OPLF Change in construction pls.

[Martin Preiss]

I encounter this kind of problem:

As you have life flames (torch or fire) in front of camera, you have reflection of it in picture as well. (Upside down) As I think this is done by reflecting high brightness in picture by OPLF filter back to lens and then back to sensor. (No filters in front of camera, not even IR)

As it happens in both cameras we have on different lenses. Still both on Zeiss UltraPrimes - small possibility that ALL Zeiss lenses due their age are not enough coated in back element of lens. But I believe more, that due to cost of the camera body, the OPLF filter is not coated well for anti-reflection in inner part (PL mount to OPLF).

My suggestion is to ANGLE OPLF filter in 45degrees (or different) to avoid any of those reflection. As this is only "suggestion" I will be more than happy to hear a opinion from RED Team. This "HW Bug" is annoying in night shooting with flames, candles etc...

(I still can be wrong and will be happy if somebody will proof me wrong or give me suggestion to avoid that)

 

[Michael Lindsay]

I believe the 'nearly in focus' 'similar in size' reflections that trouble the Red camera with very hot highlights must be the OLPF..

1: the reflections (double images) are nearly in focus and size similar (to the originating image) this suggests to me that they could not be the product of the lens rear element. Panning the camera and watching the image also tells me that it must be coming from a very close (to sensor ) surface.

2: I shot a hair promo last week with some Dino in shot. I did a little research before hand to find similar material shot on Red. I found a music video with a very similar shot. This film contained no problematic flare (ones I can't use). However only after the first days shoot did I realsise the music video was probably shot with a pre 100x camera and I would have to struggle on tweaking every shot to avoid the problematic double images/flare.

On the other hand!!!

I have never with a Red suffered with dust on the sensor. This problem plagues DSLR cameras if used for motion (unless they employ new vibrating sensors).

On balance (despite cursing Red for 15mins on the last job) would rather have to deal delicately with hot in shot light sources than be plagued with 'ruined by dust footage'.

Hopefully with Epic a vibrating sensor could be employed and the OLPF can be placed back flush on the chip. (or some other technique that I haven't thought of)

regards

Michael Lindsay

 

[Florian Stadler]

without seeing a frame it is hard to tell but its unlikely to be caused by the olpf. Since the flare is upside down I would venture to guess that it must have occured in front of the optical center of the lens. The front element would be my prime suspect. This type of thing will happen on any shooting format.

 

[Michael Lindsay]

My recent problems are not upside down... or I do not know if they are since the light sources are symmetrical about the horizontal axis..

I'll double check the footage...

M

 

[Dylan Macleod CSC]

I have spoken others who have also experienced this "ghosting" with no filters.

I think there have even been posts with photos.

This is definitely a problem and I hope RED is working on a fix.

From what I understand you need a lens with a fairly large and flat back element to get this kind of ghosting.

Dylan Macleod
Cinematographer
Toronto, Canada
www.dylanmacleod.com

 

[Ariana]

I've had the same thing happen to me on film also. A good example of this is in the USO scene scene the helicopter lands in apocalypse now.

 

[David Wyatt]

Don't these things happen on film too...some people call them "tinker-bells"?? Can happen with or without filters...ghost images of light sources, particularly candle flames...varies from lens to lens...Cooke S4s are pretty masterful in handling such things with their superior, top secret anti-flare coatings :matrix:

Nowhere near as bad as the reflection of the sensor onto the OLPF and back again onto the sensor that I assume the following images demonstrate (although this is not exclusive to just the Red camera):

http://www.reduser.net/forum/showthread.php?t=15347&highlight=olpf

 

[Martin Preiss]

Actually it happens as very focused ghost image or as purple flare in bottom of frame. Both I believe is reflection from OPLF. As they are very strong and straight.

 

[Brent J. Craig]

... the music video was probably shot with a pre 100x camera and I would have to struggle on tweaking every shot to avoid the problematic double images/flare.

I can tell you for certain that before they moved the OLPF the upsidedown flares were much worse. We shot a fireplace on one of the pre-100X cameras and the double image was quite surprising.

 

[Cail Young]

Still both on Zeiss UltraPrimes - small possibility that ALL Zeiss lenses due their age are not enough coated in back element of lens. But I believe more, that due to cost of the camera body, the OPLF filter is not coated well for anti-reflection in inner part (PL mount to OPLF).

Had the same problem with a Zeiss 12mm MkII - IMHO it's a combination of the OLPF and poor (or no) anti-reflective coating on the back element of the lens.

 

[Michael Lindsay]

I can tell you for certain that before they moved the OLPF the upsidedown flares were much worse. We shot a fireplace on one of the pre-100X cameras and the double image was quite surprising.

Thanks for that info... it does leave me wondering why I don't see these problems on my Canon DSLR??

I'm not sure if we are all talking about the same thing??

more testing for me!:detective2:

 

[Ariana]

Motion makes it more apparent. It happens on still cameras but it's not as easy to spot.

 

[Mike Prevette]

It happens on almost all cameras. I just watched the latest Batman last night and it was visible in a ton of the shots. Pretty much any old movie with car headlights in them have versions of this effect displayed.