CAC on HPX500 Lenses

[Jan Crittenden livingston]

Hi Chris,

It is a huge feature if you only have $10,000 to spend on a lens.

Best,

Jan

Jan Crittenden Livingston
Product Manager, DVCPRO, DVCPRO50, AG-DVX100
Panasonic Broadcast & TV Systems

[Seth Melnick]

I have th fuji CAC lens and you can see its effects on a vectorscope – I plan on posting these pics soon but basically when using a color chart the lines “bulge” less with CAC on

[Barry Green]

It is a *huge* feature if you’re buying an inexpensive lens. I’ve played quite a bit with seeing what the CAC function does by unplugging the lens and comparing, and it works very very well. It really minimizes, and in some cases eliminates, the purple/green fringing that is endemic in low-cost lenses.

If you can spend $50,000+ on a lens, don’t worry about CAC. But if you’re buying a $10,000 lens, by all means spend the extra $1,000 and get the CAC version, it really works.

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Get the most from your DVX camera. The DVX Book and DVX DVD are now available on ebay and at Amazon (https://www.fiftv.com/db)

[Chris Elley]

Thank you all for your responses.

I have no problem spending an extra $1,000 or so for CAC. My question arose, because I was looking for a lens that is wider than 16x. There is another Canon in the HDgc line that is 20% wider and $2,500 more expensive, but it lacks CAC.

Based on your responses, it sounds more prudent to go with the CAC lens and purchase a wide-angle converter for those situations in which I must go wider.

Someone please let me know if my conclusion is off.

Thanks,
Chris Elley

Electro-Fish Media LLC
electro-fish.com

[Adam Smith]

Interestingly – I talked to one of the Fuji reps last week and he said there’s no physical differences between a CAC and non-CAC lens, they supplied Panasonic with information on lens characteristics for certain models, and the HPX has built-in profiles that compensates/calibrate for the best image with each of those specific lenses.

—
Video Photographer / Avid Editor
Maximus Media Inc.

[Barry Green]

Exactly. The lenses are the same (well, the glass is the same). The difference with the CAC lens is that it is a digital lens with the ability to relay focal length, iris, and focus position digitally to the camera, so the camera’s CAC function can work.

If you put a CAC lens on a non-CAC body, you’ll see purple/green fringing. If you put a CAC lens on a CAC body, you won’t. If you put a non-CAC lens on a CAC body, then the level of fringing you’ll see depends on how well and how thoroughly the lens coatings compensate for fringing.

The CAC lenses don’t try to correct out the fringing with coatings; they assume the camera body’s digital processor will do it. If the body doesn’t have a CAC processor, that’s why you’ll see fringing — the body won’t know what to do with the CAC lens position info the lens is feeding it.

—————–
Get the most from your DVX camera. The DVX Book and DVX DVD are now available on ebay and at Amazon (https://www.fiftv.com/db)