damien_kunik

<p>Thank you for your answer, Ray.<br>

Yup, those are jpeg files and a look at the histogram on Gimp shows that the dynamic range is badly clipped. I can't believe I am paying for that...</p>

<p>Well, I'm leaving Japan and all of the second hand market goodness but back home, I'll have at least a proper dark room and a good scanner to do things right.</p>

<p>Oh, and I should add that I used an 81A warming filter for the test to compensate for the slightly longer shutter times. Well, this is somehow counterproductive for the test but I somehow wanted the shots to turn alright as those are my last days in Japan for quite some time and there are still so many things I wanted to capture here.</p>

<p>Thank you all for the informations on the electronic issues that an old Mamiya 645 may face. I will definitely have the camera CLA'ed the next time I am in Tokyo, but where I am heading for the coming year, finding a repair shop is nearly hopeless.</p>

<p>Okay, the negs came back from the lab today. I've asked to have them scanned to check for inaccuracies on my computer screen and at first, highlights looked pretty blown out. I was devastated, as I am quite frankly a beginner and the learning curve is quite steep here: 1) first time shooting medium format 2) quite new to the use of a handheld light meter 3) and all that with a camera that I don't know and that showed seemingly inaccurate shutter times to begin with.</p>

<p>Now, as I still don't have more precise instruments, I checked again tonight with a stop watch and the shutter times are way more accurate. Maybe it's the camera coming back to life, but it's getting better the more I use it. So why the blown-out highlights?</p>

<p>Then I checked the negs themselves. There is so much more informations in there! Clouds have texture and skies have shades while it's just big white zones on the scanned image. Could it be that the lab seriously botched the scanning process and that my camera is fine?</p>

<p>Using a stop watch is nothing scientific indeed. It was just an easy -but telling- check.<br>

I shot 2 rolls today and will have them developed by a trusted pro lab tomorrow. Then I'll see. I obviously don't plan to fix the Mamiya myself if anything seems off. I save my unlicensed surgical skills for old Russian mechanical rangefinders. That being said, the above informations about shutter time testers are pretty interesting.<br>

On a side note, I'm in love with that camera. While cheap by today's standards, it was not an impulse buy and I was pretty sure that I would be pleased, but it is so much more than that... I'll have a hard time going back to my 35mm SLR now if CLA is necessary. It appears to me that I am definitely a waist-level finder enthusiast.</p>

<p>Okay, thank you very much for your answer and for the link. This tester is a clever piece of hardware. I will definitely build one.</p>

<p>As I said before, I will shoot a test roll and see if there are some noticeable inaccuracies on the color neg, but I don't think it will show. Dried out lubricant might well be the issue here and the camera has probably sat for a long time unused. I noticed that the more I test it, the more the shutter turns out accurate (although not 100% yet, I would say). So maybe the stiff grease was slightly slowing the shutter down and my repeated test shots helped a bit.</p>

<p>That being said, my camera is quite definitely in the 20-30% tolerance bracket now. Servicing will probably be in order anyway, at least to have the camera checked. But I really really want to shoot with this week, so I only hope that I will not make things worse.</p>

 

<p>Well, not sure if this matters as you don't seem too worried about the inaccuracy, but the M645 shutter is electronically controlled, not mechanical.</p>

<p>Hi,<br />I recently bought a Mamiya M645 (the original 1/500th one) which is my first foray into medium format. The camera itself looks like it has been very well cared for with zero sign of abuse. I only replaced the gooey light seals, which a job I am accustomed to on 35mm cameras.<br /> Back home, I tested the shutter time in the most simple way, using a stop watch. This means that I only tested "testable" shutter times from 1s to 8s. I have no more precise instruments around.<br /> Now, there seems to be an inaccuracy in those slow shutter times and while this question has been around the web here and there, I cannot seem to find a definitive answer.<br /> When I time a 1s exposure, the shutter seems to be open for a bit less than 2 sec. When I test 2s, shutter is open for about 3 sec. 4s is about 5-6 sec. 8s is about 11-12sec. Nothing super precise in my test indeed, but going from 8s to 11s is obvious enough even with my primitive method.<br /> Test was first done with a fresh 6v 4LR44 alkaline battery, then repeated with a 6v (labelled 6.2v here in Japan) 4SR44P silver oxide battery. The issue is the same in both case.<br /> While I never plan to use such long exposure times, I am a bit afraid that the problem might be the same with shorter ones. I'll shoot a test roll anyway, and color neg or b&w film will probably compensate for the noted inaccuracy, but I'm pretty bugged by the issue.<br /> Do you have any idea about such a problem? Should I care? Or is it normal reciprocity failure compensation built in on purpose for slow shutter speeds?</p>

<p>Hi Starvy,<br>

Thanks for the input. Actually, I am really more interested in film based pinhole. G10 is a great camera for me, even if I don't use it as often as I should. But As the lens is not removable (its a compact camera) I don't know if it can be turned into a pinhole.<br>

I'lle be a lot around here to learn!</p>

<p>Okay, so if I follow you right, considering the above-mentioned specifications of my future camera, exposure time on a sunny day sould be around 1 sec. Now, due to reciprocity failure (thanks for the Wiki link, Niels), there is a high chance that exposure time will be longer than what is specified by Mr. Pinhole and confirmed by Bob.<br /> Actually, I am afraid of an exposure time of 1 sec. This is way to short (in terms on pinhole photography indeed) for what I intend to build. I plan to have a shutter that opens manually, but 1 sec is quite quick. Below 2 seconds is too quick actually, with a high risk of shaking the camera around and blurring the image. You don't suffer as critically of that issue when you can calmy open the shutter manually for about 10 seconds... I obviously intend to use a tripod.<br /> Do you think that I should rethink my camera design or do you think that I will be safe with my design and that thanks to reciprocity failure, the exposure time will be longer anyway?<br>

Oh, by the way, I have a full box of Ilford XP2 Super 400ISO in 120. I understand that reciprocity failure is relative to each brand and type, but I am such a newb that I don't know if I'll have some latitude about exposure time with that specific film. ISO400 is maybe quite high, but that's what I have around, so...</p>

<p>It's true that Holga doesn't specify a film speed for the Holga Wide 120, but anyway, I guess it's a common one. Even between 100 and 400 ISO, I don't see anything justifying such a difference in exposure time. Still wondering...</p>

<p>Hi,<br>

My name's Damien. The introduction is done in the New Users Introduction thread, so here's my first question.<br>

I'm planning to build my first pinhole camera. The aim is to do it right on the first shot (i.e. learning as much as possible along the way and avoid finishing with a totally unusable brick). I intend to make a wooden pinhole camera with a focal length of about 4-5cm to be used with 120 film. For now, the exact focal length is not critical. I'll calculate the optimal pinhole diameter in regard to the exact focal length once the body is done.<br>

I am using Mr.Pinhole for my calculations. This is a nice website that I'm sure all of you know about. The thing is, for a pinhole camera with a focal length of about 4-5 cm an a pinhole sized accordingly (say between 0.2-0.3mm), Mr. Pinhole says exposure time on a sunny day shoud be around 1 second.<br>

Here comes the weird part. For a ready-made pinhole camera like the Holga Wide 120 that shares much of the specifications of my camera to be (focal length and pinhole size), the recommended exposure time on a sunny day is about 7-9 seconds.<br>

I understand that pinhole building is about experimentation, but damn, going from 1 sec to 9 sec is quite a leap.<br /> What is it that I don't get?<br>

Thanks for your help!</p>

<p>Hi,<br>

My name's Damien, I live in Tokyo. I know next to nothing about photography. My father was a professional photographer, and maybe because he tried so hard to share the science, the subject seemed quite boring to me. I bought a nice Canon Powershot G10 three years ago that mostly sleeps in a drawer. That says much about my interest until now.<br>

I say "until now", because everything changed when I heard about pinhole photography. The experimentation, the DIY philosophy, the unpredictable results... I am hooked!<br>

Sadly, the father's not here anymore, and that's why I'm turning to you all. I know next to nothing, but I am willing to learn, and I can be a fast learner!<br>

So, I hope I'll find some help around. And I hope I'll be able to give some help to newbies like me in a (hopefully) not so distant future.<br>

<br />Best regards.</p>