock lens).

My knowledge of lenses is somewhat limited and I know I will need to do some research, but in the meantime my question is this:

I own a Canon XHA1S which has a zoom lens with a focal length of 4.5-90mm. I understand the concept of dividing the higher number by the lower to get the equivalent x zoom, in this case 20x (and I also understand what a relatively useless number this is!). What spec zoom lens would I need to have roughly the same reach as the Canon's longest telephoto? Would it be 90mm? I suspect that there is a lot more to it than that. Can anyone give me some pointers please?

EDIT: OK, I've started my research and I now realise that the other key factor is the focal length relative to the size of the sensor, which is clearly going to be much larger on both the AF100 (Micro 4/3) and the FS100/700 (S35). I should probably ask this question in one of those forums, but to avoid the wrath of Obstreperous Rex by double posting, I will leave it here for a little longer before asking elsewhere! Answers to my original question still welcomed!

Brian Drysdale · July 8th, 2012, 04:13 PM

You can compare the effect of various focal lengths here: AbelCine - Field of View Calculator

The 90mm on your 1/3" camera would have the same angle of view as 406.5 mm on a FS100. The AF100 is one of the cameras you can compare

Ian Stark · July 8th, 2012, 06:01 PM

Brilliant, Brian. Many thanks.

July 8th, 2012, 02:01 PM	#1
Ian Stark Inner Circle Join Date: Dec 2003 Location: Hampshire, UK Posts: 2,237	Lens focal length question Please excuse what might be a very naive question! I am looking at the possibility of buying either a Panasonic AF100 or a Sony FS100 (or even, possibly, the FS700). This will be my first foray into the world of interchangeable lenses. (Actually, not strictly true as I used to own and love an XL2, but just with the stock lens). My knowledge of lenses is somewhat limited and I know I will need to do some research, but in the meantime my question is this: I own a Canon XHA1S which has a zoom lens with a focal length of 4.5-90mm. I understand the concept of dividing the higher number by the lower to get the equivalent x zoom, in this case 20x (and I also understand what a relatively useless number this is!). What spec zoom lens would I need to have roughly the same reach as the Canon's longest telephoto? Would it be 90mm? I suspect that there is a lot more to it than that. Can anyone give me some pointers please? EDIT: OK, I've started my research and I now realise that the other key factor is the focal length relative to the size of the sensor, which is clearly going to be much larger on both the AF100 (Micro 4/3) and the FS100/700 (S35). I should probably ask this question in one of those forums, but to avoid the wrath of Obstreperous Rex by double posting, I will leave it here for a little longer before asking elsewhere! Answers to my original question still welcomed! __________________ www.vit-media.com www.classicmachinefilms.co.uk Last edited by Ian Stark; July 8th, 2012 at 02:34 PM.

July 8th, 2012, 04:13 PM	#2
Brian Drysdale Inner Circle Join Date: Feb 2006 Location: Belfast, UK Posts: 6,152	Re: Lens focal length question You can compare the effect of various focal lengths here: AbelCine - Field of View Calculator The 90mm on your 1/3" camera would have the same angle of view as 406.5 mm on a FS100. The AF100 is one of the cameras you can compare

July 8th, 2012, 06:01 PM	#3
Ian Stark Inner Circle Join Date: Dec 2003 Location: Hampshire, UK Posts: 2,237	Re: Lens focal length question Brilliant, Brian. Many thanks. __________________ www.vit-media.com www.classicmachinefilms.co.uk