Speed Graphic Shutter Checking?

[HT Finley]

I couldn't decide whether to post this is DIY or here. There seems to be some overlap. Anyway, after scouring the internet, I haven't found any reliable information on how to check (test) the focal plane shutter on a Pacemaker Speed, or even where to have it done for that matter. I have found some DIY service info, but nothing that looks like a reliable way to find out what my shutter speeds really are. Thank you.

[Jim Jones]

We used to check them by looking at an old analog TV screen through the shutter. At 1/60 or 1/30 second, you should get a complete picture with no overlap. At lower speeds there is overlap, but sometimes one could figure out how much and calculate the shutter speed. At higher speeds, you get only part of the picture: 1/2 at 1/125 second, 1/4 at 1/250 second, 1/8 at 1/500 second, and 1/16 at 1/1000 second. These speeds should be checked at top, middle, and bottom of the film gate to check for even exposure. I'm relying on distant memory for the above data, and could be wrong.

[BrianShaw]

I tested mine mine by shooting some film and reading the neg. I used a roll film back (square format) so I had 12 test exposures. That gave me ballpark answers that were good enuf.

[HT Finley]

We used to check them by looking at an old analog TV screen through the shutter. At 1/60 or 1/30 second, you should get a complete picture with no overlap. At lower speeds there is overlap, but sometimes one could figure out how much and calculate the shutter speed. At higher speeds, you get only part of the picture: 1/2 at 1/125 second, 1/4 at 1/250 second, 1/8 at 1/500 second, and 1/16 at 1/1000 second. These speeds should be checked at top, middle, and bottom of the film gate to check for even exposure. I'm relying on distant memory for the above data, and could be wrong.
I have thought about using CRT sweeps and phonograph records, and all that. Then I remembered we're dealing with a FP shutter here. Matching and mismatching direction of travel of the moving target with the direction of travel of the shutter will yield varying results. Certainly somebody in the 90 years of the manufacture of these cameras has come up with a high quality method of checking the shutter. Shooting film as Brian suggested would be good, but introduces another variable being film processing, unless I were to have an ample supply of color reversal film with its narrow latitude. I originally thought to post this in the DIY subheading, but I haven't even come across a place to send the camera for a high-quality testing job. As an aside, I've spent enough time on these photographic forums to possibly be known as a picky, exacting person. I think it was all that Hasselblad work I did that ramped up my exactitude.

[Dan Fromm]

I tested mine mine by shooting some film and reading the neg. I used a roll film back (square format) so I had 12 test exposures. That gave me ballpark answers that were good enuf.

Test strips -- four shots on the same frame 1/4, 1/2, 3/4 and 4/4 uncovered will economize on film.

[DHodson]

I bought an optical shutter speed tester off ebay (plugs into my iphone jack) and the associated app. Total cost was around $30 and it seems to work okay - pretty close when checked against lens/shutters I know are okay. The app outputs a graph showing open/close and measures shutter speed. The seller (photoplug) doesn't seem to be around anymore but it looks like there are similar products. It's no test bench but simple to use and works well enough for me as a first pass. As others have said, the negative will tell the story.

Regards
Dave

[HT Finley]

Here's where I would appreciate somebody poking holes in my logic. Let's take the 1/1000 speed. I believe we can all agree that even perfectly timed, it takes a lot longer for the slit to go from the top of the frame opening to the bottom. That particular travel time is not where the 1/1000 gets it's name. It may well take 1/10 or 1/50th or whatever to actually make the traverse down the fram opening. The 1/1000 designates any point on the film when the top edge of the bottom curtain opening passes and the bottom edge of the top curtain passes over that same point. So, a laser pointer pointed at a receiving sensor arrangement [I]should[I] work.

[hsandler]

I have done some crude checking of leaf shutters by putting a lit ipad near the focal plane, and shooting a digital camera through the lens towards the pad, then comparing brightness of the digital image timed with the digital camera vs. the analog camera's lens with the digital on B. Should work for a focal plane if you can image the entire focal plane.

[HT Finley]

I have done some crude checking of leaf shutters by putting a lit ipad near the focal plane, and shooting a digital camera through the lens towards the pad, then comparing brightness of the digital image timed with the digital camera vs. the analog camera's lens with the digital on B. Should work for a focal plane if you can image the entire focal plane.
I disagree vehemently. Like I said, the shutter does not take 1/1000 to move from top to bottom. It takes far longer than that. 1/1000 is when any point on the film is uncovered then re-covered. The whole frame isn't done at the same time. To try to measure whole-frame would not work. This is not a leaf shutter, where whole frame is done at the same time. No, I'm not getting cranky or condescending. In fact I'm seeking criticism more than anything else. Thank you.

[brucetaylor]

I bought a shutter speed tested from eBay for about $100. I have a lot of old shutters, and a lot of them are off by a fair amount. As long as they are off consistently they are usable and accurate (if not they are sent out for service). It takes one more variable out of the equation for me with the old gear I use. Why not get one?

[HT Finley]

I bought a shutter speed tested from eBay for about $100. I have a lot of old shutters, and a lot of them are off by a fair amount. As long as they are off consistently they are usable and accurate (if not they are sent out for service). It takes one more variable out of the equation for me with the old gear I use. Why not get one?

Like I said, I think it was finally that period of time when I had become immersed in Hasselblad service work that made me an absolute perfectionist. And even those weren't capable of absolutes. I'm bound and determined to get this speed graphic within 1/4 stop across the range. Probably not possible. But I discovered that straight from the factory, even Hasselblads could be a mile off in their actual tolerances versus printed tolerances. I'm just now studying Graphic FP shutters, and they can be so far off it's a total disgrace. May as well shoot with a box camera with 1 speed as to put up with that kind of inaccuracy. I'll leave off for a couple days and see what responses pile up. But I am looking for someone to crack me over the head and tell me my logic is faulty. Sometimes it takes that. Regards.

[Mark Sampson]

I posted a similar question last year or so... referring to a 1939 3x4 Speed a friend sold me. I don't recall the various answers I got... there was a certain amount of argument. In the end I decided to try it and see. I have used the camera with b/w film and luckily for me the shutter is reasonably accurate; all of the exposures I've made using the FP shutter have been close enough to use, and the shutter doesn't leak light. Luckily I don't have to use the Graphic professionally...
Given the 19th-century design of these shutters, that's good enough. Expecting any Graflex to have the precision capability of a well-adjusted 'Blad (and I've used both types extensively) will only lead to frustration on the user's part.

[Tin Can]

Derived from guillotine shutters, also slit timed, the moving curtain was always proven by empirical testing with film.

As more than a few here have already stated.

Look up the repair expert on Facebook and bring your wallet.

[Doremus Scudder]

Almost every 35mm SLR has a focal-plane shutter. Technicians and repairmen check and repair them regularly. I see no reason why the techniques used for testing a smaller focal-plane shutter will not work for a larger one.

@ OP: The optical method you mention (with laser) should work just fine. I imagine any optical method that uses a beam and a sensor will work just fine. Why not contact a camera-repair shop and just ask them?

Best,

Doremus

[jnantz]

i have a calumet shutter speed tester and used it for mine.
and
in the end i put a sheet of film ( or paper ) in it, shot 1/2 with a behind the lens shutter
and 1/2 with the FP shutter and compared the negatives

good luck !

[hsandler]

I disagree vehemently. Like I said, the shutter does not take 1/1000 to move from top to bottom. It takes far longer than that. 1/1000 is when any point on the film is uncovered then re-covered. The whole frame isn't done at the same time. To try to measure whole-frame would not work. This is not a leaf shutter, where whole frame is done at the same time. No, I'm not getting cranky or condescending. In fact I'm seeking criticism more than anything else. Thank you.

But the digital camera is on B and open during the entire time the slit is travelling, so you will see the entire focal plane, each point exposed for 1/1000s if the speed is accurate.

[Andy Eads]

Leitz devised a simple shutter speed checker for focal plane shutters. http://www.skgrimes.com/library/old-news/the-leica-drum-shutter-tester

[Dan Fromm]

If you read the instructions and follow them, you can use a Calumet shutter speed tester to measure a Speed Graphics' and Graflexes' shutter speeds. I have one now, have used it with my RB Ser. B and with my Pacemaker Speed. I didn't have it when I got my Speed, so used the test strip procedure described above.

Finley, stop objecting to what is known to work well and start doing.

[Jim Jones]

Leitz devised a simple shutter speed checker for focal plane shutters. http://www.skgrimes.com/library/old-news/the-leica-drum-shutter-tester

The Leitz system is more precise and elegant, but essentially what we did long ago by looking through the shutter at an analog television as in post #2. Ultimately the best shutter tester is an oscilloscope and a quite small high speed light sensor. This can also be made to work for measuring shutter delay and flash delay. For non-focal plane shutters a large high speed light sensor works. In years of electronics repair I found an oscilloscope to be the most valuable single piece of electronics test equipment, even more useful than a multimeter.

[Tin Can]

Jim, I used scopes at work, but no more work, so I have been looking at the new cheap ones.

And of course a link to the retail devil. The best thing about Amazon is the reviewers. Many are very good at guiding a buyer. If you read a few dozen good and bad reviews.

https://www.amazon.com/gp/product/B00SXVUETU/ref=s9_acsd_top_hd_bw_bQc7EZ_c_x_5_w?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=merchandised-search-4&pf_rd_r=Y5V151FS37WC29YEXS0D&pf_rd_t=101&pf_rd_p=ca0be545-5937-51c5-bfc8-840760f8fc16&pf_rd_i=393269011

[barnacle]

Almost every 35mm SLR has a focal-plane shutter. Technicians and repairmen check and repair them regularly. I see no reason why the techniques used for testing a smaller focal-plane shutter will not work for a larger one.

Doremus

Doremus - if I'm not completely mistaken, I think there's a complete difference between most if not all 35mm camera focal plane shutters and large format - at least based on my single sample MPP press which I assume to be a common design.

The 35mm SLRs usually have two blades, both of which move from the same edge but with one some time later than the other: the first one opens and then the second follows it, giving either a moving slit of a specific width for faster speeds, or a fully open gate for slower speeds. The thinner the slot, the less time that a particular point on the negative is exposed, even though the blades move at much slower speeds.

The large format camera I have, and a number of elderly medium format cameras (I no longer have) had a roller shutter which has a number of slots of varying width cut in a single blind. Once again the width of the slot gives the exposure for a single point on the film, but not all points are exposed at the same time. As the blind is wound to a desired speed, I'd assume that the spring tension increases for faster speeds, and that the slots are not therefore necessarily linearly related to exposure time.

To measure an exposure time for *any* type of shutter, the easiest way - if you can drive an oscilloscope - requires only a fast light sensor and the oscilloscope. An LED will generate a voltage output (at very low current) when exposed to light: green ones give most in daylight. Connect the led to the input of the scope, place it at the point you want to measure (the centre is a good place to start) and point the lens at some light. Sticking the LED through a black card will keep light from the back of the camera.

Neil

[Dan Fromm]

barnacle, a moving slit is a moving slit is a moving slit.

[LabRat]

barnacle, a moving slit is a moving slit is a moving slit.

Yea, with a Graflex, just a slit... The degree of tension can be adjusted, but providing that all pivots, moving and sliding parts have been cleaned and lubed (and you don't hear a screech or intact shutter hangs up while firing, most optical testers will work to adjust the overall tension...

The other issue that comes up with these is that sometimes the slits or shutter material stretches where some speeds/tensions are nearly right on, but one (or more) slit settings are off, but you can often work around this by making a new chart depending on what averages out... (I got lucky with my 4X5 RB D when the higher speeds dropped down a little so the speeds were now the "modern" speeds (1/800 became 1/500, 1/300 became 1/250, and down through all speeds nicely correct)...

But a film test is usually good enough for these shutters (esp E-6 chromes)...

Steve K

[HT Finley]

I wonder if something might be wrong with online accuracy reports by homemakers may be just as knuckleheaded as some of my own concoctions, or worse even. For instance, there are guys out there who have worked very hard to come up with a device for sale, and I appreciate that guys are out there trying. The contraptions that use computer sound cards and audio programs are particularly suspect. Having done that myself some time ago with results I now consider dubious, I wonder if there's any other guys out there who have taken into account the linearity and sensitivity curves of the sending and receiving sources, whether laser or using parts from a mouse, or other parts on hand. Visualize the characteristic curve of film, which is a more commonly understood concept. Certainly the optical sensors and transmitters would need to be matched or discovered. More plainly put, where is the toe of the curve? Or shoulder either. Accurate measurement can only be available in the (linear)straight line of said curve. Otherwise, if it were at and below the toe, then I'd hate to think how many guys out there measuring shutters and finding distressing results may have been closer to correct than they knew. Or vice versa. I wonder what the ordinary voltage range of a typical computer sound card is.

[Jim Jones]

HT Finley makes a strong point. Blasting the sensor with too much or too little light can cause inaccuracy. When testing shutters with a CDS cell long ago, the slow response time of the cell was a problem. The size of the sensor or source, whichever is close to a focal plane shutter, should be small in relation to the slit in the shutter. When testing the top speeds of a between-the-lens shutter, the aperture setting affects the reading. Many factors have to be considered in precise testing of cameras.

[jp]

Jim, I used scopes at work, but no more work, so I have been looking at the new cheap ones.

And of course a link to the retail devil. The best thing about Amazon is the reviewers. Many are very good at guiding a buyer. If you read a few dozen good and bad reviews.

https://www.amazon.com/gp/product/B00SXVUETU/ref=s9_acsd_top_hd_bw_bQc7EZ_c_x_5_w?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=merchandised-search-4&pf_rd_r=Y5V151FS37WC29YEXS0D&pf_rd_t=101&pf_rd_p=ca0be545-5937-51c5-bfc8-840760f8fc16&pf_rd_i=393269011

We've got one of the cheap ones about two years ago at work. They work. Battery life isn't awesome but if you keep a charger handy, no problem. The ergonomics isn't as great as the big beasts with knobs. We chose ones of the little ones for it's portability and it's very convenient for bringing aboard boats and taking on service calls.

[Tin Can]

We've got one of the cheap ones about two years ago at work. They work. Battery life isn't awesome but if you keep a charger handy, no problem. The ergonomics isn't as great as the big beasts with knobs. We chose ones of the little ones for it's portability and it's very convenient for bringing aboard boats and taking on service calls.

I used to fly with a big Tektronix scope and Ultrasonic bolt machine. I measured head bolts inside engines. This was well before 9/11 and I always got an intense check over as I had to carry it in cabin. My overlords deemed this necesssary, toys were worth 100K and trade secret at that time. Later I was instructed to teach Ford how it worked.

[Tin Can]

Here's a guy who is one of the premier experts on Graflex and Speed roller curtain shutters. Here he shows how he tests his handmade new shutters.

It's a Facebook link to a picture, you do not need to belong to FB. Just look.

https://www.facebook.com/photo.php?fbid=537290243296070&set=pcb.10154946724821148&type=3&theater&ifg=1

[barnacle]

barnacle, a moving slit is a moving slit is a moving slit.

Indeed. But the slit is not made in the same way, and I'd argue that an ability to mend one sort does not necessarily extend to the other. Though there is no doubt that a moving hole in a strip of material is a simpler technology than moving metal blades.

Neil

[barnacle]

As an experiment today, I took five minutes to use an LED and oscilloscope as discussed earlier. With the lens wide open and an LED torch pointing through the lens, the signal was about 200mV, but clearly showed that the 1/250th second was a shade slow at 4.2ms (should have been 4.0).

So this is a viable option. Note that (also as discussed) if the lens is stopped down not only will the signal get smaller by 50% per stop (though a brighter light will help) but the shutter will get faster. I didn't measure the rise- and fall-time of the signal - it was a very quick test :) - but it was under a hundred microseconds for each. The LED should have a response time in microseconds or faster.

Neil

[Jim Galli]

I think the OP is on the right wavelength (at least to my limited intelligence) with the idea of measuring the exact time in a straight line that it takes for the chosen width opening in the curtain to travel past that line.

With a movie camera if I have a 15 degree opening traveling at 250 revolutions per second (I used high speed movie cameras to gather scientific test information) I divide 15 into 360 = 24 times 250 (frames per second) = 6000 and the inverse is my speed. 1/6000th second exposure.

You'd be doing the same thing with a laser measuring the time it takes the slit to pass by. It works the same as the adjustable angle in a rotating shutter.

[jp]

As an experiment today, I took five minutes to use an LED and oscilloscope as discussed earlier. With the lens wide open and an LED torch pointing through the lens, the signal was about 200mV, but clearly showed that the 1/250th second was a shade slow at 4.2ms (should have been 4.0).

So this is a viable option. Note that (also as discussed) if the lens is stopped down not only will the signal get smaller by 50% per stop (though a brighter light will help) but the shutter will get faster. I didn't measure the rise- and fall-time of the signal - it was a very quick test :) - but it was under a hundred microseconds for each. The LED should have a response time in microseconds or faster.

Neil

If you are using a red LED, it probably has a quick response time as it is built very simple. if you are using a white LED, it probably has phosphors that hurt response time.

[Dan Fromm]

Note that (also as discussed) if the lens is stopped down not only will the signal get smaller by 50% per stop (though a brighter light will help) but the shutter will get faster.

Neil, pardon my denseness, but you've lost me again. Twice, in fact.

I can't see the earlier discussion you referenced. Please direct me to it.

And I can't see how changing the lens' aperture will affect a curtain shutter's slit width and traverse speed. I've always thought that these two controlled exposure time and are completely disconnected from the lens.

[HT Finley]

I have though about leaf shutters too. But I believe they're concerned the amount of time that the shutter is resting at full open with the open and closure time itself largely neglected. But truth is, that the shutter is actually like the diaphragm, except t goes through the range of f/infinity to f/1 billion, ten thousanth, f/256, 128,16, and such until it reached the actual f stop the diaphragm is. Then reverses back to infinity. In other words, measuring to the inward sides of the rise and fall times, and ignoring the actual rise and fall times. Both shutters are imperfect. Consider the heavy Graphic FP shutter (compared to a 35). The top of the frame opening is bound to be overexposed compared to the bottom of the frame, because it has no inertia at the top. But I'm not quite as picky as this post. I just want my shutter within Ektachrome/ Kodachrome requirements. 1/4 stop, maybe? That shouldn't be too much to ask. First a known linearity of the test method is needed. I'm sure it would be nice to have a scope with a remembered waveform. But I figure most of us guys are liable to be tinkering with cutting up mice and using sound programs and other such ideas.

[Jim Graves]

It takes longer to read this ... and the archived threads ... than it does to put a roll back on the camera and shoot & develop the film ....... which is what you are going to have to do anyway.

I have tried probably 6-7 different versions of shutter timers (including the Calumet) and found them acceptably accurate at low speeds (<1/125 sec) ... but lacking at higher speeds. And, in the end, I still had to run film through the camera to see what I had. Now the timers just sit in the drawer when I get a new shutter.

[Dan Fromm]

It takes longer to read this ... and the archived threads ... than it does to put a roll back on the camera and shoot & develop the film ....... which is what you are going to have to do anyway.

I have tried probably 6-7 different versions of shutter timers (including the Calumet) and found them acceptably accurate at low speeds (<1/125 sec) ... but lacking at higher speeds. And, in the end, I still had to run film through the camera to see what I had. Now the timers just sit in the drawer when I get a new shutter.

Jim, I agree completely on the first point.

Y'r second point puzzles me. Why do you think that erratic measured shutter speeds, if that's what your problem has been, are due to an erratic shutter timer instead of an erratic shutter or variations in your measurement procedure?

If your concern is that leaf shutters that the timer says run slow at high speeds still give perfectly good exposure, think about shutter efficiency. That is, because leaf shutters are only partially open for most of the open-close cycle at high speeds, they pass more light that one would expect from the time between fully open and fully shut.

To get back on topic, which is how best to test a Speed Graphic's focal plane shutter, these beasts are much more efficient than leaf shutters at high speeds.

Remember, shutter speed testers don't measure how much light the shutter passes. They measure the time from just starting to open to fully closed.

Finley, you wrote:


I just want my shutter within Ektachrome/ Kodachrome requirements. 1/4 stop, maybe?

This is idiotic, and not because you mentioned Kodachrome even though he last Kodachrome line shut down 12/31/2011 and K'chrome hasn't been offered for LF for more than half a century.

Your wish is idiotic because you want your shutter to be perfect. Shutters aren't perfect, but they can be consistent. That's what you need. That's what the rest of us who test instead of making silly noises check for and rely on.

[Tin Can]

And just for chuckles, tomorrow I hope to test the flapper on my Graflex RB Series B 2x3. This thing is very, very clean. I never shot it and found it today in the shed.

It has a well done BiPost flash sync installed and a small Heiland flash bracket. But no Heiland.

I don't wind these up to 1/1000 as I have had 3 flap away into display items. 2X3 versions seem very delicate and the most difficult to fix.

I know these were designed to use very long duration flash bulbs so the bulb would provide light during the complete slit movement across the emulsion.

I have flash bulbs, but none are long burn. I am going to try slow shutter speeds, big slit with Studio Strobes or LED.

This won't tell me anything about shutter speed, but it may show something about sync issues.

Suggestions Dan? Anyone?

[Jim Galli]

Dan, sometimes people engage a problem for the joy of solving it. I recall one silly person who was devising rediculous solutions for crazy long lenses on a 2X3 format camera? Remember him?

[Tin Can]

It's gets worse, I have read and forgotten everything I could find on Dan's 2X3 adventures.

[barnacle]

Neil, pardon my denseness, but you've lost me again. Twice, in fact.

I can't see the earlier discussion you referenced. Please direct me to it.

And I can't see how changing the lens' aperture will affect a curtain shutter's slit width and traverse speed. I've always thought that these two controlled exposure time and are completely disconnected from the lens.

Ack. Posting while half asleep - I conflated what I posted earlier in the thread and what I intended to/thought I had posted... I fear I have also lost myself :)

Sorry about that.

You are quite correct: for a moving slit shutter, the aperture of the lens makes no difference to the exposure time. The position of the sensor *may* make a difference depending on the acceleration profile of the shutter blind.

What I did yesterday was just a quick proof-of-concept using a single green LED as the sensor and a lens shutter. In this case a wider aperture *may* have a slightly different duration than a smaller (there's a bigger hole to expose) but the position of the sensor should make no difference. The aperture will change the amplitude of the detected signal.

As someone else pointed out, a WHITE led is unlikely to work in this approach: they are usually UV emitters surrounded by phosphors selected to glow white. I chose green as I had a bag of them on my desk and I would have had to walk into the store-room to find the bag of red LEDs - but I should do a test to see which has the higher output. I also have some two-terminal phototransistors somewhere around the place, but those require a suitable resistor and power supply to operated - though they should be significantly more sensitive.

TL;DR: Using a cheap green LED and a light source I was able to demonstrate a cheap usable timing measurement system.

Neil

[Jim Graves]

Jim, I agree completely on the first point.

Y'r second point puzzles me. Why do you think that erratic measured shutter speeds, if that's what your problem has been, are due to an erratic shutter timer instead of an erratic shutter or variations in your measurement procedure? ..............

Because, after I got such discouraging readings, I took the tested shutters to a professional camera repair shop and had them speed tested. They confirmed both that the slower speed readings were relatively accurate and that the higher speeds had been misread by my testers. Which was exactly what my film tests had indicated.

The testers I used were of two types ... photo-cell (supposedly measuring the amount of light passed) and sound card (measuring the time between opening and closing of the shutter ... which, of course wouldn't be appropriate for testing an FP shutter.) I even made sure I was using the correct light intensity at the recommended distance if such was listed. All, including the Calumet, were close at low speeds and increasingly off above 1/100.

I still use one of the photo cell testers because virtually all of my shutters max out at 1/125 or less ... except for a couple of 1/300 Optimos ... which might, on a good day reach 1/150 on the 1/300 setting.

Since I only have two FP shutters ... a 4x5 Speed Graphic ... and an 8x10 Folmer Graflex ... it makes sense to just do a speed test on each with film ... and those results will apply regardless of the lens I'm using.

Focal Plane shutter time testing is an interesting subject ... but, as my grandfather used to say ... “It is a long road to a small house.”

[Dan Fromm]

Dan, sometimes people engage a problem for the joy of solving it. I recall one silly person who was devising rediculous solutions for crazy long lenses on a 2X3 format camera? Remember him?
Mr. Galli, there's a slight difference. The silly person didn't just sit and theorize and raise objections to reasonable suggestions, he built something and tried to use it. But yes, it was an extremely silly person.

[Dan Fromm]

Jim Graves, when I first started to use my Calumet tester with my dud RB Ser. B I got bizarre speed readings. So I went looking for the instructions -- I'd got my tester used without them -- and found that, as usual, I was the problem. The procedure for measuring an FP shutter's speeds isn't quite as simple as I'd thought. And now comes the stupid and insulting question. Do you have the directions, did you follow them?

They're online here: https://1drv.ms/f/s!AggQfcczvHGNmCOeOp5cLpjG-wGo See p. 2.

As I understand what the Calumet tester does, it doesn't count photons, it just starts timing when it sees that the shutter has started to open and stops when it sees that the shutter has closed.

[Jim Jones]

. . . As I understand what the Calumet tester does, it doesn't count photons, it just starts timing when it sees that the shutter has started to open and stops when it sees that the shutter has closed.

The Calumet instructions do seem to make some allowance for shutter inefficiency, and warn against it. It demanded careful reading, more than this old man wants to do. The numbers still don't tell as much about shutter performance as does a light versus time curve on an oscilloscope. The amount of light in almost any tester has to be correctly adjusted for accuracy. The testers that rely on sound instead of light seem far removed from reality.

[Tin Can]

Well, my 4th Graflex RB Series B 2x3 just flipped its curtain. I may get this one fixed, it looks like new.

The 2X3 is much harder to work on as it has peened tapered pins that must come out. The bigger models have an easier path.

I had a strobe connected, with a DIY BiPin connector as I eagerly watched for a slit of life... :(

[Jim Graves]

Jim Graves, when I first started to use my Calumet tester with my dud RB Ser. B I got bizarre speed readings. So I went looking for the instructions -- I'd got my tester used without them -- and found that, as usual, I was the problem. The procedure for measuring an FP shutter's speeds isn't quite as simple as I'd thought. And now comes the stupid and insulting question. Do you have the directions, did you follow them? ......

Nothing stupid or insulting about that question ... it is the obvious one.

And, yes ... the tester when I got it came with the instructions ... and was the only tester I got that even took the light intensity/distance into consideration ... which seems like an obvious element for testing accuracy ... it was the Calumet tester I was referring to when I mentioned in my original post about ensuring the light intensity was correct.

I think even Calumet admits in the instructions somewhere that higher speeds pose problems with their measuring system.

I will admit that I did not continue to refine and try to adjust just to get the system as accurate as possible. After fooling with it for some time, I finally just put a roll back on the 4x5 Speed Graphic and used split frames on the 8x10 Folmer Graflex and shot film ... it was pretty easy to come up with repeatable results. Even had I continued to work with the Calumet, I still would have had to test the results with film anyway ... so I shortened the process ... burned more film maybe ... but ended up saving time and being confident in my results.

If I had a lot of FP shutters to test ... I would have continued to try to refine my results with the tester ... but with just 2 shutters to test, continuing to test with the Calumet was becoming an academic exercise instead of a practical one.

[RichSBV]

Boy you guys just love to overthink things and discuss in circles :p

In defense of both Graflex and Calumet I'll toss in my experience. Although it's been many years since I tested my shutters...

When I first got the Calumet tester, I tried it on a couple of Speed Graphics with impressive results. Well within factory specs, even before cleaning and lubing. I ran into trouble with the leaf shutters as they were all out of spec and slow at the higher speeds.... Exhaustive research provided the answer. You _never_ measure a leaf shutter at the center of the opening! Now as I said up top, it's been years so I don't remember the exact measurement, but you're supposed to measure a leaf shutter approximately one third out from the center. This will give the true speed of the shutter and is how the factories did their tests and calibrations. Yes this is documented. No, I don't remember where any more. Very probably in a Graflex service manual? So for leaf shutters, you must have the light source, shutter and tester in rigidly fixed positions to get accurate results.

During my tests, I thought about finding our just how accurate the Calumet tester truly was? Best thing I had were several electronically controlled 35mm cameras. Each one of them tested well within specs all the way up to 1/2000. I have no doubts at all that the Calumet tested is reliable at least up to 1/2000 as my results were far too good and repeatable to be coincidence.

So there's my 2 cents and worth almost that much :D

[Jim Graves]

Boy you guys just love to overthink things and discuss in circles :p

In defense of both Graflex and Calumet I'll toss in my experience. Although it's been many years since I tested my shutters...

When I first got the Calumet tester, I tried it on a couple of Speed Graphics with impressive results. Well within factory specs, even before cleaning and lubing. I ran into trouble with the leaf shutters as they were all out of spec and slow at the higher speeds.... Exhaustive research provided the answer. You _never_ measure a leaf shutter at the center of the opening! Now as I said up top, it's been years so I don't remember the exact measurement, but you're supposed to measure a leaf shutter approximately one third out from the center. This will give the true speed of the shutter and is how the factories did their tests and calibrations..........

That's interesting .... but the Calumet instructions don't agree ... they specifically direct you to “place the probe of the shutter tester at the center of the front or rear lens element” when testing leaf shutters.

[HT Finley]

I'm the OP, and I don't take offense at any naysaying that may be in this discussion. So far, IIm still leaning to the method of using a strobe-calibrated home entertainment-grade record turntable from the 80's and some x-ray film already on hand. Certainly there will be some curving of the angle lines in the negative. Just as we all remember the photo of a race car with oval wheels shot on a focal plane shutter 60 or 70 years ago. I don't think Kodachrome 1/4 stop standards are too much to ask. After all, Kodachrome had been around 14 years before my Pacemaker Graphic was made. I bet those Pacemakers came out of the factory with remarkably accurate shutter speeds. And if you want to talk about perfection in standards to the point of ending up in a straitjacket, consider the problems in calibrating the Apollo cameras. The camera was boiling hot when the astronauts were shooting on the bright side of the LEM, and bitterly cold on the other side. Don't you know how THAT played havoc with shutter speed accuracy? Shooting a phonograph record on a reasonably well calibrated turntable might be the best way for regular folks after all. At least you could be happy knowing that 1/1000 was actually closer to 1/650, plus or minus 1/4 stop. I never sought to touch off a discussion that requires large incomes for perfection in trivial pursuits. I'm grateful for what I've read here. Regards.

[BrianShaw]

Good morning Henry. I’m curious. I’ve seen accuracy specs in shutter repair manuals but never heard of a “Kodakachome 1/4 stop standard”. Is that referring to the narrow exposure range of the film or a real requirement established by Kodak on equipment using that film. What’s the source? Or is it a shorthand term for something like ‘the closest someone thinks they can get a shutter to the ABSOLUTELY EXACT timing values specified on the shutter?

The reason I ask is you may have an incorrect assumption. Graphex shutter official spec is approx plus/minus 1/3 stop, and my memory recalls even more at speeds above 1/100.

Scientific cameras are a whole other topic. But when I worked with som for a very brief period of time the focus was on reliability rather than accuracy better than OEM spec.

[HT Finley]

The "Kodachrome 1/4 stop" standard was my idea. Imagine a perfectly exposed Kodachrome/Ektachrome, and a 1/2 stop off one. Big difference. OK, I'll lower my standards. How about 1/3 stop? But I won't go to 1/2 stop, and certainly not 2/3 or a whole stop.:D

[jp]

HT, what you're delving into is a bigger picture litmus test.. Many of us are gearheads that like old mechanical things and wish for them to function with precision because we like the engineering and physics.. The other half want photos and have no interest in blaming their tools and use things like shutters with empirical experience rather than testing and heavy duty math. How accurate a shutter should be perfectly divides these crowds.

My speed graphic is pretty consistent shot to shot, but it does vary consistently based on temperature and whether horizontal or vertical.

[BrianShaw]

The "Kodachrome 1/4 stop" standard was my idea. Imagine a perfectly exposed Kodachrome/Ektachrome, and a 1/2 stop off one. Big difference. OK, I'll lower my standards. How about 1/3 stop? But I won't go to 1/2 stop, and certainly not 2/3 or a whole stop.:D

You may never get your way except for a very time consuming tailoring of speed cams on a lef shutter. I’ve never seen a shutter spec that had a single spec value across the entire speed range.

On the focal plane shutter I think you’d have to somehow design a spring that is perfect across its entire tensionnrange, but I’ve never personally met such a spring. :)

But I’m back to my first reaction... other than the sheer magnitude of the challenge and good feeling from success... why, from a practical standpoint?

[BrianShaw]

JP... same with mine but I’m blessed with warm winters so I never see much climate-based variability. I think a lot of that is the shutter cloth stiffening in the cold.

[HT Finley]

Because I shot a perfectly exposed and developed negative last week, and am not happy with the idea I was just lucky that once. For all I know the shutter could be off by half a mile. I can't stand not knowing. Besides I already know I'm a good camera technician. I've build several perfect Hasselblads and KNEW they were perfect; better than the factory. did it, if their published specs were correct. I got them focusing within 1/8 inch at 3 feet and proved it. 'Bout drove myself to the institution doing it....

[BrianShaw]

Got it. :)

My suggestion is that your shot a few more, varying the shutter tension and comparing the negs.

[HT Finley]

I think I already might have driven myself crazy jsut thinking about this.

[BrianShaw]

I think I already might have driven myself crazy jsut thinking about this.

I doubt that. :)

[LabRat]

I think I already might have driven myself crazy jsut thinking about this.

Giving up to learn to love the bomb is healthy... ;-)

Many films won't see the difference, but there's that voice in one's head that gets louder while pressing the shutter release, so if at least if the speeds are uniform/consistent (and in a variety of conditions), it's OK...

Now to the film tests!!!

Steve K

[andrewch59]

I'm sure I will be corrected if I'm wrong, but as far as speed graphics curtain shutters go, the service manual I gleaned from the dedicated site only stated that adjustment is made so the shutter just closes at the end of the "o" opening? I have three speeds plus an old Marion and thorton pickard focal plane. Don't know how it will fare but I am waiting for a Cam-Lite mini V2 to arrive, which uses a light beam, is said to accommodate most shutters, we will see.

[andrewch59]

http://www.southbristolviews.com/pics/Graphic/manual-pdf/servicemanual.pdf

[andrewch59]

I'm sure I will be corrected if I'm wrong, but as far as speed graphics curtain shutters go, the service manual I gleaned from the dedicated site only stated that adjustment is made so the shutter just closes at the end of the "o" opening? I have three speeds plus an old Marion and thorton pickard focal plane. Don't know how it will fare but I am waiting for a Cam-Lite mini V2 to arrive, which uses a light beam, is said to accommodate most shutters, we will see.

The Ca-lite mini v2 works a treat, I have adjusted the speed on my graphic curtain shutter so it is close to the speeds it should be using. Have made a cheat sheet with the actual timed speeds, which change slightly every wind. Now at least I have a reliable shutter (I have cut a speed graphic in half to use the shutter) to use on my big brass lenses.