Jump to content




Photo

Sony F65 Highlight Bloom?


  • Please log in to reply
7 replies to this topic

#1 Christopher Purdy

Christopher Purdy

    New

  • Basic Members
  • Pip
  • 7 posts
  • Cinematographer
  • Los Angeles

Posted 03 February 2016 - 09:35 PM

Has anyone else noticed an unusual blooming in highlights and hotspots on the F65?

 

In general, I think the F65 is an incredible and sorely underused camera. I've just shot some over/under tests against an Alexa, and it was remarkable to me how well it holds its own. The Alexa might be giving me an extra stop in the highlights, but the resolution on the F65 is far more detailed than anything I've seen from a 4K bayer camera, and unlike its younger brother, the F5/55, that awful chroma noise is virtually nonexistant. 

 

But I just can't seem to figure out what's causing this glowing effect. Swapping the lenses and clearing the internal filters didn't change anything, so it's either something in the optical sensor stack or crosstalk from clipped photosites. I'm wondering if it's specific to the unit I was testing, or if it's something other people have noticed as well...

 

 

 


  • 0




#2 Mark Kenfield

Mark Kenfield
  • Basic Members
  • PipPipPipPip
  • 712 posts
  • Cinematographer
  • Melbourne, Australia

Posted 03 February 2016 - 09:43 PM

Chris, can you post comparison images from the tests that show where the F65 blooms and the Alexa doesn't? I can't say I've encountered blooming with any camera that seemed to be occurring on a sensor level, rather than as an optical artifact.


  • 0

#3 Satsuki Murashige

Satsuki Murashige
  • Sustaining Members
  • 3081 posts
  • Cinematographer
  • San Francisco, CA

Posted 03 February 2016 - 09:56 PM

Has anyone else noticed an unusual blooming in highlights and hotspots on the F65? 
 


I haven't noticed this, but then I usually want highlight halation with the F65 so I usually add diffusion. I'll see if I can find some clean frames when I get home tonite.
  • 0

#4 Christopher Purdy

Christopher Purdy

    New

  • Basic Members
  • Pip
  • 7 posts
  • Cinematographer
  • Los Angeles

Posted 03 February 2016 - 10:19 PM

Here's a link to a gallery of some stills from my tests. You can click and then click again to see the full res.

 

http://postimg.org/gallery/11h14e8i8/

They are labeled as Alexa and F65, rated at 400, 800, 1600ASA respectively, at normal exposure for those EIs. No other over or under exposure beyond rating the sensors differently.

 

I can upload some of the overexposed stills as well, but even in these you can see a glaring difference (no pun intended) especially in the 1600ASA frame where the slate catches a glint of the light source.

 

Again, since we could see this on the monitor during testing, lenses were swapped, and the internal clear filter was removed to try and get rid of the blooming, but neither of those things helped mitigate it.

 

The lamp was not panned directly at either camera, but at the ground in between both, and these tests were shot side-by-side simultaneously.

 

These are in Log C and SLog3, but the bloom is even more apparent in 709.


Edited by Christopher Purdy, 03 February 2016 - 10:22 PM.

  • 0

#5 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 18789 posts
  • Cinematographer
  • Los Angeles

Posted 03 February 2016 - 11:05 PM

That's pretty unusual, I don't think that's normal for the F65.  Maybe the OPLF got dirty...


  • 0

#6 Satsuki Murashige

Satsuki Murashige
  • Sustaining Members
  • 3081 posts
  • Cinematographer
  • San Francisco, CA

Posted 04 February 2016 - 05:05 AM

Yeah, I think you've got a dirty OLPF or possibly some condensation issues in there. This is an F65 frame below with only ND filtration, scaled down from 4096x2160. You would expect to see halation on the bright exterior or the overhead fluorescent if your results were normal.

 

Rentals_Frames_05.jpg

 

 

And just for reference, here's another angle from the same scene with a Hollywood Black Magic diffusion filter. This is the amount of halation you would expect to see with this filter.

 

Rentals_Frames_11.jpg


  • 0

#7 Christopher Purdy

Christopher Purdy

    New

  • Basic Members
  • Pip
  • 7 posts
  • Cinematographer
  • Los Angeles

Posted 04 February 2016 - 12:27 PM

Thank you David and Satsuki, I think that clears up that it's definitely not normal for the camera, and is an issue with this particular unit's optical block. I'll talk to the tech about it and see if I can figure out what's going on.


  • 0

#8 Ben Rowsell

Ben Rowsell
  • Basic Members
  • PipPip
  • 13 posts
  • 1st Assistant Camera
  • New Zealand

Posted 04 February 2016 - 08:46 PM

I've seen this on an F65 before. The DOP liked the way the camera/lens combo flared/bloomed in testing so we went with that package. Nobody thought too much about it until we got an additional 3rd party body in and it didn't flare in the same way.

 

The conclusion was that the original camera bodies had previously been used on a show that had very high levels of oil based smoke FX. Over time the air filters in the front of the camera had become clogged and allowed oil to pass onto the optical block and leave a film of residue over the glass in front of the sensor.

 

We left it for the rest of our shoot (as per DOPs request), but after the movie the optics were cleaned and filters replaced, and the image went back to "normal" I guess that the issue hadn't been picked up on the previous show as it had happened gradually over a period of time towards the end of the shoot.

 

Ben R

1AC

NZ


Edited by Ben Rowsell, 04 February 2016 - 08:49 PM.

  • 0


Rig Wheels Passport

CineTape

Tai Audio

rebotnix Technologies

Aerial Filmworks

Abel Cine

Glidecam

Willys Widgets

Zylight

Paralinx LLC

The Slider

Visual Products

Ritter Battery

Broadcast Solutions Inc

Pro 8mm

CineLab

Technodolly

Glidecam

Willys Widgets

Visual Products

Tai Audio

CineLab

Abel Cine

Zylight

The Slider

Technodolly

Aerial Filmworks

rebotnix Technologies

Ritter Battery

Broadcast Solutions Inc

Paralinx LLC

Pro 8mm

Rig Wheels Passport

CineTape