In the original Photoplug there is no light. I added 2 LEDs with an external power supply simply by a battery.Very nice. I'm not familiar with the 'Photoplug.' Where is the light coming from?
In the meantime, I have written a complete article about it on my website. You can find it here:
Checking shutter speeds of Minox 8x11 cameras
So let’s measure the shutter speeds of our Minox. But how? Read my simple method to accurately measure Minox shutter speeds here.moments-of-now.com
Merci pour les explications très precises
A simpler method is to use a roll of film and shoot at1 sec, 1/2, 1/4, etc using a ND filter as needed. Develop roll of film and inspect the negative.
Where did you get the 12 ND filters? Can you show the roll of film?A simpler method is to use a roll of film and shoot at1 sec, 1/2, 1/4, etc using a ND filter as needed. Develop roll of film and inspect the negative.
A simpler method is to use a roll of film and shoot at1 sec, 1/2, 1/4, etc using a ND filter as needed. Develop roll of film and inspect the negative.
Thank you!That's not measuring the shutter speed! As Kelvin put it:
"When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind: it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be."
..when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind:
To you it is, but everyone gets to decide what standards they want to use. I've tested lots of film density with an analyzer, but I know that the old eyeball does a pretty good job too. Most people I know simply use their baby blues to determine maximum black in their prints, not a densitometer.
The eye/brain is easily fooled.
That's not measuring the shutter speed! As Kelvin put it:
"When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind: it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be."
To you it is, but everyone gets to decide what standards they want to use. I've tested lots of film density with an analyzer, but I know that the old eyeball does a pretty good job too. Most people I know simply use their baby blues to determine maximum black in their prints, not a densitometer.
That's not measuring the shutter speed! As Kelvin put it:
As an aside, the Photoplug is a great little device, I use it to measure the shutter speeds on all the old cameras I buy. On older cameras, the speeds are invariably slower than marked.
Yes, the reason it measures speeds slower than it actually is, is the fact it is measuring both slit width and sensor width. The higher the speed, the greater the error.
It also cannot measure curtain speed, which is essential for correctly calibrating a focal-plane shutter.
Look on this forum for discussion of my tester, the issue above is described in detail how my tester gives accurate results.
Kosmo photo has two interesting articles, this one, showing how to test shutters and detailing how these single sensor testers are not good.
5 Levels of Shutter Testing: How Accurate is your Film Camera?
Introduction Here at Kamerastore, we buy and sell thousands of cameras every year. With this experience, we know that the vast majority (over 80%) have some kind of issue that requires attention from our mechanics. If you buy a camera online from someone who only does basic testing, or no...kamerastore.com
Thanks for pointing this out. Actually I'm a medium format person and the shutters are invariably leaf-shutters in the lens, so I think the single sensor PhotoPlug is accurate ... am I correct? (It is a little aperture-dependent I suspect.)
No, not that simple I'm afraid. It seems so simple, use a sensor to measure how long it sees light. Alas, that just does not work.
I have updated my The Shutter Tester to include leaf shutter testing, using the formula below. However, not having a leaf-shutter, I have not been able to test it against an actual shutter, just a mock-up, which seems to work perfectly.
One does not just measure the open time in the centre of the shutter, but one also measures the time for the leaves to fully open and the time for them to fully close. The only way to do this is with two sensors, but again one has to calculate the raw readings to allow for sensor width, which then gives the correct result.
(Thanks to IC Racer, for the diagram below).
The formula is time open = centre open time + (time to open + time to close)/2
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