Red dot pattern on sun flare?

[Shawn Nelson]

I have not filed any Red support ticket because I'm not sure the nature of this problem.

Recently I took my Epic out and shot with the Canon mount and the 24-70mm f2.8L and whenever I flared the sun directly I would see a pattern of large red dots. I did not notice them on the LCD, only at home. I dont think I have a sensor problem, as shots after this not involving the direct sun are ok (or shots involving the sun lower in the horizon and not flaring out the lens are also ok). I've used this lens a ton on still cameras and never seen this. Or is it just an unfortunate intersection with this lens and how the Red OLPF likes to reflect? I do have Red's official flare thingie installed.

Watch these 17 seconds to see what I'm talking about, any thoughts are appreciated.
https://vimeo.com/57958865

 

[Nick Gardner]

That's a known issue, it's I believe a reflection off of the olpf. I am assuming you were stopped way down? Usually goes away with ND and a smaller stop/wider aperture.

Nick

 

[Mark Toia]

That's a known issue, it's I believe a reflection off of the olpf. I am assuming you were stopped way down? Usually goes away with ND and a smaller stop/wider aperture.

Nick

Dito...

Ive only seen it once in one of my shots several years ago.. had me scratching my head as well...

 

[Andy White]

Yes, this comes up every now & again - it's the OLPF and using lenses stopped down (ie F22 outside rather than ND).

Here was the last thread on it (2012) http://www.reduser.net/forum/showthread.php?72599-Weird-Red-Dots-Anybody-know-what-this-is - plus a link for the thread before that 2011 http://reduser.net/forum/showthread.php?65022-Red-circles

The flare guard doesn't stop this (it was introduced to stop the heavy gate flares that some users were getting).

 

[Shawn Nelson]

But I was only at f16, that's too much? I'd be really bummed to think that the camera itself cant handle an F16 sun flare.

Mark, what did you do? Just only flare the sun when you're f8 or more open?

 

[Bob Gundu]

F16 is considered high. As suggested, add ND's to open up the lens.

But I was only at f16, that's too much? I'd be really bummed to think that the camera itself cant handle an F16 sun flare.

Mark, what did you do? Just only flare the sun when you're f8 or more open?

 

[Shawn Nelson]

Ok, read more. Dang, so weird I never encountered this until now! I hope that Dragon doesnt have this problem

 

[John Marchant]

The circles are the shape of the photosites on the sensor I believe. Its been there since R1MX days. Can be sometimes be hard to avoid when the sun is directly in frame, depending on the contrast in the scene. Low sun with deep shade can provoke it.

 

[Andre W.]

I will agree with all posting that it is normal. It is the sun bouncing basically off of the sensor, back onto the OLPF then back to the sensor again. When you stop down your Iris, the light comes in at more of a direct angle, thus certain things start to become apparent, much like if you had dust in the lens or between the rear element and the sensor, you would start to see this show up as your iris becomes stopped down. The only way to stop this from happening in the future is ND and open up your iris.

And just so you know I have seen this happen on a vast range of cameras, not just these cameras.....

 

[Carlos Reyes]

I don't think this is exclusive to RED sensors either. Pretty sure I've seen the same thing on an iphone. I may be wrong though

 

[Brandon J.F.]

I don't think this is exclusive to RED sensors either. Pretty sure I've seen the same thing on an iphone. I may be wrong though

It's not. My cell phone camera does the same thing.

 

[Rob Macey]

Same here. Add ND and open up.

 

[Robert Ruffo New]

Alexa does the same thing.

 

[Jeff Kilgroe]

Alexa does the same thing.

All digital cameras with a low-pass filter or other structure in front of the sensor do this. They don't always look exactly the same, depends on what is in front of the sensor. Alexa and F65 OLPF flares look pretty similar to RED's.

 

[ian henry]

Is there any update on this topic or still an unavoidable issue?

 

[David Battistella]

Use the STH OLPF for best results in avoiding the "red dot" issue.

Also,

ND with larger apertures helps a lot.

David

 

[ian henry]

Thanks David

 

[Austin Reeves]

Just wanted to say thanks guys. I caught a slight red spot on a particular flare, wasn't concerned. Then shot another project with heavy sunflares and thought I had blown up a brand new sensor or something lol. Thanks for lowering my blood pressure a bit haha. As for the ND, I would have been using a Matte and ND, but been waiting for the rod mount to arrive.