FILM Camera Shutter Speed Tester, Ext Light Meter

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rfrazier

Well-known member
Sep 30, 2020
320
100
Hi all. This is definitely off topic for @Steve 's normal fare for this group. But, then again, that's why it's in the off topic forum. Still, it just might tweak the interest of some of you.

I am an amateur photographer that now has 3 fairly nice entry level digital cameras: Canon 250D / SL3, Canon M50, and Canon SX170.

BUT, recently, my wife picked up a 40-50 year old Mamiya 35mm FILM camera. The 500 TL. I've been researching how to get it up and running. Unfortunately, the light meter is inop even with a new battery. I spent a good bit of time trying to find a small affordable external light meter. I've got the following one on order, which looks pretty cool:


Thought I'd pass that free tip along. But, I need some help from you. I also want to test the speed accuracy of the shutter. That's where it gets more complicated. I've been having an extremely hard time finding a competent gadget to do this. I really don't want to build it myself. I did find a device called a PhotoPlug which plugs into a phone or tablet microphone jack and links with an app on the phone. This will be better than nothing, and I've ordered one.

The problem is that a dual curtain focal plane shutter is a bit more complex than just a simple momentary opening for light. There are two curtains that both block the light path. One of these will open, and the other will open slightly later. They traverse across the film window together forming a traveling slit which slides across the film. A single sensor can measure the time period of the light exposure at a specific point. But, it cannot measure the 1st and 2nd curtain speed nor the difference between the two. If they are different, different parts of the film frame will get different exposure.

I found this really great looking product but it's discontinued:


There's also this one from Romania on Ebay:

Camera shutter and curtain tester for speeds up to 1/8000th with light source

This might be a good option, and in fact, the inventor of the prior device says this second one is a good product.

However, I wanted to pose this question to you all and see what you know. So, do any of you uber geeks out there have a better way to do shutter speed tests on vintage film cameras? Budget wise, $ 100 is about my limit for what will be mostly my wife's hobby. Buying and processing film seems to work out to about $ 1 / print these days. A finished product would be preferable. A kit would be acceptable. A full DIY from scratch option would be my least desirable choice.

All help is appreciated.

May your bits be stable and your interfaces be fast. :cool: Ron
 
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Sep 17, 2020
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The problem is that a dual curtain focal plane shutter is a bit more complex than just a simple momentary opening for light. There are two curtains that both block the light path.
I thought the curtains travelled the same speed across the film, no matter what the speed set. It was the size of the slit that varied when you changed the shutter speed to expose the film. Smaller slit, less time. This would also explain how you could have long exposure times, ie one curtain opens, the other follows some seconds later. I think I proved the size of slit theory by looking at the shutter opening in front of on old CRT TV (strobe effect) and seeing the slit move. I don't know if this is going to help you though, just an observation.
 

rfrazier

Well-known member
Sep 30, 2020
320
100
I have a Mamiya Sekor SLR film camera that I haven't used for decades. Why all the fuss about extreme accuracy for film? I would just get the light meter, take some test photos, and see how they come out?
@Barry Wallis I haven't shot film in decades either. Since my wife bought this old camera, I was trying to figure this out. I just figured that if the shutter speed is off and the prints don't match what the light meter predicted, then that would be very frustrating, and expensive at about $ 1 / print for film and processing cost. I figured it would be better to know about a wonky shutter beforehand. But, you do have a point about experimenting.

Interestingly, since I posted this post, I've been studying cameras, including film cameras, for hours. My niece has an application in which film may be preferable to digital. She wants to get into semi professional photography of people's pets with high quality giclee prints. Apparently, the potential clients have money and are very persnickety. So, to print giclee's, the studio wants originals at 300 dpi at the final print size. If you run the numbers with a 24 MP $600 ish outfit like my Canon M50 and Tamron 18-270 mm lens, that camera produces a 6000 x 4000 pixel image. If you want 300 DPI in the final print, then that works out to only 20" x 13". This isn't big enough. Going to a medium format digital camera would cost $ 5,000 - $ 10,000. That's not happening.

I found this article which compares digital to film:


This says a frame of 35 mm film contains the equivalent of about 20 MP to 23 MP. So, you probably couldn't enlarge it much bigger with giclee quality after scanning the negative. BUT, I ran the calculations and you can enlarge a 6 cm x 6 cm negative to about 30" x 30" at giclee quality. Now we're talking. And, a 6x6 medium format camera can be had in the same $ 600 ish price range, if it works being decades old.

So, for these two reasons, my wife, and my niece, I find myself researching film cameras for the first time in decades. I wonder if there are any MODERN medium format film cameras out there. By the way, if the image is only ever displayed on a TV or monitor, this problem goes away. Even a 4K TV is only 4K x 2K pixels, which is 8 MP. Even the most dirt cheap digital camera can do that. It's the high quality large size printing that causes the problem.

May your bits be stable and your interfaces be fast. :cool: Ron
 
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rfrazier

Well-known member
Sep 30, 2020
320
100
I thought the curtains travelled the same speed across the film, no matter what the speed set. It was the size of the slit that varied when you changed the shutter speed to expose the film.
@Mervyn Haynes You're right about the small slit traveling across the film or sensor. (Digital cameras have shutters too.) And I could be mistaken on this. But, the documentation for that shutter tester that was discontinued makes a big deal about measuring the travel time for each curtain and displaying the difference. So, I guess that the curtains can get out of sync mechanically and have different travel times. The older cameras were all mechanical and were driven by gears, clockwork, and springs. This would produce a slit that varies in size as the curtains move, and could affect the exposure. But, I freely admit that this is not my area of expertise.

May your bits be stable and your interfaces be fast. :cool: Ron
 

rfrazier

Well-known member
Sep 30, 2020
320
100
Hi all. I wanted to give an update on this thread. I just got my hands on the PhotoPlug.



This is a light sensor that works in conjunction with an Android or IOS app and a light source to test the shutter speed of the camera. The sensor plugs into the headphone / microphone port of the tablet / phone. I have been playing with it for a few hours and I believe I've been able to get some reliable readings on my wife's Mamiya 500 TL. It's an interesting device and program, and it does the job, but it's very limited and somewhat confusing to use. The bottom line is that any AC powered ambient light will impose a 120 Hz (in the USA) or 100 Hz (some other places) flicker onto the reading from the sensor. This makes it very hard to take readings over 1/60th of a second, even though the sensor and tablet / phone are capable of doing more. Using a battery powered flashlight would seem to be the solution, but they often flicker as well depending on the LED driver. Finding a cheap halogen or xenon incandescent flashlight is now very difficult. Using a LED flashlight on full intensity will sometimes work.

Even with a light source with relatively little flicker, you will not see a simple off on off wave on the light intensity on the screen of the tablet / phone. For one thing, the microphone port of the tablet / phone will not respond to DC, but only to changes in intensity. Therefore, a steady light will just read as nothing. It's only during the transitions that the waveform changes. Also, mechanical shutters are not by any means perfect. Once they start moving, they have vibrations and inconsistencies which show up on the waveform from the sensor. In many cases, it is very non obvious where the beginning and ending points on the waveform are and, thus, where to measure the time period of the opening and closing of the shutter.

I believe I've gathered enough data to potentially write a longer post, with pictures, and describe the exact procedure I used to measure the shutter of my wife's Mamiya 500 TL camera. This could apply to most shutters at 1/500 sec or less. Since writing this longer post and creating and posting pictures would potentially take a few hours, I wanted to see how much interest there is here. So, please let me know if that's something you all would be interested in so I can gauge how much time I want to put into it.

May your bits be stable and your interfaces be fast. :cool: Ron
 
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Dave New

Active member
Nov 23, 2020
34
9
First of all, you really don't need 300 dpi to get a good print. I normally print at half that, about 180 dpi, and get stunning prints from my pigment printer from my approximately 20MP DSLR cameras. I learned this taking photography workshops from a master artist.

And pulleaze, stop calling them giclees. That's just a snotty name for an ink jet print, that artists use to make it sound like an ink jet print isn't really an ink jet print. It is, and calling an ink jet print a giclee doesn't do anything except insult those who know better.

A REAL artist prints their own work, and doesn't try to interface with some 'studio' for prints. That's the only way you can completely control the printing process. You want to sign your prints, and I would never sign a print I didn't make.

I question the idea that a typical pet lover really wants a 30x30 print of their pooch. Most folks won't even go for that for people portraits, much less their pets. There is only so much display place on folks' walls, and a pet portrait dominating the entry foyer would not be my first choice (or even 2nd, 3rd, etc).

Finally, yes, you can get digital backs for medium-format film cameras. Phase One is the most well-known vendor, and depending on how many MP you want, they go for $15K up to $30K or more. If you want to see samples of what one of those will do, check out Beautiful Landscape

Of course, just viewing these images on a screen doesn't really do them justice. You must actually stand in front of print done by a master artist like Alain to see what a Phase One back and printing on wide-carriage pigment printers can do.
 

rfrazier

Well-known member
Sep 30, 2020
320
100
I normally print at half that, about 180 dpi
@Dave New I appreciate your comments. Interesting info. I do know that many of the art gallery print studios ask for 300 dpi if at all possible. Don't know exactly what the clients want.
And pulleaze, stop calling them giclees.
I see your point, but, not all ink jet printers are the same. And, not all papers are the same. If a studio is advertising as a giclee house, I'm going to expect them to be at a level of quality above the prosumer level. A $ 500 printer isn't the same as a $ 5,000 printer. And, a $ 0.25 sheet of paper isn't the same as a $ 3.00 sheet of paper. Google has this definition of giclee:
"a technology for fine art or photograph reproduction using a high-quality inkjet printer to make individual copies"
Having said that, I'm sure the term has lost some of it's shine over the years as good printers get much better and more affordable. And, I'm sure many people wave the term around when they're not, in fact, art gallery quality.
A REAL artist prints their own work, and doesn't try to interface with some 'studio' for prints.
Everybody is going to have different opinions on that, and that's fine. But, I'm going to disagree. If I, as an amateur photographer or painter create a saleable or even giftable photo or painting of a horse or rainbow or mountain or whatever, that is real art. Just because I cannot afford $ 5,000 worth of gear or if I don't have the space for it doesn't change that. It may totally be the best thing for me to do to pay a print studio $ 100 or whatever to get that produced. It all depends on the circumstances.
I would never sign a print I didn't make
I think maybe I'd say I would never sign a print I didn't inspect, and vet the print shop procedures.
I question the idea that a typical pet lover really wants a 30x30 print of their pooch.
I know what you're saying. My friends are all middle class and probably wouldn't spend the $$. But maybe some would.
they go for $15K up to $30K or more
Exactly. May or may not ever act on it, but if I look into medium format film, it would be precisely because digital gear costs 10X - 30X more for equivalent sensor size to the film.
images on a screen doesn't really do them justice
Agreed. My TV is HD, which means 1920 x 1080. The "K" of the TV is basically the width. So, that's a 2K TV. That's only 2MP. An "art" display TV might be 4K, which doubles each dimension. Still that's only 8MP. Any dirt cheap camera can do that. Now, it may not do that WELL, with cheap glass, etc. But, 8MP is plenty of pixels for the purpose. So, you're right, it's the big prints, viewed close up, in good light that really put all those pixels (or grain from film) to the test.

May your bits be stable and your interfaces be fast. :cool: Ron
 

Dave New

Active member
Nov 23, 2020
34
9
The difference between a $500 printer and a $5000 printer is only in the carriage width.

The price range you mentioned will get you a 13-inch printer for $500 (actually $800) and $5000 will get you a 44-inch printer (actually $4000) at B&H Photo Video. They both use the same inks and papers, so you can print a fine art print on either of them that are indistinguishable except for the size of the print.

I own a 17-inch printer that costs $1200, and can make beautiful 13x19 prints on 17x22 paper that mats out to 18x24 (standard frame size so no special framing required). The paper is Velvet Fine Art, which is a beautiful matte paper, and the matting, mounting, and back board materials are all archival. Of course, I can make smaller matted prints that fit smaller standard-size frames, like 16x20, or 12x16.

As an artist, all my prints are done by me personally and every print is signed, A matted/framed print is the product, not loose prints (signed or unsigned) or anything displayed on a screen.
 

rfrazier

Well-known member
Sep 30, 2020
320
100
@Dave New That's really interesting information to know. At this point, I have neither the money nor space for any printer. My conventional laser printer is sitting on my microwave oven. And, my photography / art skills are very much in the beginner mode. But, it's nice to know that those options are out there.

Are you aware of the fineartamerica.com website. I guess you'd call them a print on demand company. I have one rainbow image there at this time. They can print it on a variety of fine art style papers and mountings, as well as on various products and clothing. Not what you were talking about exactly, but it does give other options for selling things. I don't think they put me in the search engine until I get 10 images, so I have a ways to go. My photography is on an as the opportunities occur concept, so no telling when it gets increased.

May your bits be stable and your interfaces be fast. :cool: Ron
 

Duckpaddle

Member
Oct 1, 2020
22
8
Hi all. This is definitely off topic for @Steve 's normal fare for this group. But, then again, that's why it's in the off topic forum. Still, it just might tweak the interest of some of you.

I am an amateur photographer that now has 3 fairly nice entry level digital cameras: Canon 250D / SL3, Canon M50, and Canon SX170.

BUT, recently, my wife picked up a 40-50 year old Mamiya 35mm FILM camera. The 500 TL. I've been researching how to get it up and running. Unfortunately, the light meter is inop even with a new battery. I spent a good bit of time trying to find a small affordable external light meter. I've got the following one on order, which looks pretty cool:


Thought I'd pass that free tip along. But, I need some help from you. I also want to test the speed accuracy of the shutter. That's where it gets more complicated. I've been having an extremely hard time finding a competent gadget to do this. I really don't want to build it myself. I did find a device called a PhotoPlug which plugs into a phone or tablet microphone jack and links with an app on the phone. This will be better than nothing, and I've ordered one.

The problem is that a dual curtain focal plane shutter is a bit more complex than just a simple momentary opening for light. There are two curtains that both block the light path. One of these will open, and the other will open slightly later. They traverse across the film window together forming a traveling slit which slides across the film. A single sensor can measure the time period of the light exposure at a specific point. But, it cannot measure the 1st and 2nd curtain speed nor the difference between the two. If they are different, different parts of the film frame will get different exposure.

I found this really great looking product but it's discontinued:


There's also this one from Romania on Ebay:

Camera shutter and curtain tester for speeds up to 1/8000th with light source

This might be a good option, and in fact, the inventor of the prior device says this second one is a good product.

However, I wanted to pose this question to you all and see what you know. So, do any of you uber geeks out there have a better way to do shutter speed tests on vintage film cameras? Budget wise, $ 100 is about my limit for what will be mostly my wife's hobby. Buying and processing film seems to work out to about $ 1 / print these days. A finished product would be preferable. A kit would be acceptable. A full DIY from scratch option would be my least desirable choice.

All help is appreciated.

May your bits be stable and your interfaces be fast. :cool: Ron
Sounds like a job for an O'Scope and a photosensor. FYI, LED's can be photovoltaic sensors. Just rig the camera up to look at a very bright light source. Set your photosensor behind and trip the shutter. The pulse width on the O'Scope will be your shutter speed.

Of course I'm an old geek with old stuff.
 

rfrazier

Well-known member
Sep 30, 2020
320
100
@Duckpaddle Those are good points. I haven't had a chance to try it with an o-scope yet although I do have an o-scope. But, the photoplug, that I mentioned somewhere in the middle of the thread is a photosensor that plugs into a phone or tablet microphone port. I was able to use it and the associated shutter speed app to do essentially what you're saying. It shows a graph of the light levels on the screen. It's not really for measuring and quantifying levels like an o-scope, but you can see the wave shape. Surprisingly, it's not a square wave as you might expect. IE shutter closed, open, closed. But the transitions have highly variable shapes. This makes it hard to figure out exactly where the transition occurs and where to measure the timing. But, I think I've been able to fairly accurately characterize the shutter. It seems to be 1/3 - 3/3 of a stop slow in most cases and a little worse at the extreme ends. Not too bad for a camera that old.

May your bits be stable and your interfaces be fast. :cool: Ron