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What is shutter speed?

eddywatson

Standard Member
Hello

First off let me say that I am really sorry if this sounds stupid but I dont know so I thought I would ask....

Is the shutter speed the time it takes from when you press the "take photo" button on your camera until the actual image is taken? So thefor you could have a slight delay... and the image you take is not actually the image you wanted as something moved in that small time its taken to press the take photo till the image is captured?

Am I right or way off?

Thank you
 

shotokan101

Banned
Simply put - shutter speed is the amount of time that your film or sensor is exposed to the light.

This is of course quite different in most cases - especially so with compact cameras - to the total time from pressing the shutter release button till the shutter closes as there will be an element of "shutter lag" between pressing the release and the shutter opening.

Jim
 

senu

Distinguished Member
Hello

First off let me say that I am really sorry if this sounds stupid but I dont know so I thought I would ask....

Is the shutter speed the time it takes from when you press the "take photo" button on your camera until the actual image is taken?
This is shutter lag
It includes the time for autofocus, camera electronics rapidly calculating and setting ideal exposure on auto and the actual exposure time of the sensor
Shutter speed is the time of exposure of the Sensor ( or film)

So thefor you could have a slight delay... and the image you take is not actually the image you wanted as something moved in that small time its taken to press the take photo till the image is captured?
This describes prolonged shutter lag
This is one area in which DSLRs are better than Compacts .. although they are getting better

Even with DSLRs there is some lag and using faster Auto focus modes , adequate lighting ( so camera AF isnt hunting as it does in the dark), are amongst other techniques used to minimize it in order to get the shot
Sometimes if you have say a fast moving child you might use a burst mode and expect one or 2 of the shots will be fine
 
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shotokan101

Banned
I must admit that these days I don't fully understand why any camera should have a noticeable shutter lag.... :(

Jim
 

senu

Distinguished Member
I must admit that these days I don't fully understand why any camera should have a noticeable shutter lag.... :(

Jim

Why?AF speed ( and accuracy) , adequate exposure "computation", ( image processor) fast moving subject,
It is true Slow shutter lag is less of an issue but it still exists especially in pocket friendly compacts but
back in the day the Canon Powershot Pro one( which was a top end bridge) was "slower" compared to the DSLR 350D despite having a far better faster lens, similar Digic processor
 

shotokan101

Banned
Why?AF speed ( and accuracy) , adequate exposure "computation", ( image processor) fast moving subject,
It is true Slow shutter lag is less of an issue but it still exists especially in pocket friendly compacts but
back in the day the Canon Powershot Pro one( which was a top end bridge) was "slower" compared to the DSLR 350D despite having a far better faster lens, similar Digic processor

No - I think you may be missing my point (as I didn't explain it very well) - if anything I think a modern compact should have a speed advantage over a traditional DSLR mechanical shutter.

AF time shouldn't enter into it as when you've half pressed the button that part of the "computation" is "done with" - and the actual, "capture" of the frame image from the sensor to the buffer should take mlliseconds - any "other processing" happens afterwards and may affect burst rates etc. but not single shot capture...

Jim
 

senu

Distinguished Member
No - I think you may be missing my point (as I didn't explain it very well) - if anything I think a modern compact should have a speed advantage over a traditional DSLR mechanical shutter.

AF time shouldn't enter into it as when you've half pressed the button that part of the "computation" is "done with" - and the actual, "capture" of the frame image from the sensor to the buffer should take mlliseconds - any "other processing" happens afterwards and may affect burst rates etc. but not single shot capture...

Jim

Why then does it happen? , especially with compacts and not with DSLRs? ( in which is does but often not really noticeable) Is that buffers add significant to cost of compacts?

IIRC AF time does count as it isn't always instantaneous with pressing the button, unless MF, a focus lock or prefocus is used
 

shotokan101

Banned
Why then does it happen? , especially with compacts and not with DSLRs? ( in which is does but often not really noticeable) Is that buffers add to cost of compacts?

IIRC AF time does count as it isn't always instantaneous with pressing the button, unless MF, a focus lock or prefocus is used

"Dunno" - that's why I said I didn't understand why it happnes these days :laugh:

I think all my cameras have had a "single shot AF" focus mode but still have a shutter lag that's noticeable :(

Jim
 

senu

Distinguished Member
"Dunno" - that's why I said I didn't understand why it happnes these days :laugh:

I think all my cameras have had a "single shot AF" focus mode but still have a shutter lag that's noticeable :(

Jim

Buffers,??
.... hard to say but a lot of users complain about " missing the shot" , which happens far less with DSLRs
 

shotokan101

Banned
Buffers,??
.... hard to say but a lot of users complain about " missing the shot" , which happens far less with DSLRs

...shouldn't that be "duffers" then ? :laugh:

Jim
 

Johnmcl7

Distinguished Member
No - I think you may be missing my point (as I didn't explain it very well) - if anything I think a modern compact should have a speed advantage over a traditional DSLR mechanical shutter.

AF time shouldn't enter into it as when you've half pressed the button that part of the "computation" is "done with" - and the actual, "capture" of the frame image from the sensor to the buffer should take mlliseconds - any "other processing" happens afterwards and may affect burst rates etc. but not single shot capture...

Jim

Compact cameras still have a mechanical shutter but with a fixed lens it's not the larger focal plane shutter in a DSLR and instead is in the lens, often the part of the aperture system itself when I've looked (difficult to tell when compacts have such tiny aperture openings though). A compact has a longer shutter cycle because it has no OVF and has to use the sensor, when you fire off a DSLR conventionally (not using liveview, using the OVF) the shutter opens, exposes the sensor then closes and the exposure is complete. On a compact camera, the shutter is always open to generate the live feed so for an actual exposure it has to first close the shutter, open the shutter for the actual exposure, close it again to finish the exposure and re-open it to resume the liveview.

You should be able to test this yourself, on the LX3 for example if I set an F8 aperture and a slow exposure (say four seconds) then look down the lens I see the following sequence:
1 - aperture blades close completely (effectively shutter closed or something beside the aperture blades, all very small)
2 - aperture blades re-open slightly to F8 (shutter open)
3 - two seconds later the aperture blades close right down again
4 - aperture blades re-open.

This is one of my annoyances with the mirrorless cameras as they have the same issue but with a large focal plane shutter instead, they also have to close the shutter, re-open, close, re-open. Panasonic seem to have improved this quite a bit in the GH2 but you still get that bit of lag which is particularly noticeable alongside the D700 which takes a picture pretty much the instant you squeeze the shutter release. Oddly while the GH2 does have an electronic shutter for its 40fps mode, you can't seem to use this for normal shots to get a silent exposure. As far as I'm aware there are some other electronic shutters but most fixed lens compacts still use a central shutter design but could be wrong on that, it's not something I see discussed very often.

John
 

shotokan101

Banned
Thanks John - I did wonder if there must still be a mechanical element slowing things up - must admit it does seem a little absurd these days :)

JIm
 

Faldrax

Prominent Member
The other big difference in the system used for AF.

When not using 'Live View', DLSR use 'Phase Detect' AF, while 'Live View' mode (used by compacts and DLSR for live view {except Sony}) used 'Contrast Detect' AF.

Phase Detect AF is much faster than Contrast Detect - allowing DSLR the 'near instant' response to the shutter.
 

nikonuser11

Distinguished Member
My new Olympus ZX-1 none,my Leica D-lux 4 has it :)

XZ-1 *cough* do you mean the XZ1 has none as in lag? I've actually been very pleasantly surprised how fast the shutter speed is on my XZ1:clap:



@JOHNMCL7 that was very interesting thank you
 

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