Color finging with Brevis35 or similar adapter? at DVinfo.net

Brandon Freeman · July 9th, 2007, 03:37 PM

Hello, I have a question. I don't own a Canon XH-A1 or G1 camera, am still looking, but a thought occurred to me regarding the color fringing on edges issue -- if one were to attach a 35mm lens adapter such as the Brevis35, would the result reduce fringing, due to the camera's lens simply filming the image off of the photo lens?

If so, this would be great news.

Dennis Murphy · July 9th, 2007, 05:26 PM

I made a DIY spinner that was lovely on my Panasonic GS400. I've had my XHA1 for about a month now, and the adapter is unusable on the Canon as the colour fringing is the equivalent to tripping on acid. There's like rainbows everywhere man *slurred giggle*.
It particularly affects all high contrast images on the outside third of the frame. The focus is fine, it's just the CA.
I'm hacking the adapter to pieces at the moment trying different things to reduce the CA, but it exaggerates it extremely at the moment.
Disclaimer: Of course, a swanky pro adapter might not do that at all. I do not have access to an achromat... just a cheap macro and +1, +2 and +4 add-ons.

I've noticed on another thread somewhere that people are developing presets that greatly reduce the fringing, but it appears that the cost is that the resulting image is washed out. I wonder what happens when you tweak it in post if the fringing just pops right out back at you again? I haven't had time to do any tests yet.

Dennis Wood · July 10th, 2007, 12:46 AM

The Brevis is being used a lot with the XH-A1. It does not remove any CA that may be present with the XH-A1 already, but it's easy to avoid by lighting properly.

This trailer is one of the best XH-A1/Brevis pieces I've seen. Patrick Moreau posts here in the wedding videography section and uses several XH-A1/Brevis setups in his operation.

Bob Hart · July 10th, 2007, 04:05 AM

It is a fairly simple choice.

Stacked single element dioptres like you are using = rainbow and blended colours problem, AKA CA.

Achromatic dioptre = truer colours and no rainbows beyond any fringing inherently in the camera system.

Apparently an apochromatic dioptre is even better but not conveniently or affordably available.

If you are really honest with yourself, you will admit to the focus or sharpness in the outer third being off as well due to radial blurring. Just desaturate the colour to black and white and you will see what I mean.

No amount of hacking at the adaptor will fix it if the relay optics are not up to scratch.

Brandon Freeman · July 10th, 2007, 08:19 AM

Perhaps then I'll be best to wait and see how the XDCAM EX works with something such as the Brevis. I was gunning for the HVX200, and still might, but the softer look due to the up-res isn't attractive to me. That's what I like about the XH-A1 - native 1440x1080 CCDs with over a megapixel per CCD (if I have read my specs correctly).

But if color fringing is such an issue with the XH-A1 (and I've seen the footage; it is strangely much more apparent than any other HD/V cam on the market), then let's hope the EX has the same amount of internal resolution (or better).

Dennis Murphy · July 10th, 2007, 01:38 PM

Quote:

Originally Posted by Bob Hart

It is a fairly simple choice.

Yes, it is a simple choice... just not a cheap one... and I'm so cheap, I steal flowers out of old lady's gardens when I want to romance my woman.

Quote:

Originally Posted by Bob Hart

No amount of hacking at the adaptor will fix it if the relay optics are not up to scratch.

After much hacking and other associated grinding noises with loud swearing, I would now agree with you.

July 9th, 2007, 03:37 PM	#1
Brandon Freeman Major Player Join Date: Feb 2007 Location: Boise, ID Posts: 226	Color finging with Brevis35 or similar adapter? Hello, I have a question. I don't own a Canon XH-A1 or G1 camera, am still looking, but a thought occurred to me regarding the color fringing on edges issue -- if one were to attach a 35mm lens adapter such as the Brevis35, would the result reduce fringing, due to the camera's lens simply filming the image off of the photo lens? If so, this would be great news.

July 9th, 2007, 05:26 PM	#2
Dennis Murphy Major Player Join Date: May 2006 Location: Whangarei, New Zealand Posts: 396	I made a DIY spinner that was lovely on my Panasonic GS400. I've had my XHA1 for about a month now, and the adapter is unusable on the Canon as the colour fringing is the equivalent to tripping on acid. There's like rainbows everywhere man slurred giggle. It particularly affects all high contrast images on the outside third of the frame. The focus is fine, it's just the CA. I'm hacking the adapter to pieces at the moment trying different things to reduce the CA, but it exaggerates it extremely at the moment. Disclaimer: Of course, a swanky pro adapter might not do that at all. I do not have access to an achromat... just a cheap macro and +1, +2 and +4 add-ons. I've noticed on another thread somewhere that people are developing presets that greatly reduce the fringing, but it appears that the cost is that the resulting image is washed out. I wonder what happens when you tweak it in post if the fringing just pops right out back at you again? I haven't had time to do any tests yet.

July 10th, 2007, 12:46 AM	#3
Dennis Wood Major Player Join Date: Mar 2005 Location: Ontario, Canada Posts: 916	The Brevis is being used a lot with the XH-A1. It does not remove any CA that may be present with the XH-A1 already, but it's easy to avoid by lighting properly. This trailer is one of the best XH-A1/Brevis pieces I've seen. Patrick Moreau posts here in the wedding videography section and uses several XH-A1/Brevis setups in his operation.

July 10th, 2007, 04:05 AM	#4
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	It is a fairly simple choice. Stacked single element dioptres like you are using = rainbow and blended colours problem, AKA CA. Achromatic dioptre = truer colours and no rainbows beyond any fringing inherently in the camera system. Apparently an apochromatic dioptre is even better but not conveniently or affordably available. If you are really honest with yourself, you will admit to the focus or sharpness in the outer third being off as well due to radial blurring. Just desaturate the colour to black and white and you will see what I mean. No amount of hacking at the adaptor will fix it if the relay optics are not up to scratch.

July 10th, 2007, 08:19 AM	#5
Brandon Freeman Major Player Join Date: Feb 2007 Location: Boise, ID Posts: 226	Perhaps then I'll be best to wait and see how the XDCAM EX works with something such as the Brevis. I was gunning for the HVX200, and still might, but the softer look due to the up-res isn't attractive to me. That's what I like about the XH-A1 - native 1440x1080 CCDs with over a megapixel per CCD (if I have read my specs correctly). But if color fringing is such an issue with the XH-A1 (and I've seen the footage; it is strangely much more apparent than any other HD/V cam on the market), then let's hope the EX has the same amount of internal resolution (or better).