Viewfinder Issues

[cody_kurtz]

<p>So I'm incredibly new to the Medium Format photography world but just purchased a used Mamiya M645 at my local camera store. Got a few lenses and I'm super stoked to get to shooting. Only problem is the viewfinder. At the store, the guy showed me that there's a line of residue in the prism that's going to throw off my focusing. Does anybody know of a good website where I can get a better one? Probably going to end up getting a waist level finder but would really prefer an eye level one. </p>

[User_502260]

<p>This issue is common with Mamiya M645 prism finders. They can be repaired. KEH and eBay would be the first two places to look. The Bronica ETR series prism finders are made differently and I have never seen the problem in one of them. A waist level can be awkward for vertical framing when used with a camera which has a rectangular format. I use the waist level finders with these cameras mostly for copy work. I like the waist level finder with my Bronica SQ series cameras. The Mamiya RB67/RZ67 cameras have the revolving back so as long as I pay attention to the lines on the focusing screen, using a waist level finder is fine. </p>

[paul ron]

a line of residue? take the prism finder off n see

what and where it is?

 

there is a problem with old prisms that had foam sitting on the peak inside the housing. the foam rotted and the silvering on the sharp line of the top glass deteriorated. this shows inside as a line.

 

if you're handy, open the housing and clean it. not much inside a prism finder. most prisms are fully glued together aside from the eye piece diopter.

 

btw: it has nothing to do with throwing off focusing, just looks strange as im sure your residue also has no effect on the actual focusing.

 

you'll hate a wlf, reverse n upside down and not as bright or sharp with so much stray light entering it.

[ondebanks]

<p>The line you see in the viewfinder will have no effect on your focusing. It might irritate you seeing it there, that's all. It's a relatively common defect as these prisms age, and many people just get used to ignoring it.<br>

I would not say that the repairing the prism is economical, unless you do it yourself.</p>

 

[ondebanks]

<blockquote>

<p>you'll hate a wlf, reverse n upside down and not as bright or sharp with so much stray light entering it.</p>

</blockquote>

<p>Only if you don't use the flip-down magnifier, which also keeps out stray light. With the magnifier, the WLF on the M645 is the brightest viewfinder I have ever used on any camera - and also offers the largest, most detailed view of the entire focusing screen. It is the only thing I really miss with my fixed-prism 645AFD body.</p>

<p>Also, a WLF never makes the image upside down - the reflex mirror corrects that orientation before the image reaches the focusing screen. But it is true that things appear reversed left-right in a WLF.</p>

[david_smith35]

<p>Absolutely agree with Ray Butler - used with the magnifier, the WLF is by far the biggest and brightest view of the focussing screen. A prism will always be dimmer, but a necessary evil on anything other than square format.</p>

[kirk_strauchler]

<p>I know this is a late response, but....</p>

<p>Paul and Ray are correct as to what the line is - desilvering of the mirror because of the old foam. It can not be cleaned, as the silver is gone from the mirror. Any attempt at cleaning would most likely make it worse. Also, getting into a prism finder isn't easy or worth the trouble IMO. Cost to repair it would be more then a replacement prism would cost you. <br>

A waist level finder for the M645 series is not cheap, to the point where I think the prices for them are ridiculous. <br>

If the line annoys you too much, or is so bad that you can't focus through it, you can get a different prism from ebay or KEH. If looking for one on ebay, make sure there is a photo from the bottom, which shows the area that the line will form (use yours to see where that is). On KEH, you'll want to get one with an EX or better rating, which should ensure that line is not present.<br>

Keep in mind that a prism finder that doesn't have the line now, will one day. The foam isn't getting any younger.</p>