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Old Apr 6, 2007, 7:18 AM   #1
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I have a K100D.What is the advantage of using a P-TTL external flash like the Pentax 360 FGZ over an external flash that is only TTL, like a Sunpak 355AF? I think the P-TTL flash uses a pre-flash and the TTL does not? Will I have exposure problems with a flash that is only TTL? Thanks for your help.
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Old Apr 6, 2007, 7:33 AM   #2
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a200user wrote:
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Will I have exposure problems with a flash that is only TTL?* Thanks for your help.
Definitely. You can only use TLL flash manually.

Daniel
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Old Apr 6, 2007, 10:04 AM   #3
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Hi a200user,

TTL flash requires a separate sensor in the lightbox which is present in the *ist D, DS, and DS2, but the DL,DL2, K100D andK10D do not have them. This flash mode reads the flash exposure in real time from reflected light from the sensor on a DSLR (during the actual exposure.

P-TTL flash uses a preflash to meter with the normal exposure meter, then adjusts the output of the flash for the actual exposure.

P-TTL flash is still evolving, and is considered by the manufacturers as potentially significantly more accurate over a wider range of ISO, aperture, and shutter settings. This, and the extra cost of installing the extra sensor are probably the main reasons why TTL support was dropped in the newer models.

Scott
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Old Apr 6, 2007, 10:24 AM   #4
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Thanks Scott and Daniel, that saved me some waisted time and money.
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