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Monochrom unknown light spot


Elsu

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This kind of ghost images is created by light reflected by two planar surfaces ...

No, it is not. You are confusing several kinds of reflections. This kind, that is, ghosts of highlights within the frame, appearing as point inversions in the frame's center, has nothing to do with filters, cameras, or sensors. The glaring surface of a digital sensor can create a couple of issues indeed—but not this one.

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Then what's the cause of these spots? Is it reflections in the optics - or something else?

 

No, it is not. You are confusing several kinds of reflections. This kind, that is, ghosts of highlights within the frame, appearing as point inversions in the frame's center, has nothing to do with filters, cameras, or sensors. The glaring surface of a digital sensor can create a couple of issues indeed—but not this one.
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No, it is not. You are confusing several kinds of reflections. This kind, that is, ghosts of highlights within the frame, appearing as point inversions in the frame's center, has nothing to do with filters, cameras, or sensors.

You get this effect if you use a filter and it vanishes when you remove the filter. This evidence is good enough for me.

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You get this effect if you use a filter and it vanishes when you remove the filter. This evidence is good enough for me.

You get this effect when you use a filter and you get this effect when you don't use a filter. Just try it.

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Not always, I tried it: http://www.l-camera-forum.com/leica-forum/2166985-post54.html

 

So, what's your explanation?

No idea. Still, your odd exception is no proof that filters were the cause, because all lenses I know show the phenomenon without any filters, on film as well as on digital. Maybe the Telyt-V 280 mm 1:4.8, without filter, needs even more contrast to show the ghost. Or maybe it's just the exception to the rule. Every rule has an exception or two ...

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No idea. Still, your odd exception is no proof that filters were the cause, because all lenses I know show the phenomenon without any filters, on film as well as on digital. Maybe the Telyt-V 280 mm 1:4.8, without filter, needs even more contrast to show the ghost. Or maybe it's just the exception to the rule. Every rule has an exception or two ...

 

 

Thanks.

Hmm, I certainly have shown cause and effect for the Telyt-V 280 mm 1:4.8.

And there has to be a rational explanation based on physics, including for the strength of the effect.

I can certainly say, this particular "feature" is easily seen with the APO-R 280/4 but not with the Telyt-V 280 mm 1:4.8 unless there is a filter attached.

But this discussion belongs in another thread.

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Ever since the M8 and its peculiar filter requirements we have had a lot of these threads about exactly this phenomenon, and nearly every time a filter turned out to be the culprit. Unfortunately Elsu didn’t tell us if that was also true in this case (only that there was a filter involved).

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This kind of ghost images is created by light reflected by two planar surfaces, first by the cover glass of the sensor and then by a filter. While a planar surface within the lens itself can achieve a similar effect, the usual culprit is indeed a filter on the lens.

 

MJH is right. This is the argument for either ditching filters or ditching them at night.

 

Personally, I don't get bothered by this stuff. It's an optical effect and it kind of amuses me.

 

-jbl

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  • 4 weeks later...

Was a bit surprised the thread has turned out to be rather interesting :)

 

I had the filter on in all those shots. And as probably mentioned in OP, among the few thousands shots, those few shots are the only ones in which the light spots are noticed.

 

I have not tried to take off the filter and test anyway.

The only thing I want to make sure is there is nothing wrong with the camera sensor as such.

It is true that they are not difficult to deal with in Photoshop.

Given the turn-out rate, they don't really bother me much at all.

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