View Full Version : Copal 0 shutter speed accuracy
Hi,
I recently purchased Schneider Symmar APO 150mm Copal 0. I conducted an improvised test with the shutter set at 1s, with the iPhone memo app. And got results varying from 1.2s to 1.28s.
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I'm sure using iPhone app is not optimal but at 1s it seems it would be good enough to tell if something is off. Should I return this lens?
Thanks:)
Leszek Vogt
6-Aug-2021, 14:06
Is the lens in good condition ? Why not have the shutter cleaned/lubed/adjusted ? Usually the faster speeds are not as accurate.
The lens is in a pretty good condition, I would say it looks great. I live in South East Europe and I have a very limited pool of people who could do CLA.
Before you get concerned, I'd suggest that you redo the test on a computer with a better application. Just about any microphone that you can plug into the computer will be adequate. What you need is an app with a good waveform display. If you're on a Mac, GarageBand, which is free and may already be on your computer, will handle this just fine. After that, my first choice would be iZotope's RX. It has a ten day free trial, but I don't recall what limits there are. You could also use Reaper, which is also excellent and which you can use without any limitations indefinitely. I would use any of the foregoing in preference to Audacity.
lassethomas
6-Aug-2021, 14:35
There is an app. "Shutter-Speed" that makes a fairly good job, att least upp to 1/125 secs.
The free version uses the microphone and audio.
Myself I wouldn't worry about 1.2 seconds compare with a second. That's pretty accurate. It's not even a third of a stop.
And being accurate at longer times is not an indication that faster times are OK I'm afraid.
And times from 1/250 and faster are almost never accurate, even when CLAd.
It the lens is fine download the app and check to see if it's ok up to 1/125.
Most of us would never use that fast times anyway.
lassethomas
6-Aug-2021, 14:50
And it really doesn't matter if speeds are off a bit as long as they are consistent.
I measure my shutters and have a spreadsheet to prepare labels with compensations that I stick to the lens board
Here is one for a Copal #3
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There is an app. "Shutter-Speed" that makes a fairly good job, att least upp to 1/125 secs.
The free version uses the microphone and audio.
The free version of that app won't be any more accurate than iPhone Voice Memos.
There's an old series of photo.net posts from Tom Johnstone that establishes that a standard audio recording waveform will show shutter speeds accurately up to 1/30 or maybe 1/60 second. I say establishes because Johnstone did his recordings right after having his lens CLA'd by S.K. Grimes, and the recording waveforms were dead on with Grimes's report. At the time, a lot of people held the view that no audio recording, by itself, would provide accurate data on shutter speed. Indeed, that view underlies the statement by the vendor of the "Shutter Speed" app that one should purchase an optical accessory if one wants greater accuracy.
I know from synchronising iPhone audio with video that there are issues with iPhone audio. More importantly, you need an application that will give you an accurate, detailed waveform display. You will get that from a Digital Audio Workstation like GarageBand (free to Mac users) or Reaper (free if you don't want to pay). You will also get it from iZotope RX, which is professional sound editing software that for this purpose would be easy to use. Indeed, I'm about to use RX8 to test two of my own lenses. I just don't recall what the limitations are on the RX trial. Audacity will work too, I just find it not very intuitive and a bit clunky :)
Mechanical shutters have plus or minus 20 or 30% specs
lassethomas
6-Aug-2021, 15:09
The free version of that app won't be any more accurate than iPhone Voice Memos.
There's an old series of photo.net posts from Tom Johnstone that establishes that a standard audio recording will show shutter speeds accurately up to 1/30 or maybe 1/60 second. I say establishes because Johnstone did his recordings right after having his lens CLA'd by S.K. Grimes, and the recordings were dead on with Grimes's report. At the time, a lot of people held the view that no audio recording, by itself, would provide accurate data on shutter speed.
I know from synchronising iPhone audio with video that there are issues with iPhone audio. More importantly, you need an application that will give you an accurate, detailed waveform display. You will get that from a Digital Audio Workstation like GarageBand (free to Mac users) or Reaper (free if you don't want to pay). You will also get it from iZotope RX, which is professional sound editing software that for this purpose would be easy to use. I just don't recall what the limitations are on the RX trial.
Well yes, accuracy will be the same as Voice Memo, but there is a build in measuring tool and direct display so it's much more convenient and faster to use.
And if you want to go for a desktop application there is also Audicity as an open source alternative
Well yes, accuracy will be the same as Voice Memo, but there is a build in measuring tool and direct display so it's much more convenient and faster to use.
And if you want to go for a desktop application there is also Audicity as an open source alternative
I was editing to include a reference to Audacity while you were posting. Audacity will work, but it would be my last choice.
As I said, there are issues with iPhone audio. I don't trust it for time measurement. I also think that it's highly unlikely that the waveform display from an iPhone app will come close to the display that one will get from a DAW or iZotope RX. I have a number of recording apps on my phone, including one from DPA Microphones (https://www.dpamicrophones.com), whose miniature mikes/lavalieres I use, and I would not use any of them for this purpose.
Drew Wiley
6-Aug-2021, 15:29
I've found modern Copal 0 shutters to be very consistent year after year, always predictably remaining within a sixth stop or so, except the very fastest stop, which is generally too far off to be worthwhile anyway. But what those exact speeds are at each setting needs to be precisely measured, and then you can just print a cheat sheet or tiny label for the lensboard itself telling you the correction factor at each speed, if any. In certain cases, I haven't found any deviation from the official one. I use a Calumet electronic shutter tester.
Much depends on how one is going to use the lens. For my work under the redwoods, all I use is B or T, depending on the length of the exposure...B if I am willing to stand there the whole time. T if I want to take a nap, or do something constructive like write my notes. Working in the sunshine is a whole different story.
The one second setting is at the far end of the range of the shutter, so perhaps not the best one to test. If your system for testing can test towards the middle of the range, that might give you a good picture of the lens' condition.
Here's what I mean about a good waveform display. The first screen capture below shows iZotope RX 8 with one of my audio recordings loaded. In the second, I've zoomed in a bit on a small part of the waveform. I can zoom into it down to the pixel. The horizontal axis right below the waveform display gives extremely accurate information on time.
I'm not suggesting that anybody buy RX, although the trial version would be a nice way to do this. My best recollection is that the limit on the trial version is that you can't save sound edits, but that doesn't matter for this. All you need is a screen capture. In any event, you can do pretty much the same thing with a DAW such as GarageBand (free for Mac users) or Reaper (they like you to pay after a couple of months, but you don't have to). Audacity would work too, if you have more patience for it than I do :)
To me, it doesn't make sense to use a smartphone app to do this given that there are much more capable applications that can be used for free.
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I was editing to include a reference to Audacity while you were posting. Audacity will work, but it would be my last choice.
As I said, there are issues with iPhone audio. I don't trust it for time measurement. I also think that it's highly unlikely that the waveform display from an iPhone app will come close to the display that one will get from a DAW or iZotope RX. I have a number of recording apps on my phone, including one from DPA Microphones (https://www.dpamicrophones.com), whose miniature mikes/lavalieres I use, and I would not use any of them for this purpose.
While I agree that a phone display is less that ideal, if the hardware is working at a specific sample rate, it should be very accurate up to the nyquist liimit, otherwise recording audio and playing it back would have bad audible jitter or or noticible frequency changes between recording and playback. So if an app eliminates the need to look sample to sample to find the start and end time, it should prodived relatively accurate timing. The caveat would be how well it can accurately determine what to consider the start and end time, which I think would have a much greater impact on accuracy.
Then of course throw in that even if the top speed of is 100% acurate, the shutter is spending most of its time of its time opening and closing with part of the opening occluded by the shutter blades unless it is stopped down, meaning that some of the light will be blocked. Smaller apertures do reduce the affect, but wide open you can loose a non trivial about of the total light. But that's a different discussion.
Drew Wiley
6-Aug-2021, 15:58
Regardless of the testing instrument, one should always test at either the f-stop most used, or consistently at some reasonable mid-point like f/22.
While I agree that a phone display is less that ideal...
Let's just leave it at that. There are better alternatives, three of which I've identified and one of which I've included screen captures for as illustration. This being a photography forum, a debate about issues with smartphone audio is unlikely to be helpful :)
Thanks for the advice on measurement. In case those initial inaccuracies are confirmed what is my best course of action? How probable is it to find one which is in case of a speed accuracy spot-on or near that (because of previously mentioned 20-30%)? I have 30 days to decide on what to do (and no camera to test it:D).
Bob Salomon
6-Aug-2021, 17:20
Thanks for the advice on measurement. In case those initial inaccuracies are confirmed what is my best course of action? How probable is it to find one which is in case of a speed accuracy spot-on or near that (because of previously mentioned 20-30%)? I have 30 days to decide on what to do (and no camera to test it:D).
Any shutter that is +- 30% is spot on to industry specs.
Links to two of the applications that could be used for this, assuming that one isn't on a Mac, which has Garageband. Both have free trials. If I recall, RX's trial is 10 days. It is used to edit the sound on just about every feature film and television show made, and it is increasingly used in music production. Reaper's trial period is 60 days. After that, they ask you to pay US$60, but they don't enforce it except through reminders when you open the app. Reaper is an unusual case. It is extremely good, very popular software that is also inexpensive for what it does.
iZotope RX (https://www.izotope.com/en/products/rx.html?utm_medium=cpc&utm_source=google&utm_campaign=SU_GN_SE_BR_UU_US_RX&utm_content=RX-iZotope_EM_KW&utm_term=izotope%20rx%7Ce%7Cg%7Cc%7C%7C472916419104&gclid=Cj0KCQjwu7OIBhCsARIsALxCUaNNqqrfzYRcJNy5mE0w1XvGbsDU7I8qU-Ly26tDv5G8s5vlYvJ4kxgaAj_pEALw_wcB)
Reaper (https://www.reaper.fm)
Leszek Vogt
6-Aug-2021, 23:56
info@paepke-fototechnik.de
This place is in Dusseldorf, Germany and they may take on your shutter or perhaps point you at the right direction (you could send the shutter).
Paul Ron
7-Aug-2021, 04:23
audio is never accurate, it isnt measuring the actual amount of light passing through at the moment the shutter opens. what you are timing is all the noise before n after the shutter opens n closes... as small as it may be, it can account for the overage.
audio is never accurate, it isnt measuring the actual amount of light passing through at the moment the shutter opens. what you are timing is all the noise before n after the shutter opens n closes... as small as it may be, it can account for the overage.
The issue of using a waveform to test shutter time is discussed in post #7. To my mind, it's desirable to use an application that provides a detailed waveform display, and to keep in mind Bob Salomon's post #18.
Paul Ron
7-Aug-2021, 05:29
audio is not an accurate test for shutters. shutter testers measure the actual light passing through to the film.
audio testers measure noise no matter how good your app is... the sounds a shutter makes before n after the shutter opens n closes is what causes discrepancies in your speed times regardless of how nice your traces are. shutter testers should mrasure light, not sounds. film doesnt see sound!
if you want to time a shutter, buy a real shutter tester. they are cheap these days on flea bay.... or make one using a photo diode as seen on the internet diy projects.
ic-racer
7-Aug-2021, 05:50
That is pretty good for an old mechanical shutter. I usually count out 'one-one thousand, two-one-thousand' etc. when I test my shutters. Because after the 1 second mark, that is how I'm timing the exposure. I also listen for how smooth the escapement action sounds. If it sounds smooth, the shutter will more likely be precise. Accuracy is less important if one bases exposure on in-camera film testing.
Just to give an update. I went today and left it for CLA. The guy said, judging by the sound, it could work better, that mechanical shutters need to be used and that he will call me next week when it is done.
Drew Wiley
9-Aug-2021, 12:26
I'd have to partially amend one of Bob's previous comments. What I think he meant is that any new shutter PREDICTABLY firing in a tight range + - 30% from its official marking is acceptable. One just factors in the difference after measuring actual speeds at the respective settings. But any shutter only as good as + - 30% RANDOMLY, I'd personally set aside, at least for color work.
May as well add this question
In your experience do both Copal 0 and Copal 1 have similar life spans
or hours to rebuild
I have a choice coming up
anybody?
The other issue with audio testing is shutter efficiency... It takes time for the shutter to fully open, and is (very slighty) exposing before fully open... Granted this is a very small amount, but for the "speed freaks" this is another factor... And yes, this changes at different aperture settings... So a light reading TTL is needed for a true picture...
This subject was much covered in the 40's, as flashbulbs had their own peak, and shutters had to allow the bulb "burn" to start, then match the two peaks for highest efficiency of the bulb output... Books from that era had detailed descriptions of how the shutter operations worked... A good source to check would be the Morgan & Lester "Graphic & Graflex Photography" series yearbooks...
But in practice, this should not be an issue if speeds are consistent (for outdoor use)... But maybe more so in studio settings, but also when the exposures are done under bright continuous lights, lens is stopped down, the longer speeds are usually used, where the speed error factor is relaxed, and minor errors are diminished...
Shoot away!!!
Steve K
Update 2. Got it back from CLA, now 1sec is 1.1 (previously it wast 1.3).
Bernice Loui
10-Aug-2021, 09:18
As tested using an optical shutter tester with certified accuracy?
Bernice
Update 2. Got it back from CLA, now 1sec is 1.1 (previously it wast 1.3).
Tin Can
10-Aug-2021, 09:30
Exactly
That is less than a 20% improvement
will it last
is it real
Tin Can
10-Aug-2021, 09:33
I will add this, to answer my own ?
I have many failed Copal 1, but no failed Copal 0 or 0.0
May as well add this question
In your experience do both Copal 0 and Copal 1 have similar life spans
or hours to rebuild
I have a choice coming up
anybody?
I measured it the same way I measured it before, with my iphone (and later my mac). I have chosen 1s to be my "victim" as its span is long enough for my iphone/mac to detect significant shifts.
Dear Tin, nothing lasts.
Bernice Loui
10-Aug-2021, 09:58
One second victim, how often will one second be used for film exposure.
Best to check each shutter speed for accuracy and consistency. Keep in mind the 20-30% timing tolerance for mechanical shutters.
Oh, example of why folks into LF should place a high value on shutter accuracy and consistency as this will go a long ways to reducing frustration with the burning of film and images made.
Bernice
I measured it the same way I measured it before, with my iphone (and later my mac). I have chosen 1s to be my "victim" as its span is long enough for my iphone/mac to detect significant shifts.
Dear Tin, nothing lasts.
BrianShaw
10-Aug-2021, 11:18
One second victim, how often will one second be used for film exposure.
Probably rarely... but that is a clear indicator that shutter service should seriously be considered.
Tin Can
10-Aug-2021, 11:22
I am happy with some shutters if T and B work
even more if sync works
BrianShaw
10-Aug-2021, 11:24
Yes, indubitably... depends upon individual needs.
lassethomas
10-Aug-2021, 11:50
I measured it the same way I measured it before, with my iphone (and later my mac). I have chosen 1s to be my "victim" as its span is long enough for my iphone/mac to detect significant shifts.
Depending on how shutters are constructed there is no way to extrapolate a one second measurement to faster times.
Speed is usually controlled by both a pallet and retard escapement mechanism but the pallet is only engaged for speeds somewhere around 1/15 and longer.
This means that shorter times can work well and the longer times might be off in the same shutter. A common problem often encountered.
So a 1 second measurement will tell you nothing about how the shutter functions for for example 1/30 or 1/125. The only way to know is to measure.
And contradictory to some other posters my experience is that audio will be good enough for most application up to 1/60.
BrianShaw
10-Aug-2021, 11:53
Very correct about no interpolation from slow to higher speeds. If the slow speed delay mechanism isn’t working correctly it always means that the shutter is dirty enough that it should be serviced… whether the higher speeds are “working acceptablely “ or not.
Same with self-timers, when they are present.
Both are harbingers of impending failure.
Bernice Loui
10-Aug-2021, 12:14
Sinar shutter has a single timing (escapement) mechanism with one adjustment. Runs from 1/60 to 8 seconds. Shutter time/speed overall is often ok when checked at the ends of it's shutter speed/time range.
Big Ilex shutters like the# 5 have a single single timing (escapement) mechanism.
Smaller (older think) Compur shutters have two timing (escapement) mechanisms and a extra high tension spring for the highest shutter speed.
Bernice
Drew Wiley
10-Aug-2021, 12:27
Interesting. The only shutter I ever owned that was spot on at the highest speed was a Compur 3; but annoyingly, it didn't even have a T setting, just a B. All the Copals were way off at the highest speed. What I care about in view camera photography is the low speeds anyway.
Welp let's hope for the best.
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