Originally posted by steve1307 Thanks Lowell I didn't actually know until now how TTL worked and the shortcoming of it.
So how come many people around here lament (if thats the word) the loss of TTL and dislike P-TTL.? Other than that P-TTL can often be inaccurate and inconsistent I mean?
Originally posted by JimJohnson If they are like me, probably because they have at least one perfectly fine Pentax TTL flash in their inventory (I had 3). We lament the loss of functionality ... and to regain that functionality, I spent a goodly amount for a decent P-TTL flash.
It isn't so much that I dislike P-TTL, but I could easily mix TTL & manual flashes (halo or background lighting). It is more difficult to mix P-TLL & manual flashes because of the pre-flash.
For me there are good and bad with all designs,
Many people tout that P-TTL solved an issue with the difference in flash metering between taking the light reflected off the film emulsion, and that off the sensor which was more reflective, although I personally think this is BS. My *istD metered just as well with a TTL flash as my PZ-1. the issue, I think came down to cost. TTL requires an additional sensor and required real time metering during exposure, P-TTL uses the normal metering sensors and is a predictive mode that simply tells the flash how long to fire, with no real time metering involved.
For me, I liked TTL for a number of reasons, (yes I did have a TTL flash (AN AF500FTZ) which I think has a much shorter full power duration than the AF540FGZ because it was designed to be used with the PZ-1 which had 1/250 sync on a full frame, and therefore had a much shorter 100% frame open time.)
- TTL is usable with legacy lenses, because it meters the actual flash illumination during exposure, and therefore does not car whether there is an M42, K or KA/later mount lens attached
- it only flashes once, and the preflash can be disturbing, there are lots of threads on this
- it can be used using specific nikon flashes as remote slaves, because some nikon flashes in slave mode turn off when the master flash turns off allowing multi flash setup with metering. There are slave units that can do this also.
- pre flash on P-TTL is also used as a focus aid, and if you are constantly pointing and aiming, you can fire the preflash a ton of times, not just for focus but also for metering, that cause the batteries to go down quickly or to overheat the flash unit
Both TTL and P-TTL have their issues, and regardless of which someone likes or dislikes, i think all the complaints about inconsistencies are the result of a lack of understanding how the systems work.
P-TTL solved a lot of problems that were real, and allowed for more intelligent slave flash control, but at a cost for some users.
I personally think pentax would be very smart, at least on the flagship camera to offer both again, like it did on the *istD