J-9 problem - any ideas?

[oscroft]

Hi all,

A while ago I had a problem with one of my Jupiter-9 lenses (I have a silver one and a black one - the problem is with the silver one) - I was getting a bright area in the centre of each frame. I opened the lens and found a grease mark on one of the elements. I thought I'd found the problem, so I cleaned it and reassembled it. But no, the problem is still there.

You can see it on the three attached examples. It's more noticeable on the two fountain photos (it's worse in brighter conditions), but note that neither of those is into the sun - on one the sun is at 90 degrees to the right, on the other it is a little forward of 90 degress to the left. It happened on lots of shots, but on some you have to look carefully to see the lower contrast patch in the centre - I've just chosen the most obvious examples to show here.

I examined the lens held up against a light source, and I saw what looked like a reflection all the way round coming from the inside edge of one of the elements (does that make sense?), so I thought that might be the problem. But it's only visible at f2 and disappears as soon as I stop down to f2.8, and in the photos below it was stopped down (f5.6, f8, iirc). Also, my black J-9 shows exactly the same reflection at f2 (and it also disappears stopped down), but the photos from that are fine. I could see no other reflections from the inside of the lens barrel (where a touch of black paint might help).

The light patch is definitely not a shutter blind problem, because I get it on different bodies with the same J-9, and I don't get it with other lenses on the same bodies.

Does anybody have any ideas what might be wrong? Or is it just a duff lens that's only fit for scrap?

 

[Spyderman]

I encountered a similar flare problem with a Jupiter 12 (the one with the big bottom ). Not into the sun, but when large part of the scene was sky.
I would say it's just flare, and that you should use a hood. If that doesn't help, then I have no idea what else it might be...

 

[Xmas]

Alan

If the hood does not help you will need to use greased paper stuck across the film plane to see where the effect origionates. Do you have a bottom loader?

Noel

 

[oscroft]

I would say it's just flare, and that you should use a hood.

It's there on shots taken directly away from the sun too, and with no sky or bright lights near the frame - it's just much more subtle then and shows as a patch of slightly lower contrast. So I doubt a lens hood is going to help. But does anyone have any idea of a suitable lens hood for a J-9?

If the hood does not help you will need to use greased paper stuck across the film plane to see where the effect origionates

Yes, I'll try that.

Do you have a bottom loader?

I do have one bottom loader, but I also have several with removable backs so I'll try one of those.

Thanks folks.

 

[oscroft]

Oh yes, I meant to add that the bright patch is always in the same place at the centre of the frame, regardless of where any light sources might be. (Whenever I've seen flare in lenses before, it appears in different parts of the frame depending on where the light is.)

 

[Hamster]

When you say reflection from one of the elements, do you mean one of the cemented groups had delaminated? Failed adhesive often looks like reflection on the perimeter of a lens group.

Also,what are the conditions of your aperture blades? Are they black and non-reflecting?

Are there a lot of tiny scratches on your front element? Perhaps the amount of diffraction caused by them were unacceptable.

I remember Spyderman posted some pictures of test shot using a badly scarred J8 with only 3 aperture blades, and there was a similar flare effect to your photos.

Is it possible that one of the internal elements were switched from another lens block, or perhaps it was installed the wrong way round?

Try taking photo of a Checkerboard pattern, perhaps it would show up the effect better. ie, shape of flare is a function of the image.

Try this at night also, with the lens off the camera, try to project an image of the light on your celing onto a flat surface, do you see any strange light source or ghosts?

 

[Xmas]

The J9 has a 49mm screw thread so the ideal hood is a Olympus SLR 85-100 mm short telephoto hood or a similar Pentax hood, etc.

Neighbourhood photo shop junk box searches or ebay. But a generic 49mm normal focal length will do if you have one in your junk box.

My j9 dont do this but Ive never tried them without an Oly hood.

Noel

 

[oscroft]

When you say reflection from one of the elements, do you mean one of the cemented groups had delaminated?

No, there are no problems like that. It's hard to describe, but if you could imagine holding a single lens element that was quite thick up to the light, the reflection would be from the inside of the thickness of the edge (not sure if that makes any more sense). It's the same on both J-9s - one with the problem and one perfect.

Also,what are the conditions of your aperture blades? Are they black and non-reflecting?

Yes, they look fine.

Are there a lot of tiny scratches on your front element?

No, it looks fine.

Is it possible that one of the internal elements were switched from another lens block, or perhaps it was installed the wrong way round?

I doubt anything is likely to be the wrong way round, because apart from the central "flare" the lens is sharp and focuses accurately. Whether any elements have been switched, I've no idea (and no way to tell, I guess).

Try taking photo of a Checkerboard pattern, perhaps it would show up the effect better. ie, shape of flare is a function of the image.
Try this at night also, with the lens off the camera, try to project an image of the light on your celing onto a flat surface, do you see any strange light source or ghosts?

I'll try both of those, thanks.

The J9 has a 49mm screw thread so the ideal hood is a Olympus SLR 85-100 mm short telephoto hood or a similar Pentax hood, etc

Ah, great, thanks - I'm sure I have a 49mm hood lying around somewhere.

Thanks for all the suggestions folks, I'll get back to you when I've tried them.