drew_persson

<p>Hi Andre, would you be so kind as to compare and contrast the image quality of 210mm KL APO vs the 250mm KL APO? Thank you!</p>

<p>Ooops, I posted a bad link and no way to edit, use this one instead: <a rel="nofollow" href="http://www.phototurbo.com/mediumformatentrancepupil.php" target="_blank">Medium Format Lens Entrance Pupil Data</a>.</p>

<p>I couldn't find much information about the entrance pupil locations for Mamiya and other medium format lenses, so I measured mine and started a chart on my web site:<br /><a href="http://www.phototurbo.com/medium_format_lens_entrance_pupil.php/">Medium Format Lens Entrance Pupil Data</a><br />Hopefully it'll help someone out, if anyone has more medium format entrance pupil data just let me know and I'll add it to the chart.<br />Drew</p>

<p>Just make sure you're turning the ring the right direction! Counter-clockwise with the lens facing you.</p>

<p>I picked up a brand-new RB67 250mm KL (part of a four lens order from Japan) at a good price, & posted it for sale on the forum here. Still in the factory box and wrapping, haven't even broke the seal to take it out of the box. Will sell outright or work it into a trade for a used 350mm APO.</p>

Thanks for the info Bob, apparently there is a 250mm KL APO as well. (Earlier I was under the impression that the 250mm wasn't available with APO glass.)

I searched quite a bit and couldn't find anyone comparing these two lenses. I read that they're both great but

suspect the 210mm probably has an edge given it's healthy price premium.

 

Comments and experiences? Is the 210mm worth the extra money? Thanks!

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.

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.

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.

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.

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>