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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 :)

Internal ND filter for EPIC/SCARLET

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Medavoym

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Hi!

Is something like this possible for Epic?

http://www.fdtimes.com/2013/04/03/arri-alexa-internal-filter-module/

Especially with the Dragon coming up (2000 ISO!!!)

I think a single ND filter would suffice. Say ND0.9 or ND1.2

Use it in daytime to effectively reduce the ISO of the camera (in a way).
Take it off at night to go back to 2000.

Simple. A single internal ND filter would make a world of difference. No more crazy external NDs when shooting during the day. A regular ND set (0.3, 0.6 and 0.9) + a regular Hot Mirror.

Possible?


Mike
 
The Motion Mount also has the advantage of changing your Epic or Scarlet into a global shutter camera. So, it is a lot less expensive than buying a whole new camera.
 
How about a single internal ND filter which simply changes your EPIC/SCARLET from a daylight camera to a night camera? (from ISO 2000 with no filter to let's say ISO 400 with filter)

Exactly the same principle as in the Alexa link above.

It should be easy to install it above the sensor/OLPF.

The price would be much cheaper than the Motion Mount, which is a great product, but more complex than a simple internal (removable) ND filter.




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There was some talk a while back, by Jarred I believe, about a user replaceable OLPF with ND built in. Haven't heard anything about that in a while. The Motion Mount may be RED's solution for a behind the lens ND filter.
 
Larry McKee said:
There was some talk a while back, by Jarred I believe, about a user replaceable OLPF with ND built in.
Click to expand...

NAB 2011

IMG_2746-laperal-red-nd640.jpg


As I recall there was a problem with the ND and they scrapped the idea.
 
Brandon J.F. said:
NAB 2011

IMG_2746-laperal-red-nd640.jpg


As I recall there was a problem with the ND and they scrapped the idea.
Click to expand...


Would be great to revive this idea. Not everyone can afford the Motion Mount.
 
ericyoung said:
Would be great to revive this idea. Not everyone can afford the Motion Mount.
Click to expand...

Agreed.

I think we don't even need multiple filters (Alexa's solution), just a single, stronger ND to effectively knock down the ISO for day shoots.

On the other hand, I do remember Jim saying at some point that there won't be any penalty in going down the ISO with the Dragon sensor. Perhaps you can switch to ISO400 for daylight shoots and incur no f-stops loss on the high end.


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George A. said:
Agreed.

I think we don't even need multiple filters (Alexa's solution), just a single, stronger ND to effectively knock down the ISO for day shoots.

On the other hand, I do remember Jim saying at some point that there won't be any penalty in going down the ISO with the Dragon sensor. Perhaps you can switch to ISO400 for daylight shoots and incur no f-stops loss on the high end.


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Click to expand...

Lowering ISO doesn't change how much light is hitting the sensor. If it clips the sensor, you could be at ISO50, and it would still be clipped. It would just look darker on the monitoring.
 
I think the latest is that Dragon isn't losing to much latitude decreasing iso so maybe that's one reason together the motion mount why they dropped the project...
 
Any word if there will ever be a simple behind the lens ND Filter solution?

The problems I have with the motion mount:

1.) The motion mount can't have a 0-Stop ND filter option, so I'm always losing light :( There needs to be a clear setting. Otherwise this requires physically removing the mount and swapping it. This negates the whole point for quick run'n'gun work where you need to quickly swap the ND setting in a compact form factor.

2.) The motion mount means I'd need to use yet another adaptor to get to the canon FD mount... VS just buying a canon FD mount online to use vintage manual glass. The behind the lens ND mount should also standard separate from the lens mount and be usable with any mount.

3.) Cost is very prohibitive, though if options 1/2 were a non-issue than at least it would be a true solution!
 
Daniel Cegla said:
Any word if there will ever be a simple behind the lens ND Filter solution?

The problems I have with the motion mount:

1.) The motion mount can't have a 0-Stop ND filter option, so I'm always losing light :( There needs to be a clear setting. Otherwise this requires physically removing the mount and swapping it. This negates the whole point for quick run'n'gun work where you need to quickly swap the ND setting in a compact form factor.

2.) The motion mount means I'd need to use yet another adaptor to get to the canon FD mount... VS just buying a canon FD mount online to use vintage manual glass. The behind the lens ND mount should also standard separate from the lens mount and be usable with any mount.

3.) Cost is very prohibitive, though if options 1/2 were a non-issue than at least it would be a true solution!
Click to expand...

Cheapest and fastest solution may be a variable ND. About $500 for a good one. I have the Singhray version and works very well.
 
Bob Gundu said:
Cheapest and fastest solution may be a variable ND. About $500 for a good one. I have the Singhray version and works very well.
Click to expand...

But that is a per-lens solution, yes? I often rotate between 3-5 different primes, and don't have the time to swap the filter between each lens (quick lens changes on field).
 
There are not only the electronic shutter thing that differ between motion mount and sticking glas between the lens and sensor on the normal mount...

Me guessing that the motion mount has an altered flange distance compared to "open mount" that would compensate for the extra glas. So basically if you would put a little square bit of glas behind the lens infront of the sensor you would probably need a new mount that took that into account or adjust your back focus quite a bit, probably out of range. Or you would need to have clear glass in there to compensate when not using the filters. So basically (I think) behind the lens ND's would demand a 3rd kind of mount or you would need to run with extra glas infront of the sensor at all times. Possibly they could do a mount that was used skimmed when using filters and then you could take the filter and skimming away when wanting to shoot clear. But that would mean you would need to remove the mount each time you wanted to remove the filter... do not think that would be so good practice. The motion mount is possible to take off but I do not think people will rip it on or off a few times a day. Such situation would easily occur with behind the lens filters.

If there was an easy solution to put ND or any other filter behind the lens without loosing back focus then I think if not RED somebody would all ready be selling them.
 
Encouraging users to field-swap the OPLF was never really a goer and would have been asking for trouble. There are enough howling kids in this backyard already without giving them something to really howl about. Speck removal off the sensor itself is not for the faint-hearted. In anything less than a clean room, whilst not impossible, the task is, let us say, somewhat of a genuine challenge to get right. There is also the IR contamination issue. Here is a really rough and ready suggestion that is full of compromises. If camera filter gel material can still be obtained, a tidily cut piece of that stuff, wedged snugly in front of the OPLF might do the trick. A round piece of 3-stop Lee lighting gel which is not optically accurate, tucked into the space behind the lens on the SI2K did not munt the image beyond all recognition. The puzzle was cutting out a perfect circle without scratching or fingerprinting the gel surfaces. It is a more critical issue for cameras with smaller sensors than Red users enjoy. Internal reflection can be an issue. If film-camera operators without the benefit of WYSIWYG were able to live with behind-the-lens gel filters, then a simple little wedge-in filter gel holder should not be such an impossible solution. Let's face it. Except for making their zoom lenses work properly, how many people are meticulously resetting mount backfocus or having their lenses collimated to a common mount position. There exists probably more collimation error already than a skinny piece of filter gel will introduce. The solution for collimation error for behind-the-lens filters is dead easy. Always have a gel in there even if it is clear and reset back-focus to accommodate any error that a gel filter in the path introduces. - Sorry for being such a pedant and as always, please heed the advice of those more qualified than I to comment.
 
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It's not the fact that the Motion Mount is always 'on' that you lose light, it's the LCD in it that does that. Even when off, you're gonna lose light. Same as Tessive.
 
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