Mamiya C330f - focus screen foam replacement advice please

[peter_b__sydney_]

<p>Arrgh. I just checked my focus again this morning after changing nothing and it is off again. I thought I had this problem licked :( The only things I haven't yet tried are<br>

1. adjusting the mirror 2. swapping lens shims 3. adjusting the 3 factory trimmed vertical posts in the body that press against the underside of the viewing screen.<br>

The discrepancy distance is about 0.6mm horizontal movement of the focus rail.<br>

Can anybody give me any other suggestions to try ?</p>

[christiaan_phleger___honol]

<p>That is a big shift. That is also a big (!!!) sign when the lens board doesn't sit flush. I'd check first that the lens board (where both sets sit on) is flat and true. That very well could be the problem, usually cause by impact or trying to pull off the lens groups without undoing the spring latch. <br>

Don't touch the factory set posts. Don't do the mirror, unless there is clear evidence that the mirror has been altered (the red Loc-tite style thread holder is off or misaligned) . I would re-Check the spacing of the lens pairs, by unscrewing the front of the taking lens group, (this is usually where a tech would place a shim, Mamiya factory shims are brass and very thin). Swap the shims around or remove them.<br>

I would take the effort to test the body with film. Setting up a focussing screen on the film rails creates more potential errors than solves IMO. Good luck!<br>

The originator of the demise of the mismatched lens pair, Christiaan.</p>

[peter_b__sydney_]

<p>Christiaan, thanks for chiming in. I appear to be getting inconsistent results. One set of measurements results in no discrepancies, another does. I have been doing this testing at distances of 0.6m, 3m, 15m and about 80m.<br>

I did notice a brass shim seated in the thread of the taking lens' front elements. I can try and take it out or swap it to the viewing lens. I'll also check the other things you mention.<br>

<br />Through searching, I am discovering that calibrating the focus of a TLR is not necessarily an easy job, well I mean it doesn't seem to be documented fully in one place (except I assume in my camera's service manual which I really need to purchase for about $35 on eBay - yet by the time it arrives I probably would have solved the problem !!).<br />Up until now I haven't worried about ensuring the taking lens focuses properly at infinity. (see <a href="http://goo.gl/0G2EY" target="_blank">here</a> , <a href="http://goo.gl/PSg8q" target="_blank">here </a>and <a href="http://goo.gl/y7oih" target="_blank">here</a>). Some posts also indicate the distance scale needs to be correctly aligned. I don't even use my distance scale. I'm learning about backsighting, collimation etc. etc. Why haven't those points been mentioned in any C330 discussions I have read ?</p>

[peter_b__sydney_]

I'll limit my responses to the following APUG

thread and summarise here once I have solved

the problem.

 

http://goo.gl/rQI0l

[contrabass]

<p>Carl, thanks for posting this guide. My C330 needs this performed, too, so it's good to see what goes into it.<br>

Now for my dumb question. :-) Where did you find 3mm thick (roughly 1/8") black foam rubber? For just $1.30 no less? My searches are coming up with some 1/16" and 3/16" options, but that probably doesn't help me much.<br>

(And now I'm noticing that while there are more recent responses in 2012, Carl posted originally in 2007. Anyway, maybe someone else can give me a lead on this?)</p>

[peter_b__sydney_]

<p>>Where did you find 3mm thick (roughly 1/8") black foam rubber? For just $1.30 no less? <br>

Hi Thaddeus ,<br>

I purchased a foam kit for my C330f when I replaced the door seal. I bought it from Jon Goodman on eBay, his website/instructions are here:<br>

<a href="http://www.kyphoto.com/classics/sealreplacement.html">http://www.kyphoto.com/classics/sealreplacement.html</a><br>

I then used foam from that same kit to redo my viewing screen recently. I can't remember if I checked for the exact thickness but it certainly works well.</p>

[peter_b__sydney_]

<p>As promised, <a href="http://goo.gl/ewR92">here</a> are two posts of my summary for how I finally solved my C330 focus issues.</p>

[ron_miller5]

<p>Carl,</p>

<p>Just wanted to thank you on this. I bought a C330f a few weeks ago along with 80, 135, and super 180 lenses. Focus was soft and I happened upon this thread. I followed your instructions using some GG I had made a while ago for my 4x5 cut down. Images from all 3 lenses are tack sharp.</p>