Lens multiplication factor 7.2? at DVinfo.net

Craig Hollenback · February 12th, 2008, 01:13 PM

Is there any info about the multiplication factor for adding a new lens?
For instance, I know that on an old XL1, if you mounted an EOS to it the factor was 7.2 times. Such that a 10mm lens would become a 72mm lens. Great for wildlife shots, not so good for interior shots. Similar thing I would presume with the addition of 1/2" or 2/3" glass from video cameras.
Is this the case with the Z7?
Thanks, Craig

Tom Hardwick · February 12th, 2008, 02:06 PM

It's not quite as easy as it sounds to get an accurate conversion figure Craig. The 4:3 and 16:9 aspect ratios are both different from the 35 mm film frame, which is 36X24, or 3:2. (1.33:1; 1.5:1; 1.78:1)

In film days a wide-angle was measured by the angle seen across the diagonal of the 35 mm frame, because the frame could be shot in portrait or landscape mode.

The video camera will (generally) only be used in landscape mode, so if you apply that same thinking to 4:3 video the lens seems to 'see wider', but that's because there's more grass and sky in the shot. Conversely with 16:9 frame there's less sky and grass.

I think it's time we all decided to equate what's seen horizontally in our v'finders, and in underscan mode (full recorded frame), too.

tom

Craig Hollenback · February 12th, 2008, 05:34 PM

I guess what I was wondering was not so much how it handled a wide format which indeed is an issue as well but rather, how a lens from a 35mm camera would work on a 1/3" chip camera. The example of the XL1/2 using a Cannon 100mm lens becoming a 720mm tele is more about what I am wondering.
Best, Craig

February 12th, 2008, 01:13 PM	#1
Craig Hollenback Major Player Join Date: Mar 2003 Location: Key West Posts: 247	Lens multiplication factor 7.2? Is there any info about the multiplication factor for adding a new lens? For instance, I know that on an old XL1, if you mounted an EOS to it the factor was 7.2 times. Such that a 10mm lens would become a 72mm lens. Great for wildlife shots, not so good for interior shots. Similar thing I would presume with the addition of 1/2" or 2/3" glass from video cameras. Is this the case with the Z7? Thanks, Craig

February 12th, 2008, 02:06 PM	#2
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	It's not quite as easy as it sounds to get an accurate conversion figure Craig. The 4:3 and 16:9 aspect ratios are both different from the 35 mm film frame, which is 36X24, or 3:2. (1.33:1; 1.5:1; 1.78:1) In film days a wide-angle was measured by the angle seen across the diagonal of the 35 mm frame, because the frame could be shot in portrait or landscape mode. The video camera will (generally) only be used in landscape mode, so if you apply that same thinking to 4:3 video the lens seems to 'see wider', but that's because there's more grass and sky in the shot. Conversely with 16:9 frame there's less sky and grass. I think it's time we all decided to equate what's seen horizontally in our v'finders, and in underscan mode (full recorded frame), too. tom

February 12th, 2008, 05:34 PM	#3
Craig Hollenback Major Player Join Date: Mar 2003 Location: Key West Posts: 247	I guess what I was wondering was not so much how it handled a wide format which indeed is an issue as well but rather, how a lens from a 35mm camera would work on a 1/3" chip camera. The example of the XL1/2 using a Cannon 100mm lens becoming a 720mm tele is more about what I am wondering. Best, Craig