Fill Flash Advice Wanted

[Steve Smith]

Next weekend I am taking a few pictures at a friend's wedding. This is not a full wedding service as I will just be doing a few formal portraits outside after the ceremony and at the reception, also outside (weather permitting!).

I hardly ever use flash so I'm no expert (obvious as I'm asking a question).

If I understand correctly, I meter as normal for exposure without flash then adjust the flash to give a -1 stop output either by setting it to a wider aperture or a higher ISO.

I have been experimenting with this using one of those alternative technology cameras that you can't put film in and I find (as I expected) that I get some blown out highlights.

As I will be using film (Fuji NPS 160) should I just not worry about this?

I assume that the digital users compensate their exposure a bit to prevent this.

I will be using my Mamiya RB67 with a Vivitar 285.

Thanks,


Steve.

 

[arigram]

If you are using TTL with the flash, yes, you can just double the iso rating to give you half the power.
Changing the lens settings with TTL isn't going to work.
If you are using an automatic exposure from the flash, you can adjust the iso there.
I really recommend a LumiQuest bounce accessory for the flash to give you a much softer light.
I've just got the Promax System which has everything one could wish for.

 

[Steve Smith]

Thanks for the reply.

When I said altering the aperture I meant on the flash dial rather than the lens. On the Vivitar, changing either the aperture or changing the ISO gives you the same final setting (a colour which you set the auto sensor to).

I was planning on using the Vivitar's own auto setting as it does not support TTL.
I was thinking about some form of diffusion rather than bounce but whatever I use, it will probably be home made or adapted rather than bought as I am not very likely to use it again.

I have had a look at Lumiquests website and given the range of thin plastics and adhesives I have here at work, I think I could easily make something similar. Something like the Midibouncer LQ-110 looks simple and effective.



Steve.

 

[eddym]

I usually give 1-1/2 to 2 stops less flash for fill. 1 stop may not be enough. But the method you are using is correct.

 

[MattKing]

Steve:

You are probably doing it right, but just in case there is a miscommunication...

1) Meter and set your camera normally. If that results in an f/stop of f/11,
2) On the flash, set the ISO correctly, and then choose the colour on the auto setting that indicates an f/stop of either f/8.0, or f/5.6.

The reason you need to experiment a bit is that the sensors on automatic flashes are programmed based on some assumptions. Mainly, they assume that you are using the flash in a situation where your subject comes close to filling the frame, and where there is at least some light from the flash reflecting off walls, or floors or ceilings.

In a lot of cases with fill flash, you are outside, and there is little or no flash light reflecting back from anything except the central subject. There is thus a tendency to over fill if you use just a 1 stop adjustment. In addition, if you are using a longer lens, the angle of view may be much narrower than that used by the sensor. If you are using a wider lens, the situation may be the reverse. As the Vivitar 285 is designed to be usable with fairly wide lenses, I expect it has a fairly wide view sensor.

This also varies a bit from flash model to flash model, because the sensors vary, in particular in respect of their angle of acceptance. I would think that a Vivitar 285 would be reasonably consistent (I used a 283 for this for years) but when I switched to Metz 60 series flashes, I noted a distinct improvement in the consistency of results.

You might consider switching to manual operation, and using the guide number for a film with twice the ISO (for a 1 stop reduction) but you should be aware that even in that circumstance there are some assumptions built into the guide number calculation.

Testing is very useful.

Hope this helps.

Matt

 

[Steve Smith]

Thanks for all of your advice.

I think I am clear on the method now. As has been suggested, I will use -2 or -1.5 stops rather than -1.

Thanks to Ari I have started some experiments in origami and I have made quite an effective slip on bounce adapter from a sheet of gloss inkjet photo paper (I knew there had to be a use for it!). I will convert this into a more robust, velcro fitted item when I get back to work next week.


Steve.

 

[Síle]

I hardly ever use flash so I'm no expert (obvious as I'm asking a question).

How to use flash in your photos...

 

[Steve Smith]

I hope they all turn out like Síle's example above!

Here is my prototype bounce attachment. Stay tuned to this channel for the final version.


Steve.

 

[MattKing]

Steve:

I note that you have the Vari-power adapter on the flash. Correct me if I am wrong, but doesn't that only work with the flash on manual?

You may, of course, be intending to use the flash with the other sensor, or on manual.

Matt

 

[Steve Smith]

The Vari-Power has manual settings of full power down to 1/16 power in 1 stop increments and also has a series of colours which represent a series of power setting on automatic.

On the setup dial at the side of the flash you set the film ISO then set the Vari-Power to the colour shown next to the aperture you want to use.

So it is manual and auto but not TTL auto.


Steve.

 

[MattKing]

Thanks Steve.

When I used to use a Vivitar 283 (and we are talking at least 25 years ago now) the accessory that permitted adjustment down to 1/16 power replaced the auto exposure control, rather than supplementing it (IIRC).

Glad yours works differently.

Matt

 

[Steve Smith]

Thanks to everyone who gave me advice, I managed to work out what settings to use, make a bounce flash adaptor (documented in another thread) and take some photographs.

I seem to have got the flash ratio right as the prints which I received on Friday look good with no obvious signs of artificial light.

I will post a couple of examples in the gallery but I will need to get the couple to agree to this first.



Steve.