> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:owner-eos@;a1.nl]On Behalf Of John > Chennavasin > Sent: Wednesday, October 30, 2002 9:24 PM > To: [EMAIL PROTECTED] > Subject: Re: EOS Sigma EF500 Super vs 540EZ > > > A-TTL uses a preflash to calculate flash exposure. On the EOS 5 (which > I've had direct experience with), it only works in (P)rogram mode, and > always seems to pick smallish apertures like f/11 which makes it > useless indoors. Plus the preflash will confuse the subject. > > I found that Canon's 4-zone TTL flash metering to be more forgiving > than E-TTL (which is essentially a spot meter based on the active > focusing point) > > Yes, you can use a Lumiquest or similar light modifier on the 540EZ. No > adjustments are neeed (although the maximum distance is reduced > somewhat). These devices eat up around 1 1/2 stops. >
Hi John, What do you mean when you say that A-TTL "always seems to pick smallish apertures like f/11 which makes it useless indoors." How does it make it useless? Do you know how to crank up the ambient exposure value and crank down the flash head's output allowing fairly good control of the balance between flash and ambient lighting on the EOS 5/A2 bodies? I don't recall the amount of adjustment available on the EOS 5 (+/- 3 stops?), as it has been several years since I've owned these fine bodies but on my current EOS 1n and EOS 1nRS bodies there's a +/- 3 stop range of exposure compensation for both ambient and flash light on the body when used in "P"rogram mode and of course almost anything goes if you use "M"anual, "A"perture or "T"ime modes. The A-TTL pre-flash is red, not white, you can easily communicate this information with your all of your subjects before hand so they will know what to expect. In any event your subjects will quickly learn that the red flash is sometimes followed by a white flash and that they can stop smiling and exhale. Regarding the light modifiers that can be attached to the flash heads. Look carefully at the designs, many of the smaller (read this as ineffective), "light boxes" will block the front sensors of the flash head when the flash is in the normal shooting position and the "box" is correctly positioned on the flash head. This of course will seriously degrade flash exposure metering performance when shooting in A-TTL mode (read this as mess up your flash exposures to the point that you think that Canon's flash system doesn't work). On the Canon EZ series flash heads, A-TTL only works when the head is pointed directly at the subject. When you tilt the head up (for those that have this feature), the flash system is automatically put into TTL exposure mode. The thing is, ALL of the large area flash head mounted light boxes (read this as effective), require you to point the flash head straight up which puts your 540EZ, 430EZ etc. into TTL mode. AFAIK, nobody who knows how to use the Canon EZ series flash heads has pointed out any difference in performance between the A-TTL and TTL modes of flash exposure operation in the real world on film and I am in this camp too. Knowing all of this there is little reason to use the small ineffective light boxes when the effective, large light boxes can be used perfectly well with TTL mode flash exposure controls. Seeing that both large and small light modifiers all seem to cost more than you want to spend the only down side I can see to the use of large light modifiers is that they suck up a lot of light (1.5-3.5 stops depending on the model and how it's used). They chew through your battery power much faster (hey, that's what they invented Turbo Batteries for), and they are somewhat more bulky on the flash head. But what do you want, something that works or something a little bit smaller and doesn't? Cheers/Chip * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
