Re: Disasterous Consequences
I should add that in the field I discovered the rear element and lensboard were loose, but I thought I took care of it (without tools)
Re: Disasterous Consequences
It's a good wide angle lens. Note the gap between the rear of the shutter and the lens board. I'm suspecting there is a light leak around the shutter as Jody suggested.
Kent in SD
Re: Disasterous Consequences
No, but the perimeter of the image on the ground glass was dimmer as I don't have a fresnel lens - yet.
3 Attachment(s)
Re: Disasterous Consequences
Here's a close up of the lens elements and the lens board contacts. Attachment 208378Attachment 208379Attachment 208378Attachment 208381
Re: Disasterous Consequences
It appears the rear element may not be screwed completely into the shutter.
Re: Disasterous Consequences
Someone posted the exact same problem either here or on photrio a few months ago. The cause were the Intrepid lens boards: Thry may look opaque but they are not! They do not block the full spectrum.
You can see an image in the center and the periphery is overexposed.
Put your lens on a different lensboard and it will be fine.
Re: Disasterous Consequences
Quote:
Originally Posted by
Nodda Duma
Someone posted the exact same problem either here or on photrio a few months ago. The cause were the Intrepid lens boards: Thry may look opaque but they are not! They do not block the full spectrum.
You can see an image in the center and the periphery is overexposed.
Put your lens on a different lensboard and it will be fine.
They’re not aluminum????
Re: Disasterous Consequences
Quote:
Originally Posted by
Nodda Duma
Someone posted the exact same problem either here or on photrio a few months ago. The cause were the Intrepid lens boards: Thry may look opaque but they are not! They do not block the full spectrum.
You can see an image in the center and the periphery is overexposed.
Put your lens on a different lensboard and it will be fine.
WOW! Never would have guessed that but looking at the images that looks correct. The rear bell of the lens was shading the negative.
Kent in SD
Re: Disasterous Consequences
This picture shows a gap between the locking nut and the lens board. I dismantled and found that it didn't quite fit into the hole. So I enlarged the hole and now the nut goes right up against the lens board. Could that have caused such a problem? I can't figure how. I guess now I need to make some test exposures with this adjustment.
Re: Disasterous Consequences
Quote:
Originally Posted by
brianentz
Picture 4 here shows the retaining ring not fully seated into the lens board. When this happens, the rear element may also not be fully screwed into the back of the shutter, and there could be light leaks around the lensboard hole.
As a quick and dirty check on whether the lensboard is not fully opaque and that could also be causing problems, you could try lining the back of the lensboard with something opaque, even aluminum foil (not ideal because it's shiny, but ok for a test).