zoom-through? at DVinfo.net

Jim Schweer · March 18th, 2004, 12:26 PM

Please help me understand "zoom-through" as regards wide-angle converters. I assume it means that the image stays in focus as the camera's lens is actively zoomed in or out. Would a converter that is not zoom-through, such as the .56 Tiffen favored in previous threads by Frank Granovski, produce a focused image at all fixed points along the camera lens's zoom range?

Thanks.

Jim S.

Frank Granovski · March 21st, 2004, 10:05 PM

Tom Hardwick would be the best to answer those.

For the 37mm thread size, the 2 best wides out there are the Raynox HD5000 and the Tiffen (37mm).

Jeff Donald · March 21st, 2004, 10:11 PM

Different manufactures apply different meanings to the term zoom through. Visually inspecting the product and testing it will insure if it meets your needs and expectations or not. Zoom through generally means that you can attach the adapter to your lens and zoom from the wide angle setting through the telephoto position. Non-zoom through adapter need to be set to the wide angle or telephoto position (on the camera) and then not zoomed by the camera controls.

Tom Hardwick · March 22nd, 2004, 01:42 AM

If I may add my interpretation of the ''zoom-through'' term. Fit a zoom through and you alter the focal lengths of the zoom. So if you have a 4 to 48mm 12x zoom and then you fit a 0.5x zoom through, you now still have a 12x zoom, but the focal length has been halved to 2 to 24mm.

I have a non zoom through 0.5X and when fitted to the above lens will give me a 2 to 10mm zoom, after which the image suddenly blurrs hopelessly, so much so that it can almost be used as an instant focus dissolve. Camcorders work with single element nonzoom throughs by using their very powerful close focusing abilities, and the closer focusing the camcorder, the more you can zoom with these 'non zoom throughs'.

Make sense? Know anyone who is pretty short-sighted? Ask to borrow their (negative element) eye-glasses, hold one lens in front of your cam, zoom to the wide-angle end and see what you see.

tom.

March 18th, 2004, 12:26 PM	#1
Jim Schweer Regular Crew Join Date: Sep 2003 Location: Kansas City KS Posts: 60	zoom-through? Please help me understand "zoom-through" as regards wide-angle converters. I assume it means that the image stays in focus as the camera's lens is actively zoomed in or out. Would a converter that is not zoom-through, such as the .56 Tiffen favored in previous threads by Frank Granovski, produce a focused image at all fixed points along the camera lens's zoom range? Thanks. Jim S.

March 21st, 2004, 10:11 PM	#3
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Different manufactures apply different meanings to the term zoom through. Visually inspecting the product and testing it will insure if it meets your needs and expectations or not. Zoom through generally means that you can attach the adapter to your lens and zoom from the wide angle setting through the telephoto position. Non-zoom through adapter need to be set to the wide angle or telephoto position (on the camera) and then not zoomed by the camera controls. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

March 21st, 2004, 10:05 PM	#2
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	Tom Hardwick would be the best to answer those. For the 37mm thread size, the 2 best wides out there are the Raynox HD5000 and the Tiffen (37mm).

March 22nd, 2004, 01:42 AM	#4
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	If I may add my interpretation of the ''zoom-through'' term. Fit a zoom through and you alter the focal lengths of the zoom. So if you have a 4 to 48mm 12x zoom and then you fit a 0.5x zoom through, you now still have a 12x zoom, but the focal length has been halved to 2 to 24mm. I have a non zoom through 0.5X and when fitted to the above lens will give me a 2 to 10mm zoom, after which the image suddenly blurrs hopelessly, so much so that it can almost be used as an instant focus dissolve. Camcorders work with single element nonzoom throughs by using their very powerful close focusing abilities, and the closer focusing the camcorder, the more you can zoom with these 'non zoom throughs'. Make sense? Know anyone who is pretty short-sighted? Ask to borrow their (negative element) eye-glasses, hold one lens in front of your cam, zoom to the wide-angle end and see what you see. tom.