Century Optic +7 Diopter at DVinfo.net

Alex Chong · November 15th, 2006, 05:56 AM

Hi all,

Can anyone help me out here. I am trying to figure out some dimensions here of the CO +7 diopter (achromat/macro). I saw on some website the achromat is very thick. Can someone tell me how thick in mm is the achromat? Really appreciate the info.

Also, I have a +4 and +3 HOYA macro I am using with my adaptor, is using the HOYA macros (which is in two pieces screwed onto each other) similar to using the one piece +7 CO diopter?

Thanks.

Bob Hart · November 15th, 2006, 11:08 AM

CO +7 ACHROMATIC DIOPTRE DIMENSIONS - COVERS OFF.

LENGTH = 23.6mm.
OUTER DIAMETER = 60.5mm.
OUTER DIAMETER OF FILTER MOUNT THREAD. 58mm (57.9mm).
EXIT PUPIL DIAMETER TO CAMERA = 48.3mm.
CLEAR DIAMETER OF FRONT ELEMENT = 48mm.
THREADED SHOULDER FRONT TO BACK = 4.7mm.
FRONT OF LENS BARREL TO FRONT OF THREADED SHOULDER = 18.9mm.

My measurements of the fractions of a millimetre may be a bit off.

FRONT OF THREADED SHOULDER is the same as front face of camcorder at the point the lens is screwed fully home in the filter thread.

The stacked Hoyas will be representing the magnifying power of the +7 but less sharply, especially at the edges of the image.

Dennis Wood · November 15th, 2006, 11:17 AM

Alex, are those hoya lenses achromats or singlets? Unless they are achromats, you will see considerably CA from them. Our new 72mm achromats (designed for HD cams) may be useful.

Alex Chong · November 15th, 2006, 08:53 PM

Thanks Bob for the info.

Hi Dennis,

Not sure what you mean singlet, but if you mean they are +4 and +3 individual macro screwed onto one another to get +7, yes. They are cheapo HOYA macro so will definitely have CA problem. My design is based on using 58mm macro. That why I am looking at the CO diopter. But i guess i can use a 72mm achromat on a small DV cam by using a step up ring. How much you are selling the achromat? Will check out your website later.

Jim Lafferty · November 17th, 2006, 12:15 PM

On the offhand chance you're interested in trying the CO adapter, I have one here with minor wear and some incidental scratches on one of the optical surfaces (doesn't affect performance negatively that I've noticed.) I'd sell it for $100.00.

My email address is: info at go-35 dot com

- jim

Alex Chong · November 17th, 2006, 10:12 PM

Hi Jim,

Thanks for the offer, but I haven't decided to get one yet. Just checking out the dimension for new adaptor that I am designing. Thanks.

November 15th, 2006, 05:56 AM	#1
Alex Chong Regular Crew Join Date: Jun 2004 Location: Brunei Posts: 140	Century Optic +7 Diopter Hi all, Can anyone help me out here. I am trying to figure out some dimensions here of the CO +7 diopter (achromat/macro). I saw on some website the achromat is very thick. Can someone tell me how thick in mm is the achromat? Really appreciate the info. Also, I have a +4 and +3 HOYA macro I am using with my adaptor, is using the HOYA macros (which is in two pieces screwed onto each other) similar to using the one piece +7 CO diopter? Thanks.

November 17th, 2006, 12:15 PM	#5
Jim Lafferty Major Player Join Date: Dec 2003 Location: Brooklyn, NY Posts: 636	On the offhand chance you're interested in trying the CO adapter, I have one here with minor wear and some incidental scratches on one of the optical surfaces (doesn't affect performance negatively that I've noticed.) I'd sell it for $100.00. My email address is: info at go-35 dot com - jim __________________ Realism, anyway, is never exactly the same as reality, and in the cinema it is of necessity faked. -- J-L G

November 15th, 2006, 11:08 AM	#2
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	CO +7 ACHROMATIC DIOPTRE DIMENSIONS - COVERS OFF. LENGTH = 23.6mm. OUTER DIAMETER = 60.5mm. OUTER DIAMETER OF FILTER MOUNT THREAD. 58mm (57.9mm). EXIT PUPIL DIAMETER TO CAMERA = 48.3mm. CLEAR DIAMETER OF FRONT ELEMENT = 48mm. THREADED SHOULDER FRONT TO BACK = 4.7mm. FRONT OF LENS BARREL TO FRONT OF THREADED SHOULDER = 18.9mm. My measurements of the fractions of a millimetre may be a bit off. FRONT OF THREADED SHOULDER is the same as front face of camcorder at the point the lens is screwed fully home in the filter thread. The stacked Hoyas will be representing the magnifying power of the +7 but less sharply, especially at the edges of the image.

November 15th, 2006, 11:17 AM	#3
Dennis Wood Major Player Join Date: Mar 2005 Location: Ontario, Canada Posts: 916	Alex, are those hoya lenses achromats or singlets? Unless they are achromats, you will see considerably CA from them. Our new 72mm achromats (designed for HD cams) may be useful.

November 15th, 2006, 08:53 PM	#4
Alex Chong Regular Crew Join Date: Jun 2004 Location: Brunei Posts: 140	Thanks Bob for the info. Hi Dennis, Not sure what you mean singlet, but if you mean they are +4 and +3 individual macro screwed onto one another to get +7, yes. They are cheapo HOYA macro so will definitely have CA problem. My design is based on using 58mm macro. That why I am looking at the CO diopter. But i guess i can use a 72mm achromat on a small DV cam by using a step up ring. How much you are selling the achromat? Will check out your website later.

November 17th, 2006, 10:12 PM	#6
Alex Chong Regular Crew Join Date: Jun 2004 Location: Brunei Posts: 140	Hi Jim, Thanks for the offer, but I haven't decided to get one yet. Just checking out the dimension for new adaptor that I am designing. Thanks.