So this has been bothering me for some time…
So the maximum flash sync speed for a purely mechanical shutter on a dslr is the fastest shutter speed where the flash can fire while the shutter is “fully open” (ie any faster and the 2nd shutter curtain will cut off part of the flash, leaving a black bar over the image)
On the other hand a camera with an electronic/hybrid shutter can theoretically sync as fast as the actual flash duration, since the mechanical shutter is open for a relatively long time, and the “shutter” is actually just the electronic “slice” of the exposure (yes I know that’s not technically entirely accurate, sue me)
For example – my fancy-shmancy SLR can only sync to 1/180 of a second, wheras my humble little canon G9 can sync at 1/1000 or even 1/2000!
Now a few dSLRs actually do have an electonic shutter (the Nikon d70 and d40 come to mind) so they can actually sync faster than their rated sync speed.
So the question is:
Does anyone know if there’s a technical/practical reason *not* to use an electronic/hybrid shutter in a dSLR as opposed to a purely mechanical shutter?
Seems to me a high sync speed is a strong selling point, and the easiest way to get a high (unlimited essentially) sync is to use an electronic shutter (like the d70 etc…). However, to the best of my knowledge none of the higher end/pro SLRs have this – some of them have high(er) syncs, but it’s purely a faster mechanical shutter.
I’m just wondering why dlsr manufacturers would just put a hybrid/electronic shutter in all their cameras and tout them as having a 1/2000 sync or such? Seems kind of odd, unless there is a drawback to the electronic shutter I am unaware of…
The sensor in most DSLRs is more light sensitive than the ones in point and shoots. My understand is that you want to avoid long term bright direct light as it can damage the sensor. Something about a bayer dye layer that is damaged by light accumulation.
In human terms I guess it would be equivalent to staring at the sun.
right, which is why they use a hybrid mechanical/electronic shutter. Basically the mechanical shutter opens at a slow speed – something like 1/60 I believe, and while it is open, the electronic shutter “fractionalizes” a part of it for a faster shutter speed. So the mechanical shutter operates exclusively for exposures of 1/60 or less, and the “hybrid” for faster exposures, and this prevents overexposure of the sensor (to my understanding)
I believe this is how the Nikons work. I just curious why they wouldn’t use the same system in the higher end cameras.
Actually the major manufacturers started with a hybrid shutter in their high-end models. Nikon’s D1/D1X/D1H and Canon’s original 1D all had the hybrid type shutters. As a D1X owner, I have used the ultra high speed sync with great results, but it comes at a big price. First thing is reliability. These shutters were notoriously unreliable when coupled with the demands of professional use. Mine has had to be replaced twice. When you are shooting hundreds of thousands of frames over the life of the camera, these more simplified shutters just don’t cut the mustard. Second is lack of exposure consistency. Because the electronics and CCDs are affected by environmental factors like temperature and humidity as well as having to charge and discharge the CCD for every exposure, inconsistency can be common place at faster speeds. With the Nikon D1 Series you could shoot three consecutive exposures (ambient light) at the same settings and each exposure would be slightly different (and thoroughly frustrating!). Lastly there is the issue of speed, or lack thereof. Due to the time it takes for the shutter to move out of the way and the CCD to charge, a longer shutter lag is necessary thus making the camera less responsive for the professional. As the cost of manufacturing came down, the manufactures were able to cost-effectively integrate high precision electro-mechanical shutter’s back into their pro models. The hybrid shutters are used in the less expensive models because, let’s face it, they are much cheaper to build and the need for extreme reliability is not warranted.
Good question! I’d love the sync speed to be a tad higher, particularly for high speed sport shooting.. I dont find it a problem for landscape work, portrait work, etc. but some sport shooting would benefit from a little faster shutter / flash work..
So I bought a G9 a couple of days ago. I feel like I did my research I’m excited, it’ll be here tomorrow. I have what is probably a dumb question but here it goes. I use to love my 24mm lens on my old SLR and I’d love to have a wide option for this thing. Does it make any sense to buy one of those add-on lenses? If so should I only buy the Canon?
many thx
–david
I think with an electronic shutter, each photosite on the CCD has a companion “dark” site, allowing the entire image to be dumped almost instantaneously. The disadvantage is that only half the CCD surface is used for image capture so it is likely to be noisier than a normal sensor arrangement. Maybe that’s why it isn’t more popular.
As an aside, I thought that “humble” cameras like the G9 had a leaf shutter, because they are easy and cheap to do where you don’t have an interchangeable lens to contend with, and of course sync at higher speeds.
Some good answers, thanks all. I think Mark G has the long and the short of it, sounds like a good reason to me.
Steve, I thought the G9 had a standard FP shutter, not a leaf, albeit a hybrid one – in other words, the mechanical shutter works up until a certain speed, after which point the ccd simply takes thinner and thinner “slices” to get the exposure (I could be wrong though)
David, it’s kind of a tradeoff. Personally I love wide angles, but I bought the G9 specifically for a fully featured “compact-go-anywhere” camera. Attaching the add on lenses and mounting ring *significantly* increases the size/footprint of the camera, in which case I might as well just take a small slr/lens like the k100d+ltd primes.
On the other hand plenty of folks swear by the wide angle add on lens for the G9
I thought the G9′s max flash sync speed was 1/250 without using the FP function on an external flash?
Joey-
while the sync speed is *officially* only 1/250, the hybrid electo-mechanical shutter design of the G9 allows it to sync manually (and unofficially) at faster speeds as described above – this is simply a function of the shutter design, and not an official “feature” of the camera – a few other SLRs that have the same shutter design can do this as well (Nikon D70 for example)
Note this is *not* the same thing as the “official” HSS or high speed sync supported the manufacturers, which uses a strobed, ttl flash to sync at speeds higher than the “official” sync.