Audii-Dudii
16-Nov-2019, 06:46
I'm building a hybrid, plate-type, technical camera to provide rise / fall movements with my Sony A7R and the gap between the fixed and sliding carbon fiber panels is slightly less than .004" because I cannot slide a piece of copy paper into it. (If you're curious, you can learn more about my project here: https://www.largeformatphotography.info/forum/showthread.php?155095-FrankenKamera-V-teaser)
When I shine a very bright flashlight at this gap from just the right angle, a very thin line of light appears in places where the width of the lens panel is narrowest (i.e., 12 mm on either side of the 55 mm diameter center hole), but I doubt this amount of light will have any significant affect on a photo, especially since I photograph outdoors usually in the dark, late at night, when there isn't much ambient light around.
The gap is too thin for me to install a paper gasket and I don't want to spread the two panels any further apart because this will change the FFD very slightly, plus require me to potentially compensate for this dimensional change by tweaking the construction of the camera in several ways.
So instead of using a gasket, I'm thinking about using a very thin smear of grease or oil instead. Not only will this fill the gap between the two panels, but it will lubricate them, which should make them slide more easily against each other than they do dry.
The potential downsides I can foresee with this approach are several, however: 1) Even though the two panels will completely cover the grease / oil, it can attract dirt and grit over time and require maintenance (i.e., cleaning and replacement) at some point; 2) Its viscosity may change over time, gumming up, and making it more difficult for the panels to slide against each other, not easier; and 3) It may migrate to other areas and/or outgass fumes that eventually form a film on the lens elements nearby (of course, the easy and obvious solution to this is to not leave lenses mounted on the camera, which will minimize their exposure to both of these effects.)
I'm fairly knowledgeable about the mechanical aspects of cameras, but not so much about lenses, so I can't judge how consequential any these effects might be or how likely they are to occur.
But I'll bet there are many contributors to LFF who are knowledgeable about these issues, hence my query ... thoughts?
And thanks in advance for any input you can share with me!
When I shine a very bright flashlight at this gap from just the right angle, a very thin line of light appears in places where the width of the lens panel is narrowest (i.e., 12 mm on either side of the 55 mm diameter center hole), but I doubt this amount of light will have any significant affect on a photo, especially since I photograph outdoors usually in the dark, late at night, when there isn't much ambient light around.
The gap is too thin for me to install a paper gasket and I don't want to spread the two panels any further apart because this will change the FFD very slightly, plus require me to potentially compensate for this dimensional change by tweaking the construction of the camera in several ways.
So instead of using a gasket, I'm thinking about using a very thin smear of grease or oil instead. Not only will this fill the gap between the two panels, but it will lubricate them, which should make them slide more easily against each other than they do dry.
The potential downsides I can foresee with this approach are several, however: 1) Even though the two panels will completely cover the grease / oil, it can attract dirt and grit over time and require maintenance (i.e., cleaning and replacement) at some point; 2) Its viscosity may change over time, gumming up, and making it more difficult for the panels to slide against each other, not easier; and 3) It may migrate to other areas and/or outgass fumes that eventually form a film on the lens elements nearby (of course, the easy and obvious solution to this is to not leave lenses mounted on the camera, which will minimize their exposure to both of these effects.)
I'm fairly knowledgeable about the mechanical aspects of cameras, but not so much about lenses, so I can't judge how consequential any these effects might be or how likely they are to occur.
But I'll bet there are many contributors to LFF who are knowledgeable about these issues, hence my query ... thoughts?
And thanks in advance for any input you can share with me!