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Author Topic: Is it flare, internal reflections or a ghost  (Read 5194 times)

Skirball

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Re: Is it flare, internal reflections or a ghost
« Reply #30 on: September 27, 2013, 12:10:15 PM »
I found that my 50 1.4 did this same thing a lot, so I put a high quality multi-coated filter (like Hoya or B+W) and it took care of it.  It won't fix flare from the sun or really bright lights, but should work in the example you posted.

You find you get less flare with a filter on?

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Re: Is it flare, internal reflections or a ghost
« Reply #30 on: September 27, 2013, 12:10:15 PM »

mackguyver

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Re: Is it flare, internal reflections or a ghost
« Reply #31 on: September 27, 2013, 12:18:53 PM »
I found that my 50 1.4 did this same thing a lot, so I put a high quality multi-coated filter (like Hoya or B+W) and it took care of it.  It won't fix flare from the sun or really bright lights, but should work in the example you posted.

You find you get less flare with a filter on?
Yes, with that and some other older lens designs that were pre-digital.  I know it seems backwards, but if you think though it, the reflections are coming off the sensor (not an issue with film) and reflecting back on the front element.  If the filter cuts down on the (internal) reflection with a modern multi-coating, that explains it.  Again, it's no good in bright light, but helps with this specific type of reflection on lower intensity lights.
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Skirball

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Re: Is it flare, internal reflections or a ghost
« Reply #32 on: September 27, 2013, 12:53:31 PM »
I found that my 50 1.4 did this same thing a lot, so I put a high quality multi-coated filter (like Hoya or B+W) and it took care of it.  It won't fix flare from the sun or really bright lights, but should work in the example you posted.

You find you get less flare with a filter on?
Yes, with that and some other older lens designs that were pre-digital.  I know it seems backwards, but if you think though it, the reflections are coming off the sensor (not an issue with film) and reflecting back on the front element.  If the filter cuts down on the (internal) reflection with a modern multi-coating, that explains it.  Again, it's no good in bright light, but helps with this specific type of reflection on lower intensity lights.

Multi-coating or not, no surface is going to reflect less than coated surface.

Mostly though, it's just opposite of my experience, even with the same lens.  You can easily see the results of cheap un-coated filters in dark situations with bright points of light.  When I moved to nice multi-coated Hoya filters I noticed a significant reduction in the same situation, and it colors them so they don't stand out as much, but they still show.  I'm a filter guy (we don't need to re-hash this hackneyed discussion), but if I'm out at night, even in dusty, crowded, third-world streets, I take off my filter because of this very problem.

mackguyver

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Re: Is it flare, internal reflections or a ghost
« Reply #33 on: September 27, 2013, 01:07:19 PM »
I found that my 50 1.4 did this same thing a lot, so I put a high quality multi-coated filter (like Hoya or B+W) and it took care of it.  It won't fix flare from the sun or really bright lights, but should work in the example you posted.

You find you get less flare with a filter on?
Yes, with that and some other older lens designs that were pre-digital.  I know it seems backwards, but if you think though it, the reflections are coming off the sensor (not an issue with film) and reflecting back on the front element.  If the filter cuts down on the (internal) reflection with a modern multi-coating, that explains it.  Again, it's no good in bright light, but helps with this specific type of reflection on lower intensity lights.

Multi-coating or not, no surface is going to reflect less than coated surface.

Mostly though, it's just opposite of my experience, even with the same lens.  You can easily see the results of cheap un-coated filters in dark situations with bright points of light.  When I moved to nice multi-coated Hoya filters I noticed a significant reduction in the same situation, and it colors them so they don't stand out as much, but they still show.  I'm a filter guy (we don't need to re-hash this hackneyed discussion), but if I'm out at night, even in dusty, crowded, third-world streets, I take off my filter because of this very problem.
I understand and it doesn't exactly make sense, but it does work under the circumstances I mentioned.  That's all I can say.  With newer lenses with coatings optimized for digital sensors, filters can only hurt.
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Sporgon

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Re: Is it flare, internal reflections or a ghost
« Reply #34 on: September 27, 2013, 01:47:21 PM »
I've had random green internal reflections with the 24-105 when shooting into intense light. On one occasion I was shooting a lighthouse and cliffs as the sun was just rising above the horizon. For quite some time I thought I had found something like green copper under the water, below the cliffs.  :-[

photonius

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Re: Is it flare, internal reflections or a ghost
« Reply #35 on: September 27, 2013, 02:51:13 PM »
I found that my 50 1.4 did this same thing a lot, so I put a high quality multi-coated filter (like Hoya or B+W) and it took care of it.  It won't fix flare from the sun or really bright lights, but should work in the example you posted.

You find you get less flare with a filter on?
Yes, with that and some other older lens designs that were pre-digital.  I know it seems backwards, but if you think though it, the reflections are coming off the sensor (not an issue with film) and reflecting back on the front element.  If the filter cuts down on the (internal) reflection with a modern multi-coating, that explains it.  Again, it's no good in bright light, but helps with this specific type of reflection on lower intensity lights.

Actually, physically this makes no sense.   A filter in front of the lens will not prevent light bouncing off the sensor from  reflecting from the front element or any other internal element. Once the light is through the filter, nothing can prevent any internal reflections.

mackguyver

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Re: Is it flare, internal reflections or a ghost
« Reply #36 on: September 27, 2013, 03:26:37 PM »
I found that my 50 1.4 did this same thing a lot, so I put a high quality multi-coated filter (like Hoya or B+W) and it took care of it.  It won't fix flare from the sun or really bright lights, but should work in the example you posted.

You find you get less flare with a filter on?
Yes, with that and some other older lens designs that were pre-digital.  I know it seems backwards, but if you think though it, the reflections are coming off the sensor (not an issue with film) and reflecting back on the front element.  If the filter cuts down on the (internal) reflection with a modern multi-coating, that explains it.  Again, it's no good in bright light, but helps with this specific type of reflection on lower intensity lights.

Actually, physically this makes no sense.   A filter in front of the lens will not prevent light bouncing off the sensor from  reflecting from the front element or any other internal element. Once the light is through the filter, nothing can prevent any internal reflections.
I'm not an optical engineer by any means, but I believe it works because it lessens the amount of the light from bouncing off the sensor from bouncing back into the sensor, which is what's causing the ghosting.  The reflection off the sensor is going to hit the foremost piece of glass and reflect back into the sensor.  By putting a better coated piece of glass in the front, I think it reduces the ghosting.

That may or may not be sound logic, all I can say is that when I got my 50 1.4, I couldn't believe how badly it ghosted with night shots very similar to the OP's.  I screwed a multi-coated filter on the front and the problem practically disappeared.  Going back in my mind, it was a 450D, 50 f/1.4, and a Hoya HMC Super filter. 
EOS M | 5D III | 1D X
EF 24 1.4L II | 50 1.2L | 85 1.2L II | 180 3.5L Macro | 300 2.8L IS II 16-35 2.8L II | 24-70 2.8L II | 70-200 2.8L IS II
TS-E 24 3.5L II :: Extender 1.4x III | 2x III :: EF-M 22 2 | 18-55mm 3.5-5.6 IS

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Re: Is it flare, internal reflections or a ghost
« Reply #36 on: September 27, 2013, 03:26:37 PM »

Skirball

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Re: Is it flare, internal reflections or a ghost
« Reply #37 on: September 27, 2013, 04:03:27 PM »
I found that my 50 1.4 did this same thing a lot, so I put a high quality multi-coated filter (like Hoya or B+W) and it took care of it.  It won't fix flare from the sun or really bright lights, but should work in the example you posted.

You find you get less flare with a filter on?
Yes, with that and some other older lens designs that were pre-digital.  I know it seems backwards, but if you think though it, the reflections are coming off the sensor (not an issue with film) and reflecting back on the front element.  If the filter cuts down on the (internal) reflection with a modern multi-coating, that explains it.  Again, it's no good in bright light, but helps with this specific type of reflection on lower intensity lights.

Actually, physically this makes no sense.   A filter in front of the lens will not prevent light bouncing off the sensor from  reflecting from the front element or any other internal element. Once the light is through the filter, nothing can prevent any internal reflections.
I'm not an optical engineer by any means, but I believe it works because it lessens the amount of the light from bouncing off the sensor from bouncing back into the sensor, which is what's causing the ghosting.  The reflection off the sensor is going to hit the foremost piece of glass and reflect back into the sensor.  By putting a better coated piece of glass in the front, I think it reduces the ghosting.


But, 'no glass' is a better coated piece of glass than the best coated pieces of glass.

mackguyver

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Re: Is it flare, internal reflections or a ghost
« Reply #38 on: September 27, 2013, 04:30:37 PM »
But, 'no glass' is a better coated piece of glass than the best coated pieces of glass.
Like I said, it works, and thus addresses the OP.  My degrees are in Arts & Management, not Science :)
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Skirball

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Re: Is it flare, internal reflections or a ghost
« Reply #39 on: September 27, 2013, 05:16:12 PM »
But, 'no glass' is a better coated piece of glass than the best coated pieces of glass.
Like I said, it works, and thus addresses the OP.  My degrees are in Arts & Management, not Science :)

That's fine, but you were the one postulating theories of the allegedly observed results of your experiment; consider this your peer review.   That is science.  :)

Edited to add smily  :)
« Last Edit: September 27, 2013, 05:22:39 PM by Skirball »

WillThompson

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Re: Is it flare, internal reflections or a ghost
« Reply #40 on: September 27, 2013, 07:04:16 PM »
I tried several lens/camera/exposure combinations this morning and found only my most expensive 24-105 Canon L lens produced this problem and only when I have (relatively) bright light in the subject.

Has your 24-105 been in for the recall for the lens flair problem?

When this lens first came out there was a recall and I sent my lens to canon and they exchanged it for an updated lens.

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LetTheRightLensIn

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Re: Is it flare, internal reflections or a ghost
« Reply #41 on: September 27, 2013, 10:12:13 PM »
Occam's Razor suggests ghost  ;) ;D

photonius

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Re: Is it flare, internal reflections or a ghost
« Reply #42 on: September 28, 2013, 05:16:41 AM »
I found that my 50 1.4 did this same thing a lot, so I put a high quality multi-coated filter (like Hoya or B+W) and it took care of it.  It won't fix flare from the sun or really bright lights, but should work in the example you posted.

You find you get less flare with a filter on?
Yes, with that and some other older lens designs that were pre-digital.  I know it seems backwards, but if you think though it, the reflections are coming off the sensor (not an issue with film) and reflecting back on the front element.  If the filter cuts down on the (internal) reflection with a modern multi-coating, that explains it.  Again, it's no good in bright light, but helps with this specific type of reflection on lower intensity lights.

Actually, physically this makes no sense.   A filter in front of the lens will not prevent light bouncing off the sensor from  reflecting from the front element or any other internal element. Once the light is through the filter, nothing can prevent any internal reflections.
I'm not an optical engineer by any means, but I believe it works because it lessens the amount of the light from bouncing off the sensor from bouncing back into the sensor, which is what's causing the ghosting.  The reflection off the sensor is going to hit the foremost piece of glass and reflect back into the sensor.  By putting a better coated piece of glass in the front, I think it reduces the ghosting.

That may or may not be sound logic, all I can say is that when I got my 50 1.4, I couldn't believe how badly it ghosted with night shots very similar to the OP's.  I screwed a multi-coated filter on the front and the problem practically disappeared.  Going back in my mind, it was a 450D, 50 f/1.4, and a Hoya HMC Super filter.

Ok, so how is a filter (let's say it lets 95% of the light through) supposed to lessen the amount of light bouncing off the sensor?  The only filter that can reduce the incoming light is a neutral density filter, but it just makes all darker if you didn't adjust exposure (which would actually reduce reflections because light intensity is less)

Regarding your 50mm f1.4 experience, the most likely explanation is that you did not do it under controlled circumstances, i.e. the shots with and without filter were not identical. You can only compare if you put it on a tripod and do with and without filter.
« Last Edit: September 28, 2013, 06:21:42 AM by photonius »

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Re: Is it flare, internal reflections or a ghost
« Reply #42 on: September 28, 2013, 05:16:41 AM »

brad goda

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Re: Is it flare, internal reflections or a ghost
« Reply #43 on: September 28, 2013, 07:35:51 AM »
very much lens flair
the 24-105 does this well... I like this lens for shooting concerts because of the way it flares
again... yes it flairs... it is a zoom lens and zoom lenses flair more than primes...
if you want to control your flair then use prime lens and no filters over the lens...


mackguyver

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Re: Is it flare, internal reflections or a ghost
« Reply #44 on: September 28, 2013, 03:09:05 PM »
I found that my 50 1.4 did this same thing a lot, so I put a high quality multi-coated filter (like Hoya or B+W) and it took care of it.  It won't fix flare from the sun or really bright lights, but should work in the example you posted.

You find you get less flare with a filter on?
Yes, with that and some other older lens designs that were pre-digital.  I know it seems backwards, but if you think though it, the reflections are coming off the sensor (not an issue with film) and reflecting back on the front element.  If the filter cuts down on the (internal) reflection with a modern multi-coating, that explains it.  Again, it's no good in bright light, but helps with this specific type of reflection on lower intensity lights.

Actually, physically this makes no sense.   A filter in front of the lens will not prevent light bouncing off the sensor from  reflecting from the front element or any other internal element. Once the light is through the filter, nothing can prevent any internal reflections.
I'm not an optical engineer by any means, but I believe it works because it lessens the amount of the light from bouncing off the sensor from bouncing back into the sensor, which is what's causing the ghosting.  The reflection off the sensor is going to hit the foremost piece of glass and reflect back into the sensor.  By putting a better coated piece of glass in the front, I think it reduces the ghosting.

That may or may not be sound logic, all I can say is that when I got my 50 1.4, I couldn't believe how badly it ghosted with night shots very similar to the OP's.  I screwed a multi-coated filter on the front and the problem practically disappeared.  Going back in my mind, it was a 450D, 50 f/1.4, and a Hoya HMC Super filter.

Ok, so how is a filter (let's say it lets 95% of the light through) supposed to lessen the amount of light bouncing off the sensor?  The only filter that can reduce the incoming light is a neutral density filter, but it just makes all darker if you didn't adjust exposure (which would actually reduce reflections because light intensity is less)

Regarding your 50mm f1.4 experience, the most likely explanation is that you did not do it under controlled circumstances, i.e. the shots with and without filter were not identical. You can only compare if you put it on a tripod and do with and without filter.
It worked for me, on a tripod, shooting skyline shots of Miami the first time.  I had the filter off, it ghosted.  I put it on, it didn't, or didn't nearly as much.  I pointed it at other light sources over the 3-4 years I had the lens with and without the filter, and every time, the filter helped suppress the ghosts. 

I won't debate this any further. It worked. Period.
EOS M | 5D III | 1D X
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TS-E 24 3.5L II :: Extender 1.4x III | 2x III :: EF-M 22 2 | 18-55mm 3.5-5.6 IS

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Re: Is it flare, internal reflections or a ghost
« Reply #44 on: September 28, 2013, 03:09:05 PM »