What's lurking in your lens?

[Stagecoach]

I recently used my old Sigma 10-20mm for the first time in quite a while, the pictures were flat and washed out. High contrasty bright sunny day scenes that would normally fill the histogram on the D300 did not.

Looking through the lens with the aperture wide open was like looking through bubble-wrap. As I have had this lens many years and originally bought it second hand and it having spent a fair time on the beach and in very high humidity it was not going for repair.

A quick search found a You Tube video showing how to strip half of it and a Flkr page showed some more.

So out came the tools ..............................

No 1

No 2

No 3

No 4

No 5


All the elements have been cleaned and show no signs of fungus, dust or grunge to my eyes any more. It's fully reassembled and a quick test using flash indoors has proved AF is working fine and the images are no longer flat.

Tomorrow, weather permitting some controlled tests outside.

[Dave Humphries]

Amazing what can be achieved when there's 'nothing to lose'

Well done, Dave

[Black Pearl]

Fascinating isn't it. I've taken countless knackered cameras and lenses apart when I worked in a camera store and was always intrigued to see the complex design that get into each.

[Tronhard]

I love the occasional cross-section that you see through a lens or camera such as below:
https://www.dpreview.com/articles/42...-cross-section
https://www.dpreview.com/articles/13...p-2015-edition
https://www.dpreview.com/articles/06...es-cut-in-half
https://www.dpreview.com/articles/00...en-cut-in-half
and finally, this really amazing video of a Canon camera disassembled then rebuilt in CADD
https://www.youtube.com/watch?v=6-HiBDLVzYw

I continue to be amazed at the complexity of the technology we often take for granted.

cheers Trev

[Stagecoach]

Amazing what can be achieved when there's 'nothing to lose'

Well done, Dave

Exactly Dave, and nothing left over

Fascinating isn't it. I've taken countless knackered cameras and lenses apart when I worked in a camera store and was always intrigued to see the complex design that get into each.

I think it's also fascinating to see the complex design mixed with good and bad engineering practices that go together to make something that works.

I love the occasional cross-section that you see through a lens or camera such as below:
https://www.dpreview.com/articles/42...-cross-section
https://www.dpreview.com/articles/13...p-2015-edition
https://www.dpreview.com/articles/06...es-cut-in-half
https://www.dpreview.com/articles/00...en-cut-in-half
and finally, this really amazing video of a Canon camera disassembled then rebuilt in CADD
https://www.youtube.com/watch?v=6-HiBDLVzYw

I continue to be amazed at the complexity of the technology we often take for granted.

cheers Trev

That Canon assembly video done in CAD has to be one of the sexiest movies I have seen in a long time

[miatab]

I have to add a + 1 for me re not frequently used lenses being on the front line for deterioration. I bought a Cosina mirror lens about thirty years ago, used it once, was not impressed with the results, and stored it in its case under my desk in our basement. Twenty years later, when I decided to try it one more time, it had fungus right around the mirror about 1/2" wide. I pulled it apart, realized getting it repaired would cost more than multiple replacements, and let it sit another ten years in a glassware cabinet in the kitchen. From there, it migrated to the garbage. I no longer keep any lenses in possibly damp, unmoving air, like under a desk against a wall in a basement study! And I never missed, do not miss that lens. A bad case of monkey see, monkey want.

[NorthernFocus]

That's pretty interesting, Grahame. Maybe you've discovered an opportunity for a side business

As an engineer I'm rarely awed by the complexity of equipment nor what is possible with technology. But what does astound me is the relatively low costs to the consumer of many complex items. Consider the cumulative cost of design/development, tooling, manufacture, packaging, marketing, and transportation plus profit to the manufacturer, distributor, and retailer. Particularly with consumer electronics the relatively low cost of items is amazing. In preparation of our recent trip to NZ I purchased two sets of ear buds on sale at a local retailer for under ten USD each. I find it hard to believe that price even covers the packaging and transportation costs. Luckily my ear is not highly discriminating and I don't require the $200 Bose noise cancelling headset

[IzzieK]

Darn! That looks complicated to me and wouldn't even dare do it to any of my lens...knowing me, perhaps I will...good job.

[Stagecoach]

Darn! That looks complicated to me and wouldn't even dare do it to any of my lens...knowing me, perhaps I will...good job.

Hi Izzie,

It's only complicated if you get stuck

The most daunting part was the last part of the assembly which entailed putting the rear plate which contains the contact pins onto the lens body whilst keeping a number of shims (spacers) aligned along with the aperture control lever.

Having spent a frustrating 15 minutes attempting to and pondering over a possible way to do it I luckily remembered gravity and the advantage it would give me if I turned it all upside down to work on

[IzzieK]

My way is to take a photograph of the process of dismantling so putting it back together isn't that PITA. Problem is, I got to have a whole room with a lockable door to myself to put it back together or else I lose a part when the dogs decided to share my space. How many times have I tried to find a screw and looked around foolishly for it then in frustration decided to ask Tucker if he can help me find that screw? His answer? -- spit it out of his mouth!!! I can't win around here.