Studio lighting

[kfw03]

Hello, newbie here. just set up a studio by clearing and converting my garage. Its 5.5 m x 6.0 m and I bought an elinchroms Bxri 500 kit with softboxes for main/fill plus I have SB800's for backlights, hairlights etc. Just been taking a few shots of the family but couldn't get f stop lower than f8, even on lowest power setting and with lights positioned about 4 m away from subject. (ISO 200, 1/125 sec). Are the lights too powerful for studio or am I missing something? I suppose I could move them back a bit further but everything I've read so far says to get the softest light position as close as poss to subject! There's no way I can open up the apeture to blur the background with the strobes any closer, any advice most welcome please!

[gbkirk]

You can get gels(gray plastic sheets) to put over the softboxes to lower the lights in stops.

Graham

[GeoffWessex]

If you shot at ISO 100 that's an immediate change to f/5.6 - I take it you're shooting at 1/125th for the sync, but most cameras are capable of 1/250th for sync (worth checking anyway) and that would 'give' you another stop to f/4.
Other than that, I think you're into the gels situation, as gbkirk says.

[kfw03]

Thanks for advice, guys. I 've got some nd filters that I could also use but I don't know how it will affect a white background,so I'll have to experiment.
Yes Geoff I was using 1/125 to stay well within sync speed so I could go with a higher shutter speed to get 1 more stop. Again I'll have a play around with settings and see what I get. One more point - I moved the strobe against the back wall (approx 5 metres from backdrop) and metered it. Result: f5.6 against backdrop; f7.1 aprox 12" from backdrop and f8 about 18-24" fron backdrop. I'm sort of familiar with inverse square law, but I didn't think there would be so much variation in light levels over such a relatively small distance, another reason to get the lights up close! Thanks again.

[GeoffWessex]

The ND filter idea could work - and it shouldn't affect the white..... however, some filters (notably Cokin) do give a colour cast. Of course, if shooting Raw you could easily get the white back, but doing that to all the shots in each and every session is going to be a hassle. (Even though Lightroom or Aperture can do large batches). Best to find another way.

[PaulMontgomery]

Surely changing the shutter speed won't have an impact unless there's a lot of ambient light in the mix?

[GeoffWessex]

Changing the shutter speed could put it out of sync with the flash - you still need a sync-speed, usually 1/125th or 1/250th.

[kfw03]

You're right Paul, the strobe is firing at around 1/1500 sec so it doesn't affect the exposure as the ambient is totally overpowered by the flash (even at it's lowest setting). I've just tried it at 1/250 and 1/320 on my D300 and the f stop remains constant. I want to shoot some portraits close up focussing on the eyes but can't open the apeture wide enough I need at least f2.8 but can't get nowhere near it with this set up.Guess I'll have to keep trying and find some gels as suggested.