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Is this a camera or lens artifact?


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#1 James Martin

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Posted 26 September 2010 - 08:51 AM

Hi Guys,

I have recently seen some interesting "artifacts" on images from my camera, they are rare, but they happen. No-one has complained to me about them, YET, but I have to say they annoy me. Typically I get it when a bright object is against a fairly dark background. However, I want to be sure this artifact is coming from my lens, which is significantly cheaper and crappier than my camera.

The artifact always seems to be diagonal to the bright object, ie. never just vertical or just horizontal....

I hope this isn't a sign of a knackered CCD?

The camera is a Sony F900/3, the lens is a Fujinon HA14x8EVM. Sadly, I've never been in a situation with a different lens to be able to make a direct comparison - the easiest way of finding out which is which, I guess.

I've included frames from two different projects for reference.

Thanks for your help.

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  • RAW Films 10.jpg
  • Damaged - heating the iron.jpg

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#2 Rob Featherstone

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Posted 27 September 2010 - 07:29 AM

Do you have a filter on the lens?

Say a UV filter?

This kind of ghosting can happen when

the light bounces around between the lens and the filter.

-Rob
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#3 James Martin

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Posted 27 September 2010 - 07:40 AM

Hi Rob,

That was my first guess, the second picture, with the blowtorch, had probably two filters in, however the first had none.

My camera would have had ND and maybe a CC in, but they're behind the lens, so I guess shouldn't be a problem?

I suppose this means it is probably a lens issue - piss poor highlight handling?

James.

Do you have a filter on the lens?

Say a UV filter?

This kind of ghosting can happen when

the light bounces around between the lens and the filter.

-Rob


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#4 Rob Featherstone

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Posted 27 September 2010 - 07:51 AM

I guess so.

I have had it happen with a BPM or UV filter.

Maybe the front element was dusty?

Or had a flare on it?

-R
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#5 John Sprung

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Posted 27 September 2010 - 01:13 PM

James -- Get a cardboard box, about a foot cube or a little larger. Paint the inside all black, and one side on the outside all white. Then cut a hole in the middle of the white side about an inch in diameter, and close the box. Take some shots of this with the hole in the middle of the frame, near each corner, and near the middles of the sides. Then borrow another lens, and repeat this black hole test.




-- J.S.
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