203FE - how precise are the longer shutter times supposed to be?

[philipus]

Ok my 203FE saga (which began with the thread just below concerning my Frankenstein film magazine) continues. I am noticing that long shutter times, 10s and longer, are off by a few seconds. For instance if the meter reads 16s for a very dark scene the shutter will close at 13s.

I realise this may not be a big problem during, for instance, night photography but I am wondering if it may be indicative of also other shutter times being off. And I am of course wondering how precise are longer times supposed to be on this model? I would have thought that, given the electronics, they would be more or less on the proverbial dot time-wise.

Thanks very much in advance for any help
Philip

 

[Gerald C Koch]

13/16 is a 20% error, not bad for a mechanically controlled shutter. With mechanical shutters it is the higher speeds that are most inaccurate sometimes by 60% or more. .

 

[summicron1]

not sure what a 203 FE is, but in any case, as the man says, 20 percent off is not too bad and not even half a stop. Your bigger concern with long speeds like that is going to be reciprocity failure.

 

[itsdoable]

The 203fe AE meter will set the shutter to 1/10 steps. The meter display only goes to 1/2 stop. The shutter is probably exposing what the meter measured, and displaying the closest setting. Electronic (in this case RC) timing circuits rarely go off. To get a good measure on the timing, use a manual shutter speed setting. There is a 60x manual shutter speed multiplier available for the 200/2000 series to make manual timing easier... um, and for long exposures.

 

[shutterfinger]

Shutter speed tolerances, according to http://www.flutotscamerarepair.com/Shutterspeed.htm , are 20% for speeds 1/100 and slower; 30% for speeds 1/125 and faster. Compur states their shutters should be 15% for speeds 1/100 and slower and 25% for speeds 1/125 and faster. Mechanical shutters base their speeds on the 1 second setting with some having adjustment available at 1/15 or 1/25 and the fastest speed.
Electronic shutters are electronically controlled mechanical devices. Electronic timer circuit determines when the shutter is closed.
The shutter tolerances are basically 1/3 stop either side of the selected (marked) speed. A shutter should be serviced by the time it reaches 1/2 stop off from the marked speed.
An electronic shutter that uses an adjustable oscillator circuit such as a quartz watch would need an adjustment of .5° or less on a circular dial for a 3 second error at 16 seconds.

The components in your shutters timer circuit are probably 1% or 5% tolerance and none are out of tolerance.

 

[film_man]

13/16 is a 20% error, not bad for a mechanically controlled shutter. With mechanical shutters it is the higher speeds that are most inaccurate sometimes by 60% or more. .

The 203FE has an electronic shutter.

 

[philipus]

Thank you very much for the quick and detailed replies.

The 203fe AE meter will set the shutter to 1/10 steps. The meter display only goes to 1/2 stop.

Thank you. I now discovered a sentence in the manual which I had previously overlooked about how the display works.

I feel more confident now that the camera is within limits. I'm shooting rolls of Provia to check the speeds.

br
Philip

 

[itsdoable]

One more way to check the shutter timer in AE mode is to put a lens cap on, close the viewfinder, and trip the shutter. The longest shutter speed should be 32 seconds.

 

[philipus]

Thank you that's good idea, I'll check when I get a magazine from the dealer replacing my Frankenstein magazine.

 

[itsdoable]

Thank you that's good idea, I'll check when I get a magazine from the dealer replacing my Frankenstein magazine.

Actually, you do not need a film back to test the shutter - you don't even need the lens, just put the body cap on.

 

[cowanw]

Actually, you can do with the plastic protection back, I think.
The instructions describe that flash can be tested with the protection back with the middle grey patch on it, so I presume the meter reads of that.

 

[250swb]

I am noticing that long shutter times, 10s and longer, are off by a few seconds. For instance if the meter reads 16s for a very dark scene the shutter will close at 13s.

Philip, you and your camera are both off by far more than a couple of seconds. If your meter is reading 16s then with reciprocity failure you should be making an exposure of at least 40 seconds with an average film (all films vary, but I'm just highlighting the principle).

Steve

 

[philipus]

Steve, thanks (I think).

Br
Philip

 

[250swb]

Well my point was that longer than four seconds you are dealing with exposures double, triple, or quadruple the metered time, so a couple of seconds difference in the actual shutter speed becomes inconsequential. Use 'B' or 'T'.


Steve

 

[itsdoable]

Actually, you can do with the plastic protection back, I think.
The instructions describe that flash can be tested with the protection back with the middle grey patch on it, so I presume the meter reads of that.

The grey spot on the back cover is for the OTF flash sensor. For regular exposure metering, the sensor gets it's TTL reading from a sub-mirror.

Well my point was that longer than four seconds you are dealing with exposures double, triple, or quadruple the metered time, so a couple of seconds difference in the actual shutter speed becomes inconsequential. Use 'B' or 'T'.

I agree that 20% exposure change is not significant on film. But at 16 seconds, reciprocity is minimal on most modern films. However, the exercise was to verify that the camera shutter accuracy was "as it should be", which in the case of electronic timed shutters, should be better than 10 seconds when set to 16s (which would indicate that something was wrong).

 

[250swb]

But at 16 seconds, reciprocity is minimal on most modern films.

Delta 100, for instance, is a modern film, and a 15 second meter reading requires a 50 second exposure (or thereabouts) according to Ilford's own data sheet. Well it's not as bad as Fomapan I suppose, but 'minimal'?

So for modern film's it isn't a 15 or 16 second meter reading that the shutter needs testing against by making a 16 second exposure, it is how accurate it is at 1 minute.

Steve

 

[itsdoable]

Delta 100, for instance, is a modern film, and a 15 second meter reading requires a 50 second exposure (or thereabouts) according to Ilford's own data sheet....

Delta 100 was introduced in 1992 - older than the camera the OP is asking about. I have not used Delta since the late 90s, but maybe I should revisit it - it is easier to get Kodak films where I live.

For some reason I can't download the Delta data sheets, but the last recirpocity table I have (circa 2002) shows 19s for a 15s exporsure. But if I google, I see everything from 19s to 60s. TMax, ADOX and NeoPan are ~1/2 stop at 15s, where as Formapan, Tri-X APX and Ilford show ~2stops at 15s - arguably the difference between older and newer emulsions?

Fuji Velvia, Provia, Astia show no reciprocity correction till 60s.

However, Portra (arguably a "modern" film) needs more than a stop at 15s. So I was probably too optimistic when I said "most" - Portra is one of my favorite films.

 

[250swb]

Delta 100 was introduced in 1992 - older than the camera the OP is asking about. I have not used Delta since the late 90s, but maybe I should revisit it - it is easier to get Kodak films where I live.

For some reason I can't download the Delta data sheets, but the last recirpocity table I have (circa 2002) shows 19s for a 15s exporsure. But if I google, I see everything from 19s to 60s. TMax, ADOX and NeoPan are ~1/2 stop at 15s, where as Formapan, Tri-X APX and Ilford show ~2stops at 15s - arguably the difference between older and newer emulsions?

Fuji Velvia, Provia, Astia show no reciprocity correction till 60s.

However, Portra (arguably a "modern" film) needs more than a stop at 15s. So I was probably too optimistic when I said "most" - Portra is one of my favorite films.

To put what you say into perspective Fomapan 100 and a 15 second meter reading needs 150 seconds exposure. If it is a one stop increase in exposure for Portra 160 that still means it is a 32 second exposure for a 16 second meter reading. So answer me, what really is the point of testing the shutter speeds for a 16 second meter reading by making a 16 second exposure? If you can't find any reciprocity graphs try Google, but if you don't already have an instinct or knowledge of the reciprocity failure of film you clearly have never used film much in situations where longer exposures are required.

Steve

 

[RalphLambrecht]

13/16 is a 20% error, not bad for a mechanically controlled shutter. With mechanical shutters it is the higher speeds that are most inaccurate sometimes by 60% or more. .

I'm confused;isn't a higher shutter speed a faster shutter speed? long exposure times are the result ofslow shutter speeds;no?

 

[itsdoable]

To put what you say into perspective Fomapan 100 and a 15 second meter reading needs 150 seconds exposure. If it is a one stop increase in exposure for Portra 160 that still means it is a 32 second exposure for a 16 second meter reading. So answer me, what really is the point of testing the shutter speeds for a 16 second meter reading by making a 16 second exposure?

The original poster asked about testing the shutter speed on a recently purchased camera to verify if it was operating as it should. Testing the easily timed long exporuses is a very legitimate way of verifying that it is doing what it should be doing. The fact that a 20% exposure variation is well within mechanically timed shutter (and exposure) limits was not the issue. An electronic timed 15 second exposure should run 15 seconds, and if it does not, then the mechanism is faulty, which raises questions about the condition of the camera.

.... but if you don't already have an instinct or knowledge of the reciprocity failure of film you clearly have never used film much in situations where longer exposures are required.

Steve, insults about what I know or dont' know, do not belong in this thread.

 

[250swb]

The original poster asked about testing the shutter speed on a recently purchased camera to verify if it was operating as it should.


Steve, insults about what I know or dont' know, do not belong in this thread.

In which case a 16 second shutter time should be compared with an accurate timer, not a meter reading!

As for insults if you want to pick the bones out of a general principle then think before you pick.

Steve

 

[philipus]

The original poster asked about testing the shutter speed on a recently purchased camera to verify if it was operating as it should. Testing the easily timed long exporuses is a very legitimate way of verifying that it is doing what it should be doing. The fact that a 20% exposure variation is well within mechanically timed shutter (and exposure) limits was not the issue. An electronic timed 15 second exposure should run 15 seconds, and if it does not, then the mechanism is faulty, which raises questions about the condition of the camera.

Thanks for this, which I find very helpful indeed.

I was a bit confused by the interesting (at least largely) discussion about reciprocity. It seems to me that if a long shutter speed is off by 20% on an electronically controlled shutter then that error will remain on other speeds, and thus affect the reciprocity correction too.

I guess at the moment we have in one corner of the ring the potential that the differing timing results from the fact that the display is only able to display 1/2 stops whereas the shutter is more fine-tuned than that. In the other corner, we have the completely logical fact that an electronically controlled shutter should remain open for as long as as is set. The problem is that I didn't actually "set" a time - I shot in AE mode when I tested.

So next step is to shoot in manual at different speeds and see what happens.

Thanks for your continued help.

Br
Philip

 

[philipus]

Hello again

Today I received the replacement ECC magazine which works like a charm. I also received my second magazine, an A-12 bought from the excellent Finnish shop Kameratori.fi. I have used the camera in M L.E. mode and tried shutter speeds from 1s to 32s against a timer. The shutter closes within the right second, so to speak (my timing skills are not more precise than that) so it appears that the camera is likely OK. I'm very happy about this because I was a bit worried.

Thanks for all the help I've received in this thread. I've learnt a lot.

br
Philip