Rodenstock 40hr strange flare?

[Pemihan]

Going through my images from a recent trip I'm finding some of them shot with the Rodie 40HR has a rather peculiar flare or whatever it is.

The images shown here are some of the worst examples, others are more subtle or somewhere in between.

I know the lens is sensitive to flare and needs to be shaded and I'm using the Cambo Compendium and always try to make sure no light is hitting the lens.
Can it be caused from stray light entering from the side/back and being reflected into the lens?

What's going on here?

The first image is with no shift, but some rise. The second is with the same rise and 10mm shift.

 

[Pemihan]

Here's another example, 10mm shift, don't remember if there were any rise/fall.

 

[dougpeterson]

Were you using a center filter?

Are these before or after applying LCC?

Is the pattern visible in the LCC frame?

Are you using a glossy or matte LCC panel?

 

[goesbang]

I assume you are referring to the circular artefacting most evident in the dark corners in the sky, but pretty much occurring all the way around.
Firstly, it appears these images haven't had LCC applied yet.The falloff and colour shift suggests this. If, as I suspect, one of the culprits is Lenscast, then the problem is easily solved.
In your first shot however, the brightest part of the image is smack in the centre of your frame and as such, it is possible it is the source of the flare. I am leaning less towards this possibility as the dynamic range in the image, if you ignore the deep shadows below the rocks, is not that large. One can sometimes notice this type of flare when you have a small, very bright part of the image in an image that is overall relatively dark.
If the images aren't yet corrected for lens cast, do that and show us the images. We'll take it from there.
I have a 40HR myself and find it only flares if there is a bright source of non-image-forming light just out of frame and when it does, it manifests as a directional flare from the direction of the light source, not as a circle.

 

[Pemihan]

Hi Doug,

No center filter.

The images shown above are before LCC.

In some of the LCC frames the pattern is worse, in some the same and in some less.

I'm using a matte LCC panel.

Peter

Were you using a center filter?

Are these before or after applying LCC?

Is the pattern visible in the LCC frame?

Are you using a glossy or matte LCC panel?

 

[Pemihan]

Thanks Bryan,

Yes it's the circular patterns I'm referring to.

I'll upload the images with LCC applied in a moment.

Peer

I assume you are referring to the circular artefacting most evident in the dark corners in the sky, but pretty much occurring all the way around.
Firstly, it appears these images haven't had LCC applied yet.The falloff and colour shift suggests this. If, as I suspect, one of the culprits is Lenscast, then the problem is easily solved.
In your first shot however, the brightest part of the image is smack in the centre of your frame and as such, it is possible it is the source of the flare. I am leaning less towards this possibility as the dynamic range in the image, if you ignore the deep shadows below the rocks, is not that large. One can sometimes notice this type of flare when you have a small, very bright part of the image in an image that is overall relatively dark.
If the images aren't yet corrected for lens cast, do that and show us the images. We'll take it from there.
I have a 40HR myself and find it only flares if there is a bright source of non-image-forming light just out of frame and when it does, it manifests as a directional flare from the direction of the light source, not as a circle.

 

[Pemihan]

Here are the same images as above but with LCC applied:

 

[Shashin]

Do you have a UV filter on your lens? It also seems this happens when the sun is high in the sky.

 

[Pemihan]

Here's an LCC frame which is way worse than the actual image (not one of the above)

 

[Pemihan]

No filters at all.

I haven't analyzed all the images with the problem yet, but yes on the images above the sun is high in the sky..

Bear in mind I also have many images from the Rodie 40 which doesn't exhibit this problem.

Thanks
Peter

Do you have a UV filter on your lens? It also seems this happens when the sun is high in the sky.

 

[Shashin]

Peter, would it be true to say when you look down the lens, somewhere between the outer glass of the front element and the aperture, there is a metal feature like a retaining ring for another element or a series of rings? I have only seen one image of this lens from the front. I am wondering under a strongly illuminated landscape, that an internal reflection from such a feature is visible in the image? Just like a aperture is reflected in the optics, which we are more accustomed to as flare.

 

[Pemihan]

Will, I don't have the lens with me at the moment and won't be able to check before Monday but will surely do so and report back.
If anyone else have the lens and care to check before then it would be great..

But the thing is that I have images shot just before or just after with the same kind of strongly illuminated scenes that doesn't exhibit the issue at all..

A wild shot, probably not likely but could it be an issue with the Copal shutter?

Peter

Peter, would it be true to say when you look down the lens, somewhere between the outer glass of the front element and the aperture, there is a metal feature like a retaining ring for another element or a series of rings? I have only seen one image of this lens from the front. I am wondering under a strongly illuminated landscape, that an internal reflection from such a feature is visible in the image? Just like a aperture is reflected in the optics, which we are more accustomed to as flare.

 

[goesbang]

Here's an LCC frame which is way worse than the actual image (not one of the above)

This looks like an uncorrected frame shot with the LCC filter......

 

[goesbang]

Just to eliminate this possibility, you have checked the box for Tech-cams in the LCC window, right?

 

[Pemihan]

Bryan,

Yes it is a frame shot with the LCC plate. Nothing has been done to it besides resizing and comverting to jpeg.

Peter

This looks like an uncorrected frame shot with the LCC filter......

 

[Pemihan]

Right....

Peter

Just to eliminate this possibility, you have checked the box for Tech-cams in the LCC window, right?

 

[goesbang]

Given the amount of shift you are using, I'm very, very surprised at how prominent the bright and also the dark rings are. I don't remember ever having seen it with my own 40HR. I'm just going to shoot a test LCC frame.......

 

[goesbang]

I've just shot an LCC frame with my 40mm on my IQ180 with 15mm shift on the long axis.
It shows neither the light nor the dark ring, just the expected magenta/green cast and a continuous tonal falloff. As the 80MP sensor exhibits the worst lens cast, I would have expected to see it here if that is the issue. I'm starting to lean towards a lens problem but its hard to test without another 40mm test lens on your setup.
What back are you using?

 

[Pemihan]

Thanks for testing Bryan,

I'm using a IQ160...

I'm thinking it is either a lens problem or some kind of weird flare caused by light hitting the ring of the compendium being reflected into the lens..

I will need to do some controlled testing once I'm back home Monday.

Peter

I've just shot an LCC frame with my 40mm on my IQ180 with 15mm shift on the long axis.
It shows neither the light nor the dark ring, just the expected magenta/green cast and a continuous tonal falloff. As the 80MP sensor exhibits the worst lens cast, I would have expected to see it here if that is the issue. I'm starting to lean towards a lens problem but its hard to test without another 40mm test lens on your setup.
What back are you using?

 

[Paul2660]

I believe I know exactly what you are seeing, nothing wrong with the hood.
Lighter band, is the penumbra, you will need to look that up for the true definition but with the Rodenstocks and a long shift, you hit the penumbra and it creates the lighter band. The dark band, is the edge of the disc, that Rodenstock places inside the lens to make sure you don't shift too far past their intended image circle. Stupid design IMO. They should leave the disk out. In Guy's review of the Rod 28mm he shows several good examples of "hitting the disc" i.e. the wall of the IC with a Rodenstock Lens. I don't believe you should be seeing it with 10mm of shift however, but it looks just like the effect I get with my 28mm when it's shifted past the useable image circle. As far as I know Rodenstock doesn't make a CF for the 40mm, but they might need to look at your lens if this is showing up at only 10mm of shfit.

The disc also helps to make the penumbra stand out even worse.
The 40mm on your back should shift to about 18mm before you really see the disc (dark vignette). It will always show up worse on a solid blue sky like you have. The LCC will not correct it and in fact may make it worse IMO.

This is something that I get into all the time with the Rodenstock 28mm with shifts past 5mm. The penumbra shows up at about 6mm, the white band and then you will see the hard vignette of the disc.

Rodenstock IMO should not do this, as their lenses many times will easily go past their intended IC, I know the 28mm without the disc would get to 10mm before it was totally soft as I can shift it to there and see the edges in the middle of the shift not blackened out by the disc.

On my 260, I can get to 15mm clean horizontally. I can push the lens to 18mm, but I will start to see both the white band, and then the dark vignette. My 40mm does not show the penumbra band as bad or as harsh as your images shows. That looks just like my 28mm however.

Phase Backs will show less of this on rise fall, than on shift, i.e you can get a bit more rise or fall before you start to see it. Where as the older Leaf backs are just the opposite and you can get a bit more shift. It's due to the layout of the chip. X, Y axis.

Paul

Paul