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Author Topic: Filters and ghosting  (Read 2938 times)

dreed

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Filters and ghosting
« on: March 31, 2011, 09:47:02 AM »

Tonight I was shooting sunset and upon putting a ND filter in front of the lens, I noticed some amount of ghstong showing up. My suspicion is that this is light reflected off the front of the lens, back onto the filter and then back down the lens.

Is there something that can be done to avoid this?
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solardarkroom.com

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Re: Filters and ghosting
« Reply #1 on: March 31, 2011, 02:52:40 PM »

I expect that's optical as you guessed. Assuming you had a specific reason to lengthen the exposure is it possible you could lower your ISO any further or stop down instead of the ND?
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dreed

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Re: Filters and ghosting
« Reply #2 on: March 31, 2011, 06:38:24 PM »

I wasn't trying to lengthen the exposure but rather make the top section (with the setting sun) a bit darker so that the exposure was more even with the bottom section.
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solardarkroom.com

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Re: Filters and ghosting
« Reply #3 on: March 31, 2011, 08:28:14 PM »

Ahhh... A Graduated ND. Now that's different. Sounds like a job for HDR, or a dual exposure merge if the horizon isn't too busy...
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Paul Sumi

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Re: Filters and ghosting
« Reply #4 on: March 31, 2011, 08:28:50 PM »

I wasn't trying to lengthen the exposure but rather make the top section (with the setting sun) a bit darker so that the exposure was more even with the bottom section.

Assuming you were using a rectangular grad ND, were you using a filter holder or hand-held?  If the latter, not holding the filter flat against the front of the lens can cause ghosting.

Paul
« Last Edit: March 31, 2011, 08:30:38 PM by Paul Sumi »
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dreed

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Re: Filters and ghosting
« Reply #5 on: April 01, 2011, 09:16:29 AM »

Assuming you were using a rectangular grad ND, were you using a filter holder or hand-held?  If the latter, not holding the filter flat against the front of the lens can cause ghosting.

Paul


Good suggestion. I was using a filter holder. Next time I'll try hand held and flat up against the lens.

Thanks,
Darren
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Paul Sumi

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Re: Filters and ghosting
« Reply #6 on: April 01, 2011, 10:11:38 AM »

Good suggestion. I was using a filter holder. Next time I'll try hand held and flat up against the lens.

Hand holding a GND filters can introduce problems of its own (e.g., scuffing, inadvertent fingers in picture, etc).

IMO filter holders work better if time if time permits.

Paul

Lonnie Utah

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Re: Filters and ghosting
« Reply #7 on: April 04, 2011, 01:07:50 PM »

This thread is full of all kinds of free advice.  Remember, you get what you pay for...
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Kerry L

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Re: Filters and ghosting
« Reply #8 on: April 06, 2011, 10:09:59 AM »

Tonight I was shooting sunset and upon putting a ND filter in front of the lens, I noticed some amount of ghstong showing up. My suspicion is that this is light reflected off the front of the lens, back onto the filter and then back down the lens.

Is there something that can be done to avoid this?


Most of the holders for rectangular grads are designed to hold multiple filters, so there are lots of light leaks behind the filter especially the slot for the round polarizer. Perhaps the stray light came in through one of these openings. Try shading the lens front and holder to reduce these leaks.
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OnlyNorth

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Re: Filters and ghosting
« Reply #9 on: April 06, 2011, 02:02:37 PM »

Hi,
For many years I used(and use) Cokin P and Z series filters with original holders without any problems  :)
Radu
 
 













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stamper

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Re: Filters and ghosting
« Reply #10 on: April 07, 2011, 04:37:45 AM »

Hi,
For many years I used(and use) Cokin P and Z series filters with original holders without any problems  :)
Radu
 

It all depends on the direction of the sun. If it is coming from either shoulder - 90 degrees to the subject - then sometimes there is a problem . There is a manufacturer - I think Lee - who have a some kind of cover round the holder that covers the gap between the holder and the lens.
 










Lonnie Utah

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Re: Filters and ghosting
« Reply #11 on: April 07, 2011, 11:08:28 AM »

If you shoot wider than about 22-24mm, neither holder does a good job and you get vignetting.  With most of my work being under 20mm, I've found myself hand holding, alot. It's easy to do once you get the hang of it.  It doesn't work well for exposures longer than about 1 sec...
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OnlyNorth

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Re: Filters and ghosting
« Reply #12 on: April 08, 2011, 05:15:48 AM »

Hi
Below I present an unusual situation when the ghosts appear(16mm,640ASA,1/200,f/11)  
« Last Edit: April 08, 2011, 05:23:46 AM by OnlyNorth »
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