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EB: What is the difference between Auto and TTL Auto

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SteveDP

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for FL-36 (indoor flash). I have followed your flash guideline. What I found that the images tended to be underexposed when I focused on darker subject in TTL Auto mode. The exposure usually was correct if I switched to Auto mode or if I set F-stop number the lowest (2.8 or 3.5 for 14-54mm).

Thanks.

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Olympus E-300 (firmware 1.3), 14-54mm & 40-150mm, HLD-3, FL-36, Hoya Super HMC UVs, Manfrotto 676B Monopod, Sandisk Ultra II 1.0 & 2.0 GB CF Cards, Tamrac System 6 Bag
 
SteveDP said:
for FL-36 (indoor flash). I have followed your flash guideline.
What I found that the images tended to be underexposed when I
focused on darker subject in TTL Auto mode. The exposure usually
was correct if I switched to Auto mode or if I set F-stop number
the lowest (2.8 or 3.5 for 14-54mm).
Click to expand...
Auto measures the light reflected from the subject at the time of exposure via the "auto light receptor" on the front of the flash. TTL takes the measurement Trough The Lens, hence TTL, during a pre-flash immediately before the actual exposure. The angle of coverage of the "auto light receptor" is fixed, TTL is the dependent on the field of view of the lens.

Regards,
Scott

--
As we celebrate mediocrity all the boys upstairs want to see
How much you'll pay for what you used to get for free
  • Tom Petty
 
Thanks. Based on the manual it explains TTL Auto as:

"Flash is controlled automatically by performing pre-flash according to the camera setup."

On the E-300 unit, does the FL-36 always do a pre-flash in TTL auto mode?

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Olympus E-300 (firmware 1.3), 14-54mm & 40-150mm, HLD-3, FL-36, Hoya Super HMC UVs, Manfrotto 676B Monopod, Sandisk Ultra II 1.0 & 2.0 GB CF Cards, Tamrac System 6 Bag
 
Can anyone help me on my new FL-36.

Does the FL-36 light meter do a better job of measuring light/exposure than the TTL light metering? I was debating on which is the best mode to set the flash/camera (auto or TTL auto).
 
I think the AF illuminator (on FL-36) will work in either Auto or TTL Auto mode with a 4/3 camera. You may turn either the camera's or flash's AF illuminator off.

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Olympus E-300 (firmware 1.3), 14-54mm & 40-150mm, HLD-3, FL-36, Hoya Super HMC UVs, Manfrotto 676B Monopod, Sandisk Ultra II 1.0 & 2.0 GB CF Cards, Tamrac System 6 Bag
 
in that your subject suggest the issue is one of achieving auto focus. The text refers to exposure control, a completely different issue. Perhaps you could clarify which is of concern.
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Garry
 
For my E-500 the AF assist is the built-in flash, correct? If so i would not be able to use the AF assist on the camera because the built-in flash is disabled.

Does the AF assist on the FL-36 do a better job than the camera's AF assist? just curious.
 
SteveDP said:
Thanks. Based on the manual it explains TTL Auto as:

"Flash is controlled automatically by performing pre-flash
according to the camera setup."

On the E-300 unit, does the FL-36 always do a pre-flash in TTL auto
mode?
Click to expand...
Yes.

Regards,
Scott

--
As we celebrate mediocrity all the boys upstairs want to see
How much you'll pay for what you used to get for free
  • Tom Petty
 
From my understanding,(correct me if i am wrong) the AF assist helps with the autofocusing camera mechanism in low light.

My question was which AF assist worked better for achieving autofocus, the FL-36 AF assist or camera AF assist? I think for my E-500 the AF assist comes from the flash (in the form of preflash pulses) which i can't use with the FL-36.
 
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Olympus E-300 (firmware 1.3), 14-54mm & 40-150mm, HLD-3, FL-36, Hoya Super HMC UVs, Manfrotto 676B Monopod, Sandisk Ultra II 1.0 & 2.0 GB CF Cards, Tamrac System 6 Bag
 
is it better off setting the FL-36 in Auto mode (rather than TTL Auto) and using FL-36's light receptor/sensor? I seem to have more consistent exposure when doing so.

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Olympus E-300 (firmware 1.3), 14-54mm & 40-150mm, HLD-3, FL-36, Hoya Super HMC UVs, Manfrotto 676B Monopod, Sandisk Ultra II 1.0 & 2.0 GB CF Cards, Tamrac System 6 Bag
 
SteveDP said:
is it better off setting the FL-36 in Auto mode (rather than TTL
Auto) and using FL-36's light receptor/sensor? I seem to have more
consistent exposure when doing so.
Click to expand...
In theory, the camera's TTL system should give the best results. Auto flash (where the flash uses its own metering) doesn't see through the camera's lens, and has a vague idea of where the camera is pointing. For example, if you photograph a person in the middle of an empty field at night and fill the frame with the person, with auto flash you would get overexposure, since the flash will try to illuminate the whole sky, while in theory with TTL flash, the camera would meter off of the person, and set the settings approptiatly.
 
Sorry I wasn't available when you first asked your question. As JScott (and others) pointed out very suscintly, Auto flash exposure is an older form of metering that was new 30-40 years ago. The TTL-Auto metering through the lens is the newer, usually more accurate metering. Typically TTL-Auto metering will give you a more accurate exposure than than Auto metering EXCEPT when your subject is more than 50 feet away or you are using an ISO above 400.

If TTL-Auto metering of your flash exposure is giving you consistently underexposed results I would suspect that the flash is the victim of manufacturing tolerances. If so, the easiest way to rectify the situation is to set an appropriate exposure compensation setting on the flash using the big dial near the bottom.

If you'll refer back to my suggested indoor flash settings, you might notice that near the bottom, I think paragraph i, I mentioned a little overexposure on very close subjects that can be remedied by the use of a diffuser (or exposure compensation again on your flash.)
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Good Shooting,
English Bob
 
Auto works just fine. Sometimes it seems to me it works better.
--
One of the B&H 6
 
david0649 said:
For my E-500 the AF assist is the built-in flash, correct? If so i
would not be able to use the AF assist on the camera because the
built-in flash is disabled.
Does the AF assist on the FL-36 do a better job than the camera's
AF assist? just curious.
Click to expand...
I've never seen the results of any study, formal or informal, which looked at the relative effectiveness of focus assist built into the E-500 versus that provided by the FL-36/50. I don't think anyone can answer that question.

The IR focus assist provided by the FL-36/50 is much less obtrusive and obvious than that provided by the E-500.

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Good Shooting,
English Bob
 
Thanks EB. With TTL Auto, the expsoure is very good 90% of the time. It appears that when I focus on a darker object, I tend to have underexposed images. This is very strange and I don't know others have similar experience.

Example: A black keyboard with a white book next to it.

In TTL Auto mode: If I focus on the keyboard, the image is underexposed. If I focus on the book, the exposure is good. Or if I lower the F-stop from 5.6 to 3.5, the exposure is also good.

In Auto mode: I get nicely exposed images no matter where I focus.

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Olympus E-300 (firmware 1.3), 14-54mm & 40-150mm, HLD-3, FL-36, Hoya Super HMC UVs, Manfrotto 676B Monopod, Sandisk Ultra II 1.0 & 2.0 GB CF Cards, Tamrac System 6 Bag
 
This (TTL Auto) has become a problem for those who have darker hair. if I focus on the face, the exposure is fine. But I usually get underexposed images if I focus on the hair.

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Olympus E-300 (firmware 1.3), 14-54mm & 40-150mm, HLD-3, FL-36, Hoya Super HMC UVs, Manfrotto 676B Monopod, Sandisk Ultra II 1.0 & 2.0 GB CF Cards, Tamrac System 6 Bag
 
During my recent shooting with the flash, I did notice that E-300 locked the focus faster (almost instantly) in very low-light situations when used with FL-36. I was actually pleasantly surprised with that.

Hope this helps,
Alex.

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Oly E-300 (ver. 1.3) & IS3.
Oly 14-54 & 50-200, Sigma 55-200, HLD-3 & FL-36.
EC-14 1.4x Teleconverter, Extension Tube EX-25.
OM 4/3 Adapter, OM 50mm 1.8 & Vivitar 400mm.
PD70X 40GB PSD.
 
in TTL Auto mode. Any setting that I might have missed?

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Olympus E-300 (firmware 1.3), 14-54mm & 40-150mm, HLD-3, FL-36, Hoya Super HMC UVs, Manfrotto 676B Monopod, Sandisk Ultra II 1.0 & 2.0 GB CF Cards, Tamrac System 6 Bag
 
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