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Gear Talk => EOS Bodies - For Stills => Topic started by: jwilton on September 18, 2013, 06:43:26 PM

Title: Is it flare, internal reflections or a ghost
Post by: jwilton on September 18, 2013, 06:43:26 PM
I have a new camera and new lens photographing an old subject matter. Since the new camera+lens (Canon 6D and Canon 24-105 f4 L) I have been getting a green ghost image(s). Does anyone know what this is and how to avoid it?

It looks like internal reflections of the really bright lights on the bridge and the wharf.

On this photo are two examples of the problem:
- Top centre green boxes (5)
- Centre centre green dots (7) that appear just above the bridges arch
Any and all help appreciated.
Title: Re: Is it flare, internal reflections or a ghost
Post by: JimKarczewski on September 18, 2013, 07:35:29 PM
Is there a filter on the lens?  If so is it a $10 POS or a high quality multi-coated filter?

I see a lot of stuff like this when there is a filter and a crap one at that on a lens.
Title: Re: Is it flare, internal reflections or a ghost
Post by: jwilton on September 18, 2013, 07:41:12 PM
No filter just a hood.
Title: Re: Is it flare, internal reflections or a ghost
Post by: arjay on September 18, 2013, 07:43:54 PM
These are reflections, could be internal...
Title: Re: Is it flare, internal reflections or a ghost
Post by: Mt Spokane Photography on September 18, 2013, 07:46:50 PM
You mention other images that have this, can you show them?  It does look like some sort of internal lens reflection.  Those bright lights below the bridge are pointing right at you, and its obviously a long exposure, so even a very minimal reflection will show up.
Title: Re: Is it flare, internal reflections or a ghost
Post by: jwilton on September 18, 2013, 07:49:12 PM
Thanks Arjay, that makes sense. How does one fix this problem? Apart from not pointing lens at bright lights.

Is it a fault with the camera/lens or the user (me) or both?
Title: Re: Is it flare, internal reflections or a ghost
Post by: AUGS on September 18, 2013, 07:58:26 PM
These are reflections, could be internal...
Agreed, definitely reflections.  If you use this image and the drawn centre by Arjay, you will find less obvious (fainter) reflections of the lights as well.  They are not stars as they are stationary and not starting to have a trail like the few stars you can see.
These happen with most lenses when pointed towards or at a bright light source.  Night photography makes them far more obvious because the bright light reflection(s) inevitably end up on a dark sky.  Sometimes you just cannot avoid them.
To fix, I use Lightroom to spot heal where I can.
Title: Re: Is it flare, internal reflections or a ghost
Post by: arjay on September 18, 2013, 08:00:22 PM
Some lenses have more flare and internal reflections than others.  Manufacturers try to cut down on this with coated lenses and whatnot, but, you can't really eliminate this flare with the lens you have. (Photoshopping it out of the sky isn't hard, other places maybe harder...)
Title: Re: Is it flare, internal reflections or a ghost
Post by: jwilton on September 18, 2013, 08:03:45 PM
Thank you Arjay and AUGS. Noted user error.
Title: Re: Is it flare, internal reflections or a ghost
Post by: jwilton on September 18, 2013, 08:06:45 PM
Mr Spokane Photography - two examples one is with 6D from another angle and other with 40D similar position.

Note these are not long exposures (10-15sec) so no star trails etc.
Title: Re: Is it flare, internal reflections or a ghost
Post by: arjay on September 18, 2013, 08:09:30 PM
Thank you Arjay and AUGS. Noted user error.
User error, perhaps... but more like running into limitations of equipment that has less than 100% of internal reflections suppressed.
Title: Re: Is it flare, internal reflections or a ghost
Post by: jwilton on September 19, 2013, 05:56:39 PM
Thank you all.   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.  Most disappointed that the lens does not manage the internal reflections better. Though on balance I still like my new lens.

Test combinations included 40D, 6D - Canon 24-105L, Canon 75-300, Samyang 14.
Title: Re: Is it flare, internal reflections or a ghost
Post by: Marsu42 on September 19, 2013, 06:19:18 PM
Most disappointed that the lens does not manage the internal reflections better.

Flare/Reflection control is a very underrated characteristic of a lens and seldom mentioned - the 24-105 is general purpose, so it probably was not the main design concern. For dedicated landscape lenses it's different, that's why I'm very happy with my 17-40L which doesn't show any flare or reflection (yet) no matter where you point it...
Title: Re: Is it flare, internal reflections or a ghost
Post by: Lichtgestalt on September 19, 2013, 06:34:21 PM
j.j.abrams is messing with your files!!!
Title: Re: Is it flare, internal reflections or a ghost
Post by: Mt Spokane Photography on September 19, 2013, 08:34:32 PM
Since it is a new lens, I'd exchange it for another.  Sometimes there can be a manufacturing defect that makes internal reflections worse.
Title: Re: Is it flare, internal reflections or a ghost
Post by: Frodo on September 19, 2013, 11:10:22 PM
There was a recall of early version of that lens for flare: http://www.luminous-landscape.com/essays/canon-flare.shtml (http://www.luminous-landscape.com/essays/canon-flare.shtml)

I have a 24-105 and I find it to be quite ghost resistant.  My 70-200 f4L non-IS was terrible with ghosts when shooting into bright lights, such as the sun - my 24-105 was much better.

The contrast range in your night photos will challenge most lenses, especially zooms with large numbers of lens elements.  Your highlights are completely burnt out (no criticism of the photo), while the skies are relatively dark.  Even so, I've shot night cityscapes with that lens on a 5Dii (e.g. under the Sydney harbour bridge) and I can't remeber ghosts being a problem - I'll check.  Is the sensor of the 6D shinier such that it causes more internal reflections?
Title: Re: Is it flare, internal reflections or a ghost
Post by: ejenner on September 19, 2013, 11:13:22 PM
I was thinking the same thing.  The scene will test any lens for sure, but I find that lens to be quite flare resistant.  Hard to say without comparing the scene with another lens (either the same model, or something similar).
Title: Re: Is it flare, internal reflections or a ghost
Post by: Frodo on September 19, 2013, 11:22:32 PM
Here is a photo of a nightscape with my 24-105 @ 24mm and f8 (the bridge photos were with a different lens).  Although I've used just the centre of this image, I've looked at the full frame and ghosts, if at all present, are inconspicuous.

(http://)
Title: Re: Is it flare, internal reflections or a ghost
Post by: wickidwombat on September 20, 2013, 10:15:05 PM
Since it is a new lens, I'd exchange it for another.  Sometimes there can be a manufacturing defect that makes internal reflections worse.

I doubt it most 24-105s i've seen and used do this when shooting into hard large spotlights
Title: Re: Is it flare, internal reflections or a ghost
Post by: Frodo on September 21, 2013, 06:19:58 PM
Just tidying up some photos from last year and here is a photo of the 24-105 shoot straight into the sun on a 5D @ f11.  I think I would have left my Hoya Pro-1 UV filter attached because of the conditions in Antarctica.  I think that the flare resistance is more than acceptable for a zoom.  The green ghost was easily cloned out.

(http://)
Title: Re: Is it flare, internal reflections or a ghost
Post by: jwilton on September 23, 2013, 06:36:43 PM
Since it is a new lens, I'd exchange it for another.  Sometimes there can be a manufacturing defect that makes internal reflections worse.

I doubt it most 24-105s i've seen and used do this when shooting into hard large spotlights
Met a young chap, DJ, who was taking photos of the bridge early this morning. He had just purchased the same camera as mine. I asked him if he was getting internal reflections, explained why etc. and he was not.  Even composed same photo and could not reproduce the internal reflections.

SO I found at least one example of the lens that does not mis behave.
Title: Re: Is it flare, internal reflections or a ghost
Post by: jwilton on September 23, 2013, 06:38:08 PM
Just tidying up some photos from last year and here is a photo of the 24-105 shoot straight into the sun on a 5D @ f11.  I think I would have left my Hoya Pro-1 UV filter attached because of the conditions in Antarctica.  I think that the flare resistance is more than acceptable for a zoom.  The green ghost was easily cloned out.

(http://)

Thanks, love the photo.
Title: Re: Is it flare, internal reflections or a ghost
Post by: Skirball on September 23, 2013, 07:03:24 PM
I'm putting my money on it being ghosts.  Your best bet is to return the lens, or buy a shirt that says "My camera sees dead people".
Title: Re: Is it flare, internal reflections or a ghost
Post by: jwilton on September 23, 2013, 07:09:48 PM
 
I'm putting my money on it being ghosts.  Your best bet is to return the lens, or buy a shirt that says "My camera sees dead people".

 :)
Title: Re: Is it flare, internal reflections or a ghost
Post by: Pi on September 23, 2013, 07:26:17 PM
The lights are extremely bright for the exposure. I have taken many night shots with this lens without visible problems. Still, with extremely bright light sources, you will see ghosts symmetric to the light sources about the center, like the green flare right here, in the lower left corner.

(http://farm3.staticflickr.com/2889/9905830385_c2f14b3201.jpg) (http://www.flickr.com/photos/plamen-stefanov/9905830385/)
 (http://www.flickr.com/photos/plamen-stefanov/9905830385/#) 

On the other hand, the next shots seems to be OK, the "flare" around the highlights are due to the high humidity and pollution:

(http://farm4.staticflickr.com/3807/9558118957_0d51240089.jpg) (http://www.flickr.com/photos/plamen-stefanov/9558118957/)
The Shanghai oriental pearl tower (http://www.flickr.com/photos/plamen-stefanov/9558118957/#)
Title: Re: Is it flare, internal reflections or a ghost
Post by: surapon on September 23, 2013, 09:06:20 PM
These are reflections, could be internal...

+1

Great Engineer's Thinking, Dear Arjay
In my Idea, and It happend to me long time ago.  just 1 small reflective dust on the  front of UV. filter, that create the UFOs  on the dark sky for me. I hope that are the real UFOs, that I can sell to the Newspaper for millions Us Dollars.----Ha, Ha, Ha.
Surapon

OH-O-----I might wrong again---Sorry  "  just 1 small reflective dust on the  front of UV. filter, that create the UFOs  on the dark sky for me. "---Sorry for my Low tech of Photographic undestanding.
Title: Re: Is it flare, internal reflections or a ghost
Post by: Frodo on September 23, 2013, 09:11:03 PM
These are reflections, could be internal...

+1

Great Engineer's Thinking, Dear Arjay
In my Idea, and It happend to me long time ago.  just 1 small reflective dust on the  front of UV. filter, that create the UFOs  on the dark sky for me. I hope that are the real UFOs, that I can sell to the Newspaper for millions Us Dollars.----Ha, Ha, Ha.
Surapon

Dust on the filter would not cause "UFOs".  More likely dust on the sensor.  A filter will increase the chance of ghosts, a dirty filter will increase the chance of veiling (a lack of contrast).
Title: Re: Is it flare, internal reflections or a ghost
Post by: Pi on September 23, 2013, 09:19:21 PM
Dust on the filter would not cause "UFOs".  More likely dust on the sensor.  A filter will increase the chance of ghosts, a dirty filter will increase the chance of veiling (a lack of contrast).

In the OP case, those are reflections from the sensor reflected back by the lens. See this, for example:

http://www.fredmiranda.com/forum/topic/1120319 (http://www.fredmiranda.com/forum/topic/1120319)
Title: Re: Is it flare, internal reflections or a ghost
Post by: surapon on September 23, 2013, 09:41:34 PM
These are reflections, could be internal...

+1

Great Engineer's Thinking, Dear Arjay
In my Idea, and It happend to me long time ago.  just 1 small reflective dust on the  front of UV. filter, that create the UFOs  on the dark sky for me. I hope that are the real UFOs, that I can sell to the Newspaper for millions Us Dollars.----Ha, Ha, Ha.
Surapon

Dust on the filter would not cause "UFOs".  More likely dust on the sensor.  A filter will increase the chance of ghosts, a dirty filter will increase the chance of veiling (a lack of contrast).
Thanks you, Sir, Dear Frodo. Sorry, I make the mistake and Misunderstanding of the UFOs.
Surapon
Title: Re: Is it flare, internal reflections or a ghost
Post by: mackguyver on September 27, 2013, 11:06:45 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. 
Title: Re: Is it flare, internal reflections or a ghost
Post by: Skirball 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?
Title: Re: Is it flare, internal reflections or a ghost
Post by: mackguyver 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.
Title: Re: Is it flare, internal reflections or a ghost
Post by: Skirball 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.
Title: Re: Is it flare, internal reflections or a ghost
Post by: mackguyver 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.
Title: Re: Is it flare, internal reflections or a ghost
Post by: Sporgon 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.  :-[
Title: Re: Is it flare, internal reflections or a ghost
Post by: photonius 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.
Title: Re: Is it flare, internal reflections or a ghost
Post by: mackguyver 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. 
Title: Re: Is it flare, internal reflections or a ghost
Post by: Skirball 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.
Title: Re: Is it flare, internal reflections or a ghost
Post by: mackguyver 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 :)
Title: Re: Is it flare, internal reflections or a ghost
Post by: Skirball 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  :)
Title: Re: Is it flare, internal reflections or a ghost
Post by: WillThompson 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.

Will T.
Title: Re: Is it flare, internal reflections or a ghost
Post by: LetTheRightLensIn on September 27, 2013, 10:12:13 PM
Occam's Razor suggests ghost  ;) ;D
Title: Re: Is it flare, internal reflections or a ghost
Post by: photonius 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.
Title: Re: Is it flare, internal reflections or a ghost
Post by: brad goda 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...

Title: Re: Is it flare, internal reflections or a ghost
Post by: mackguyver 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.
Title: Re: Is it flare, internal reflections or a ghost
Post by: photonius on September 29, 2013, 05:38:25 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.
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.

If it really worked, I would be very interested to see a sample.