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#1
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Can TTL be used with bounce flash?
I have access to two flashes that have a TTL mode: the Metz Mecablitz
54 MZ-4 and the Sony HVLF32X. I am trying to understand what TTL is, and in particular if I can use it when bouncing the flash light off a ceiling. I *think* that TTL means that the camera determines how much light is needed, and then signals the flash unit to emit that much light. If my understanding is correct, then TTL cannot be used when performing "bounce flash." This, because the camera does not know how reflective the ceiling is. Therefore, its determination of needed light is not possible. Am I understanding this correctly? Both of these flash units will do bounce flash in TTL mode, without complaining. So I suspect that my understanding is faulty. These two flash units also offer another automatic mode, wherein the camera signals the flash gun what aperture, shutter speed, and ISO sensitivity it is using. The flash unit then measures the output of its own flash light hitting a sensor on the flash unit itself. The flash unit cuts power to its flash tube when its sensor has absorbed the proper amount of light for the signalled aperture, shutter speed, and ISO sensitivity. Right? To me, this second mode seems suitable for use with bounce flash. Neither the camera nor the flash unit need to know about the optical properties of the ceiling. The flash unit uses the good old empirical method, measuring light returning from one, two, or more reflective surfaces. I'd appreciate any corrections to my (very weak) understanding. -- David Arnstein | Have fun with your spams: | http://www.bluesecurity.com |
#2
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Can TTL be used with bounce flash?
In article , David Arnstein
writes I have access to two flashes that have a TTL mode: the Metz Mecablitz 54 MZ-4 and the Sony HVLF32X. I am trying to understand what TTL is, and in particular if I can use it when bouncing the flash light off a ceiling. I *think* that TTL means that the camera determines how much light is needed, and then signals the flash unit to emit that much light. Exactly how TTL flash metering works depends as much on the camera as it does on the flash, but usually it means it meters the light coming back from the subject through the lens, so it will take the reflectivity of the bounce screen into account. Depending on the camera, this metering can be achieved during the actual exposure itself or based on a lower power test flash emitted either when the shutter release is half pressed or immediately before the shutter opens. -- Kennedy Yes, Socrates himself is particularly missed; A lovely little thinker, but a bugger when he's ****ed. Python Philosophers (replace 'nospam' with 'kennedym' when replying) |
#3
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Can TTL be used with bounce flash?
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#4
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Can TTL be used with bounce flash?
TTL flash works great with bounced light.
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#5
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Can TTL be used with bounce flash?
David Arnstein wrote:
I have access to two flashes that have a TTL mode: the Metz Mecablitz 54 MZ-4 and the Sony HVLF32X. I am trying to understand what TTL is, and in particular if I can use it when bouncing the flash light off a ceiling. I *think* that TTL means that the camera determines how much light is needed, and then signals the flash unit to emit that much light. If my understanding is correct, then TTL cannot be used when performing "bounce flash." This, because the camera does not know how reflective the ceiling is. Therefore, its determination of needed light is not possible. Am I understanding this correctly? Both of these flash units will do bounce flash in TTL mode, without complaining. So I suspect that my understanding is faulty. These two flash units also offer another automatic mode, wherein the camera signals the flash gun what aperture, shutter speed, and ISO sensitivity it is using. The flash unit then measures the output of its own flash light hitting a sensor on the flash unit itself. The flash unit cuts power to its flash tube when its sensor has absorbed the proper amount of light for the signalled aperture, shutter speed, and ISO sensitivity. Right? To me, this second mode seems suitable for use with bounce flash. Neither the camera nor the flash unit need to know about the optical properties of the ceiling. The flash unit uses the good old empirical method, measuring light returning from one, two, or more reflective surfaces. I'd appreciate any corrections to my (very weak) understanding. TTL = "thru the lens". The expression came into common parlance when light-metering was changed from external, hand-held light meters to built-in meters at or near the film plane. Judging by the current demand for old Weston Master light meters on E-Bay, it would seem the photographic world is going into reverse. I can imagine a whole gaggle of digital photographers waving their old Westo n Masters around, not believing the aperture/shutter info on the digital screen, and going to full manual set-up for each shot. Progress? Don't make me laugh! Dennis. |
#6
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Can TTL be used with bounce flash?
As a related point of interest, how do automatic compact digital
cameras get the exposure right when the built-in flash is used? |
#7
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Can TTL be used with bounce flash?
Clint Kirk wrote:
As a related point of interest, how do automatic compact digital cameras get the exposure right when the built-in flash is used? My Olympus C310ZOOM uses preflashes to measure the exposure in the same way the iTTL and dTTL modes do on Nikon DSLRs. Ronnie |
#8
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Can TTL be used with bounce flash?
"Clint Kirk" wrote in message
ps.com... As a related point of interest, how do automatic compact digital cameras get the exposure right when the built-in flash is used? Hi. Some of them do it the old fashioned way. I read it in a manual for one, but cannot remember which. The Autofocus gives a distance setting, and the camera then sets the aperture. Guide Number divided by distance equals aperture is the formula which we all used to use before Auto Flash, Flash Meters and TTL became common. It works remarkably well. We should all have these figures in the back of our minds when using Flash, so that we will know what to set when the Automation lets us down, as it does. Roy G |
#9
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Can TTL be used with bounce flash?
In article , Ronnie Sellar
writes Clint Kirk wrote: As a related point of interest, how do automatic compact digital cameras get the exposure right when the built-in flash is used? My Olympus C310ZOOM uses preflashes to measure the exposure in the same way the iTTL and dTTL modes do on Nikon DSLRs. Not surprising really. Olympus pioneered TTL flash metering 30 years ago when they introduced the OTF metering OM-2 and the QA-310 flash unit. -- Kennedy Yes, Socrates himself is particularly missed; A lovely little thinker, but a bugger when he's ****ed. Python Philosophers (replace 'nospam' with 'kennedym' when replying) |
#10
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Can TTL be used with bounce flash?
Kennedy McEwen writes:
In article , Ronnie Sellar writes Clint Kirk wrote: As a related point of interest, how do automatic compact digital cameras get the exposure right when the built-in flash is used? My Olympus C310ZOOM uses preflashes to measure the exposure in the same way the iTTL and dTTL modes do on Nikon DSLRs. Not surprising really. Olympus pioneered TTL flash metering 30 years ago when they introduced the OTF metering OM-2 and the QA-310 flash unit. However on film cameras, TTL flash measures the reflections off of the film, so it didn't need a preflash. Digital cameras typically will emit a preflash, measure the strength of the pre-flash, and then issue the flash for real. Unfortunately if you have slave flashes (or studio strobes), these will get confused by the pre-flash. There are slave triggers and slave flashes that know about the pre-flash. -- Michael Meissner email: http://www.the-meissners.org |
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