bmpcc 6k film plane mark

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mimimilus

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bmpcc 6k film plane mark

PostTue Aug 18, 2020 8:30 am

Hey!
My camera did not came with the film plane mark. Which would be no problem, because I want to put a screw on my rig where the tapemesure can hang from.
But sadly, I did not found any information about where the sensor is located...
So if you know. Can you tell me in milimeters how far is it back from the front of the lens mount?
I would highly appreciate it. Thank you in advance. :)
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GalinMcMahon

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Re: bmpcc 6k film plane mark

PostFri Oct 08, 2021 4:06 pm

Bump. It is crazy that there is no mark for this. Someone said to measure back 19.25mm from the front inside of the lens mount but didnt specify whether it's the metal mount or the plastic part with the connectors. This is a critical measurement for focusing so I am baffled as to how BM didnt print this standard mark.
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John Griffin

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Re: bmpcc 6k film plane mark

PostFri Oct 08, 2021 8:22 pm

GalinMcMahon wrote:Bump. It is crazy that there is no mark for this. Someone said to measure back 19.25mm from the front inside of the lens mount but didnt specify whether it's the metal mount or the plastic part with the connectors. This is a critical measurement for focusing so I am baffled as to how BM didnt print this standard mark.

EF focus plane to lens flange in 44mm. Not sure why you need this on a digital camera for focusing when you have a live feed from the sensor?
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cj-adams

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Re: bmpcc 6k film plane mark

PostTue Oct 04, 2022 1:27 am

Actually.....there is one new very good reason to have this information....in some cases we are now using 3d Lidar systems to actually do live autofocus with these cameras on gimbals like the DZjI RS3 Pro...and they require the measurement from the focal plane to the front of the lidar unit for calibration!
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dsbnola

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Re: bmpcc 6k film plane mark

PostMon Nov 07, 2022 7:40 pm

Yes, I'm trying to figure out this as well so I can use the Lidar system with DJI's Ronin RS 3 pro gimbal stabilizer. Any help would be appreciated!
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Mark Foster

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Re: bmpcc 6k film plane mark

PostMon Nov 07, 2022 8:53 pm

https://en.wikipedia.org/wiki/Flange_focal_distance

6K, 6K G2, 6Kpro = EF = 44mm
4K = MFT = 19,25mm


focal-flange-distance-4.jpg
focal-flange-distance-4.jpg (81.14 KiB) Viewed 8072 times

©brian smith
https://briansmith.com/flange-focal-distance-guide/




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cjadams

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Re: bmpcc 6k film plane mark

PostMon Nov 07, 2022 9:03 pm

Mark Foster wrote:https://en.wikipedia.org/wiki/Flange_focal_distance

6K, 6K G2, 6Kpro = EF = 44mm
4K = MFT = 19,25mm

I think i did it right - Well i think i did it right.. I basically did what support said..
Started at the metal mount and then subtract 35mm Should be the focal plane...- then add or subtract depending on if your in front of or behind that point.


focal-flange-distance-4.jpg

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https://briansmith.com/flange-focal-distance-guide/




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cjadams

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Re: bmpcc 6k film plane mark

PostMon Nov 07, 2022 9:04 pm

Mark Foster wrote:https://en.wikipedia.org/wiki/Flange_focal_distance

How did you end up with 44?

6K, 6K G2, 6Kpro = EF = 44mm
4K = MFT = 19,25mm


focal-flange-distance-4.jpg

©brian smith
https://briansmith.com/flange-focal-distance-guide/




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kgilchrist21

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Re: bmpcc 6k film plane mark

PostThu Dec 15, 2022 3:09 am

Any confirmations? I've following the convo because I too have the LiDAR Range Finder on the RS3. I have the BMPCC 4K, and determining where to calculate the focal plane, to the end of the LiDAR has been a guess. I've left it at the default of 75mm (2.95 inches), but I don't REALLY know if that's accurate.
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carlomacchiavello

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bmpcc 6k film plane mark

PostMon Dec 19, 2022 10:21 am

Do you have lenses with backfocus control?
Are you sure that focus distance on lenses are exactly what you measure on real world.
With exception of expansive cine lens and broadcast lenses, classic lenses not are so perfect on focus metering, then to setup linear autofocus is better to do visual (monitor) control of focus and distance recorded.
With a friend of mine we tested many lenses (L series) with rs3 and lindar system and everyone give us a small (mm) difference, but enought to go out of focus when you are close to a subject.


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Uri1977

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Re: bmpcc 6k film plane mark

PostMon May 15, 2023 10:49 am

Any solution for this...? We need this distance to be put in the RS3 Pro...

Best regards, Uros
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Howard Roll

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Re: bmpcc 6k film plane mark

PostTue May 16, 2023 9:13 pm

Uri1977 wrote:Any solution for this...? We need this distance to be put in the RS3 Pro...

Best regards, Uros


Why? It’s already been answered a couple times. MFT=19.25mm, EF=44mm. The flange depth is the (corrected for ND, IR) distance from the mount face to the sensor if it is still unclear.

Good Luck
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roger.magnusson

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Re: bmpcc 6k film plane mark

PostWed May 17, 2023 9:44 am

They did add a marker for the sensor plane to more recent camera bodies, the 6K Pro and 6K G2.

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