Showing posts with label adjustable. Show all posts
Showing posts with label adjustable. Show all posts

Photography Improvised macro lens mould study

I got another lens from a junk bin in a camera store.

This one is a canon f 1.4, 35-80mm zoom.

It has an auto focus motor that makes a sound a bit like you might hear if you put a blender in a blender, but the auto focus still works.

The bits that dont work so well, are the lenses.






The problem is mould inside the lens.

Not uprising for a 500 Yen lens sitting in the junk bin of a camera store in the country that invented humidity.


Thats a ridiculously close up shot of the mould.

Ridiculously close up.





I dont have any way of doing macro shots with my new camera, so I had to improvise.

I took the shot of the mould with this home made bit of kit.

The blue lens cloth is there to keep the light out of the improvised macro lens, because the small length of toilet roll acting as an extension tube  isnt light tight.

The lens attached (thats a generous description) to the camera is actually on backwards, and is resting against the other end of the toilet roll tube.

The lens resting on the red kitchen scrubber is the new one with the mould garden inside.



The torch is a torch.

The torch is there because the cameras lens has the aperture set as small as it will go (f36) to try to get at least some of the mould in focus.

I didnt really achieve that.

The exposures were around 30 seconds long (many minutes without the torch), and other people were working in the house at the time. My desk is a wobbly kitchen table top heavy with old CRT computer monitors, and all the other junk I like to keep at hand. As as a result it amplifies any movement from people, traffic, and the fridge and freezer compressors.

If you put a glass of water on a desk like mine and look at the reflection, you will see the reflected image dance all over the place. Normally it isnt a problem, because the camera and lens would both move at the same time, but with this contraption, there was nothing of substance connecting the lens and the camera.

Tricky.

Anyway...

The lens has mould in it.

The image on the left was taken with the canon 18-55mm lens that came with the camera.

The image on the right is taken with the mouldy 35-80mm lens.

The camera was set to the same settings for both shots.



Mould is not a friend of the lens.

The point of all this, is to point out that I wont be taking an angle grinder to my lens in some future post  without reason.

Actually Ill try to open it up and clean it, but there is a fair chance its bits of glass are coated in a very delicate plastic coating, called coating. If thats the case the mould may have become a permanent fixture by etching its way into the coated bits.

The mould appears to be on only one element, so I might be able to salvage some other bits and make a proper, mould-free macro lens.



120 Things in 20 years warns that when I say "proper" I mean the improvised macro lens might employ slightly fewer toilet paper tubes, and where they are unavoidable, they might be made a bit less wobbly and light leaky.
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Stirling engines Adjustable Stirling engine crankshaft

Ive been busy making the tips of my fingers raw.

Wire seems to enjoy hurting people.

But I love the stuff.

My time learning how to make screw in eyelets for my hand made fishing lures was well spent. Every new skill I pick up seems to inform my next project. Working with wire is a really worthwhile thing to learn.


  • This post appears to be in bullet point style.


One thing I dont really understand is the relationship between the size of the cams on the crankshaft and the performance of my little tin can Stirling engines. With this lack in mind, I thought Id build a completely adjustable crank shaft.

It looks like this.

With it, it should be easy to try a stack of different configurations to see what they do.

The cams (bits that are offset from the main shaft) should offer different combinations of engine torque, and speed when they are adjusted to different heights.




I think.

Ideally I need an adjustable chamber for the displacer as well. Ill have to feed that idea through the invention engine at some stage because I have no idea on that one.

All the brass fittings come from the brass bits in strip electrical connectors.

Once the screws are undone as far as they can go, all the brass bits fall out with tap and a jiggle.

Lots of taps and jiggles actually, but they all come out in the end.





In my adjustable cam, the brass tubes that accommodate the cams have had an extra hole drilled through. Brass is very easy to drill, and a pleasure to work with. I dont think Ive ever done anything with brass before.

I officially like brass.


  • Bullet points


Also, many other people have used these as the adjustable bits on Stirling engines, and my only contribution to the science is to take their use to absurd levels.



120 Things in 20 years - No time to post because Im too busy learning stuff about Stirling engines.












All the brass bits are taken from a strip of electrical connectors.


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