Pocket 4k blue purple window ghost patterns

I am not sure if this is what people are talking about when discussing the "purple grid pattern" but I am getting what appears to be a reflection from off the chip itself. I purchased the Pocket 4k this week to shoot interiors and that means bright windows. I am getting a blue/purple in focus reflection of my windows and I am getting it even when the windows have plenty of detail in them and are not blown out.

I have shot these same exact rooms in my house many many times with the exact same lens on the GH5s and I did not ever get this so I am fairly certain it is coming from the chip itself and the design of the camera.

I am shooting with a Lumix 7-14 lens which has served me well for many interior shoots.

I have contacted Blackmagic but in effect this renders this camera useless to me.

Has anyone else run into this?Is it lens specific or lighting specific?

Is there any point trying a different lens? I could purchase an 8-18 but there isn't one for rent here so that is an extreme solution.

Do you have other lenses you can put on the camera to see if they give the identical result?

What happens when you pan across that angle? Does the ‘ghost’ image appear identically in the exact same place or does it disappear and reappear?

Where is the main source of light in that still? Do you see the ghost much earlier or later as the sun moves significantly?

I would have to rent other lenses. My main camera is a Sony.
It does disappear and re appear depending on camera angle. It is showing up in a lot of the shots but is more pronounced if the sun is in front of me, even though the sun is high and hidden by roofs etc. however it is there, though much more subtle , when the sun is behind me.

I have rented and tested this with the 12-24 and that lens does not create this problem.... hmmmm
Now is this a problem with all extreme wide angles? Anyone ran into this before??

Just guessing but based on the performance of the 12-24mm zoom, I thinks it’s the flare of the 7-14mm zoom, not sensor ghosting.

I am using the Olympus 7-14mm f/2.8 with the PCC4K and have never seen this kind of flare.
And the sensor of the PCC4K is wider than the sensor of the GH5s:

18.96 mm vs. 17.3 mm

There does seem to be some flare on the wall, but the reflection of the window is coming from somewhere; what do you think is causing the reflection of the window? I don’t think the sensor is ghosting.

Looks like a reflection in the coating of one of the lens elements.
And this lens seems to get it with some Olympus bodies too:

https://www.dpreview.com/forums/thread/3370371

So it might either be a combination of certain camera bodies and the lens, or Panasonic does some active artifact suppression in camera. Maybe CA suppression does already the job.

Well I am buying a 8-18 Lumix later today and praying that this will solve the problem. It seems to me that it has to be coming from the chip because I think that once light enters the lens the next time it is truly in focus is when it is projected onto the film/chip plane. Since the purple ghost is in focus I don't se how it could be a problem with the lens and that lens does work great on the GH5s.
I am hoping that since the Olympus lens isn't causing you a problem that changing to another wide angle will solve this and that it is just some strange thing about the placement of the rear element in the 7-17 Lumix and the way it interacts with the Pocket 4k chip.

Fingers crossed and thanks for the feedback.

Is the right side cropped? There’s more information in the ghost than the primary image. In the flare the corner of the roof is visible as well as well as more of the neighboring roof.

Deep stop? I believe you’re focusing on the front glass and that is why the flare is so defined. With a small aperture and an ultra wide like 7mm one can just about focus down to the front element. It’s also a pretty safe assumption that the ffd is not identical. If the ffd on the P4K is short, and it likely is, then that lens will go macro.

I’m curious to see the same shot at F4 with focus at infinity.

The pink grid was an oblique reflection that skipped off the chip and flared the back of the IR which is why it was pink. This purple color is more reminiscent of fringing and less like either IR or any electronic issue that will manifest in a primary or secondary color. No color channel clips to purple.

Good Luck

When it's sharp like this it says to me that this is a FILTER or LENS internal reflection.

You can see the trees and roof line actually reflecting somewhere in the optics of the lens. It's from the hot window out to the right.

If it was a sensor cover glass reflection, they don't tend to be sharp and defined like this, they tend be softer. That's my guess.

JB

Looks like a reflection in the coating of one of the lens elements.

I agree, I have a similar problem with a Helios 44M-7 lens. It may be a reflection from the multiple coatings of the lens. Does the software in a Panasonic camera correct this, and YMMV when using a Lumix lens on a non-Panasonic camera?

Here is a shot from my vintage Zenit MC HELIOS 44M-7 58mm f2 with a Fotodiox M42-EOS(V2) adapter on a BMPCC4K. This is the MC (Multi Coated) version of this lens and is supposed to have better veiling flare resistance than the earlier versions. The flare on this lens is interesting but I did have significant purple CA on the tunnel wall against the blown out outside entrance that I removed most of in Adobe Lightroom. Look for it behind the sillouetted woman.

Re: Using vintage lenses
viewtopic.php?f=2&t=17134&p=519916&hilit=+%2485.00+USD+today+#p519916

In comparison, this earlier Helios 44-2, with it's simpler coatings does not have the purple ghosting. This is the same setup at the same place.

Here is a 1976 Helios 44-2 58mm anamorfake lens with a fixed oval aperture of F/3.5 and a string for flaring compared to the 1993 Helios 44M-7 with it's MC coating. Again, using a DEC Lensregain EF to MFT focal reducer to mount it to a BMPCC 4K. I used a lot of dehaze in Lightroom to bring out the colors. Drag the image to reveal the one to compare it with underneath.

Re: Russian vintage lens
viewtopic.php?f=2&t=70922&p=551058&hilit=44m+7#p551058

I have rented and tested this with the 12-24 and that lens does not create this problem.... hmmmm
Now is this a problem with all extreme wide angles? Anyone ran into this before??

I have the same issue when using Blackmagic Camera app on iPhone 15 Pro.