f3nikon:
Thanks for the education but this article just confirms all the negatives I have on TTL. Personally, I think the author didn't have much of a clue on what he was talking about.
http://www.wetpixel.com/i.php/full/inon-d-2000-s-ttl-strobe
First off, iTTL is VERY awesome, I just don't feel that one should be blind in using technology. iTTL/dTTL works, and VERY well for many subjects, so don't assume TTL is bad, it's just another tool in the box. The meters we use to judge exposure is an example of a reflective TTL meter.
f3nikon:
Here are some of the reasons why:
The VELVET reflects back the light, the BLUE WATER does NOT! When a TTL strobe is fired at a wide blue water NO light is reflected back to the camera's TTL sensor, which is looking for the light to bounce back from something, anything!
There seems to be a lack of understand of how reflective meters work in general, and TTL flash meters as well. First one does NOT want the water to reflect the light as it's NOT the subject.
So using TTL the flash will fire until camera system *thinks* that the subject is exposed properly based on the aperture. if the subject is more reflective (like a mirror) than the camera meter may be fooled into shutter down the flash prematurely. The link you posted is using S-TTL, and I have no idea exactly how that works. However with iTTL the meter is rather sophisticated, and the camera attempts to determine where the subject is in the frame, and how far the subject is from the focal plane. it does this using the 3D matrix metering which is highly complicated, but uses the focus distance and other factors to determine where in the fame the subject is, and also what percentage of the fame the subject occupies.
f3nikon:
Since no light is bounced back, the camera does NOT tell the strobe to stop, the strobe just keeps pumping out the light until the caps. in the strobes are fully DUMPED!
Well, that is only true of you have no subject.
As the light hits the subject it is measured. Once the meter detects the correct amount of light based on the aperture it will shut down the flash.
f3nikon:
Oh, and the fish or reefscape that was the real target for the strobe, which was not in the CENTER of the frame, where the camera's TTL sensor is monitoring for the reflected light. It just went to the OVER EXPOSED Round File!
This of course depends upon the type of TTL that is used in camera, but MOST DLSR's are a LOT more complex than what you are describing. Nikon introduced 3D matrix metering in the 80's on the 8080 and F4 camera's, so very good flash TTL is nothing new.
f3nikon:
Then it just went all down hill on this comment:
"I'm not sure exactly what happened, but the strobe is certainly not throwing as much flash into the second picture. I reset the strobe from S-TTL Low to S-TTL as recommend by the instruction manual, and tried again:"
The first pictures of the regs. at f3.2 are overexposed, the black rubber knob is now a light grey! The reg. at f8.0 is under exposed! The correct aperture is somewhere around f5.6! Hey, I thought TTL was "Set It And Forget It"?
A couple of the examples used in the article posted are flawed, and I can tell youi exactly what went wrong. Flashes are NOT infinately adjustable, and most have a range of six or so stops. Flash TTL will NOT change the way a flash works, and obviously in the example provided, this flash was too close to the subject, and producing too much light even at it's lowest setting.
f3nikon:
Actually the TTL strobe/camera combo is working as it should, the camera on TTL mode is programed to make everything 18% GREY! White sand and snow it will turn GREY, a black bear or blackbird, to the camera, it should be GREY! The shiney reg. and the black knob should be GREY??? Sometimes? Maybe?
No. The 18% grey average assumes that if you take an average scene and dump all the colors into a bucket and mixed the results would be grey. However todays camera's have a heck of a lot more going on than the 18% grey meter even if they are based on that technology. In any event learning how a meter behaves is part of the process of becoming a good photographer, and if the snow is coming out grey, then that's an error on the photographers part.
f3nikon:
Then there are the burned out, washed out pictures of the cleaner and scorpion fish that are suppose to be good TTL shots? Could it be the he ran out of aperture? The camera was limited to only f8.0 he needed f11 or f16 to make that work. Or he was shooting so close that the camera could not turn off the TTL strobe fast enough to prevent overexposure!
I think I'll pass on TTL....... and stick with TTM (Through The Mind) for now.
Dive Safe
Flash TTL is just a tool. It's not bad. I however use TTL often when shooting, and it can be a very valuable tool.
The implementation of the Inon S-TTL is likely nothing close to the Nikon iTTL, or Canon E-TTL. While most PnS camera's do a series of four or less preflashes, Nikon dTTL does 18. That should tell you something right there.
As for what works best, well my bet is on iTTL if ikelite manages to do a good job of implementing it. I generally shoot in TTL flash mode, and use the exposure compensation on the flash to adjust when I need to change the flash exposure.
Another favorite way I shoot is to set the flash exposure compensation to -2 stops in TTL mode. This results in a VERY effective fill flash with the natrual light being the main, and the flash just pushing the shadows back a bit.
If you are shooting with an F3, you have rather missed the Nikon flash TTL developments. iTTL is a great tool, and people would be foolish to not take advantage of such a powerful tool.
Happy Shooting!