3D CAD drawing:
Pentax 645 300 mm ED front cover

Contents:

1. Pentax 645 300 mm ED front cover

Note:
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1, CAD Pentax 645 300 mm ED front cover:

Introduction:

With my latest lens, the Pentax 645 300 mm ED lens I have a small problem. It's difficult to get the front cover in place at the lens. To have it in place I must retract the lens hood (that is very deep) all the way back which is not possible. I have the dew heater behind the lens hood and the mount for the lens also. Here I design a new front cover that slips on the outside of the lens hood.

Front opening of the Pentax lens:

The lens hood of the lens protrude in front of the lens. Because of the dew heater and the mount it's not possible to slip the lens hood all the way back.

The original front cover, it's not possible to loose the lock, not even with the nails when it sits behind the lens hood.

3D CAD design of an outside front cover:

Now I design a new front cover the slips over on the outside of the lens hood. Print this front cover with ABS-Pro filament. I have sometimes problem to the the first layers to stuck to the printer bed. After reading about his problem I found recommendations to have a little bit higher nozzle temperature, I increased it from 225 C degree to 230. I also reduced the fan speed to 50% according to the recommendations.

Direct out from the printer, worked much better now, I have increased the nozzle temperature from 225 C degrees to 230 C.

Fits perfect but I can reduce the height of it, it's now 30 mm, 20 mm will work too. Later I print it with black filament and then I can use it to take darks too, for now I cover the inside with black paper. If I can add some sort of lock mechanism it will be even better.