weird white artefacts with D500 : sensor problem ?

<p>Dear all,<br>

I experience on some shots (not only with backlight) some weird white points or patterns on pictures taken with the D500, either with the 200-500 or the 80-400.<br>

This only appears on some pictures and seems completely random.<br /><br />A part of it may be flare, but there is something that definetely does not look like a lens problem (all the more as it appears with 2 different lenses). Where do those white patterns come from ?<br>

How to avoid it ?<br>

Have any of you experienced the same problem ?</p>

<p><a href="https://www.dropbox.com/sh/buxrrvpvpgsbjkk/AADr5G465UhJUJs7s9xJpWfUa?dl=0"><strong> </strong></a><br>

<a href="https://www.dropbox.com/sh/buxrrvpvpgsbjkk/AADr5G465UhJUJs7s9xJpWfUa?dl=0"><strong>https://www.dropbox.com/sh/buxrrvpvpgsbjkk/AADr5G465UhJUJs7s9xJpWfUa?dl=0</strong></a></p>

<p>Thanks for your help</p>

<p>Didier</p>

<p>I would bet at least some of them (in photos of the child) could be simple dust particles suspended in the air and illuminated by the bright sunlight shining in the window behind the child. The Web site below discusses this phenomenon. </p>

<p>http://webpages.charter.net/bbiggers/DCExperiments/html/spots_.html</p>

 

<p>probably not a lens or dusty sensor issue since the spots appear in different locations and are different sizes. flare has different characteristics and created bigger rings. does it also do this in non-backlit photos?</p>

Dust particles suspended in

the air nearly always look

like unfocussed blobs. These

look much more like hot

pixels.

 

The shot of the eagle in

particular has me puzzled.

Are you using a filter by any

chance? If so try removing

it.

 

I'd also suggest shooting

some tests of blank frames -

lens cap on. If those still

show spots then check the

position of the spots from

frame to frame. Hot pixels

will always be in the same

place.

Addendum.

 

I once used a demo of an

image processing program that

would create random coloured

spots on the picture.

Needless to say it was

quickly discarded. However

it's another possibility.

<p>Dear all,<br>

to answer your questions l:<br>

1) same results with different lenses (80-400 and 200-500, the latter had no filter on it)<br>

2) the pb looks quite random, as the white spots are not always at the same place !<br>

3) some of the shots are not back-lit<br>

4) for quick imports of pictures I use Apple Photo</p>

<p>Thanks for your input !</p>

<p>Didier</p>