Bounce Flash/TTL metering

[reactan]

a while back, i posted a question on the need to have exposure compensation when using bounce flash here: previous thread

I'm using a minolta 404si and 3500xi external flash. I experimented with the flash during some recent shots...but even with the flash set on auto, i'm not getting good results, for example,

1) When using a bounce flash with a low ceiling, the pictures all turn out too dark.

2) When using the external flash as a fill flash in bright sunlight, the subjects still turn out too dark.

The flash works fine when i point it directly at my subject in low light conditions.

So i have a few questions
1) where exactly is the meter located in the camera?

2) Does the camera take the metering just prior to shutter release, or is there a "dynamic" metering, ie: metering while the shutter is open

3) Do you guys think that the 3500xi lacks the power for bouce flash shots?

Thanks,
Al

 

[NashVillian]

I use to own the 3500xi, no it is not too weak for bounce, but perhaps u could provide us with more details:

The bounce flash: was the angle set properly? remember. angle of incidence = angle of reflectance. Day / night shoot?

Direct Flash: were you shooting against light?

Flash to subject distance for both?
Flim speed?
Are you on auto or manual mode?

 

[reactan]

I use to own the 3500xi, no it is not too weak for bounce, but perhaps u could provide us with more details:

The bounce flash: was the angle set properly? remember. angle of incidence = angle of reflectance. Day / night shoot?

Direct Flash: were you shooting against light?

Flash to subject distance for both?
Flim speed?
Are you on auto or manual mode?

I was shooting with provia 100 in both cases.

Bounce flash: distance was about 3m, at night, with a low ceiling. cant remember the angle now, probably 70 degrees. I looked at the photo, and dont see any bright spots in front or behind the subjects.

Direct fill flash: shooting at high noon, sun directly overhead, with everything on auto, as per advice from the previous thread.

I'm sorry i dont have examples to show you, perhapes when i do evantually get then scanned.

Al

 

[NashVillian]

do scan in ur pics...as this is beyond me...sorry
but will try once ur pics are scanned

 

[sulhan]

Hiee....

Looks like the problem you are having may be due to the follwing factors :
- ceiling is too high
- flash does not have enough power (for the distance)
- Wrong tilt angle of flash head

I also own and use the 404si. Have tried with 3600HD and 5600HS. For ceiling Bounce....3600HS would probably be good only for HDB housing ceiliing height - which is painted with light color e.g white.

With the 3600HS the coverage is basically best at 70 degrees for subject about 2~3metres and 45 degres for further. For the 45/70 degrees, i would recommend using a bounce card or a omnibounce.

That means, a light shower form the top and a about 1/3 forward light . Or else your picture will be underexposed.

You said you are using ISO 100......a little tough ....

In Program Mode...

I would recommend a minimum for indoors ISO 200.....and with the flash in bounce....(tilt up) - you need to do a +1/3 EV (in some cases, if poor lighting may be up to +2/3 EV - for the 404si...you only have +0.5 steps so +0.5EV compensation.

So next time, if you just tilt the head up - then just push the EV up +0.5

One way is to do a slow sync (Press the "SPOT" button prior to pressing the shutter button), but this you need to make sure the subject stay still and you have a tripod or minimally a monopod.....AND a fast lens (f2.8 /f 3.5/ f4).....as due to the limited power of the flash...shutter speed may go to unsafe values....

All these inputs are based on my personal experieces with my 404si...a capable camera....

rgds,
sulhan

 

[NashVillian]

hmmm...just wondering if the 404si has any form of indication that flash power might be insufficient..., like blinking flash symbol or something...

 

[reactan]

hmmm...just wondering if the 404si has any form of indication that flash power might be insufficient..., like blinking flash symbol or something...

dont think so....dont see it in the manual. Anyway, i was using new batteries on my external flash, so should not have been a problem.

Al

 

[TME]

sulhan's comments are valid and mirror my experience with the 3500xi and a 505si.

The 3500xi is quite weak especially when u are trying to capture a large group of people indoors. U need to be within 2 meters if it's direct flash and much less than that if u bounce. Always try for the largest aperture available.

Also ISO100 is too slow for indoor... u might want to try ISO400. ISO200 is a little stretching the limit too especially if the indoor venue is particularly dim.

Bounce card would be excellent, no need for EV if u stand close enough....

The golden rule to remember when u tilt your flash or bounce it off a card or use OmniBounce is that u tend to lose about 1/2 your flash power (in other words your flash coverage distance), this is especially pronounced for the 3500xi.... when I upgraded to the 5600HS, I had little of this problem of coverage again....

Also u need to evaluate the brightness background even if it is indoors. I had a shot ruined cos of a very bright spotlight shining almost directly into my lens.... I didn't quite have a choice then cos it was a huge family photo and I was not too experienced either.... that spotlight fooled the camera's meter into thinking it was brighter than it really was when measured from the subject's face...

Spot metering works as well but u're probably going to get really low shutter speeds like <1/10 sec if u are using the kit lens and even prosumer lens without constant f/2.8 apertures.... doesn't work for me since my maximum handhold shutter speed is 1/30 sec....

Hope this helps...

 

[sulhan]

Hieee...

Just take note.....if there are other photographers, be sure to coordinate so that you guys will not rush to shoot at the same time. Your metering may be thrown out of the boat if some one else's flash is "on" and you are trying to take the shot at that same instance.......that will make your picture blacko!!!!


rgds,
sulhan

 

[reactan]

Thanks...thats all great advice. will take note the next time i'm shooting with flash!

But i'm still curious...does anyone know where the metering is taken in TTK metering? ie: where is the meter physically?

 

[TME]

Thanks...thats all great advice. will take note the next time i'm shooting with flash!

But i'm still curious...does anyone know where the metering is taken in TTK metering? ie: where is the meter physically?

Inside the camera behind the lens under the mirror.... some of the incident light is split I think and falls on to a sensor which measures the amount of reflected light from the scene.