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Old Nov 29, 2006, 3:55 PM   #11
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Hi illidan,

"And one other thing could you explain me the difference between TTL and P-TTL?"

TTL dedicated flashes for Pentax use a separate metering sensor in the light box to get a reading from the reflection of light from the film (or sensor) plane during the exposure. My experience with my DS is that it works well as long as the subject is not too close, and I'm using apertures towards the middle of the range of the lense (as opposed to wide open or really closed down). The D and DS are the only bodies that support this flash mode. The problem with this type of system is that the CCD sensor in digital bodies is more reflective than film, so calibration is different. The major advantage is that with only one flash, there is less chance of "droopy" or closed eyes from fast reacting people or animals, and standard slave flashes will work without any problems.

P-TTL dedicated flashes for Pentax use the regular exposure meter to get a reading before the actual exposure using a pre-flash just before the shutter opens. You can actually see the preflash in the viewfinder just before it blacks out. This is obviously more economical as the mfg doesn't have to mount and calibrate a seperate sensor, and this mode of preflash metering is what all mfgs are going with now. Because of the pre-flash, only "digital" slaves that fire on the second flash will work correctly with a P-TTL flash unit.

"At one of oficcial Pentax sites they the focusing system is TTL... Does it has anything to do or are the focusing and the flash system separate?"

TTL merely stands for "Through The Lens", so both the metering system and focusing system can be and are TTL, but they are completely separate.

I commiserate with the inability to use the 500FTZ automatically with the newest Pentax DSLRs, since I also have one, but I guess that's the price we pay for progress.


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Old Nov 29, 2006, 6:28 PM   #12
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That is the really strange thing(bad) about Pentax dslrs. You can use lenses that are decades old, but have to buy a brand new flash at a cost of $250-450. Sure you get more features, but really, could they not have included TTL also? PMO. I had to go manual for my Thanksgiving shots. What a PITA.
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