Uploaded July 2019 | Updated September 2026, 1 day ago
I did a quick demo of the Fotodiox B4 Magic on the GH4 in 4K to show vignetting and coverage with my Canon J15x8B4 IRS ENG lens WITHOUT the doubler engaged.
NOTE: Back focus not set for this adapter and this camera. I use my lenses on different cameras and one should always adjust and set the backfocus for your particular lens / adapter / camera setup. This was just a quick & dirty demo. So lack of critical focus is just because I don't normally have this adapter in between my lens and my camera. Also, I didn't white balance and filming up into the sky is not a great idea either.
It has a bit of corner vignetting when enlarged with the B4 Magic. 8mm it is visible, increasing a bit at 15mm, and then moving out till it was out of view at 30mm. Pulling the focus in closer, like 2.5 feet from the sensor, brings the corners in, and pushing the focus further pushes the corners out.
Not every lens has the same coverage, YMMV. But this is a very common 2/3" B4 lens and coverage should be typical of good 2/3" ENG lenses.
I did a quick demo of the Fotodiox B4 Magic on the GH4 in 4K to show vignetting and coverage with my Canon J15x8B4 IRS ENG lens WITHOUT the doubler engaged.
NOTE: Back focus not set for this adapter and this camera. I use my lenses on different cameras and one should always adjust and set the backfocus for your particular lens / adapter / camera setup. This was just a quick & dirty demo. So lack of critical focus is just because I don't normally have this adapter in between my lens and my camera. Also, I didn't white balance and filming up into the sky is not a great idea either.
It has a bit of corner vignetting when enlarged with the B4 Magic. 8mm it is visible, increasing a bit at 15mm, and then moving out till it was out of view at 30mm. Pulling the focus in closer, like 2.5 feet from the sensor, brings the corners in, and pushing the focus further pushes the corners out.
Not every lens has the same coverage, YMMV. But this is a very common 2/3" B4 lens and coverage should be typical of good 2/3" ENG lenses.
