Chromatic aberration

[Tom Hardwick]

Mark, I assume you moved the camera between takes, as the anamorphic is in reality a 0.5x wide-angle converter but in the horizontal plane only, and your pictures don't show this.

Also the Iscorama has a focus ability does it not? Are you leaving the Fujinon at infinity and focusing with the A lens?

tom.

[Mark David Williams]

Originally Posted by Bill Ravens

The PP settings won't be the cause of CA.(doncha just love acronyms?)
But, my question to you is what aperture settings did you use on the shot with and without CA. CA, in hi quality optics, is made worse by long zooms and apertures too far from the sweet spot. If you were shooting down around f/8 or less, this would be my guess. Also, how does the adapter mount to the cam lens? If it's tilted, even slightly, relative to the lens axis, you could induce CA.

Hi Bill. No the aperture was wide open.

The adapter screws on although the adapter is heavy 1k I thought it should be fine for a quick test. Do you think it would make a difference if I used a support?

[Mark David Williams]

Originally Posted by Tom Hardwick

Mark, I assume you moved the camera between takes, as the anamorphic is in reality a 0.5x wide-angle converter but in the horizontal plane only, and your pictures don't show this.

Also the Iscorama has a focus ability does it not? Are you leaving the Fujinon at infinity and focusing with the A lens?

tom.

Hi Tom. Yes I did move it and it is different. So not a fair test. Although more pictures show the same difference. I could set this whole thing up with a tripod and support if you think its worth it. Yes I am focusing with the A and my EX-1 is set to just before infinity.

How I did this was took a snap from the vegas timeline after reseting the properties pixel aspect ratio to 1, 4568 not quite 1.5

[Mark David Williams]

The camera is now on a tripod with the A supported. The lens is set to infinity and the A is set for two metres Its minimum setting. The distance is about 6 and a half feet which the A is limited to 5 feet so this might be a problem? This is with the shutter off and the aperture fully open. The picture was taken in vegas 8 with properties set for widescreen and media properties set the same. The frame and comp were an exact match.

http://www.freewebs.com/markwilliams...%20OFF%201.png

Any questions or any more ideas! Im running out of them.

[Tom Hardwick]

I've suddenly thought of this. I use a Bolex Aspheron (designed for 16 mm cameras) as a wide-angle converter for my camcorders. It works beautifully on anything from the TRV900, through VX2000 and now my current Z1. But when I borrowed an EX1 for a week I found there was no way I could get a sharp image using this lens, and it made me think that maybe the Fujinon's internal design doesn't lend itself well to add-ons. Could this be a contributory factor do you think?

I think you need to tripod the combo and connect the ouput up to a nice 1920 TV. Of course you'll be seeing horizontally compressed images, but you'll also have time to play with the focus settings (Fujinon and A) and the apertures to see if things clean up at all when stopped down. Abnd is that pincushion distortion I see on the LH edge?

tom.

[Mark David Williams]

Tom I think you may be on to something. And yes the side of the TV is warping much more than it should. Something is not right with this picture! I don't yet have a 1920 monitor just a HD ready one. I'll connect that up tomorrow and report back. I wonder if others are having problems adding lenses?

[Scott Karlins]

Sony sells a wide angle adapter just for the EX1. Has anyone used this successfully?

I am about to buy an EX1 and accessories, and I have included the Sony one in my purchase list.

Thanks, Scott K.

[Tom Hardwick]

They certainly are. There are posts on this site about the new Century w/a converter being a big disappointment at the edges - just like yours.

[Mark David Williams]

Tom just checked my firmware version V1.02_0337 Do you think the fault may be with the camera?

[Tom Hardwick]

I don't think you can lay blame at Sony's door if the Fujinon on its own is good at all focal lengths and all apertures and then you go and fit another's aftermarket optic. Sony's w/a is a feeble 0.8x, which may or may not tell you something.

[Mark David Williams]

Yes I agree with that The camera alone works fine. But I want to know its limitations and to know if they can be overcome. Letus had to make a corrective lens for the EX-1. I wonder if this could be where my problem lies?

[Paul Curtis]

I didn't realise the camera was moved with those first shots, hence the question about why the adaptor one was not wider.

Having said that what is the camera actually recording. If you are at 1920 x 1080p and you put the adaptor on and you get a 1920x1080p anamorphic image, right? But aren't anamorphic ratios usually designed for less wide sensors (4:3 usually, right?). So you're going to get a huge squeeze on a 16:9 sensor assuming it covers the entire image?

If you're getting weird distortions through the lens you could always create a warp layer in AE or something similar to unwarp the image because the warp would probably the same all the time. Long winded and a complete pain, but possible

Just curious...

cheers
paul

[Mark David Williams]

Originally Posted by Paul Curtis

I didn't realise the camera was moved with those first shots, hence the question about why the adaptor one was not wider.

Having said that what is the camera actually recording. If you are at 1920 x 1080p and you put the adaptor on and you get a 1920x1080p anamorphic image, right? But aren't anamorphic ratios usually designed for less wide sensors (4:3 usually, right?). So you're going to get a huge squeeze on a 16:9 sensor assuming it covers the entire image?

If you're getting weird distortions through the lens you could always create a warp layer in AE or something similar to unwarp the image because the warp would probably the same all the time. Long winded and a complete pain, but possible

Just curious...

cheers
paul

Paul after reading your post I had a thought and just put a straight line against the TV.. Its not straight. I dont think there is distortion here at all now especially when everything else is straight. Look at the VHS opening near the bottom. That problem is now solved! Just the edge colours now. What do people think? Is the colour bleed such big problem that it would be noticeable on a large screen?

[Sean Donnelly]

I think that's to be expected. It could be the result of sending the squeezed image through a prism, or it may be the nature of the adapter. I think any reasonably priced anamorphic is going to have trouble with CA. I've never used the iscorama 54 before, but I have done a few jobs with Panavision anamorphics. How does it mount to the camera? The compression is very sensitive to vertical alignment, so perhaps if the lens if rotated just slightly that could cause similar problems to what you're seeing.

[Mark David Williams]

Originally Posted by Sean Donnelly

I think that's to be expected. It could be the result of sending the squeezed image through a prism, or it may be the nature of the adapter. I think any reasonably priced anamorphic is going to have trouble with CA. I've never used the iscorama 54 before, but I have done a few jobs with Panavision anamorphics. How does it mount to the camera? The compression is very sensitive to vertical alignment, so perhaps if the lens if rotated just slightly that could cause similar problems to what you're seeing.

The Adapter screws in and I had it supported. It can be rotated and I did it by eye There is a white line on the camera to help.. I had the lens on and off a few times I dont think its that.

Sean do you think it would be noticeable on a 40' screen?