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wideangle
12-02-2012, 11:18am
Am planning on taking a sports group formal shoot and was wondering if a flashgun would prove useful? It will be shot in the late afternoon, so there should be ambient light. I would like to use flash to catch-light their eyes, so would like to use Av mode. The group will be of about 11 people, so I plan to shoot standing back a little way shooting with a 50mm lens which will give me a 80mm focal length.

Being that I will need to stand someway back to shoot, should I bump the ISO up in order for the flashgun to 'reach' the subjects eyes? Or if for example I was to use 100 or 200ISO will the flashgun compensate and give more power output after assessing the distance of the subject?

Brian500au
12-02-2012, 11:55am
It is fairly difficult to give specific advice here without a little more information. As general advice though think of these points

1. If you are shooting a group of people and using on camera flash, the people at the front will get more light than the people at the back. This won't be too bad if you have the group fairly packed close together - front row kneeling. But if you spread them out a little, the problem is significant.

2. If you are shooting off camera flash to one side (and the flash it right of the camera) then the people on the right of the group will get more light than the people on the left (more noticeable than the first example).

3. The canon system in ETTL will compensate for the correctly exposed people - so the people furthermost away will be under exposed.

4. If you are in AV mode and the shutter speed is higher than your sync speed of your body, then canon locks the shutter speed to your body sync speed, but does not lock the aperture, resulting in over exposed shots - if you notice this, set your flash to HSS.

5. You might be best to set every thing to manual and chimp looking at the histogram on the LCD of your camera body. That way you can control the power of the flash and not let the canon system be tricked by distances. If you are using on camera flash I would suggest you use some type of reflector with the flash to spread the light. Not sure if you are going to notice catch lights in a group shot - it is more about removing unwanted shadows.

Hope this helps
Kel

wideangle
12-02-2012, 1:02pm
Thanks heaps for your detailed response, sounds like a flash might not even be necessary for this kind of shot then considering it's a group shot like you say and the eyes will be smaller, and the issues related with uneven flash exposure on all subjects when shooting with flash on camera. I take it that these problems will exist even with a dedicated off camera flash unit attached to the camera? I wouldn't be using on-camera flash if this makes any difference to the original question?

From your advice, maybe it's best to shoot at my intended focal length of 50mm with camera on tripod with appropriate ISO/shutter combo without a flashgun. I suppose the only reason to use a flashgun on the camera would be if the sun was behind the subjects so I can get some fill light happening.

Brian500au
12-02-2012, 5:37pm
My advice in this instance would be go to bunnings and buy yourself a couple of large white boards from the hardware department - get two assistants to hold the boards so the reflection of the light bounces towards your group. I think I bought two of them for $10 each - if you have a flash - set it as fill flash but it will only help rather than be your primary source of fill light.

I would still set everything to manual to so you have full control over exposure.

Kel

wideangle
13-02-2012, 10:05am
My advice in this instance would be go to bunnings and buy yourself a couple of large white boards from the hardware department - get two assistants to hold the boards so the reflection of the light bounces towards your group. I think I bought two of them for $10 each - if you have a flash - set it as fill flash but it will only help rather than be your primary source of fill light.

I would still set everything to manual to so you have full control over exposure.

Kel

Thanks for your help Kel, I might try this method another time, for now may just face them at angle to the afternoon sun and shoot.

kiwi
13-02-2012, 11:05am
Prertty easy, bump up your iso to get a lot of ambient light, 800 even, and use your flash in manual to add fill. TTL may not give the right result.

wideangle
13-02-2012, 12:26pm
Prertty easy, bump up your iso to get a lot of ambient light, 800 even, and use your flash in manual to add fill. TTL may not give the right result.

Thanks Darren, may give it a go.

kiwi
13-02-2012, 12:30pm
What I do is have two OCF, each side of me with two brollies in a "crossfire" pattern

wideangle
13-02-2012, 5:03pm
Does the same rule in terms of effective flash reach/length apply to both an external and on camera flash? I was wondering if standing back say 15m, would you be able to use ISO100 with a dedicated external flash unit because it would have more power, or would you still need to use a higher ISO for 'reach'?

kiwi
13-02-2012, 5:51pm
Yes, same rules......15m seems a long way away.....but it really depends on

a) the number and power settings of the flash(s)
b) distance to subject
c) the ambient lighting available

wideangle
13-02-2012, 8:24pm
Yes, same rules......15m seems a long way away.....but it really depends on

a) the number and power settings of the flash(s)
b) distance to subject
c) the ambient lighting available


would only be one external flash on the camera, an 80mm equivalent focal length shooting 11 people (2 rows) in afternoon light. Hence why I estimated 15m back to get the entire group of people in, can only predict that 2 get two rows of 11 people in I would likely be that far away in order to get them all in. Maybe it would be 10m - but in that range I reckon 10-15m - worth using a flash in this instance? Would it achieve filling in any shadows if there were any, or best of with none?