White spot on sensor after pointing at sun.

3rd post was just saying he used 1/8000th of a second... not whether he was viewing and composing the shot using live view.
 
Canon Bob said:
I've just been trying to reproduce this and failed. I have an old film body (mirror taped up and the shutter curtains removed) that I use for finding the NPP of lenses using a laser. I popped on a Zeiss 85/1.4 and focussed at infinity and then put a piece of black paper where the film would be. I could see the bright spot focussed on the back of the paper to keep it positioned but couldn't get the sun to mark it let alone burn it.....30 seconds or so and it's bright and sunny here.
In the scenario described by Mark then the sensor/shutter curtains would have only been exposed to this for the very brief time that the mirror was up.... <1/100 second.

Bob
Click to expand...
Thanks for the effort Bob. We should take in consideration that I actually looked trough viewfinder to compose the frame, so shutter's curtain might be exposed for at least 5-10 seconds. Anyway, I will be able to inspect curtain and the sensor when I get home. I will make sure I add some macro of the affected area.
psenior1 said:
but he wasn't shooting video or using liveview, so it shouldn't be possible to fry a sensor in this way.

As said earlier, visually inspect the sensor with a loupe or torch and get in touch with Nikon...
Click to expand...
Will do!
 
MLse7en said:
Thanks for the effort Bob. We should take in consideration that I actually looked trough viewfinder to compose the frame, so shutter's curtain might be exposed for at least 5-10 seconds. Anyway, I will be able to inspect curtain and the sensor when I get home. I will make sure I add some macro of the affected area.
Click to expand...

If you could see through the viewfinder then the mirror was down and blocking the light path to the shutter curtains Mark.

Bob
 
Canon Bob said:
If you could see through the viewfinder then the mirror was down and blocking the light path to the shutter curtains Mark.

Bob
Click to expand...
This makes sense Bob, it is nice that our community has experts like you.
 
MLse7en said:
This makes sense Bob, it is nice that our community has experts like you.
Click to expand...
Thanks Mark.

Just to expand a little further....

The mirror is transmissive in that it allows about 40% of the light through and reflects the other 60% up into the pentaprism for the viewfinder. The central portion of the light allowed through the main mirror will then strike the sub-mirror and be reflected downwards to the AF sensors. This leaves the shutter curtains exposed to the light passing through the main mirror ( again, about 40% of the total) outside the region blocked by the sub-mirror assembly.

Bob
 
Wow this is a very interesting thread, I was going to ask how the mirrors/curtains worked.
from what @Canon Bob has said and looking at the location of the mark maybe a burn has occurred on the shutter curtain?

watching this thread with interest.
 
The test is easy: look at the image in live view. If there's no bright spot, it can only be the shutter.

It's unlikely that any shutter problem is related to the shooting the sun incident, just coincidence. Hard to imagine the sun would cause any damage in the situation described. If it is a mechanical problem with the shutter, it might be inconsistent.

Edit: super slo-mo of a Canon 5D2 shutter in action

 
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HoppyUK said:
It's unlikely that any shutter problem is related to the shooting the sun incident, just coincidence.
Click to expand...

I'm of the same opinion Richard, it would be a very widespread problem if it was that easy to damage the internals so quickly.

Bob
 
Indeed, it's hard to imagine how a steel or titanium shutter curtain blade could be damaged through exposure to direct sun for just a fraction of a second.
 
I must admit I doubt very much if the shutter is damaged as it would not give a spot like that any how it would be a smear effect as the shutter moves across the sensor.

I suspect the sensor or some filter has been damaged just enough so that when the ISO is being pumped up it is showing up.
 
Mr Bump said:
I doubt very much if the shutter is damaged ... I suspect the sensor or some filter has been damaged ...
Click to expand...
Well, the OP can test this with two series of experiments:
(1) Fix ISO and vary shutter speed.
(2) Fix shutter speed and vary ISO.
If the problem is with the shutter then test (1) will show it, eg bright spot at fast shutter speeds.
If the problem is with the sensor than test (2) will show it, eg bright spot at high ISO settings.
 
I bought a camera once that had a similar issue but mine was across the top edge, turned out to be a damaged shutter (looked like it closed on someone using a poor approach to sensor cleaning)

As odd as it appears, the result is as if you've burnt a hole in the shutter (although I can't imaging that happening) thus causing an over exposure in that area

to test, you'll probably find you'll get differing amounts of overexposure in that spot dependent on shutter speed used
 
Just out of interest was the camera on a tripod with the shot held in the same position for a while?
 
Mr Bump said:
Just out of interest was the camera on a tripod with the shot held in the same position for a while?
Click to expand...
The cameras was hand held. It was pointed at the sun for max 5-10 seconds, but again - shutter speed was 1/8000 and I was framing using viewfinder.
 
Ok guys, so the test shows:
1/500

1+500+f+1.9.jpg


1/15

1+15+f4.jpg


1 sec

1+f16.jpg


These are the pictures. And the test video:

 
Sensor appears fine on video... so looking like a shutter problem most likely.
 
And thses are the pictures of sensor and mirror.
1.
DSC_1714.jpg

2.
DSC_1715.jpg

3.

DSC_1716.jpg

4.
DSC_1722.jpg

5.
DSC_1724.jpg

6.
DSC_1725.jpg

7.
DSC_1726.jpg


So, if you guys have any thoughts I am open for your suggestions.
 
MLse7en said:
Ok guys, so the test shows:
1/500

1+500+f+1.9.jpg


1/15

1+15+f4.jpg


1 sec

1+f16.jpg
Click to expand...
If the problem is persisting with a 1 second exposure, then I can't see how it can be the shutter. In round terms that exposure consists of 1/250th when the shutter is opening, 1/250th when the shutter is closing, and 248/250ths when the shutter is fully open.
 
I think that your tests have eliminated the sensor or the shutter as being the culprit so a couple of questions;

Do you see the overexposed portion when viewing the shot on the camera's LCD screen?
Are these JPG's from the camera or processed RAWs?

Bob
 
Television cameras fitted with tubes were highly susceptible to burning if they were left pointed at the sun** but I've never heard of it happening with a stills camera.

** http://en.wikipedia.org/wiki/Video_camera_tube - see 3rd para. (A set of three replacement tubes used to cost around £5k on a broadcast camera).
 
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i can see "something" on pic 4 on the bottom left, remember it will (if i remember right) be inverted and flipped by the camera prism.
 
Canon Bob said:
I think that your tests have eliminated the sensor or the shutter as being the culprit so a couple of questions;

Do you see the overexposed portion when viewing the shot on the camera's LCD screen?
Are these JPG's from the camera or processed RAWs?

Bob
Click to expand...
Whenever I am framing a shot, there is no white spot neither in viewfinder, neither on LCD.
These are Processed RAWs from Nikon D5100
Ozei said:
Television cameras fitted with tubes were highly susceptible to burning if they were left pointed at the sun** but I've never heard of it happening with a stills camera.

** http://en.wikipedia.org/wiki/Video_camera_tube - see 3rd para. (A set of three replacement tubes used to cost around £5k on a broadcast camera).
Click to expand...
Article says that in can disappear in meter weeks. This doesn't quite work for, since I have some plans on shooting stuff with my camera, so at this point I would really love to have an idea of what I am dealing with, so I can plan my budget a bit more. I can imagine that a sensor replacement + work + delivery + collection can go up to 50%-80% of this camera's cost (£550).


RumpFace said:
i can see "something" on pic 4 on the bottom left, remember it will (if i remember right) be inverted and flipped by the camera prism.
Click to expand...

On a closer inspection there is nothing there - reflections are the same color all over the sensor and there are no blurry or somehow different spots.
 
It would be bottom right, not left.

Process RAW's.....you haven't left a radial filter active in the software that you use?

Bob
 
If you display the image on the cameras LCD is the circle there.
Sorry if this has been asked before.
 
Mr Bump said:
does it do it with another lens?
Click to expand...
Yes, it happens with all lenses. I tried zoom, prime, kit and one late 1960's lens made by soviets.
Canon Bob said:
It would be bottom right, not left.

Process RAW's.....you haven't left a radial filter active in the software that you use?

Bob
Click to expand...
No filters, that is just plane PS with auto WB and auto exposure tweeking.
I locked the mirror again and inspected the sensor once more, nothing on bottom right or any other corner. The same applies to the mirror.
 
This is the damnedest fault I've ever heard of. Stewart R is right.. the 1 second image rules out shutter.

As unlikely as it may seem that's it's sensor damage... it's time for Occam's Razor. It wasn't there before he took the first shot on page one with the sun in the top right. From then on, there's been a light blob in exactly the same place as the sun was in that shot. He's not using any processing that could have a radial filter set as a pre-set or action, and it also appears on very long shutter speed images thus ruling out a shutter issue.

ergo - it's a sensor issue. While everything I know is suggesting this is unlikely... in all seriousness... I'm left wondering what else it can be.
 
FlyingShrapnel said:
This might sound a little crazy but maybe worth a try, leave the battery out of the camera over night as a 'hard reset' for the electronics to see if any residual effects from being pointed at the sun would disappear?
Click to expand...
I left the camera overnight after the first day, it didn't go away.

Pookeyhead said:
This is the damnedest fault I've ever heard of. Stewart R is right.. the 1 second image rules out shutter.

As unlikely as it may seem that's it's sensor damage... it's time for Occam's Razor. It wasn't there before he took the first shot on page one with the sun in the top right. From then on, there's been a light blob in exactly the same place as the sun was in that shot. He's not using any processing that could have a radial filter set as a pre-set or action, and it also appears on very long shutter speed images thus ruling out a shutter issue.

ergo - it's a sensor issue. While everything I know is suggesting this is unlikely... in all seriousness... I'm left wondering what else it can be.
Click to expand...
At this point I have no clue either, so I am going to send it away and them hopefully get an explanation.
 
I think that's pretty much all you can do anyway. I think this thread exists just because we're all curious. Sending it away whatever the findings of this thread is still the only sensible outcome from all this now we've ruled out processing as a possible cause.
 
Sure is puzzling :confused: (& an interesting read)

Probably not related, but it seems like the mirror is quite `dirty` & wondered if that had any bearing. (is there an imperfection or tiny damage causing light refraction...?)

Good luck with it.
 
OldCarlos said:
Sure is puzzling :confused: (& an interesting read)

Probably not related, but it seems like the mirror is quite `dirty` & wondered if that had any bearing. (is there an imperfection or tiny damage causing light refraction...?)

Good luck with it.
Click to expand...


The mirror plays no part in the actual image making process... it's moved up and pressed firmly against the focusing screen when the shutter opens.
 
MLse7en said:
Article says that in can disappear in meter weeks. This doesn't quite work for, since I have some plans on shooting stuff with my camera, so at this point I would really love to have an idea of what I am dealing with, so I can plan my budget a bit more. I can imagine that a sensor replacement + work + delivery + collection can go up to 50%-80% of this camera's cost (£550).
Click to expand...

The usual method to attempt a fix on a television camera that had (sun)burnt tubes was this: set up a flat, non-reflective, brilliant white surface and light it with relatively powerful continuous lamps (e.g. 2kW Blondes) from close range. Point the camera at the white surface with iris wide open and lens defocussed. Leave it like this and check the tubes every 20-30 minutes. The idea was to 'out-burn' the burn. If, after several hours, the tubes had not recovered, then they would have to be replaced - this usually meant all three tubes, since on broadcast cameras they were in matched sets and they were only rated for a set number of hours anyway.

If the D7100 sensor is burnt (and we don't know if it is or not), then the same technique might work. I wouldn't try it though unless I was absolutely certain it's a burnt sensor. I fail to see how the sensor could get burnt by the sun in an 1/8000th of a second handheld. A TV camera would have to be left stationary (i.e. on a tripod) far longer than that to burn the tubes. The one I referred to in post 60 was left pointing at the sun for over 20 minutes - mind you it did wreck two of the three tubes.
 
Rob 80386 said:
A couple of things may have happened, either you burnt the IR filter on the sensor or the coating on the lens.
Click to expand...

It won't be the lens coating as all of the lens transmits light to every part of the sensor.

It's more likely damage to the filter layers in front of the sensor.

Pointing a camera directly at the sun is no different to using a magnifying glass on a sunny day to focus the sun into a spot to burn writing into a tree or to fry poor unsuspecting insects like we did at school.


Steve.
 
At about noon today, I took a shot using a CSC which included the Sun in shot. I was using a wide angle (18mm on a 1.5 x sensor) and the sensor hasn't suffered at all. (I've shot into the Sun quite often and never had any problems on any type of camera.)
 
Steve Smith said:
Pointing a camera directly at the sun is no different to using a magnifying glass on a sunny day to focus the sun into a spot to burn writing into a tree or to fry poor unsuspecting insects like we did at school.


.
Click to expand...

Have you tried this Steve?......I did (as described in post #37) and failed to burn anything with an 85mm lens.

Bob
 
Canon Bob said:
Have you tried this Steve?......I did (as described in post #37) and failed to burn anything with an 85mm lens.
Click to expand...

No... and to be honest, it doesn't sound likely with an 85mm lens as the sun would be too large an area. It could be a problem with a wide angle lens though, focusing the sun to a small dot.

It also doesn't sound likely with metal shutter blades or with a mirror covering the shutter all the time except when the shot is taken.

However, it was a problem for rangefinder cameras with cloth shutter curtains.

http://leica.nemeng.com/025b.shtml


Steve.
 
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