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02-09-2012, 08:56 AM   #61
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Can't find the link, but (counterintuitively) when California wanted to prohibit black paint on cars (to save on airconditioning increase in fuel consumption) the required study discovered that there is no appreciable difference in heat absorbtion under sunlight between light colored and dark colored cars. The proposal died in committee.

02-09-2012, 09:12 AM   #62
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QuoteOriginally posted by m8o Quote
... so is that what one calls "embracing their weaknesses"? ... i.e. if you have terrible subject focus isolation, go completely the other way.
You can make a pinhole lens with a body cap (you just need to get the right size hole) so it better be cheap. it falls in line with the toy lens line. it really is becoming a digital holga they need to get it into the Lomo stores for sale I think
02-09-2012, 09:19 AM   #63
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QuoteOriginally posted by ogl Quote
DA40XS is in roadmap
That's because it was announced on the day the roadmap was released.
02-09-2012, 09:20 AM   #64
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QuoteOriginally posted by monochrome Quote
Can't find the link, but (counterintuitively) when California wanted to prohibit black paint on cars (to save on airconditioning increase in fuel consumption) the required study discovered that there is no appreciable difference in heat absorbtion under sunlight between light colored and dark colored cars. The proposal died in committee.
I find that a bit hard to believe actually. It is basic physics after all. This one is about roofs, not cars, but the idea is the same:
http://docserver.nrca.net/pdfs/technical/457.pdf
If I decipher that correctly, color matters when insulation is poor...e.g. in cars.

Now as to what that required study found out and how, and why the committee decided to do nothing, I have no idea.

02-09-2012, 09:38 AM   #65
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Color is a big marketing strategy in big lenses. When you do birding or sport in group, you know exactly what brand of lenses peoples use. This is a big $$$$ business
02-09-2012, 09:45 AM   #66
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QuoteOriginally posted by bobmaxja Quote
Color is a big marketing strategy in big lenses. When you do birding or sport in group, you know exactly what brand of lenses peoples use. This is a big $$$$ business
Camo webbing has a brand following ?
02-09-2012, 10:01 AM   #67
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QuoteOriginally posted by Boucicaut Quote
I find that a bit hard to believe actually. It is basic physics after all. This one is about roofs, not cars, but the idea is the same:
http://docserver.nrca.net/pdfs/technical/457.pdf
If I decipher that correctly, color matters when insulation is poor...e.g. in cars.

Now as to what that required study found out and how, and why the committee decided to do nothing, I have no idea.
Cars are a closed environment witha lot of glass, so the internal temperature rises to 170+ degrees almost immediately when in full sun, regardless of the paint color. Apparently the largest controllable variable is whether the car has tinted windows
02-09-2012, 11:06 AM   #68
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QuoteOriginally posted by bobmaxja Quote
Color is a big marketing strategy in big lenses. When you do birding or sport in group, you know exactly what brand of lenses peoples use. This is a big $$$$ business
So Pentax should make theirs pink

02-09-2012, 03:20 PM   #69
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QuoteOriginally posted by boriscleto Quote
I would hope that it is based on the 1.4, but with 6 blades instead of 8. It would make no sense to base it on the 1.7 and then make it a 1.8.
I would think so to, but as both designs have their followers and comprehensive tests doesn't agree on which is the best lens, I didn't want to restrict myself for just one possibility.
02-09-2012, 03:24 PM   #70
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QuoteOriginally posted by Frogfish Quote
For sure they would be hotter ! However I'm also sure Nikon/Sigma considered that a black finish may negatively affect the optical qualities of their lenses. If they still went with black then obviously there is no visibile image degradation.
Can we agree on that it would be a bad idea to paint one side of the lens black and one white? In which case the lens would probably curve itself in strong sunshine...

BTW, regarding Nikon and Canon long lenses. Aren't in-lens-image-stabilized lenses by definition always misaligned a bit as soon as the image stabilization is active? When some lens elements move to correct for motion and vibrations, they deviate ever so little from the ideal lens diagram, which may very well be a larger effect than any temperature changes. Maybe this is what Nikon and Sigma realized.
02-09-2012, 03:26 PM   #71
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Ditto ...

QuoteOriginally posted by Docrwm Quote
Glad to hear that they have already been added to the database. I am looking forward to seeing how the 50/1.8 handles, if it is anything like the 35/2.4 it will be a real bargain.
On est d'accord ... 100% !!!

May look "cheap" to some, but doesn't shoot like it, IMHO ...

A+, J
02-09-2012, 04:19 PM   #72
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QuoteOriginally posted by TOUGEFC Quote
Away with f/2.

Do it proper with f/1.4 or dont bother at all
Agreed!

I also wish the new DA50 was a 1.2. I'd also like a 30/1.2
02-09-2012, 04:32 PM   #73
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30/1.2? That would need about 86mm front filter or so, correct?
02-09-2012, 04:49 PM   #74
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QuoteOriginally posted by monochrome Quote
Cars are a closed environment witha lot of glass, so the internal temperature rises to 170+ degrees almost immediately when in full sun, regardless of the paint color. Apparently the largest controllable variable is whether the car has tinted windows
I agree - you can quickly feel how hot the exterior paint of a black auto is. On the other hand, most of us don't ride on the outside of the auto .....

In another and (perhaps) more serious vein, a building's roof is rather static. A moving auto, OTOH, is shedding heat by conduction as the "moving" air carries the heat away as well as by radiation.

If California were really worried and had a legislature with a slightly smaller proportion of the victims of modern education, they'd figure out that the real improvement would come from banning black tarmac streets and car parks, replacing them with white concrete. I'm filing a patent tomorrow from my shell company in Tyler, Texas. (That last sentence really does make sense if you've been following the legal/IT news this week.)
02-09-2012, 06:30 PM   #75
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QuoteOriginally posted by ElJamoquio Quote
30/1.2? That would need about 86mm front filter or so, correct?
fine by me
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