- Posts: 55
- Joined: Fri Sep 22, 2017 3:04 pm
- Location: Germany
Hi,
I am trying to figure out the best (most reliable) way to remote control the aperture of EF-lenses mounted on the BMPCC 6K.
The developer manual gives us three options:
Source: https://documents.blackmagicdesign.com/ ... ontrol.pdf
While using the great BlueMagic32 Library (https://github.com/schoolpost/BlueMagic32) you are going to control the aperture via ID 0.3
source: https://github.com/schoolpost/BlueMagic ... roller.cpp
This way controls the aperture by sending values from 0-1.
Unfortunately the aperture on EF-lenses is not stepless, so it is not easy to figure out which value to send to get to the next valid value.
Reading about ID 0.4 I thought this might be an easy way to cycle through the available apertures by sending values from 0 to n.
So I added some code to the library files (the .cpp and the .h files).
It seemed to work out of the box, but...
Unfortunately my Sigma 8-16mm (not the best, but the widest...) seems to pretend to have more valid aperture values, as it really does. The BMPCC 6K (and the BLE Controller) shows new "in between" values, but you can clearly heare that the aperture in the lens has not moved. There is also not change in the histogram.
A few questions...
Has anyone noticed the same issues?
Has anyone found a good solution?
Has anyone tried to control the aperture via ID 0.2? (I guess I will try this soon.)
And one small disclaimer...
I think this could be a completely different story at the BMPCC 4K, as M43 lenses can change their aperture almost stepless. (Even though most camera bodies do not support this. I could proof this on a GH5S via Wifi.)
Thank you,
Chris
I am trying to figure out the best (most reliable) way to remote control the aperture of EF-lenses mounted on the BMPCC 6K.
The developer manual gives us three options:
- BMD-Aperture.jpg (38.58 KiB) Viewed 1363 times
Source: https://documents.blackmagicdesign.com/ ... ontrol.pdf
While using the great BlueMagic32 Library (https://github.com/schoolpost/BlueMagic32) you are going to control the aperture via ID 0.3
- Code: Select all
void BlueMagicCameraController::aperture(float value)
{
if (value < 0 && value > 1) //BTW: This line does not make sense to me.
return;
uint16_t val = mapFloat(value);
uint8_t xlow = val & 0xff;
uint8_t xhigh = (val >> 8);
uint8_t data[10] = {255, 6, 0, 0, 0, 3, 128, 0, xlow, xhigh};
source: https://github.com/schoolpost/BlueMagic ... roller.cpp
This way controls the aperture by sending values from 0-1.
Unfortunately the aperture on EF-lenses is not stepless, so it is not easy to figure out which value to send to get to the next valid value.
Reading about ID 0.4 I thought this might be an easy way to cycle through the available apertures by sending values from 0 to n.
So I added some code to the library files (the .cpp and the .h files).
It seemed to work out of the box, but...
Unfortunately my Sigma 8-16mm (not the best, but the widest...) seems to pretend to have more valid aperture values, as it really does. The BMPCC 6K (and the BLE Controller) shows new "in between" values, but you can clearly heare that the aperture in the lens has not moved. There is also not change in the histogram.
A few questions...
Has anyone noticed the same issues?
Has anyone found a good solution?
Has anyone tried to control the aperture via ID 0.2? (I guess I will try this soon.)
And one small disclaimer...
I think this could be a completely different story at the BMPCC 4K, as M43 lenses can change their aperture almost stepless. (Even though most camera bodies do not support this. I could proof this on a GH5S via Wifi.)
Thank you,
Chris
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