3D Printed Nikon Dew/Light Shield

[Mognet]

As it's been cloudy a lot since getting my 3D printer, I thought I'd put it to some use for printing astrophotography related things. One thing I needed was a dew shield to stop my camera lens misting up during sessions, and it should hopefully double up as a light shield for those nights when the neighbours forget to turn the lights off! Not had chance to try it out yet as I only printed it last night

I use OpenSCAD for model creation (it's a free download, but look for the latest snapshot as that has all the features), and the code is very simple. If it needs to be adapted to another fit, then just update the radiusOpening value. Canon users will need to check how their lens hoods fit as I don't know if they're the same.

radiusOpening = 59 / 2;
radiusBottom = radiusOpening + 5;
radiusTop = radiusBottom + 12;
length = radiusOpening * 2 * 1.5;
thickness = 1;

$fa=1;
$fs=1;

// Base
difference() {
    cylinder(r = radiusBottom + thickness, h = 1);
    cylinder(r = radiusOpening, h = 1);
}

// Mount
rotate_extrude(angle = 60) translate([radiusOpening - 1, 0, 0]) square(1);
rotate([0, 0, 180]) rotate_extrude(angle = 60) translate([radiusOpening - 1, 0, 0]) square(1);

// Shield
difference() {
    cylinder(r1 = radiusBottom + thickness, r2 = radiusTop + thickness, h = length);
    cylinder(r1 = radiusBottom, r2 = radiusTop, h = length);
}

 

Once printed it should look like this

 

[Chriske]

Printed as 'spiral vase'...?
looks nice btw..!

[Gina]

I looked at OpenSCAD and couldn't seem to get my head round it - don't really know why as I'm used to programming.  Guess I just prefer WYSIWYG, probably because most of my models are pretty complicated.

[Mognet]

5 hours ago, Chriske said:

Printed as 'spiral vase'...?
looks nice btw..!

Thanks. I printed it vertically so that no supports were required. The narrow camera end has a flat ring with a couple of smaller parts to mate with fixture on the lens, so it is basically a vase

5 hours ago, Gina said:

I looked at OpenSCAD and couldn't seem to get my head round it - don't really know why as I'm used to programming.  Guess I just prefer WYSIWYG, probably because most of my models are pretty complicated.

For some reason I just get it, but maybe that's the way my mind works. It's usually running at  different angle to every one else's!

[Mognet]

On 1/9/2018 at 10:09, Gina said:

I looked at OpenSCAD and couldn't seem to get my head round it - don't really know why as I'm used to programming. 

I think I can understand why now. The language has some idosyncracies, to put it politely!

Discovered this morning that variables are set at compile time, not run time https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/The_OpenSCAD_Language#Variables_are_set_at_compile-time,_not_run-time and there are some oddities around scope of variables too. Found it when trying to debug a function that contained the code

    if (rounding == "true") {
        actualTorusDepth = torusDepth - thickness;
    } else {
        actualTorusDepth = torusDepth;
    }

Which would be perfectly valid in any normal programming language that I've dealt with, but in OpenSCAD the value would only exist for the scope of the bracketed section in which it was set. Stealing a trick from C and Java I've found the following works to perform the same action.

actualTorusDepth = rounding == "true" ? torusDepth - thickness : torusDepth;

 

I think after this project I should find a better tool

[Mognet]

While working on a new version of this dew/light shield that should fit most lenses, I thought I'd test internal baffles with this version first. It's created in OpenSCad again, which seems to take a long time to generate what I thought would be a fairly simple addition. I haven't uploaded the STL file this time as it's 30MB!

I haven't been able to test it on the skies yet as it's been cloudy, and it looks like it will be for a while at least. But it looks like it should work better than the previous version. And cope better with the neighbours lights too

Nikkor 35mm Dew Shield.scad