Shutter Speed (Technical)

[usayit]

Electronic shutters can flash-sync much faster too. Mine syncs at 1/2000 . But ES are silent.

Its slightly different.... The 1/250 or 1/125 X-sync still applies. Modern cameras establish high speed flash sync by "cheating" a little by emitting a series of strobe fires repeatively.

 

[Bifurcator]

I'm not exactly sure what you mean. 1/2000 works OK with off-camera flash - either wireless or through the PC cable.

 

[usayit]

Once the you get beyond the fastest Xsync speed of a camera (1/60 to 1/250 typical), the rear curtain starts to close before the first curtain is full open. Essentially, creating a "slit" from which light exposes the film plane as it "travels". This slit means that a single firing of a flash would incorrectly only expose a portion of the frame. This is the reason why you have to stay below Xsync shutter speed when using flash. So in summary, max sync speed is the fastest shutter setting that a camera's shutter is completely open at any one time... to allow for proper flash exposure.

Modern cameras with "High speed sync" capabilities overcome this limitation by "cheating". They fire the flash repeatively numerous times as the "slit" travels across the film plane. This is how they obtain proper flash exposure for shutters faster than max sync. This comes at a price..... power.. battery consumption.

[edit] misread your post.. you were discussing electronic shutters... ah well what camera? [/edit]

 

[Do'Urden's Eyes]

Once the you get beyond the fastest Xsync speed of a camera (1/60 to 1/250 typical), the rear curtain starts to close before the first curtain is full open. Essentially, creating a "slit" from which light exposes the film plane as it "travels". This slit means that a single firing of a flash would incorrectly only expose a portion of the frame. This is the reason why you have to stay below Xsync shutter speed when using flash. So in summary, max sync speed is the fastest shutter setting that a camera's shutter is completely open at any one time... to allow for proper flash exposure.

Modern cameras with "High speed sync" capabilities overcome this limitation by "cheating". They fire the flash repeatively numerous times as the "slit" travels across the film plane. This is how they obtain proper flash exposure for shutters faster than max sync. This comes at a price..... power.. battery consumption.

Thats what i was trying to explain usayit, put alot nicer of course. Wait so electronic shutters do not work the same way? Or do electronic shutters just have no physical curtains and thats why Bifurcator said theyre 'silent'?

 

[usayit]

I'm a little confused as to what we mean as electronic shutters.... I was assuming that it was something I'm not familiar with...

I know horizontal cloth shutters.
I know leaf shutters
I know vertical shutters.

Once Bifurcator said "silent" I started to think that it was a type of shutter that I am unfamiliar with....

If it is a vertical or horizontal shutter, my entire previous post applies. You have max sync and high speed sync which is cheated by todays advance cameras.

 

[Helen B]

'Electronic shutter' can have a few meanings - it can be an electronically-timed mechanical shutter, for example. It can also refer to the use of the sensor to time the exposure while the mechanical shutter is open. For a CCD the collected electrons are dumped into the substrate until the exposure time begins, than they are collected to build up a charge over the required exposure time, then the charge is transported from the photosites at the end of the exposure time.

Does that help?

Best,
Helen

 

[usayit]

yes it does... but which one is being discussed?

Thanks.

 

[Garbz]

The latter. The idea of larger sync times is that the shutter fully opens, and that the CCD is electronically timed to get the exposure. This happens on some cameras above the 1/250th where the shutter becomes a travelling slit.

 

[Bifurcator]

[edit] misread your post.. you were discussing electronic shutters... ah well what camera? [/edit]

Ah, hehehe that's where we missed. Yeah, no curtains or leaves in this camera. It also has a mechanical shutter (or so I read) but it's probably a Isosceles trapezoidal hole in a wheel or something.

I guess the electronic shutter takes over at something low like 125 or so and up. I explained what I /think/ happens above.

Anyway, yeah full flash-sync at 1/2000.

The Camera is the Konica/Minolta A2.
http://ca.konicaminolta.com/products/consumer/digital_camera/dimage/dimage-a2/10.html

High-Speed Sync (HSS)
High-Speed Sync synchronizes with all shutter speeds. This function is greatly helpful when taking a portrait picture with day-light sync.

Wireless/remote high-speed synchronization allows off-camera flash control at all shutter speeds. The wireless design makes setup fast and easy for dramatic and beautiful flash results in any lighting situation.
​

 

[usayit]

Your Konica Minolta A2 has a mechanical shutter and also does the same thing....

From FAQ on you camera:
-------
Question: Does Flash syncronize cover all range of shutter speed?
Answer: Yes, it does, but it may be underexposure at the high shutter speed range.( Exposure time is shorter than flashing, therefore it is difficult to get enough light.)
The following shutter speed is as a standard maximum speed:
Built-in flash: 1/1000 sec.
External Flash: lower than 1/250 sec.

*For daylight sync. , flash can be used in higher shutter speed.
*For studio Flash via PCT-100, please set the shutter speed lower than flash recommended value.

If flash does not recommend any shutter speed, please set lower than 1/125 sec.(Some flash may be delay to fire.)
-------

 

[Bifurcator]

EDIT: That sounds like a really messed up faq. Where's that from, and who compiled it? It's actually wrong in 2 or 3 places. About the external flash most importantly. I have, I've used, I know. And I quoted the manufacturer above there too (the indented text in #24)
--

Reading down I see some confusion over which kind of electronic shutter is in the A2 after bragging of the 1/2000 sync. I don't know exactly but I believe I have both kinds. I can't remember where I got the info tho. Minolta official video clip/tech release, web site, of from a konica/minolta company representative. (I'm looking for it now) Anyway I listened/read that the A2 has both. an electronically controlled wheel speed (I guess???) technically refered to as an "electronically-controlled, vertical-traverse, focal-plane shutter" and CCD electronic managed shutter. Why they would need both I don't know - maybe the (electronically controlled) mechanical one produces better results at lower speeds, or maybe the CCD is difficult to control at lower speed accurately. No idea really.

By researching it looks like a made a small boo-boo. It's not 1/2000 that it can sync to but instead it will sync to 1/4000. This is either a misprint on dpreview's part or 1/4000 is only available in an auto mode. In M, S, or P the highest I can set is 1/2000. :-/ I think it's a misprint tho. It also says the Bulb is limited to 30sec. and I've used it at 55min. with no problem. I am using the newest firmware tho. Hmmm... :raisedbrow:​

I know the existence of both types of shutters in one body is not unique to this model and probably not unique to this brand either. I do believe it's more common in P&S and bridge cameras though. For example: http://www.fuzing.com/vli/000770e33312/80Mega-Pixels-digital-camera-with-25LCD , http://www.buy-n-shoot.com/news/casio/casio-exilim-zoom-ex-z150-digital-camera.asp and etc.

Ah, here it is, my camera: http://www.megapixel.net/reviews/minolta-a2/a2-specs.php (Again with the wrong information about Bulb-length though )

I probably won't be able to find out just exactly how they work together nor exactly what the (electronically controlled) mechanical shutter physically looks like. My money is on a swing arm/wheel design. It even sounds like the second-hand of a medium sized clock.

 

[usayit]

EDIT: That sounds like a really messed up faq. Where's that from, and who compiled it?

http://ca.konicaminolta.com/support/americas/digital_cameras/dimage-a/dimage-a2/faq/index.html

Its direct from what's left of their site.


The reason for the confusion is marketing. They claim sync at all speeds but don't let you know the limitations of using high speed sync. Even the specs on the website tell nothing about the max shutter speed for "slow-sync". THat info is buried.

On most DSLR (that I know), by default the camera is set to slow-speed sync with a max of between 1/125 to 1/500 of second. They advertise that spec and open about it. Then then advertise the "option" for high speed sync.

THe difference is subtle...

Other DSLRs will say... max sync to 1/500 with the option for high speed sync at higher shutters.

You camera will say... high speed sync at all shutters with the option for "slow sync".

Consumers will most likely remember "max sync to 1/500" and "high speed sync at all shutters". The later sounds a whole lot better... and easier for a retailer to sell.

its all marketing...

 

[Bifurcator]

I'm not following. At all really. Sync is sync. Either the shutter and flash sync or you get a partially exposed stripe in your image. (EDIT: Or an all black image...)

Here's mine at 1/2000 f/8.0 in light the camera's meter says should be 1.3 seconds at f/2.8 without flash. I can and have done the same thing with external flash too. <shrug>

It's been JPEGed to death but... 1/2000, f/8.0​

.