The cameras I have with stepless mechanical shuttter speeds (Nkon F2, Leicaflexes, Leica M6) lose their stepless function around the flash sync. speed.
They do work at speeds above & below.
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The cameras I have with stepless mechanical shuttter speeds (Nkon F2, Leicaflexes, Leica M6) lose their stepless function around the flash sync. speed.
They do work at speeds above & below.
I never tried mine at in-between speeds below the X-sync speed, just because the manual said it only worked above it. That of course doesn't mean it wouldn't have worked.
Quoting the manual:
You can also use the intermediate settings for more precise exposure except at speeds slower than 1/80th second.
Nicholas Lindan
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All (well, almost all) focal plane shutters are stepless.
The mechanism varies the slit size as the shutter speed knob is turned. Obviously, this is a continuous process. The only steps are the detents in the shutter knob - in this it is like an aperture mechanism.
So, why are they stepless? Because it would add cost and complexity to add steps.
Some FP shutters are also stepless at slower speeds, where a clockwork retarder delays the closing of the second shutter curtain. However, most shutters used a stepped cam to set the slow speed mechanism and setting intermediate speeds is a hit-or-miss affair.
Electronic shutters are stepped when speeds are set manually. The camera reads the speed setting from a set of contacts that are sequenced as the knob is turned. In automatic the shutter speeds can be continuous with a granularity of 100 micro-seconds or so (in a simple implementation with a slowest speed of 6.5 seconds and a straight 16 bit counter). The VF display of the shutter speed may be rounded to the nearest 1/3 of a stop, but that doesn't mean the actual shutter speed is limited to these values.
I don't know what you consider snide remarks or insults, but for an internet discussion this one has been pretty dang civil. But coming on an internet forum and making absolute statements is always an invitation for others to dispute them.
I for one think I have a pretty good idea of what you're talking about- I just think it is realistic to expect an electronically controlled shutter to be more accurate only up to a point, and no one "needs" an exact speed like 1/450, even if it were possible to set it to that speed and get it accurately.
I am not so much interested in changing your mind as I am in challenging some statements which are either demonstrably incorrect, or make a claim which is valid in some circumstances and not others, but are stated as absolute.
As to your methods, only you can change them. If you cannot get good exposures using a mechanical camera with slide film, I think you need to reconsider your methods. But you seem determined not to. That's your business.
But only a few mechanical camera manuals recommend using in-between speeds-many say not to. Maybe because the manufacturer has calibrated only at marked speeds, and doesn't want to guarantee in-between speeds' accuracy.
My old Fujica ST801 seems to have a lockout for in-between speeds-that is, it selects either the higher or lower speed. For instance, anywhere in between 1/2 and 1 second on the dial, it gives 1 second.
From the manual for the Olympus OM-3Ti (a mechanical camera)--Page 102:
"Q: Can I set shutter speed to a position halfway between settings?
A: No, the ring has to be clicked into place."
If my memory serves me, all of the other OM instruction manuals say the same thing.
"Q: Can I set shutter speed to a position halfway between settings?
A: No, the ring has to be clicked into place."
If my memory serves me, all of the other OM instruction manuals say the same thing.
Read my post #100 in this thread.
Your statement is not correct for any of the camera models I listed.
The term "stepless" does not appear on any of those manuals.
- Leigh
I didn't refer to your list but as you can see I provided my own (all film and none digis) and the manuals all state stepless.
To be sure, I don't remotely agree with the premise that fully mechanical cameras cannot make accurate exposure on film as obviously Kodachrome was released in the 30's and that film - probably more then any other film, requires reasonably accurate exposure and obviously fully mechanical cameras - even the limited Argus C3, can do so without fanfare.
You said:
"All Nikon SLR's with electronic shutter and aperture priority auto exposure have stepless shutter speeds "
That's not correct.
The models I listed meet your criteria, i.e. electronic shutters and auto-exposure, and do not have stepless shutter speeds.
I believe only one person in this thread thinks there's an exposure problem with mechanical shutters.
He's vastly out-numbered.
- Leigh
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The premise:
If I get it right, there are two mechanism governing shutter speeds, which can clearly be seen in old cameras like a Leica III and its clones.
The first, the simple one, as said, only governs the interval between the two shutters.
An additional mechanism, the "retarder", is like a stopwatch counting fractions of seconds for long times. This can be a delicate piece of watchmaking.
You can see this in the fact that less sophisticated shutters up to the sixties or so did not have shutter speeds slower than 1/30 or so.
My Voigtländer Vito CLR has a leaf shutter which arrives to 1/15 but does not go below that (if we exclude Bulb).
Certain Zorki, Kiev or FED lack the slower shutter times, maybe also certain Leica. That's because this "retarder" was eliminated in order to cut costs. When the retarder is present, it can have a different dial.
When you bring your camera to a repairer for a shutter accuracy check, I understand that what is really checked is the slower speeds. The faster speeds will all work well if the shutter appears generally healthy. For the faster shutter speeds not to work there must be a fundamental problem with the shutter mechanism, which would be visible on all speeds. On the other hand the shutter might be in good shape but the "retarder" might be off, broken etc.
The conclusion:
With certain cameras, if you set the retarder in intermediate positions you can damage it and if the knob is the same one for fast and slow speeds, as it normally is, the producer will tell you not to use intermediate positions on ALL shutter speeds, while in fact, probably, the only ones with a risk of being damaged are the slower ones, those with a retarder. That's basic common sense, the producer either inserts an anti-damage mechanism in his shutter dial, which might be costly, or must squarely say to the user that he must not do something that might damage or stress it, I even forgot that I had to push the aperture ring in my PC-Nikkor I can figure out how easy would have been to forget that you cannot use intermediate position on certain intervals.
If I get it right, there are two mechanism governing shutter speeds, which can clearly be seen in old cameras like a Leica III and its clones.
The first, the simple one, as said, only governs the interval between the two shutters.
An additional mechanism, the "retarder", is like a stopwatch counting fractions of seconds for long times. This can be a delicate piece of watchmaking.
You can see this in the fact that less sophisticated shutters up to the sixties or so did not have shutter speeds slower than 1/30 or so.
My Voigtländer Vito CLR has a leaf shutter which arrives to 1/15 but does not go below that (if we exclude Bulb).
Certain Zorki, Kiev or FED lack the slower shutter times, maybe also certain Leica. That's because this "retarder" was eliminated in order to cut costs. When the retarder is present, it can have a different dial.
When you bring your camera to a repairer for a shutter accuracy check, I understand that what is really checked is the slower speeds. The faster speeds will all work well if the shutter appears generally healthy. For the faster shutter speeds not to work there must be a fundamental problem with the shutter mechanism, which would be visible on all speeds. On the other hand the shutter might be in good shape but the "retarder" might be off, broken etc.
The conclusion:
With certain cameras, if you set the retarder in intermediate positions you can damage it and if the knob is the same one for fast and slow speeds, as it normally is, the producer will tell you not to use intermediate positions on ALL shutter speeds, while in fact, probably, the only ones with a risk of being damaged are the slower ones, those with a retarder. That's basic common sense, the producer either inserts an anti-damage mechanism in his shutter dial, which might be costly, or must squarely say to the user that he must not do something that might damage or stress it, I even forgot that I had to push the aperture ring in my PC-Nikkor I can figure out how easy would have been to forget that you cannot use intermediate position on certain intervals.
The list I provided is correct for the statement I made as they are all in the manuals.
Obviously I can't speak for other repair shops, but...
When I was repairing Nikons, we checked every marked speed on the camera, from fastests to slowest, and made sure that they were all in spec before it left the shop.
- Leigh
It may be correct for the models that you listed, but that's not what you said.
You said "All Nikons...". That statement is absolutely false, and you know it.
- Leigh
I expressed myself a bit clumsily. Yes all the shutter times are checked, I meant it's the slowest that are typically found to be off and that would need tuning. Does it conform to your experience as a repairer?
If in fact there are any Nikon SLR's with electronic shutter and aperture priority auto exposure that do not provide stepless shutter speeds - even if outside of the list I provided, that I am not aware of it then please let me know as I believe I have researched them all and would be happy to know of one or more that I may have missed.
After reading all the comments, I'm pretty sure two small expert groups will form, one specialising in designing the most accurate mechanical shutter, the other group in designing the best electronic one. I imagine the new camera for these shutters would have at least two shutter speed dials, a 'normal one' with the usual values and a 'fine setting one', preferably with values +/- 1/10th or 1/100th EV, somewhat resembling a screw mount Leica.
A third group might also emerge from the shadow of the shutter designers who would feel they were left out of the fun. For them the seldom encountered 1/10th of a stop aperture scale wouldn't be enough and they would build the most accurately tracking aperture system with fine setting.
Despite the high number of posts I can't see why it is important for an electronic shutter to be practically stepless in AE mode when it's metering system is fooled so easily (at least on those cameras I used) that the possibility of setting exposure time to the single critical value itself doesn't matter much.
A third group might also emerge from the shadow of the shutter designers who would feel they were left out of the fun. For them the seldom encountered 1/10th of a stop aperture scale wouldn't be enough and they would build the most accurately tracking aperture system with fine setting.
Despite the high number of posts I can't see why it is important for an electronic shutter to be practically stepless in AE mode when it's metering system is fooled so easily (at least on those cameras I used) that the possibility of setting exposure time to the single critical value itself doesn't matter much.
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even with today's camera the shutter speed accuracy is only to within 1/3 stop. I am not saying that 1/10th isn't possible it's just that manufacturers don't seem to want to work on that. Besides, 1/3 stop is sufficient for most application any way. Also any further development of the shutter is for the requirements of the digital sensors and not film. I don't think anybody is doing R&D on film photography any more. Even the meter, which is easy to achieve 1/10th stop accuracy, are not that accurate as far as built in meter is concerned.
Leigh. I believe that the D300s has stepless shutter speed too when in automode although the manual said otherwise. Of course, we have to test to find out. However, stepped or stepless doesn't make a difference like Fstop said.
If you choose to disregard the manufacturer's literature, you can believe whatever you wish.
I don't choose to do so.
- Leigh
The reply to fstop to which you referred made no distinction regarding camera type.I don't own any Nikon DSLRs . . .
Since you note in post #133 that you didn't look at my list, your subsequent comments cannot be based on that distinction.
You simply said 'All Nikons'.
- Leigh
It is a known premise that here on APUG that means film only.
However, I also don't consider AF Nikons either . . .
One aspect that seems to have been omitted (unless I've missed it) is the latitude of film. Even with the most demanding, old school, low speed reversal film a viewer won't detect a fraction of a stop and in reality half a stop won't kill a slide. Black and white has more latitude and colour neg has enormous range, something like 5 stops.
Fractional f-stops systems usually come with highly automated metering systems. Most of the time you're handing over your metering to a logarithmic 'brain' unless you spot meter every shot on manual. I'd be more worried about the assumptions on which the camera's metering system was based than an 'enth of a stop appearing in the final photograph.
Fractional f-stops systems usually come with highly automated metering systems. Most of the time you're handing over your metering to a logarithmic 'brain' unless you spot meter every shot on manual. I'd be more worried about the assumptions on which the camera's metering system was based than an 'enth of a stop appearing in the final photograph.
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