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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Focus assist on DSMC2

Mar van de Sande

Mar van de Sande

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Hello REDuser users :)

i have a bit of a problem with the current focus checker. i work a lot in dark environments where i need to handle quick and with the current focus checker i can't really see if i'm in focus or not.
is it possible for the next update to include a focus assist with a red or other color that shows the in focus objects?
 
Have you tried using Edge focus?
 
Edge focus in low light doesn't work that well. Especially is you lose focus, it can get totally dark. For now, I would suggest getting an external monitor with this feature. The color focus assist has been requested for a while now and no one said if its in the works or not.
 
Fabricio Morato said:
Edge focus in low light doesn't work that well. Especially is you lose focus, it can get totally dark. For now, I would suggest getting an external monitor with this feature. The color focus assist has been requested for a while now and no one said if its in the works or not.
Click to expand...

Yeah, it's pretty disappointing that we are forced to use an external monitor for such a basic feature that is found in $99 monitors, but not a $2500 RED monitor.
This issue has been brought up so many times over the years here and RED has never commented on why they they don't add it in. Maybe we need to get in touch with Trammel at magic lantern to make it happen hahahah
 
It might be possible for a module connected on the back of the Brain to perform (a different implementation of) edge detection.
Sending a low resolution video signal over wireless 802.11g would be to too laggy and too low res..

Canon : I think their engineers had been iterating their their DryOs to get face & edge detection to work with a lower CPU overhead (with 'acceptable' lag).

ML : To get super high frame rate edge detection, I think someone hand-coded and hand-optimsed a thousand line routine in pure assembler, and then stored the code directly in the ARM instruction cache.... Not something that would be ideal in a RED code base that changes frequently.

http://magiclantern.wikia.com/wiki/2.0.4_AJ

AJ
 
Antony Newman said:
ML : To get super high frame rate edge detection, I think someone hand-coded and hand-optimsed a thousand line routine in pure assembler, and then stored the code directly in the ARM instruction cache.... Not something that would be ideal in a RED code base that changes frequently.
AJ
Click to expand...

Can you elaborate on how frame rate effect edge detection? And I wouldn't necessarily consider 300fps super high frame rates either, thats pretty tame considering there are A trillion FPS cameras :) lol.
Perhaps I am missing something but with the computing power of RED's, I find it very hard to believe that colored focus assist isn't possible because it's a technological road block, when my $99 cinemartin monitor has it at any frame rate.
If i am not mistaken, the RED One had it when it first launched. Then it disappeared once the new bodies came out.
 
Cameron,

+) The more complex the edge detection -> the more calculations per processed pixel.
-> As simple edge detection may involve checking the Greyscale (luma) value of a pixel with each of the surrounding 8 pixels
-> More advanced algorithms can attempt to dynamically adjust this in 'low contrast' areas (but with a higher CPU cost)

+) The higher the frame rate (of displayed edge detection image) -> the proportionally greater the number of pixels processed

Arbitrary Example (with approximate maths)

If 8 maths operations were required per pixel, on a 32 Megapixel image at 4 fps
32 Million x 8 SUBTRACT operations = 32,000,000 x 8 x 4 fps = 1 Billion Operations a second (1 Ghz of Maths operations)

If this was done in a CPU, it would already consume a lot of power.
It would also create considerable memory contention (with other critical processes).
With hardware assistance, this could be reduce, but other compromises make be used to reduce the overal burden on the system.

I can't offer insight as to what RED have decided is a priority for real-time processing, but do note that edge detection can eat into a systems resources (especially if adaptive contrast detection are desired).

AJ
 
interesting technical discussions but it still doesn't explain why my $99 monitor from eBay has focus peaking and my $30,000 red camera does not

I think one of the issues is these cameras are now being used in ways that we didn't think they would like running gun and documentary
 
I would also love a better focus peaking.
Operating with 5" or 4.7" RED touch display can be really difficult.
But maybe I'm getting old ;-)
 
Antony Newman said:
Cameron,

+) The more complex the edge detection -> the more calculations per processed pixel.
-> As simple edge detection may involve checking the Greyscale (luma) value of a pixel with each of the surrounding 8 pixels
-> More advanced algorithms can attempt to dynamically adjust this in 'low contrast' areas (but with a higher CPU cost)

+) The higher the frame rate (of displayed edge detection image) -> the proportionally greater the number of pixels processed

Arbitrary Example (with approximate maths)

If 8 maths operations were required per pixel, on a 32 Megapixel image at 4 fps
32 Million x 8 SUBTRACT operations = 32,000,000 x 8 x 4 fps = 1 Billion Operations a second (1 Ghz of Maths operations)

If this was done in a CPU, it would already consume a lot of power.
It would also create considerable memory contention (with other critical processes).
With hardware assistance, this could be reduce, but other compromises make be used to reduce the overal burden on the system.

I can't offer insight as to what RED have decided is a priority for real-time processing, but do note that edge detection can eat into a systems resources (especially if adaptive contrast detection are desired).

AJ
Click to expand...

That sounds really impressive and technical. What it sounds like is we should all be giving Cinemartin a round of applause for accomplishing something at a $99 price point when RED is unable to do it at any price point.

While the camera may be recording higher frame rates, the action is still happening in real time and the monitoring is still happening in real time.
Sorry AJ, I just don't buy it that a $30,000 cinema camera doesn't have the technological ability to do colored focus peaking when it already has that silly over-sharpening feature. Just make it a color, done.
 
You may have a point.

My guess is that dedicated screens companies bought IP Blocks to perform Sobel (or other) edge detection in hardware (ie in an ASIC).
My guess would also be that RED have carefully constructed an implementation of Edge Detection in a 'programmable logic array' (FPGA).

FPGAs are much faster & efficient than CPU, but still consume a lot more electrical power (and are slower) than ASICs.
There is also a limited amount of space within a FPGA that may been to be dedicated to other (more critical logic).

FPGA-vs-ASIC-small.jpg



Perhaps post IPP2 rollout, reclaimed FPGA space could be used to implement a more capable Edge detection algorithm or 1:1 magnify-loupe-while-recording.

AJ
 
The edge focus check currently is helpful, but most of the time it takes me out of the scene just seeing black and white edges, this to me is perfect for the AC to get spot on focus, but not at all for contextual framing of moving subjects for a DP, and yes when in darker scenes it just doesn't show up at all. Alternatively the regular focus check is the other option to use but it is quite hard to see when outside in the sun and just isn't very easy to see. A colored peaking version with and intensity adjustment like the one my cheap monitors and stills camera have would be pretty awesome Red. Not sure why it hasn't been mentioned or implemented by now, I have also seen tons of people ask about it.
 
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