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-   -   Achromatic diopters for closeup work (http://www.dvinfo.net/forum/canon-xl1s-xl1-watchdog/4375-achromatic-diopters-closeup-work.html)

Jay Gladwell October 16th, 2002 12:45 PM

Achromatic diopters for closeup work
 
Has anyone here used any of the Century Achromatic Diopters? How did they do? Was the image sharp? Was there a shift in color?

I've got a shoot coming up and will need to tape some details of materials up close.

Thanks!

Don Berube October 16th, 2002 11:19 PM

I tried some of them at a show this past year, did not notice any chromatic aberrations. The image was very sharp. Century Optics, as you know, is of the highest quality.

What camera do you plan on using it with? Did you consider renting some from a local camera rental outfit?

- don

Jay Gladwell October 17th, 2002 06:05 AM

Thanks, Don. I'm using an XL1s. The few items I've attempted to rent have been pretty beat-up. If I can find a way to "absorb" the cost of such an item in a paid job, I'll just buy it outright.

Yes, I know Century products are high quality. They're a division of Schneider Optics, and they're hard to beat. That's why I was looking at them.

Jeff Donald October 17th, 2002 06:12 AM

They are not true flat field reproduction. The corners are a little soft, but they are much better than the standard 1 element units.

Jeff

Andre De Clercq October 17th, 2002 08:18 AM

If you need real close shooting (diopter >3) you would be better off by using a single diopter achromat instead of combining diopters. This avoids glare if they are not perfectly multicoated, which is often the case. I have a 50mm diameter/10 dioptry coated achromat for close work from from Edmund Optics (http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=1749). Field flatness /distortions/chromatic aberations and sharpness are impressive

Robert Knecht Schmidt October 17th, 2002 03:11 PM

If it's 50 mm, how do you attach it to the lens of your XL1?

Andre De Clercq October 18th, 2002 04:17 AM

In my case (VX1000/ 52mm thread) I glued the lens into the ring of a (broken) hazefilter. A step up (step down) ring would be OK too I suppose. I get from 90 mm (zoomed out) to 9 mm (zoomed in) with the D 10 lens mounted. I keep the camera focus fixed on infinite.

Chris Korrow October 18th, 2002 05:22 AM

I just had the chance to check out some CU insect stuff I've been doing on a 48" -or there abouts tv- and was very impressed with the sharpness. I'm working with a set of Hoya diopters, having used extension tubes for all my 35mm work I was leery of using diopters but as I said I was pleasantly surprised at the quality of an $80 investment.
As for color shift, I can't really say because the color on the TV was questionable at best.

Chris

Andre De Clercq October 18th, 2002 05:41 AM

Extension tubes are the way to go if you have them available on removable lens camcorders. Or maybe just 35mm optics can already do the job on your XLS.

Jeff Donald October 18th, 2002 06:10 AM

Canon makes a set of 2 element achromat close-up filters. They are available in 72mm and 77mm size and two strengths. The advantage to them is you do not loose any light. Extension tubes cause a loss of light and this mey result in loss of critical DoF (opening the aperture). However, the filters are not as flat field as I would like. The corners are not as sharp as the center. For maximum sharpness and flat field use I recommend the use of the Canon EF adapter and the Canon EOS EF 50mm or 100mm lens.

Jeff


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