Why not all white
May 1, 2019 16:26:20 #
Ken Owen
Loc: mid-Michigan
Originally Canon produced the white finish for their lenses that used any number of flourite elements. The black lens barrels caused too much heat within the lens distorting the elements, and the white finish was the solution.
May 1, 2019 16:30:24 #
DeanS wrote:
Awww, just go with 120 grit carbon sandpaper.
Well, Duh! But that is just to polish the surface after you get the paint off with the razor blade. Any idiot knows that!
May 1, 2019 16:33:51 #
DeanS wrote:
Awww, just go with 120 grit carbon sandpaper.
That's being a little rough on the barrel, don't ya think!?š
May 1, 2019 16:47:50 #
rmorrison1116 wrote:
That's being a little rough on the barrel, don't ya think!?š
The barrel? Of course you wouldn't sand the barrel! Are you nuts? We were discussing getting over-spray off the lens elements after painting the barrel white. Sand the barrel! My gosh, now I have heard everything!
May 1, 2019 16:48:23 #
billnikon
Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont
burkphoto wrote:
Heat reflection...
Black absorbs light, transforming it to heat. Heat expands glass, messing with the optical performance.
Black absorbs light, transforming it to heat. Heat expands glass, messing with the optical performance.
That's interesting. So that's what my BLACK Nikon 500mm 5.6 lens, after being out in the Florida sun for 5 hours straight, NOTHING HAPPENS TO IT'S OPTICAL PERFORMANCE.
So, do we then call your post, FAKE NEWS? Seems like it.
Yet another misinformation rant from someone who just wants to rant without any PROOF.
May 1, 2019 17:08:55 #
LFingar wrote:
Well, Duh! But that is just to polish the surface after you get the paint off with the razor blade. Any idiot knows that!
You have to be so careful with razor blades. Most of them are sorta sharp, doncha know!
May 1, 2019 17:11:19 #
rmorrison1116 wrote:
That's being a little rough on the barrel, don't ya think!?š
I would NEVER touch my barrel with sandpaper. My barrel is just waaaaay too sensitive.ššš
May 1, 2019 17:12:48 #
LFingar wrote:
The barrel? Of course you wouldn't sand the barrel! Are you nuts? We were discussing getting over-spray off the lens elementsee my earlier post. ššš after painting the barrel white. Sand the barrel! My gosh, now I have heard everything!
See my earlier post. ššš
May 1, 2019 17:55:14 #
DaveC wrote:
I also have read that the reason NASA picked Nikon was partly for that and partly because Canon glass tended to crack under the rapid acceleration of launch.
Extremely unlikely. The Apollo launches experienced a max of 4 G's and that was only for a very short period just before 1st stage cut off. If the launches had anything to do with NASA's decision it would almost certainly be due to the vibration at launch which could be very strong. I could easily see that damaging lenses of a particular design or material. 4 G's won't even break a piece of cheap window glass.
May 1, 2019 17:57:48 #
DeanS wrote:
You have to be so careful with razor blades. Most of them are sorta sharp, doncha know!
Yeah, but I heal quick. Besides, it makes it easier to put on the finishing touch: The red band around the barrel!
May 1, 2019 18:48:31 #
LFingar wrote:
Yeah, but I heal quick. Besides, it makes it easier to put on the finishing touch: The red band around the barrel!
ššš
May 1, 2019 19:01:15 #
8
I was stationed at Wright-Patterson AFB, near Dayton, OH, from 1965-1967. While there, I was a volunteer guinea pig at the Aero Med Research Lab. I served on several panels such as impact, vibration, etc for abt two yrs. The most Gās experienced was abt 14. I can tell you, that is one helluva load. Both of those panels were in support of lift-off and reentry. Vibration was a challenge, trying to monitor a dashboard of dials and guages, trying to keep them within some spec range. When oscillations reached l/o range, it was damn near impossible to even see the dash panel. The impact panel was to ck reaction and damage upon capsule water landing.
All-in-all, very interesting experience.
LFingar wrote:
Extremely unlikely. The Apollo launches experienced a max of 4 G's and that was only for a very short period just before 1st stage cut off. If the launches had anything to do with NASA's decision it would almost certainly be due to the vibration at launch which could be very strong. I could easily see that damaging lenses of a particular design or material. 4 G's won't even break a piece of cheap window glass.
I was stationed at Wright-Patterson AFB, near Dayton, OH, from 1965-1967. While there, I was a volunteer guinea pig at the Aero Med Research Lab. I served on several panels such as impact, vibration, etc for abt two yrs. The most Gās experienced was abt 14. I can tell you, that is one helluva load. Both of those panels were in support of lift-off and reentry. Vibration was a challenge, trying to monitor a dashboard of dials and guages, trying to keep them within some spec range. When oscillations reached l/o range, it was damn near impossible to even see the dash panel. The impact panel was to ck reaction and damage upon capsule water landing.
All-in-all, very interesting experience.
May 1, 2019 20:28:35 #
rgrenaderphoto wrote:
Because it looks cool and nobody else did it until recently.
Not totally true. There is an old and fairly rare Pentax super-tele-photo that was white. And I've seen a few other white long lenses, Minolta film era? But yes, Canon has a lot of long white lenses. And from my understanding for heat handling reasons. Why Nikon does not seem to need white paint might be an interesting question.
May 1, 2019 20:39:54 #
DaveC wrote:
I had read that the type of glass used in some of their lenses way back would actually crack due to thermal expansion of the surrounding metals. The white eliminated the problem. I also have read that the reason NASA picked Nikon was partly for that and partly because Canon glass tended to crack under the rapid acceleration of launch.
Not likely per G-force. Others have stated NASA's launch max at 4G. I am not going to verify that. But I do know that Top-Fuel Dragsters and Funny Cars in NHRA drag racing can experience more than 4G and up to -7G when the parachutes open! These cars can exceed 332 mph at 1000 ft! Point being, sometimes they have a camera on the car to show the run from the driver's perspective and the lenses don't crack. I also very much doubt any of those cameras are Nikon or Canon, more likely Go-Pro or something similar.
What are the G-forces on Fighter Jets?
May 1, 2019 21:50:38 #
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