Strange behavior of Hasselblad XCD 45P on X1D II at widest aperture

[parityB]

Hi,

I noticed a strange behaviour of my XCD 45P on my X1Dii body.

If you take the first picture after starting up the camera at f4 and with shorter shutterspeeds (roughly from 1/400 up to 1/2000) the resulting picture is 2-3 stops underexposed, although the settings would lead to a technical correct exposed image and even the live view shows correct exposure.
If you switch to another aperture once (for example f4.5) take a picture and go then back to f4, everything is fine and exposed correctly.
It happens at any ISO speed and both in M and A.

Both, body and lens have the newest firmware and I also tried a downgrade, but it didn't change anything. Also true exposure has no effect on this behaviour.
I also checked if the aperture stays fully open during exposure and it does. I don't think it is a mechanical problem.

I found a thread, there someone had the same problem, but it came never out, if there was a solution. Unfortunately I can't reach out to the author @anGy, because I'm new to this forum and can't start conversations yet.

So I hope, this thread will maybe bring up a solution.

Thank you for your help
Christian

 

[Photon42]

What I understand:

1. Camera off and 45p attached
2. Camera switched on, set to correct exposure, fixed on tripod or equivalent, manual mode, focussing the subject
3. First frame taken: frame is underexposed
4. Second and consecutive frames taken with the identical settings and identical lighting: Frames are correctly exposed

Is that correct?

 

[parityB]

Yes, almost

You start the camera and you want to take a picture at f4 and with a higher shutter speed. Images are way underexposed (although they should have been exposed correct).
Switch to any other aperture once, take a picture and then go back to f4 with the exact settings as in the beginning, everything is fine and correctly exposed.

 

[Photon42]

So it is not only the first frame, but when you close the aperture a little and then go back to f4, everything is fine. Interesting. First I thought, maybe the shutter is a little sticky and the move of the aperture blades gives it "a kick", but then, I am not sure at all. I would probably go ahead and ask Hasselblad service. They are really responsive.

 

[parityB]

No, it is as long as you start with f4 and don't take at least one picture with another aperture setting.
I don't think, it is really a mechanical problem.

I already reached out for Hasselblad today but all they told me, is to send the lens in. I actually wanted to avoid this and hoped for a special trick or just some setting i did wrong, but seems I have to send the lens to service

 

[Photon42]

Do you have another lens to test?

 

[parityB]

Only H-Lenses with the adapter, no other XCD lens.
It does not happen with the H-Lenses.

 

[fjablo]

Sounds like a problem with the shutter (maybe just wonky communication between lens and camera). If you start the camera with aperture set to something else than f4 it works correctly?

 

[parityB]

Yes, it happens only, when you start with f4. Any other aperture setting works fine with all shutter speeds. f4 also, as long as you took at least one picture with any other aperture setting.
Don't think it's the shutter, because underexposure would mean shorter shutter speeds and the shutter is limited to 1/2000 max. But the underexposure also occurs at f4 & 1/2000. I first thought the aperture is maybe closed a bit during exposure.But this is also not the case.
Think it is more a problem with electronics and signal processing induced by the lens.

 

[Photon42]

Did you send the lens in? I don't think there is any magic button sequence we can press to bring this lens back to normal.

 

[parityB]

Yes the lens is now at Hasselblad for repair.
It is still under warranty, so repair will be for free.

Hope they won't need 3 month for a lens repair like Fujifilm, when I needed there service the last time

 

[parityB]

Just wanted to post the result:

The lens came back today from Hasselblad and is fully working again. Unfortunately there was no report, so I don't know the exact cause of the faulty behaviour.

But I was really impressed by the service from Hasselblad. It took only 12 days getting the lens back repaired and this includes shipping from Germany to Sweden and back again.