Pocket Wizard Normal TTL Mode

richlewt

New member
Hi
I have just bought a pair of PW FlexTT5's to be used with my SB700 Speedlight and D7000. With the flash on camera I can turn from TTL-BL to normal TTL by selecting the spot metering option on the camera. Does this method work when you have the PW,s fitted?
 

Geoffc

Senior Member
Hi
I have just bought a pair of PW FlexTT5's to be used with my SB700 Speedlight and D7000. With the flash on camera I can turn from TTL-BL to normal TTL by selecting the spot metering option on the camera. Does this method work when you have the PW,s fitted?

Are you saying it changes automatically or you alter the flash? On mine I put the flash in ttl mode, slide it on the tt5 and then turn on the tt5. The flash then automatically goes into ttl-bl and works. I don't think bl means the same when the pw is attached as it does that when I'm controlling power manually with my sekonic 478dr.
 

WayneF

Senior Member
Hi
I have just bought a pair of PW FlexTT5's to be used with my SB700 Speedlight and D7000. With the flash on camera I can turn from TTL-BL to normal TTL by selecting the spot metering option on the camera. Does this method work when you have the PW,s fitted?


I don't know much about the TT5, but the camera does all of the TTL metering, and merely informs the flash (via whatever means) about what power level to use to accommodate it.

Yes, Spot metering always has to be Spot metering, which is TTL instead of TTL BL.
 

richlewt

New member
I don't know much about the TT5, but the camera does all of the TTL metering, and merely informs the flash (via whatever means) about what power level to use to accommodate it.

Yes, Spot metering always has to be Spot metering, which is TTL instead of TTL BL.

So in spot metering mode, the PW-Camera-Flash are working together ignoring ambient unlike TTL-BL?
 

WayneF

Senior Member
Two subjects here, spot and ambient.

I am speaking of the camera meter here, which is a reflected meter. Incident meters are rather different.

The concept of spot metering ignores ambient, by definition. It is a spot, period. It does NOT see ANY of the rest of the image area. Beginners beware, Spot metering is anything but a general purpose point&shoot method. It requires some thinking and experience. Center and Matrix is more point&shoot.

Beginners imagine meters make exposure be "correct". But wrong concept, not possible. Instead the only concept is that the result is made to be a middle tone, not too dark, not too light. Regardless if it should be middle tone or not (black dress, white dress).

Any light meter averages its metering area into one exposure reading, and tries to make that reading's average come out about middle tone. Meters are dumb (cannot recognize the scene and what it needs, like human brains can). This is only way the meters can work. Center metering for example. Matrix metering too, which supposedly watches a few extremes too (in some undisclosed way).

Most scenes (landscapes, portraits, whatever) do tend to have enough range to average out to about middle tone, so this works, often (but some surprises, white dress and black dress for example). But a Spot is just a spot, and that spot area will be made to come out about middle tone too. Should a face be middle tone? (no, white skin ought to be about a stop brighter). So you have to choose your spot properly, or at least know how to compensate for that spot. Not for unthinking point&shoot.

Assuming we are not Spot metering, the relationship of TTL and TTL BL is that TTL ignores ambient, and TTL BL honors ambient. TTL BL (balanced) keeps the flash at fill level well less than ambient (if any significant ambient). TTL always does exactly what the flash meters, regardless of any ambient or not. If significant ambient is present, then TTL properly exposes, and ambient properly exposes, which is two proper exposures, and 2x is one stop overexposed (of the flash area). This is why we know to compensate TTL fill flash about -1.7 stops in bright sun. But TTL BL we don't necessary compensate (except for errors and choices), because TTL BL does this pull back automatically.

Spot metering only sees that spot. There is no concept of ambient. None of the rest of the frame is considered.

See How light meters work
 
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richlewt

New member
Assuming we are not Spot metering, the relationship of TTL and TTL BL is that TTL ignores ambient, and TTL BL honors ambient. TTL BL (balanced) keeps the flash at fill level less than ambient. TTL always does exactly what the flash meters, regardless of any ambient or not. If significant ambient is present, then TTL properly exposes, and ambient properly exposes, which is two proper exposures, and 2x is one stop overexposed (of the flash area). This is why we know to compensate TTL fill flash about -1.7 stops in bright sun. But TTL BL we don't necessary compensate (except for errors and choices), because TTL BL does this pull back automatically.

Spot metering only sees that spot.

See How light meters work
Hi Wayne
Thanks for a very comprehensive answer.
The reason I engage spot metering mode, as that is the only way of making the SB-700 work in full normal TTL mode, otherwise if you have centre weighted or matrix selected it will make the SB-700 work in TTL-BL mode.
What I was trying to establish, is, if for example I want to use my PW's indoors and want to work in normal TTL mode (i.e. without TTL-BL), if I set my camera to spot, does the PW convey this to the flash.
I cant find anywhere in the PW literature that this is the case, I am sure it is, but was hoping someone could confirm this. I say this because the display on the SB-700 when used with a PW does not change, it always reads TTL irrespective of what mode is set in the camera. It appears to work perfectly outdoor so it is obviously balancing daylight nicely. I will do some internal shots later.
 

WayneF

Senior Member
I understand, the SB-700, SB-400, and camera internal flash only select TTL BL mode. The camera does this metering, but some flashes have a menu button to choose it. It is unknown to me if those flashes can select anything with the TT5, I assume all communication is one way, from the camera? Hot shoe via radio possibly could be different, but is it? Nikon Commander for example is one way communication from Commander, and with any flash model, Commander is always TTL BL too (unless Spot metering tells the camera otherwise). The Nikon system is TTL BL. TTL or TTL BL mode is shown in the extended Exif, as a way to know for sure how it metered.

But Spot metering... perhaps the cure is worse than the disease? We ALWAYS have to watch flash results anyway, to know when to use Flash Compensation, to get the result our own brain thinks is wanted. Knowing how to use Flash Compensation is the exclusive secret of TTL success. FC is how you control what the automation does.

So speaking indoors, TTL BL simply just needs a bit more Flash Compensation than TTL mode does. You might start by simply dialing in +1 EV Flash Compensation for TTL BL mode (indoors, not outdoors in ambient). And simply adjust that base point as necessary for each situation. This then allows Center or Matrix metering, to consider more of the frame.

This is assuming insignificant ambient indoors. It could be a moving target (so watch results, and standby with Flash Compensation). The automatic compensation done by TTL BL varies with ambient level, to nearly -2 EV in bright sun (this number is not visible to us). So two cooks, both salting the broth, better keep an eye on each other. The point is though, you can compensate what it does.
 
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Geoffc

Senior Member
I would just like to re-state a point,but firstly I totally agree with Wayne's explanation off TTL-BL in normal on camera flash operation. When you attach a flash like my SB900 to a TT5 it will always display TTL-BL unless I manually override it. This even happens when the Pocket Wizard is not operating in TTL mode or being controlled by the camera. Specifically, when I have it set up so I can use the Sekonic 478DR to set power it still shows TTL-BL. I don't know why it behaves this way but is does, all the time. I am suggesting that the BL bit may not be all that it seems in the particular case.
 

FastGlass

Senior Member
I use the flex tt5 with m SB800. Same thing happens. It goes into TTL-BL. Which simply means, fill flash. I'm assuming it automaticaly does this because when you use the flex, it knows its off camera. And as soon as I choose auto fp in my camera menu, it also pops up on the flash. Doen't mean its always going to use it but as soon as I go over 1/200 it will.
 

Des Barry

New member
I use a Nikon D3, With various Nikon lenses(70 to 200VR 2) and an SB 910 flash gun. My photographic interests include African wildlife (Botswana,Namibia and South Africa) casual fashion,lifestyle. artistic nude and nude.
Up until say a year ago, i'd been using the SB 910(SB800 previously) in TTL BL mode -- tethered to the camera through the hotshoe. That gave me what i was lookingfor -- natural light with balanced fill flash -- TTL BL. Very natural lighting.
I then changed to Pocket Wizard -- Mini TT1 on thecamera, and Flex TT5 receiver with the SB 910 flash -- to take advantage of the radio capabilities. That has worked out very badly -- I cannot any longer get TTL BL -- just TTL FP. No consistency and very variable images.
I've just spent a few hours again reading the Nikon SB910 Manual -- no mention of a TTL FP mode.
Not a happy photographer.
Regards
Des Barry
 
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Geoffc

Senior Member
I find it works fine in a studio, however at my daughters wedding the outdoor shots in sunlight were overexposed. I understand this was a known problem. I haven't had chance to test it properly since.


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