Topic: Lightning Streamer, reflection or digital internal reflections?

[Jimmy Deguara]

Here is the image. First the full size image, then just the left hand side cropped and lastly the suspect area zoomed in. Now I know that pretty much nobody will be able to say for sure what it is but note that if it was a reflection, it seems to stop abruptly at it's brightest point before the edge of the frame and the structure of the lightning that is visable doesn't resmble the suspect area in the slightest.








Jeff.

[Jimmy Deguara]

Hi Jeff,

Pardon my possible scepticism, although I am not sure, but I am thinking this may be a good example of reflection due to the picture being taken with an angled windscreen as you had suggested. We certainly cannot rule out the 3D lightning properties reflection. If this is the case, you have exposed a 3D effect of that particular lightning which is obviously unique and you would not have been able to do with the single image itself.

You suggested that internal reflection effects occur with video cameras which is absolutely correct. The variable that required to be non-existent was the windscreen. Internal reflection on video effects tend to be aligned in a similar orientation though somewhat displaced. The above example, if it was a reflection is in line with an angle reflection consistent with the angled orientation of the windscreen.

Any other thoughts?

Regards,

Jimmy Deguara

[Jeff Brislane]

I was lead to believe though that the effect that occurs specifically with video cameras is caused by ghosting within the camera itself and not due to an angled sheet of glass in front of it. That effect is as far as I know unique to video cameras and slr's have never as far as I know had the same problem. Also  note that my Rav-4 has a very flatly angled windscreen and I was point the slr up at the time so the glass in front of the camera is not really angled that much at all.

I have shot a lot of cg's through my windscreen and this is the first time i've ever seen something like what's present in the photos above. The photo below was the image before and the cg in it struck about 500m away just over the hill.



Jeff.

[Jeff Brislane]

Jimmy, maybe you could suss out some examples of video reflections to compare to the images above?

Jeff.

[Mike]

Jeff, well here's my two-bob's worth. 

Either it's a reflection off the main exit point from the top of the CG that has actually gone over your car also and out of your view and the camera has captured it from the bottom of the windscreen inverted.  The main stroke obviously goes out of sight over the top of you and the windscreen would have gotten the reflecton, as the bottom of the glass would be angled towards the rear view of your roof anyway.

The other theory is that you have in fact gotten what I view as 'incomplete leader vein that is heading for your car.  If you look closely you can see 2 leader veins along the top dissappearing into the background and at the very top of the faint line at the LHS it is actually heading toward or coming from the main branching toward the bottom.

I'm not an expert but my money is the latter.  If you were ever close to being struck then this would be it and you've captured a path in which the strike did follow through on...mmm I reckon you've caught something very, very rare and probably you'd be nanoseconds from the car being hit - it does look like it gets more in focus the closer it gets to you...


 Would you mind if i emailed the photo to a meteorologist friend for his interpretation?

Mike

[Jimmy Deguara]

Hi Jeff,

I guess you were there are the time and I was trying to act upon the information provided and provide a possibility of how features can occur. I agree and perhaps did not explain the fact that video camera "ghost" image is not what I was suggesting here. However, is it impossible to have internal reflection within the digital camera itself?

To me the feature does in fact looks remarkably similar in length and approximately in structure given the change in orientation. There was rain falling at the time so water film on the windscreen can indeed introduce some refraction. What makes my "possible" explanation at least something to condisider is the fact that the lightning was more overhead. Was it perhaps a reflection off the bonnet to the window and lens? You were pointing either more downwards or had a wider angle setting. There are far more variables to consider and given I was not there makes it difficult to make sense out of it all.

Regards,

Jimmy Deguara

[Dave Nelson]

I also believe its a out of position image caused by the camera I get them regularly when doing
lightning shots.  some times.... not always you can see the true position of that strike on a
preceeding or later frame  let me post a few examples.
  I see it so often now on my pics and other peoples pics  it has made me well aware that it is
a artifact created by the imaging system of the various cameras. 

  many of them look as tho they are within a few, 1 - 5, metres of me  and it happens regardless of
if I'm shooting through a window (eg car) or if I'm outside.

Wished I had got the true image of this part of the multipulse strike ... look at the fine filament
(branches) coming off it ... they werent visible in the subsequent frames


and


and


and  The red coloured long close strike is a "fore-image" of the main strike a couple of frames later
which was really several km away



and finally


you can see that the foreground strike has the same path shape as the true strike further away
the main strike was still close !!! within 1 km approx

cheers
Dave N

[Dave Nelson]

   It seems to be more prevalent with CCD imaging chips rather than with CMOS chips.
It isn't visible light reflections within the camera,  rather that the image is ....  for want of a
better word ....  bled back onto previous frames of the CCD chip prior to that frame being stored.
I have had it explained better to me .... hopefully you get the idea 

  the image is usually shifted out of place, horizontally or vertically but sometimes can be rotated.

I have yet to see it when doing still pix,  only when I have been doing movies.

cheers
Dave N

[Mike]

I still don't think it's a reflection of the main in picture strike.  Does not look anything like the one in the photo.  The 'ghost' or whatever it has a lot more twisting to it. A reflection off the bonnet?  Nope I have serious doubts about that.

 I'm of the view that if it is a reflection, it's from the unseen branching over the top of the car (if there was one) but like i said, the whole strike is not in the picture, the reflection through the windscreen would have picked that up for sure.

 I've taken the trouble to draw the 'ghost' and overlayed it onto the screen to see if it is similar. I've inverted, twisted, stuck it on sideways and that 'ghost' is not the original strike in the photo. theres just too many twists in the 'ghost', whereas the main pic is more defined and clean.


Mike

[Jimmy Deguara]

Mike,

I did suggest that there could have been something above the car as well. But as to almost being in the position to striking the car - not so.

You could be correct in regards to the reflection not breing the visible strike. I was trying to imagine a distortion based on a curved surface and a 3D tranformation rather than 2D.

Regards,

Jimmy Deguara

[Mike]

Oh no dramas with that, Jimmy.  Pity there was not more in the shot!  It's a good topic as I still have the drawing over the screen as I type - it's one of those things that you just have to nut out even if it kills you!  Still got me miffed though.  Even though the camera may have taken a reflection - just does not seem right for some reason. 

The colour of it would be the same definition would it not if it was a reflection?  If it's from the branching at the top, that's pretty well illuminated, so unless his windscreen is tinted (which i doubt) why is it dull?  If the branching at the top has kept its same thickness for part of the way which is out of shot, then why is the 'reflection' not reflecting that also?  You can see three faint veins running off the 'reflection' and the end one extends back toward the CGs tail - surely if it was a path that the current was taking but was an incomplete connection then what is captured is just that, no? 

 If we excluded the option of a reflection, then what other explanations we can deduce!

(jump in anyone else!!!)

Mike

[Jeff Brislane]

Dave,

This image was not shot with viedo. It is a still image taken with an slr (with a cmos sensor). the image reflection problem that occurs with digital has never in my knowledge been atributed also to slr's. Jimmy, even if you there you wouldn't be able to figure it out any easier. It happened instantaniously. The thunder was instant. The branching you see in the lightning above the ground is I believe very very close to me and could have been the main stroke if it had grounded first.

My reasons for believing it is is firstly it starts inside the edge of the camera frame, very unlikely with a mere reflection. secondly it's brighter at the ground and gets progresively weaker in intensity as it rises. Thirdly it doesn't resemble the branching above in any way. fourth, i've never heard or seen a reflection from a bonnet display so clearly in a photo like that. Fifth, it is realatively weak in illuminosity which would match the nature of a filament.

Jeff.

[Jeff Brislane]

I do recall that Nick recently shot a very close cg through a windscreen in rain. Perhaps we can find where it is again and paste it here?

[Jeff Brislane]

I found the shot by Nick Moir that he took this year of a very close cg through a windscreen or window with rain on it. Here it is.

Shot copyright of N.Moir.

[Mike]

Hello Jeff.  I still stand with my view that it's not a reflection - could be totally wrong - but it is electricity we're talking about!

PS - what's a cmos sensor?

Mike