Dust removal for the 50mm f/1.2 (middle elements)

[richardHaw]

https://richardhaw.com/2016/05/01/repair-nikkor-50mm-f1-2-ai-s-dust-removal/

a simple routine maintenance

[armando_m]

Very nice write up

[richardHaw]

Very nice write up

Thanks, Armando!

[simsurace]

Very nice. When I got my 50/1.2 it had grains of sands inside. I had it cleaned by a professional, but with these instructions I should be able to do it myself next time.

[richardHaw]

Very nice. When I got my 50/1.2 it had grains of sands inside. I had it cleaned by a professional, but with these instructions I should be able to do it myself next time.

hi! those are not sand grains but chipped paint from the element and loctite
it is an indication that the lens has been worked on prior.

a history of my 50 1.2

december: bought brand new
the next day: asked for a replacement because the lens is soft @1.2
the day after: the replacement sucked even more
next week: sent to nikon for recalibration
3 wks after: nikon called back, will send to factory
4 more wks after: got it back from nikon. now sharp at 1.2!
the next day: sent it back to nikon, oily aperture (how? i dont know)
after a day: oil cleaned for my use in CP+ (NPS is awesome)
the day after: found some junk inside
later that wk: i decided to clean this myself

so there you go

[richardHaw]

this just shows that buying brand new is not a fool-proof thing nowadays. and on a manual lens no less!!!

[simsurace]

The seller told me it was sand. It looked like it for sure (red-brownish, gritty) but I would not know if it was from a different source.

It's really handy if you are able to service your own lenses.
What about alignment? Is it at least conceivable to do this on your own?
The technician I brought my lens to has all sorts of collimators to check alignment.
But I wouldn't even know where to begin adjusting individual lenses. How is this done normally? Are the lenses designed to be re-positioned via some screws?

[Akira]

hi! those are not sand grains but chipped paint from the element and loctite
it is an indication that the lens has been worked on prior.

a history of my 50 1.2

december: bought brand new
the next day: asked for a replacement because the lens is soft @1.2
the day after: the replacement sucked even more
next week: sent to nikon for recalibration
3 wks after: nikon called back, will send to factory
4 more wks after: got it back from nikon. now sharp at 1.2!
the next day: sent it back to nikon, oily aperture (how? i dont know)
after a day: oil cleaned for my use in CP+ (NPS is awesome)
the day after: found some junk inside
later that wk: i decided to clean this myself

so there you go

Rick, where did you take your lens for calibration?  You should have gone to the Nikon service in Ginza, not Shinjuku.  The people are nice at both service centers/showrooms, but, for whatever reason, the repair sucks when you give your camera/lens at Shinjuku.   

I've taken my lenses for repair several times to Shinjuku service several times over the years, and the repair sucked.  I talked about my experiences to a couple of people (including a friend NPS photographer and the manager of Nikon House in Ginza), and they told me that I should ask at Ginza service for repair.

[richardHaw]

The seller told me it was sand. It looked like it for sure (red-brownish, gritty) but I would not know if it was from a different source.

It's really handy if you are able to service your own lenses.
What about alignment? Is it at least conceivable to do this on your own?
The technician I brought my lens to has all sorts of collimators to check alignment.
But I wouldn't even know where to begin adjusting individual lenses. How is this done normally? Are the lenses designed to be re-positioned via some screws?

oh, i have no way of doing that. i just measure things by eye and by the marks that i do. i would use a caliper from time to time

so long as you do not disturb the optics then it should be OK. some lenses are more sensitive to this. most are OK.

[richardHaw]

Rick, where did you take your lens for calibration?  You should have gone to the Nikon service in Ginza, not Shinjuku.  The people are nice at both service centers/showrooms, but, for whatever reason, the repair sucks when you give your camera/lens at Shinjuku.   

I've taken my lenses for repair several times to Shinjuku service several times over the years, and the repair sucked.  I talked about my experiences to a couple of people (including a friend NPS photographer and the manager of Nikon House in Ginza), and they told me that I should ask at Ginza service for repair.

yes, that is what they told me. for advanced repair, go to ginza
maybe it is because shinjuku was re-opened in 2010 (i remember that it was a big thing) and most of the important staff is in ginza. but that is OK. i am now happy. but it was really 面倒くさい to go back and forth and arguing that my lens sucks and is below nikon standard

[simsurace]

oh, i have no way of doing that. i just measure things by eye and by the marks that i do. i would use a caliper from time to time

so long as you do not disturb the optics then it should be OK. some lenses are more sensitive to this. most are OK.

I see.
I just wondered whether the lenses are designed to be adjustable in that way.
If I understand you, when you get a lens which has had a bad knock you have to give it to someone else to realign its elements?
When you remove entire groups of elements such as when cleaning the 50/1.2, you don't run the risk that the elements will be put back in a slightly crooked fashion, giving e.g. uneven sharpness across the frame?

[richardHaw]

I see.
I just wondered whether the lenses are designed to be adjustable in that way.
If I understand you, when you get a lens which has had a bad knock you have to give it to someone else to realign its elements?
When you remove entire groups of elements such as when cleaning the 50/1.2, you don't run the risk that the elements will be put back in a slightly crooked fashion, giving e.g. uneven sharpness across the frame?

giving you unequal results over the frame is very possible. however it is very hard to see unless you go out of the way to test it.

realigning a lens needs special tools (collimator). in case of a bad knock or a bad batch (like my case) only a collimator will fix that.

with manually cleaning stuff, the only case of getting the tolerance wrong is when tightening an element's casing. there are times when a lens focuses to infinity fine before you open it but after you put the lens back together, the lens will not focus to infinity properly. the cause is maybe you have over tightened the casing for the rear element too much or not enough at all. the spacing of the rear element is crucial to focusing to infinity as it is the exit point.

i am not a lens scientist so i am pulling this all up from my ass hahaha

[Akira]

but it was really 面倒くさい to go back and forth and arguing that my lens sucks and is below nikon standard

LOL!  That coincides exactly with my experiences (plural form, unfortunately).

[Erik Lund]

So, how much dust is now in the lens,,, 

[richardHaw]

So, how much dust is now in the lens,,, 

not much. at least not the ones that i see originally

the ones that i saw were chipped paint from the glass element. they look like salt and pepper that is the closest thing i can think of. they are surely going to be visible on the bokeh.

what is left now are small ones that i find acceptable because they are not visible unless you flash a LED. maybe less than a handful