T-90 flash sync

[gregory_nicholson]

Hello,

I've read many posts that state 'I like the T-90, its flash will sync

at 1/250'. Please explain where the 1/250 flash sync is better than

the 1/60 or 1/90 of the other slower FD cameras. Is it fill flash

only? Beside the T-90, does the 1/250 do things that were earlier

not possible? hey thanks for any input...

[NK Guy]

Well, yes, with fast shutter speeds you can shoot with a large lens aperture and still use fill flash. So it's good for portraits outdoors where you want a little flash to fill in the shadows but want a large aperture so you get a blurry background.

[s2vach]

also a flash sync of 1/250th is desirable for action photography during the day with flash. for example, i shoot skateboarding and 1/250th sync is pretty much a necessity for 35mm cameras in skate photography... anything less during the day is blurr city. for instance here's a shot that really needed fill (that i was able to provide by shooting the t90) that wouldnt be possible with like an A1 or some other slower syncing camera:

[s2vach]

forgot to link you

 

http://www.geocities.com/skovachs/pages/marko_jazbinsek_9.htm

[david_goldfarb]

High-speed sync lets you use fill flash in bright light (usually outdoors), without having to have an enormously powerful flash unit to balance the sun, or at subject distances where even an enormously powerful flash unit isn't going to be enough to balance the ambient light (a common situation in wildlife photography).

 

Leaf shutter lenses can sync at any speed (with a few exceptions involving high-powered studio lights that may have a longer duration than some shutters at top speed), so this has actually been an option for as long as there have been variable-speed leaf shutters and flash. Cameras like the T-90 made it possible to use this technique with a focal plane shutter.

[s2vach]

"Leaf shutter lenses can sync at any speed (with a few exceptions involving high-powered studio lights that may have a longer duration than some shutters at top speed), so this has actually been an option for as long as there have been variable-speed leaf shutters and flash"

 

yeah... no doubt. i use a 40 year old mamiya c33 for action stills sometimes too. what does that have to do with the question though? no man. foc. canon cameras have leaf shutters!? anyways, just pointing out that the guy who posted the question wanted to know why higher x-sync is desiraqble in the first place, and to clarify there are 2 reasons:

1- to shoot with fill flash, when it is bright out, with a wider aperture... which can also be accomplished by newer high speed sync camera/flash combo.

2- to use flash with a rapidly moving subject when it is bright out... high speeed sync doesnt help you as much here, because it is actually like a rapid fire series of flash bursts (with a decreased output too) that spans the length of time that the shutter is open. a conventional high power single flash burst when used with a camera with a higher syncing speed can help you freeze action better.

[tim_brown5]

One more reason to use high sync speed: shooting when fluorescent lights are around. By using bounce flash and fast sync you can reduce off-colors in the background.

[gregory_nicholson]

Hello again,

So the answer to the question is- faster flash sync will allow fill flash at the same time as stop action shots, outdoors in bright light.

 

 

As for the fill flash in bright sun where you want a larger aperture, can this be successfully accomplished with ND filters? If it can would you set the camera (A-1/F-1N/199A) to the film speed plus the filter factor (ND4X + 100ASA =25ASA) and set the flash to the 100ASA film speed? If that works, would the film be processed at 25 or 100 speed?confusing I know, I almost got the dots connected, I just need confirmation.

 

 

a)yeah... no doubt. i use a 40 year old mamiya c33 for action stills sometimes too. what does that have to do with the question though? no man. foc. canon cameras have leaf shutters!?

 

the answer to your question Steve- Beside the T-90, does the 1/250 do things that were earlier not possible?

 

 

 

b)at subject distances where even an enormously powerful flash unit isn't going to be enough to balance the ambient light (a common situation in wildlife photography). I don't get the message, are you saying that a camera/flash 1/250sync will get the light out farther than camera/flash 1/90sync? or is it that the 1/250 will allow a more natural(less blue?) light color? please elaborate a little.

 

 

 

c)high speeed sync doesnt help you as much here, because it is actually like a rapid fire series of flash bursts (with a decreased output too) that spans the length of time that the shutter is open. Is this how the T-90/300TL works or is it how ALL 1/250 flash sync cameras work? If you use multiple flashes can you overcome this to stop even faster motion?

 

 

 

Maybe the answers I'm looking for might be too lengthy, anyone know of a book or web-site that will explain these and other flash properties and techniques. The Flash Techniques book my local photo shop has is pretty uninspiring.

 

 

thanks again Greg Nicholson

[david_goldfarb]

Let's back up a bit. Say you're outdoors in bright light. The sun is high, so you want to use some fill to soften shadows on the subject. The flash duration is significantly shorter than the sync speed, so you can change the shutter speed up to the maximum x-sync speed, and the flash output will not change. The amount of ambient light, however, will change when you change the shutter speed. So if you are using the flash as fill light and the sun as the main light, you can vary the contrast ratio by keeping the flash power constant and increasing or reducing the shutter speed to increase or decrease the amount of ambient light recorded on film.

 

The problem is that the sun is much more powerful than most flash units, so you either need a monster flash unit to balance the sun in this way, or you need to reduce the contribution of the sun to the exposure by increasing the sync speed.

 

A ND filter or slow film is not really a solution to this problem, because those would reduce both the flash exposure and the sun exposure equally, and what you want to do is reduce the ratio between the flash and the sun.

 

The wildlife example has to do with the fact that wildlife subjects are difficult to approach, so usually one uses a long lens and if you are using flash, you need a powerful flash with a special telephoto attachment to narrow and maximize the beam, and even still, it can hard enough to get enough power (because of the flash-to-subject distance and the inverse square law) to balance the ambient light with flash if your sync speed is 1/60 sec. At 1/250 sec, you keep the flash power the same, but you reduce the ambient light by two stops, giving the flash a fighting chance against the sun.

 

You can also apply these principles in the opposite way in low light conditions, using the ambient light as fill and the flash as the main light. In that situation, you might "drag the shutter" or use "slow-sync" to increase the contribution of the ambient light while keeping the contribution of the flash the same. Say you are indoors shooting candids with flash, and you want to show some of the room as well as the subject. Set the flash for the subject, but set the shutter speed slower than the X-sync speed (try 1/30 or 1/15 sec.), and you'll get a more balanced look.

[gregory_nicholson]

I got it, thank you Mr David Goldfarb, I don't know if you could have done a better job explaining. That must be how Canon can use small built in flashes on their EOS cameras, by raising the flash sync they can effectively lower flash output. Raising the sync speed will increase the flash ratio over the ambient light, that would explain why the flash works being so small. thanks again...

[david_goldfarb]

There are a couple of other things going on there. A small flash is still a small flash if you want to use it as the main light. Also on some of the newer cameras, these very high sync speeds are achieved by reducing flash power to speed up recycle time and fire the flash repeatedly as the shutter slit passes over the film. The law of diminishing returns comes into effect in that case, because you have to reduce flash power to get a fast enough recycle time in order to do the kind of repeat flashing required for a 1/1000 sec. sync speed.