Wikipedia:Reference desk/Archives/Science/2018 March 24

= March 24 =

Tilting lens extension tube
Is a tilting lens extension tube available for any camera mount? I am interested in this since tilting lens adaptors do not provide autofocus. A tilting lens extension tube can trivially provide autofocus. I'm aware that distant focus would be impossible. --Masatran — Preceding unsigned comment added by 117.246.89.134 (talk) 00:26, 24 March 2018 (UTC)


 * It depends on your camera. If you have say a Nikon or a middle of the road Canon with  standard screw threads  on the lens mount then you have choices. Don't worry about focus. That just needs a bit of experimentation to become familiar with titling lenses and manual focus. Start by using a very small aperture (for maximum depth of field), then open up and use your eyes to check for focus on the main subject.  --Aspro (talk) 01:38, 24 March 2018‎ (UTC)


 * Our article is at Tilt–shift photography. Graeme Bartlett (talk) 00:32, 25 March 2018 (UTC)

Janitorial questions.
When janitors see a sticker taped on the floor, I see sometimes they spray or pour a liquid solution 1st on it, then scrap the sticker off from the floor. What is that solution?

When janitors mop floors, with the flooring or Pinesol solution, do they add a little bleach to it? I was a janitor at a residential building before, and I was taught to add a teaspoon of bleach to the bucket. But at a retail clothes store, they don't use bleach, because they think it will change the color of the floor or damage it (or whatever reason). I don't believe bleach is harmful to floor tiles and such. Is there certain flooring material where you shoudnd't use bleach? Thanks. 67.175.224.138 (talk) 18:55, 24 March 2018 (UTC).
 * The solution to get rid of the sticker probably varies. Distilled white vinegar does wonders for that sort of thing.
 * I have to wonder if that retail store was using a cleaner that reacts with bleach (it's possible to make mustard gas with bleach and other certain common cleaners). As a general rule, cleaners that are safe to mix are an exception to the rule "never mix cleaners."
 * Then again, my experience at Walmart leads me to believe that it's entirely possible that "bleach harms the floor" might not have been the original reason. Not that they were lying to you or anything, but the person who told you that may have been told that by someone who forgot why they actually don't use bleach, and/or the decision to not use bleach was only half-informed and didn't give a very clear reason to begin with.  -- But that's just from my experience at a poorly managed Walmart in a bad neighborhood, I understand that some retail places aren't proof that Satan is real and active in the world. Ian.thomson (talk) 19:12, 24 March 2018 (UTC)
 * I agree. People are incredibly stupid and will mix bleach and ammonia, so any lie you can tell them to prevent them using bleach will persist, since people that know better don't want the stupid to die. Abductive  (reasoning) 19:24, 24 March 2018 (UTC)


 * There's Goo Gone and Goof Off, and even Fabuloso contains alkyl alcohol ethoxylates. Abductive  (reasoning) 19:22, 24 March 2018 (UTC)


 * FWIW, I have found that to remove stickers and their residue from solid surfaces and – most particularly in my case – (glossy) paperback book covers, lighter fluid is usually effective and leaves no stain or colour bleeding, though one should always test beforehand. {The poster formerly known as 87.81.230.195} 2.218.14.51 (talk) 23:57, 24 March 2018 (UTC)


 * Other sticker removing liquids are orange oil or eucalyptus oil. The first may stain, but both smell good. Graeme Bartlett (talk) 00:30, 25 March 2018 (UTC)


 * I have seen packaged floor tiles that include manufacturer's instructions saying "do not use bleach" on the tiles. Bus stop (talk) 00:47, 25 March 2018 (UTC)


 * Linoleum contains linseed oil, so I was thinking bleach might do lipid peroxidation, more or less. I looked this up and found sites saying don't use it.   Second link actually blames the pH.  Clorox claims you can use it, if diluted.   Honestly I have no idea.  To add to the fun, the pigments in flooring might be anything, and who knows if they resist bleach or not?  I see why caution rules the day since it must be hard for a janitor to blame a whitened or cracked floor on sorority drinking games. ;) Wnt (talk) 01:42, 26 March 2018 (UTC)


 * Bleach would also likely damage the clothes, so prohibiting its use in a clothing store would avoid accidents (either spill/spash while cleaning, or product falling in residue afterwards). DMacks (talk) 06:41, 26 March 2018 (UTC)