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Canon EOS Full Frame for HD
All about using the Canon 1D X, 6D, 5D Mk. IV / Mk. III / Mk. II D-SLR for 4K and HD video recording.


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Old December 29th, 2009, 01:24 PM   #1
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Back on with the AA Filter

Hi,
I have been too busy in the last couple of months to pursue my Anti Aliasing filter, but I am back on track. After failed attempts with a Chinese optical company I am now using a British firm. The filter sits behind the lenses, in front of the mirror above the lens pins.

This is what we have right now.

http://www.millerandmiller.co.uk/5DMK2AA/

It's not a great test but it's repeatable. There is no video on this webpage just grabs.
Shot from a 50mm at 2.8 ISO 100

Sorry for the poor web page I just threw it together a moment ago.

James

For more images and downloads follow the link.
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Back on with the AA Filter-ss_secgrab.png  
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Old December 29th, 2009, 10:02 PM   #2
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James,

Have you ever tried using one of these??DSCF2700600.jpg (image)

From the original Kodak/Canon DCS cameras. I've been trying to find one to have a go.

Dan
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Old December 30th, 2009, 02:19 AM   #3
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Hi Dan, that's where I started, like the removable kodak OLPF.
There are two OLP filters in the Canons. I have been adding a third double layer removable filter in much the same place as the kodak.

You could remove the internal OLPF's and replace with optical glass, tricky job as one is on the cleaning plate. The benifits would be control over still or video with a pop in filter to suit each shoot.

Anyway I am using what is basically a plastic filter. It's amazing what abuse you can give a filter behind the lens glass. When you are done shooting video just pop it out.

I have now taken the job to a British firm as it was taking too long between testing, apart from lost in translation. It's amazing how long it took to get across that more powerful in optical strenght, and not less breakable.

What I did find is the firm in China would get back to me very quickly (even got a Christmas card), the British firms would take days or they would not reply at all.

If it stops raining today I'll do some more testing on the current version.

I'll keep you posted. James
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Old December 30th, 2009, 06:40 AM   #4
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James,

Much like you I was thinking of just leaving the built in OLP filter on the CMOS sensor but adding the Kodak one in as well. From memory they were quite strong and designed for a 2MP sensor (not unlike the Canon HD video mode). The Kodak is of course all glass and already designed to fit in a Canon body. Have you actually tried the Kodak specifically? have you any reason to think the ones you are having built would work better?

Dan
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Old December 30th, 2009, 10:09 AM   #5
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Dan, I have not managed to find a DCS drop in filter, I would have loved to try one. Using glass represents a tricky design to get it to fit in the 5D body, You have to compromise a mirror lockup position, although not a problem using in live view. Mine were made from lithium niobate.

Canons AA filters run at 90˚ and -90˚one separating the image in a vertical direction one in horizontal. To get the same effects but stronger, you have to have 2 sandwiched together, making 4 in total. On the plus side the distortion turns a 16mm into a 14mm. Downside is loss of light, focus will not hold on parafocal lenses throughout the zoom range.

I have tried so many birefringence materials, but have found one that works very well. There are always going to be compromises and tradeoffs finding the balance is a tough call. Together with quality control & production variations.

So nice to shoot architectural or man made structures with out the shimmers.

Took some shots out the window today, rain, very dark and overcast. I'll try and post them on Vimeo asap.

James
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Old December 30th, 2009, 12:17 PM   #6
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Hi James,

well done on this work, looks very promising!

Because it's behind the lens, does that mean that one strength has the same effect across all focal lengths?

If so, that would be great.

I thought your test images showed great success with this device and I would be extremely keen to buy one.
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