Dust inside Mamiya 50mm RZ ULD elements, how bad is this? (photos)

[drew_persson]

Just received this used but "mint" Mamiya 50mm RZ67 ULD lens from an online dealer (not KEH, btw) for a decent

price. Description said "some internal dust but nothing that would effect image quality".<p>

 

If I shine a flashlight through the lens there are lots of tiny particles spread evenly across the internal elements.

These don't worry me, but four of the dust particles are MUCH larger than the rest (chunks of something, as opposed

to fine dust), am I paranoid to consider returning this lens? And these particles aren't inside the front element,

they're somewhere in the middle of the lens. (really hard to tell where they're located) Having the lens disassembled

and cleaned would wipe out most of my savings compared to a nice used one from KEH.<p>

 

Here are photos of the larger three particles.<p>

 

Particle in center of image circle:<br>

<img src="http://www.phototurbo.com/temp/mamiya50center.jpg"><p>

 

Particle along edge of lens:<br>

<img src="http://www.phototurbo.com/temp/mamiya50edge1.jpg"><p>

 

Another particle along edge of lens:<br>

<img src="http://www.phototurbo.com/temp/mamiya50edge2.jpg"><p>

[martin_ywain]

I think you were conned. Those look like huge specks of dust to me, it will show as shadows on your image. I had

fungus in my Canon 50mm f1.8 mk II before and it appeared in my images, the fungus in comparison looks much smaller.

 

I doubt cleaning it would cost 919USD - EX+ price from KEH... ask around the local shops for more quotes. If the

cost + cleaning costs close to or less than 900USD, don't bother sending it back. There's no guarantee that a

"new" one from KEH would be significantly better.

[craig_supplee]

Seeing as how you already own the lens, why don't you just take some shots with it to determine if there is a

problem. I doubt very seriously if you will get any shadows from those specs. Try to shoot an evenly lit light color

wall. If you do a google search on lens dust and the like, you will find info on lenses that have far greater problems

that take exceptional pics. Won't know until you try though.

[sattler123]

It seems that something is flaking off the lens - could be famous Schneideritis. The only way of knowing if it will impact your pictures is to use the lens and see what you get, What would worry me more is the future of this lens - is the flaking gonna get worse? Will there be bigger chunks coming off? Honestly, if I were you, I would return the lens. You will always wonder if it still OK to use.

[greg_jones1]

More than likely, someone has opened up the lens probably by unscrewing the rear lens group. I have this same lens, but have not had it open as it has never been needed. However, I often find used lenses that someone obsessing over a molecule of dust have opened up the lens to clean it, usually leaving it in dirtier shape than when they went in. In your case, these specks should be removed. In looking at my 50 ULD lens, it appears that a spanner wrench (such as those from Micro Tools for this purpose) can easily unscrew the rear lens group. Then you can use compressed air to blow out this crud. (Do not use the stuff that comes in a can from Comp USA!!!) I dont know how the front of the lens is built, or how complicated due to the floating element system. If you are not confident doing this then send it either to MAC or your local competent camera repairman. Cleaning this stuff is not a big deal for a competent repairman, believe me.

[drew_persson]

I got it for about $300 less than an "EX" condition lens from KEH, and read that Mamiya charges about $190 to clean a lens. With shipping I'd end up pretty close to the cost of a nice one from KEH.

 

I'll see if I can get a spanner wrench locally and crack it open (couldn't make it any worse), I'm a hobby machinist and fairly mechanical.

[drew_persson]

Forgot to mention; I can't take any test shots because I bought the lens for a Cambo Ultima 35 project I'm building.

(don't own a MF body) I still have to make an RZ lens panel for the view camera, and the return period for the lens

will expire before

I have time to machine an adapter.

[drew_persson]

By closing the shutter & using a flashlight I figured out where the particles are located; they'e pretty close to the front element (second or third surface back) so it's probably fine. The dust appears to be above the floating element section, so I'll probably get a rubber ring tool and take off the first few elements and see if I can't make it worse.

[greg_jones1]

Drew-

 

I would use extreme caution on this lens, particularly on the front side. Sometimes these dust particles appear to be in places where they are actually not. I would unscrew the back group first, blow out with compressed air, and see if that doesn't cure the problem. DO NOT TAKE APART THE LENS GROUP COMPONENTS (i.e., individual lens elements).

 

This lens has 15 elements in all, some of which are in the front "group" and some of which are in the rear "group" behind the shutter. The part that I am recommending you unscrew, with the optical spanner wrench, is the rear group. I would even bet money that these chunks are between the front and rear groups, where the shutter is located. Whatever the case let us know how you make out.

[greg_jones1]

By the way, did you get this lens from Adorama? Just curious, seems any used lens I buy out of Nuevo Yorka seems to always have this kind of crud.

[drew_persson]

Bought it from TMR Promotions on Fleabay. Their response email said the auction said there was dust (and that the

price reflected the dust), but this is more like Schneideritus. They said they would take it back however, or they

would have their repair facility clean it for $75 plus shipping both ways.

 

I'm pretty confident the particles are on the front side of the shutter, I stopped it down and could see the chunks

between the blades and the front glass. There are even more little white specs around the periphery, on the black

housing. I ordered a spanner from SK Grimes and a 77mm rubber lens ring tool off Fleabay. I'd take your advice and

see if the particles can be moved with air from the back of the lens before I crack open the front.