What's this called ?

<p>I got this in with a bundle of other stuff.I'd like to know what it is for and whether there is some part of it missing . Is it something to do with slide viewing ?<br>

<img src="http://s20.postimg.org/617nayftp/DSC_0001.jpg" alt="" width="459" height="378" /></p>

 

<p>It's a porro prism for a Mamiya TLR camera made by Nippon Kogaku (Nikon). Ebay seems to be littered with them for some reason.</p>

<p>Just do a Google search for Mamiya porro prism.</p>

<p>That looks like a pentaprism viewer for an old nikon SLR to me. It should just slide on to older interchangeable prism SLRs. It could be something else but I don't know what it could be</p>

I think Joe must be right. My first thought was also that it must be a prism for an F or F2 but I don't think they ever made

any under the Nippon Kogaku brand. Is the opening square? That would indicate it's for a medium format camera e.g. an

older Mamiya. I've seen these on C3 and C220 cameras.

<p>Rodeo is correct. I have one of the versions (I forget which without pulling it out to look at it) on my my Mamiya C330. They made one that was built with mirrors inside and a better one with an actual solid prism. I think they called the one with mirrors a porrofinder and the one with a prism a prism finder, but the two are very similar.<br /><br />If you put a ruler on the bottom opening you'll find that it's roughly 2.25 inches square. The opening on the bottom of a Nikon SLR finder is about 1x1.5 inches.</p>

<p>Just search Google images as I suggested above, you'll see pictures of the identical item being sold as a prism finder for the Mamiya C22, C33, C330 etc. TLR cameras.</p>

<p>I knew I'd seen one before a long time back, but couldn't quite place it until I did a bit of Googling. Ugly great lumps those Mamiya TLRs, and not made any prettier or lighter by the addition of a dirty great prism stuck on top. An interchangeable lens TLR? I wonder what fool came up with that idea? And how it wasn't laughed off the drawing board.</p>

<p>Many thanks for all your responses. The 'other stuff' was an old NIKON F camera and some slide making equipment and some other make cameras. The aperture is about 2 3/4 '' square and the thing contains two mirrors. So I just need to find the right camera -- the Mamiya camera looks the place to start.</p>

<p>Many thanks once again.</p>

<p>Spot on. Cheers.<img src="data:image/jpeg;base64,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" alt="" />

</P>

 

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<A HREF="http://www.leitzmuseum.org/CameraMakes/TLR/1976-Mamiya-C330f-3.jpg">http://www.leitzmuseum.org/CameraMakes/TLR/1976-Mamiya-C330f-3.jpg</A>

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<p>The aperture fits the frame size for 6x6 plus some area on the side that's blocked off by camera mechanisms. 6x6 is a common frame size for cameras that take 120 and similar medium format film. The film is 6cm wide, and 6cm is the nominal frame height as well. (Other common formats that take the same film use 45mm, 70mm, 80mm or even 90mm frame heights.) You take off 2mm each side to get the exposed film area of 56x56mm. This is definitely Mamiya fit and will work on several of the Mamiya TLR models, though I don't know if all the models support interchangeable finders. I have a C220 and it looks like it would accept a finder like that.</p>

<p>The Nippon Kogaku version seems to be called a porroflex.</p>

<p>Thanks for the responses. Following your inputs I came across the thread :<br>

<a href="/medium-format-photography-forum/004fTL">http://www.photo.net/medium-format-photography-forum/004fTL</a></p>

<p>so the R stands for Rorroflex ?</p>

<p>And the slide sized stuff has Rollei and Rolleikin written all over it so probably has little to do with slides.<br>

Please forgive idiot questions : The Nikon F bits consisted of camera and viewfinder. Presumably the black pyramid on the camera is removable and gets replaced by the separate viewfinder. Why ?</p>

<p><img src="http://s20.postimg.org/4ro2ki74t/DSC_0006.jpg" alt="" width="471" height="312" /></p>

<p>The black pyramid is the pentaprism, it bounces light around so the image you see in the viewfinder isn't upside down [unlike a waist level viewfinder]. I think the reason they made them changeable was because some people might want to swap out older prisms for newer brighter prisms, or a viewfinder with a built in meter as opposed to the non metered variety</p>

The different finders have different features. The one on the camera is a simple finder. That would have been the default

option in the least expensive. The other one has a built-in light meter.

<p>Which is presumably why the aperture teeth on the lens connects to the separate viewfinder and is irrelevant for the pentaprism bit.<br>

Many thanks for your answers.</p>

<p>The Mir website has loads of information on the Nikon F system and the wide range of finders available for it.<br /> The metering "Photomic" viewfinder you have looks like the original and first model.</p>

<p>The Mir site is here: http://www.mir.com.my/rb/photography/hardwares/classics/michaeliu/cameras/nikonf/ffinders/fmeterprism.htm</p>

<p>BTW. The lens attached to the camera looks like it might be the 55mm f/3.5 micro-Nikkor. Nice lens if it is! It might be the version with automatic aperture compensation, and worth a bit more to a collector than the later non-compensated version. Not worth a fortune, but worth advertising for sale at maybe $100 or so.</p>

<p>Many thanks for the heads up. Micro-NIKKOR Auto 1:3.5 f=55mm Nippon Kogaku No. 197046.<br>

May be some compensation for the camera which seems to have a bit of play on the rhs back plate.</p>

 

<p>"So I just need to find the right camera -- the Mamiya camera looks the place to start."<br /><br />This porrofinder will fit on any Mamiya C220/C330 TLR.<br /><br />I agree with Rodeo that the Mamiya TLRs were big and clunky. I used them for a couple of years when I was first starting off because that's what the newspaper I was at gave us, and I still have one that I picked up later. The upside is that they are built like locomotives and virtually indestructible. They were much cheaper than a Hasselblad and were very popular as wedding and portrait cameras. I didn't see anything at all wrong with interchangeable lenses on a TLR. Made a lot more sense that Rollei's idea of selling a wide angle camera, normal camera and telephoto camera with fixed lenses. </p>

<p>Actually the plain black Nikon F prism finders are sought after and probably worth more than the large metering finder, if not more than the camera itself. Its probably because the metering finders often don't work properly nowadays.</p>

<p>By the way acquiring an accessory amongst a bunch of other stuff, and starting to want a camera to fit it, is a risk factor in the slippery slope to becoming a collector.</p>

<p>Martin, what you have there in addition to the plain prism is the original Photomic finder. This had a fully coupled meter, but did not read through the lens, but rather through the window on the front. There is an accessory tube screwed to the side, which is used for telephoto lenses, and, if I recall correctly, a white screw on cover under that for use as an incident light meter as well. </p>

<p>I had one of these long ago, and it worked pretty well, but it was a fully averaging meter, and the aiming of the telephoto tube was always a little suspect, as its precise aim depended on how well the prism clamping mechanism in the camera worked. Later Photomics had a more secure clamping system. </p>

<p>I believe old Photomics, if still working, might be worth a little more than some of the other meter prisms, but if not working, it's not much use at all. It used a single mercury battery, and like all Photomic F meters, it needs some compensating or recalibrating to work properly with modern batteries. It also is not automatic indexing, which means that every time you install a lens, you must check or reset the maximum aperture on the meter.</p>

<p>Oddly enough, it was more common in those early days to have a black finder on a chrome body than the reverse. </p>

<p>If I were keeping this camera to use I'd stick with the plain prism unless it's damaged. Because the old Photomic doesn't meter through the lens, its only advantage over a hand held meter is the coupling, and when I had mine, I generally used it only as a starting point anyway. </p>

<p>Depending on the age of the camera, it may not accommodate later meter finders without some modification. But a black plain prism F is a beautiful thing anyway, so I'd stop right there. </p>

<p>Thanks for your comments. I agree the black prism affair looks smarter than with the separate viewfinder attached. Its a pity though - the separate viewfinder seems to be in pristine condition. Random button pressing elicits no response from the meter however.</p>

<p>I would be surprised if the battery in the Photomic meter is still good. It's been many years since I had one, but as I recall the batteries live under a cover on the right side. The earliest Photomics did not have the tele and incident light adapters attached. This one has its battery (or batteries, I forget) underneath those.</p>

<p>Unfortunately, Nikon battery boxes, including this one, I think, have one contact on the side, rather than the end, of the battery, and because of this you cannot use a smaller battery with an O-ring. You must either fudge it with foil, or use metal rings. There do exist alkaline batteries in the correct size, which I think you can still get from Radio Shack. The mercury batteries are long gone, and I believe that the silver oxides, which were the best option for modernizing, are also gone. You can get Wein cells, which fit the voltage right, but they're a bit expensive and short lived. </p>

<p>It isn't necessarily for a Mamiya. I had a Nikon porroprism for a twin lens Rollei. Lightweight but a smaller and dimmer image than the real thing. </p>

<p>Many thanks. Would the fit be specific to Rollei. Thread noted above mentions porroflex with R inscribed, presumably for Rollei ? On google there are porroflex's with M inscribed, presumably Mamiya ?</p>

<p>Many thanks for all your inputs. This seems to clinch it :<br /> <a href="http://www.dzp-camera-cafe.com/#!product-page/cg7d/2319074e-812c-8aea-d015-4d3d17752786">external link with similar item for sale from DZP</a><br /> The item was a Porroflex for Rollei TLR cameras.<br /> Sorry about the post in a Nikon forum but I was fooled by the company it was keeping and the Nippon Kogaku make.</p>