TTL fill flash in daylight

[frederick_lau1]

How should I set both my camera (I use FM3A & F4) and flash (SB-24)

if I want to use TTL fill flash using a sync speed (e.g. 1/8, 1/15,

etc) lower than the X-sync (1/250s in both cases). Also how should I

set both the camera and flash if I want 1:2 or 1:4 fill.

 

I would prefer to utilize the "auto" TTL function of my flash.

[joseph_smith3]

See if this link to Moose Peterson Nikon flash techniques helps.

http://www.moose395.net/howto/flash.html

 

Joe smith

[arnabdas]

For your F4, I think you can either go with the built-in daylight balanced fill-flash mode or set your flash unit to straight TTL (not balanced) and dial in -1.7 to -2 stops flash exposure compensation.

<P>

For fill flash using FM3A, the following links might be helpful:

<p><a href="http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=005TNL">FM3A

balanced fill flash in TTL mode: How to achieve?</a>

<BR><a href="http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=005Xbo">I

LEARNT FILL-FLASH with the FM3A !!</a>

[steve_levine]

Frederick,there is unfortunately no subsitute for studying that (badly written)SB24 instruction book,and your camera manuals as well.Your questions are based on a lot of basics that are easily found in the manuals.

 

Nikon fill flash is quite simple,once you understand the principles involved.You can either have the camera do all the thinking and exposing of both ambient & flash levels.or you can use the manual compensated mode (which they call "standard" fill or something idiotic that no one else uses).

As for setting light ratios,you would have to "do the math" with a flash/incident meter in hand.This is made more diffilcult too,since TTL flash only can be read when film is exposed.So you would lose a frame of film measuring the flash.But you certainly could calulate any key to fill ratio desired,using the sky or sun as a main light.

 

Nikon suggests using -2/3rds of a stop fill flash in the shade.And they suggest +2/3rds stop when subjects are backlit in sun.I find these are both good starting points,but I prefer a bit less in the shade,and a bit more in backlight.

[mskovacs]

Since getting my FM2N, I find that auto flash is the easiest for most of my subjects. E.g. if I set my flash at f/8, I simply use the aperture on the ambient exposure accordingly to adjust my fill flash ratio. E.g. -1 f/11, -2 f/16 etc. If you are setting up a "posed" situation, manual fill flash using fractional power settings is even more reliable than TTL. I always set my flash to the widest angle setting and also add the wide angle diffuser. It eats more power but gives a softer, more even lighting.

 

I covered a friend's entire wedding using the FM2N and a medium format Rolleiflex TLR using auto or manual fill flash. In the wedding situation, TTL and auto flashes have a rough time exposing for white brides and black grooms. The matrix TTL systems probably handle this better than the primitive TTL on my F3HP or the FM3A/FE2.

[jim_gifford]

Frederick, step one is not to confuse TTL flash and auto mode flash. TTL mode uses electronics inside the camera to tell the flash that enough light has been thrown at your subject, so the flash can quit. Auto mode uses a sensor on your SB-24, not one within the camera, to tell the flash when to quit.

 

Both are automatic technologies, but only one is named "auto mode."

 

Okay, semantics lesson for the day has ended.

 

Settings for fill flash? The SB-24 probably works somewhat differently on the F4 from the way it works on your FM3a... and you could learn different methods for each camera or try a "lowest common denominator" system that will work the same way on BOTH cameras.

 

Here's my "lowest common denominator" suggestion. Set the SB-24 on Auto flash mode. Whatever aperture you select on the camera, you lie about the aperture to the SB-24. If you want your fill flash to be slightly muted, lie by one stop (for example, if you're really shooting at f/8 set the SB0-24 for f/5.6). If you want even less fill flash in the shot, lie by two stops (for example, camera is shooting at f/8 but you set the SB-24 to f/4).

 

What this does is convince the flash a wee bit early during each exposure that it has sent "enough" light, because it thinks your film is merrily gathering photons at a rapid clip given the aperture you've told the flash you're using. Meanwhile, your real aperture is narrower, so the flash really winds up being a bit underpowered, which is exactly what you intended to accomplish.

 

By the way, your SB-24 is a wonderful flash but it does not have feelings and it will not get all sullen when you lie to it all the time. It is a very mellow, California-sunshine sort of device, with a "sure, dude, like, whatever you want" unruffled attitude and it will happily toss photons onto your subjects for years no matter how often you lie about the f/stop you're really using.

 

And no, Nikon does not make spouses, sorry.

 

Be well,

[frank uhlig]

I think nobody has picked up on the following in the post:

 

"... to use TTL fill flash using a sync speed (e.g. 1/8, 1/15, etc) lower than the X-sync (1/250s in both cases..."

 

1/8 of a second is 32 times slower than the X-sync speed of 1/250 sec, so there should be absolutely no problem syncing. It is 1/500 and faster that will pose problems with syncing.

 

So my advice is: just set -1 compensation on the flash and shoot in daylight at these relatively long exposures. Are you working with f/32 or plenty of filters or ISO 25 to use those 1/8 sec in daylight?

 

-1 for 1:2 (=2^{-1}) fill (kind of normal, but you will better know after you see the fill and the light variations); -2 for 1:4 (=2^{-2}) fill flash reduction etc. -3 for 1:8 (= 2^{-3}) ...

 

Incidentally, how TTL fill reacts to/with the camera meter is somewhat different for each camera (and taste). So you need to experiment and bracket a bit while keeping good notes.

[jim_gifford]

Frank, I'm not sure he will be allowed to "set -1 compensation" using an SB-24 on an FM3A. I have an FM3A and an SB-28 flash (admittedly not exactly the same setup) and the flash compensation features of the SB-28 simply do not work on an FM3A. When I use the flash on my N90s, sure, I can adjust it that way. Easy as pie, just touch the little button and watch the setting change in the LCD display on the back of the flash. Not when the flash is set to TTL mode atop the FM3A. The buttons have no effect once film speed is set. But in Auto sensor mode I can use those buttons to adjust the aperture used in the flash calculations.

 

That is why I suggested Frederick use auto-mode flash and lie to his SB-24 by one or two f-stops. It's the only way I know to accomplish the same thing you suggest -- to "set -1 or -2 compensation" -- using an FM3A body.

 

Be well,

[frederick_lau1]

Thanks for all your valuable info & advice.

Jim, I will try your suggestion first and see how it goes.

Frederick