Barn and Silo

[Doug A]

First results with Asahi Optical Company Super-Multicoated-Takumar 500mm F4.5. lens. Big and heavy lens with 4 elements. The back of the screw thread (M42) lens  breaks apart via bayonet allowing 52mm filters to be inserted. There's plenty of room for a 52-49 step down adapter, Hoya U360 and Schott S8612 filter inside. Picked this lens up years ago for little money because the aperture ring mechanism is broken. I disassembled the lens and set it to F11. Kolari Vision full spectrum modified Pentax K-1 and a sturdy tripod. 

 

This lens is a handfull, but I like the reach and the way it enhances fog and haze.  F11, 0 .8 second at ISO 400.

 

Thanks for looking,

Doug A

 

 

[Nate]

Nice shot Doug, lens seems to do well. I think I'd be well into seconds at f11 with all mine.

[Andrea B.]

Yes on that sturdy tripod indeed !!

 

The "fade" of the background is quite interesting in this scene. I think you will have a lot of fun with this lens. 

[Fandyus]

Interesting, the silo is very bright and shiny compared to the surrounding material.

[Andy Perrin]

Metals usually reflect well across all wavelengths (with occasional notches like we saw for silver in UVC). That’s why the silos are bright. 

[Bill De Jager]

56 minutes ago, Andy Perrin said:

Metals usually reflect well across all wavelengths (with occasional notches like we saw for silver in UVC). That’s why the silos are bright. 

One exception is galvanized steel which in my experience is dark in the near IR.  My understanding is that the surface layer is actually zinc carbonate rather than zinc metal.

[Andy Perrin]

Bill, that may have more to do with surface texture than chemistry. You can make anything dark if you roughen the surface the right way. For example, ultra dark materials are made by forming the surface into deep pillars so light gets caught between them.

 

 When you electroplate the steel, the zinc could grow into some microscopically rough surface structure and that would explain it. (And btw I would expect zinc oxide not zinc carbonate because where is the carbon coming from?)

[Doug A]

Thanks everyone. 

 

@NateI was lucky with exposure - it was a slightly overcast day that boosts UV. Still it was almost a full second exposure. It would have been worse with my older filter stack.

 

@Andrea B. I was also drawn to the fade. Haze is so interesting in UV. The  lens weighs 7.7 lbs. Luckily I had the big Gitzo tele-Studex tripod. 

 

@FandyusI hadn't thought about the bins being shiny. Perhaps it is surface smoothness like @Andy Perrinmentions. Could also be that most "dark" metal is coated or painted.

 

@Bill De Jager didn't know that about galvanized steel. Great Info.

 

Thanks everyone,

Doug A