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12-21-2014, 07:32 PM   #1
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Why is exposure limited to 30 seconds in manual mode? This seems arbitrary

Today I took some sunset pictures and as it got darker I constantly had to switch to Bulb mode to get exposures longer than 30 seconds. It's really tedious to have to pull out my intervalometer as it gets darker. I can see that the longer the exposures, the more noise, but it should be up to the user to make that call. Especially in a "Pro" camera like the K-3. And you can get around it with Bulb mode anyway.

12-21-2014, 08:25 PM   #2
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Actually, I've been wondering the same thing. 30s seems to be a heritage from the 70-80's where that max was boosted from the former max of 1s. The only real reason for it I can see was the reciprocity failure of film with longer time than that and after that the immature sensor tech that got overheated with long exposure times.

Now our sensors can work for hours with relatively low heat build-up so there isn't really a reason. Actually with the Astrotraces in the GPS unit the max time suddenly bumps up to 5min!
12-21-2014, 09:04 PM   #3
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QuoteOriginally posted by VisualDarkness Quote
Actually with the Astrotraces in the GPS unit the max time suddenly bumps up to 5min!
I'd say Astro tracer limit is based on the amount of rotation/movement SR system can accommodate.

The 30s must be an engineered line in the sand re: heat as mentioned above, because by default, DFS kicks in after that.
12-21-2014, 10:07 PM   #4
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QuoteOriginally posted by maxxxx Quote
Today I took some sunset pictures and as it got darker I constantly had to switch to Bulb mode to get exposures longer than 30 seconds. It's really tedious to have to pull out my intervalometer as it gets darker. I can see that the longer the exposures, the more noise, but it should be up to the user to make that call. Especially in a "Pro" camera like the K-3. And you can get around it with Bulb mode anyway.
30 sec is pretty much the standard among the mfr. I guess the limitation could be due to heat generated by the sensor.

12-21-2014, 10:29 PM   #5
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At night I do much longer exposures regularly without problem but I always have used Bulb mode so far.

Just looked up specs of D810 and canon 5D and they have that limit too.

It's just weird that I can go up to 30 in manual mode and for 35 I have to use my intervalometer.
12-22-2014, 04:56 AM   #6
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Getting below the reliable minimum lighting level for exposure to be reliably calculated?
12-22-2014, 09:02 AM   #7
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Yes, 30 seconds is just a remnant from the past. Bulb mode can do several minutes without too much noise or damaging the sensor, but many manufacturers constrain M mode to 30 sec. I saw one m43 camera, either an Olympus or Panasonic, at a photo show that allowed several minutes in M mode. Long exposure is such a small niche that I doubt Ricoh will think to enable > 30 sec.
12-22-2014, 09:05 AM   #8
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I think it is a limit on calculating exposures with the meter, not a sensor limitation. (Because obviously you can use bulb for as long as you want.)

12-22-2014, 09:37 AM   #9
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I questioned this before I bough as to WHY ?
Dont think it has anything to do with sensor damage or heat at all. Believe it simply to be that the programming must be cut off somewhere and this is simply a holdover from alot of cameras for the fact very few shoot even close to 30sec and many more will never go higher than that.

Thank god for BULB Mode....... alot of 1-6 minute exposers here with no problems and minimal noise.....ISO 100... remote shutter and weighted tripod.
12-22-2014, 11:08 AM   #10
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I'd be happy with the 30s. My SV and K1000 only go to 1s before going to Bulb. The SV has a Time position also. 1 click to raise the mirror and open the shutter and a 2nd click to close the shutter and lower the mirror. With the K1000 you have to have a cable release with a lock or your thumb will go to sleep!
12-22-2014, 11:28 AM   #11
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30 sec is not a problem regards heat, but it may be the DFS feature. Nevertheless, i find this a needless bother too, i.e. dragging out my bulb mode cable. To avoid that i often will bump up the iso for long exposure shots to avoid the 30 sec limitation.

Was looking at camera specs recently, and there is one mfr that has bumped up the 30sec to 60 sec. I think it may have been Olympus or Panasonic - cheers to them.
12-22-2014, 12:46 PM   #12
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QuoteOriginally posted by DeadJohn Quote
Yes, 30 seconds is just a remnant from the past. Bulb mode can do several minutes without too much noise or damaging the sensor, but many manufacturers constrain M mode to 30 sec. I saw one m43 camera, either an Olympus or Panasonic, at a photo show that allowed several minutes in M mode. Long exposure is such a small niche that I doubt Ricoh will think to enable > 30 sec.
I wish they would an extended exposure mode like they sometimes do with ISO

---------- Post added 12-22-14 at 11:48 AM ----------

QuoteOriginally posted by vonBaloney Quote
I think it is a limit on calculating exposures with the meter, not a sensor limitation. (Because obviously you can use bulb for as long as you want.)
I can see how metering would be a problem but the restriction is there in Manual too.
12-22-2014, 01:30 PM   #13
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QuoteOriginally posted by maxxxx Quote
Why is exposure limited to 30 seconds in manual mode? This seems arbitrary
It is my understanding that the limit is a characteristic of the Copal shutter's command set. This limitation extends to other brands that use similar shutters. If you need a longer exposure time, you may use a remote and "B" mode. My wired remote allows for arbitrary exposure times up to several hours.


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12-22-2014, 02:29 PM   #14
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Long exposure on film results in something called reciprocity failure. In other words, a 1 minute exposure may not result in twice the density as a 30 second exposure. There is a long explanation that gets down to atomic and molecular level physics. It would not surprise me if a sensor exposed to bright light for too long would not be damaged. This was a huge issue some time ago. It may have something to do with being a safeguard against a sensor memory issue.

At night this would not be an issue, but it may be if it was accidently done with a bright daylight scene.
12-23-2014, 01:35 AM   #15
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QuoteOriginally posted by maxxxx Quote
Today I took some sunset pictures and as it got darker I constantly had to switch to Bulb mode to get exposures longer than 30 seconds. It's really tedious to have to pull out my intervalometer as it gets darker. I can see that the longer the exposures, the more noise, but it should be up to the user to make that call. Especially in a "Pro" camera like the K-3. And you can get around it with Bulb mode anyway.
Traditionally it's the point where the sensor linearity to light vanishes therefore you can no longer define a correct exposure solution (electronically) for the light available in any generic way that could be applied to every camera made it would need to be calibrated uniquely as each camera came off the production line.

I would assume this is still true as base ISO still hangs out at 100 or 200 so sensor linearity is still a concern for manufacturers
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