Why is shortest possible shutter speed 30s?

Hi Simon,

It may just be a carry over from film camera days where 2 - 3 minutes had such a potentially large degree of error engrained in it that getting reproducible exposures was seen to be beyond the then technology.

Things have clearly changed - but without people pushing for adaptations such as this (which clearly makes sense with astro photography and other long exposure shots) then it does seem odd it isn't a simple option now - there's plenty of other things included which few people use....

Best regards, Neil.

I think it's a throwback to electronic film SLRs , where the bodies were then used for DSLRs , using the same type of shutter etc.

The shutters are controlled electronically , and if I remember correctly power is used to hold a shutter open when it's a time setting being controlled by the camera , regardless of what exposure mode your in .
So if your in aperture priority mode , with an ND 3 ( 10 stop ) filter on , ISO 100 and f/22 , and low light , where the exposure could be a couple of minutes , you would be draining the batteries .

Using a cable release ( mechanical or electronic ) and the camera set to "bulb " the shutter is opened , and as long as you keep the button pressed down no power is being used to hold the shutter open . Releasing the button shuts the shutter .

This was very important when your camera used a couple of tiny LR44 batteries ( like in my Minolta X700) or some AA batteries or the expensive 2CR5 batteries .

Quite why a modern camera with all its computing power can't be set to alter how the shutter is kept open automatically depending on shutter speed , I don't know .

I think it's a case of that's how it's always been done since the 70's , so why change now ?

@nandbytes , when you say that the a1/9 has no bulb mode on electronic shutter , I presume they still have bulb mode on mechanical shutter ?

If so their might be a reason that that the sensor based shutters can't function like this , rather it just being the manufacturer not implementing it .

Edited by neilt3 - 07 January 2022 at 14:47

neilt3 wrote: @nandbytes , when you say that the a1/9 has no bulb mode on electronic shutter , I presume they still have bulb mode on mechanical shutter ? If so their might be a reason that that the sensor based shutters can't function like this , rather it just being the manufacturer not implementing it .

Yes A1/9 (and all other Sony bodies) have bulb mode with mechanical shutter only

If you re-read my comment above I already gave examples of manufacturers implementing bulb mode with only sensor based shutter (i.e. electronic shutter)
Nikon Z9 and sigma FP both have no mechanical shutter whatsoever and can still shoot in bulb mode.

In fact sigma FP doesn't even have a stacked sensor with fast readout speeds and they've still implemented it albeit with a 300s limitation (Z9 seems to have no such limitation).

So its definitely Sony's arbitrary limitation as far as I can see.

nandbytes wrote: Yes A1/9 (and all other Sony bodies) have bulb mode with mechanical shutter only If you re-read my comment above I already gave examples of manufacturers implementing bulb mode with only sensor based shutter (i.e. electronic shutter) Nikon Z9 and sigma FP both have no mechanical shutter whatsoever and can still shoot in bulb mode. In fact sigma FP doesn't even have a stacked sensor with fast readout speeds and they've still implemented it albeit with a 300s limitation (Z9 seems to have no such limitation). So its definitely Sony's arbitrary limitation as far as I can see.

Quite right , I should have done a better job reading your post !

Also , I wasn't ware of cameras such as these not having mechanical shutters , so clearly the technologies there already .

Tricky01 wrote: addy landzaat wrote: More likely is imo that over 30s the bulb timing is good enough - it doesn't matter if you're off by one or two seconds when you have a shutter time of two minutes. I think that is why they did not bother over 30s: just use bulb, it is good enough. the problem is, I wouldn’t trust my finger to stay steady for an exposure of 5 seconds, let alone 30+, so it’s less a matter of precision, and more a case of not wanting to accidentally add any movement to the camera.

Most wired remotes can lock - so you simply push and lock and walk away if you want, coming back to unlock and end the exposure

Phil Wood wrote: Tricky01 wrote: addy landzaat wrote: More likely is imo that over 30s the bulb timing is good enough - it doesn't matter if you're off by one or two seconds when you have a shutter time of two minutes. I think that is why they did not bother over 30s: just use bulb, it is good enough. the problem is, I wouldn’t trust my finger to stay steady for an exposure of 5 seconds, let alone 30+, so it’s less a matter of precision, and more a case of not wanting to accidentally add any movement to the camera. Most wired remotes can lock - so you simply push and lock and walk away if you want, coming back to unlock and end the exposure

Yep.

I don't know if any digital cameras have this, but on some earlier cameras there was a T setting. Different from B, you press the release once and the shutter opens. Press it again -- whether 1 second or 1 day later -- to close the shutter.