jim_gardner4 Posted December 19, 2011 Share Posted December 19, 2011 <p>Further to my post of a week or so ago, I have now bought a Hasselblad PME51 meterd prism.<br> However, there is a problem. When I checked it against my seckonic spot meter it read just under 2 stops differnt. My first and obvious thoughts were, which one is correct and is the spot meter reading the same subject as the centre weighted Hass?<br> I then selected an evenly lit light toned wall and took readings with a Nikon F2AS, a cllibrated Nikon F2A, a Bronica with a meterd prism, a Pentax spot meter and a Seckonic spot meter. The difference between the "largest" and "smallest" measurment was half a stop. OK, now try the Hasselblad and it was approx 1.5 stops away from my average.</p> <p>So that all seems straight forward, the Hass must be wrong. Next I telephoned Hasselblad to see about sending it in for checking/repair. They said they would check it over but it was very unlightly it would be wrong because it uses "solid state circuitry" (I have no idea what that means) and while it is possible that it may be broken to the point of not showing any reading at all they virtually never show the "wrong" reading.</p> <p>Doeas anyone have experience of a Hasselblad metered prism showing incorrect readings and if so can they be mended?</p> <p>I did have the film speed and max app for the lens in use set correctly.</p> Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted December 19, 2011 Share Posted December 19, 2011 The first thing you should check is that you have the correct aperture set on the meter.<br>It does not suffice to set the correct ISO value. You must (!) also tell the meter what f/stop the light it is metering has come through.<br>So make sure that when you're metering through an f/4 lens, the lens is indeed open, and that f/4 is set on the prism. Link to comment Share on other sites More sharing options...
jim_gardner4 Posted December 19, 2011 Author Share Posted December 19, 2011 <p>QG Yes I understand. That is what I meant by the last line of my post.<br> I.E Film speed set the same of every camera and meter. <br> 2.8 set on the Hass meter for the 80mm planar I was using. D.o.F button not engaged.</p> Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted December 19, 2011 Share Posted December 19, 2011 Good.<br>Next thing to check: what type of screen are you using?<br>(And - screen and meter versions must match - is the meter prism the one you think it is? Does it say PME51 on it?) Link to comment Share on other sites More sharing options...
jim_gardner4 Posted December 19, 2011 Author Share Posted December 19, 2011 <p>Good point about wether it is actually a PME51. I have posted it to Hasselblad so cant check now. The screen is the standard one that comes in a 503cw so it would be an acute matt I guess. I am assused a PME51 is compattible with that screen and standard 501 screens but not with 500 cameras.</p> Link to comment Share on other sites More sharing options...
john_a5 Posted December 19, 2011 Share Posted December 19, 2011 <p>I have had issues with both of my metered prisms. I even sent in my PME45 and paid probably its retail used value, $800+ to have it fixed. That was several years ago but it hasn't worked right since--about 6-8 months after it was fixed. My PME90 worked longer, but it doesn't work properly now. I guess it is ok, since I prefer metering by hand anyway, but could have saved a lot of money getting prisms without the meter. I have to admit that these are my only complaints with regards to Hasselblads, I have both V and H systems. The H system meter has always been right on.</p> Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted December 19, 2011 Share Posted December 19, 2011 With screens being interchangeable, i'm afraid you need to check, no matter what type camera it is in.<br>Acute Matte D screens are easiest to identify by the D-shaped cut out in the rim of the screen.<br>The non-D Acute Matte standard screen is recognized by the reference cross not being painted on, but formed by raised lines in the plastic underside. You can also identify Acute Mattes by holding them up to the light: the optical elements create a repeating colour pattern, while the old style screens are just matte white.<br><br>There are lots of misleading advertisements, and sales, mispresenting screens (usually posing an old style screen next to an Acute Matte box), or prisms (any old style PME is often advertised as the latest model, and cameras that came with an Acute matte screen off factory are fitted with a cheap (in the region of $ 10 - 20) old style screen when they are sold, the seller hoping to sell the screen by itself for a bit more (in the region of $ 100 and up). So you always have to check and double check.<br><br>The Acute Matte screens were introduced quite a while ago, when the current metered prism finder was the 'original' PME/VFC-6. You can find many of these that are recalibrated to work with Acute Matte screens. Many others that are not. From the PME 3 onwards, the prisms were calibrated to work with the brighter Acute Matte screens.<br>Any mismatch will result in an error of about 1 stop: Acute Matte calibrated finder with non-Acute Matte screen will give a reading that's about 1 stop too low, and vice versa.<br><br>But even if there's no mismatch: meter prisms can be calibrated, and can also be out of calibration. No matter that they consist of solid-state electronics (no moving parts) or not. And if your prism's meter is out of whack, Hasselblad should have no problem detecting and fixing it.<br><br>As you will know, it's rather hard to have two different meters agree on what reading a certain scene should produce when metered. I'd consider a discrepancy between meters of 1/2 stop quite normal, nothing to worry about. So maybe if the extra 1 stop would be due to a meter-screen mismatch, the problem will be solved. Link to comment Share on other sites More sharing options...
jim_gardner4 Posted December 19, 2011 Author Share Posted December 19, 2011 <p>Q.G Looking at my screen, op the top side at the bottom of the left hand edge, there are 2 small semi circles cut out. Looking at the underside though, I would say the lines are raised.<br> When holing it to a bare, not frosted bulb, there is a "rainbow/starbust" type effect.<br> It has a split image.</p> Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted December 20, 2011 Share Posted December 20, 2011 It's an Acute Matte D screen.<br>So if the prism is indeed a PME 51, the two should work together and give correct readings.<br>Could well be that the meter needs calibrating. Link to comment Share on other sites More sharing options...
phil_hanson Posted December 21, 2011 Share Posted December 21, 2011 <p>So long as the reading is consistently "wrong" I wouldn't bother about it -- just compensate. If it's all over the place, that's another matter. I've used three metered prisms over the years (and now a built-in one in my 203FE) an have found them all reliable and accurate.</p> Link to comment Share on other sites More sharing options...
jim_gardner4 Posted December 22, 2011 Author Share Posted December 22, 2011 <p>Phil, Yeah I could but have only just bought it, so it annoys me a little that it is so far out. Still waiting for Hasselblad to look at it.</p> Link to comment Share on other sites More sharing options...
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