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12-03-2017, 04:53 AM   #1
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Where's the weak link?

I've been shooting a lot of portraits at work lately, and my new K-1 is working like a dream with the 28-105 mounted. But I'm starting to feel that my flash (Sigma EF 530 DG ST) is the weak link. But I'll be the first to admit that I don't really know how to use it. Sigma's manual is to all intents and purposes non-existent.

To clarify, my portraits are usually just individual or group portraits, typically shot indoors, under typical office fluorescent lighting. I just put the flash in P-TTL mode and usually have a lightsphere mounted on top as well. My clients (colleagues) expect me to rattle off a few shots in a couple of minutes, and get good results. And I *have* been able to deliver good results, but too often that's because the impressive K-1 DNGs have allowed me to rescue poorly exposed shots. So I'd like to get more consistent results.

Thus: if I'm the weak link, should I just read through Nigel McGregor's guide? (I will anyway, just downloaded it). Or is there some other guide more specific to the flash that will help me?

Or, if the flash is the weak link here, what's the consensus on a good quality flash to get? Advice about triggers would also be welcome, because I'll sometimes hire professional lights.


12-03-2017, 05:57 AM   #2
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Certainly read Nigel's guide and you will learn heaps of things about flash use that you didn't know before. Without seeing some examples it is a bit difficult to give any advice. One thing to remember is the lightsphere, while giving a more diffused light, will cut down on your maximum range.

What mode are you using the camera in ?
12-03-2017, 06:08 AM   #3
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If you can post any samples of a typical portrait that you're questioning, it would help.

There is nothing wrong with your flash, but better portraits are usually going to be shot with a natural back light and fill flash, or in a studio with multiple units. Shooting with ambient fluorescent light is going to mess with your color balance and skin tones and being pressured for time doesn't help unless there is a dedicated space for these portraits.

If there is space, the ideal set up would be without ambient lights, using a slave flash as your key light with a reflectasol type umbrella or soft box, another slave as a 'kicker' to rim light the subject's head and shoulders from behind, and then using an on-camera flash as the eye light and master fill to soften the shadows. To keep costs down, the kicker could be a bright ambient daylight balanced flood light so you're not shooting in the dark.

Ideally the room would have walls and a floor that was a neutral white or grey and set your white balance to 'flash'.
12-03-2017, 04:26 PM   #4
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The basic P-TTL operations and how the flash / camera modes interact is the same with any dedicated system flash, so you will find plenty of relevant info in my Guide and the Supplement. It's tailored more specifically to the Pentax flashes, but there's a lot of generic stuff also that I hope might be helpful. Perhaps you could check out the section in the Supplement on "Automatic Flash Photography"..... This has guidance on exposure issues with flash.

The LightSphere is designed to be used pointing upwards or slightly sideways also, and then it will 'spray' light around bouncing off multiple surfaces .... There's also a good amount of direct front fill from it as well. It is quite a good choice for group shots in small to medium rooms. If your shots are underexposed then perhaps the space is too large and there's not enough power available? In which case then a higher ISO might help. Again, there's specific ideas about this in the Supplement document.

Give us an example or two with the settings you used (Camera mode, ISO, Aperture, Shutter Speed, any ambient and flash compensation set ...). This should help people to get better idea and be able to help more

12-06-2017, 05:58 AM   #5
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Thanks for your advice, everyone. I won't share any photos, since the subjects have a reasonable expectation of privacy.

Yes, I use the Lightsphere pointing upwards -- I find it's really conducive to flattering results. But my flash shooting is not as consistent or as predictable as I'd like. On the whole, I err towards over-exposure -- but not consistently. Since the flash is to all intents and purposes undocumented, it's not clear to me how to control its output, so I leave it in P-TTL and try to find suitable settings on the camera.

In the process of shooting people and keeping them engaged, I tend to find that good old Program mode is as reliable a choice as any. That has the advantage of allowing me to maintain that connection with the subjects, but it seems like a slightly "brain dead" approach. It's not an approach that encourages me to grow as a photographer.

Anyhow, it's pretty clear from your responses that I'm the weak link here (which doesn't surprise me), so I'm looking forward to exploring Nigel's guide. Thanks again folks!
12-06-2017, 07:04 AM   #6
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Yes, have a read and think about the issue of your ambient / flash exposure balance. P mode will often lead to a balance heavily slanted towards a flash exposure only (i.e. very low amount of natural light recorded). Indoors you might get nicer looking results with a balance of natural and flash light .....(well it's something worthwhile to explore) . If you are using P or Av mode, then switch the camera to the "Slow Speed Sync" flash mode ....this will open up longer exposures and allow more Ambient light to record. Keep an eye on the shutter speed to ensure you can still get steady shots. A higher ISO can assist with this also.

You could test it out and practice with a vase of flowers on a table (or a doll or teddy bear etc). Stand about the same distance you would for your group shots, and point the flash head or light sphere away from the subject (i.e. Bouncing from a wall /ceiling surface). Try these settings to start with :

Slow Speed Sync Mode ..... Av Camera mode ...... F5.6 .......Fixed ISO 800 .....Flash P-TTL mode .....Flash compensation (on the Sigma) set to minus 0.7 stops.

Try a few shots and adjust both the flash compensation and camera exposure compensation and see the effects. You can post the examples on here for comments and opinions.

If you run into steadiness problems because the ambient light is too low, then you have the following choices ...... get brighter ambient light .... set a wider aperture ........set a higher ISO.

In dim indoor conditions then it may prove impossible to record any ambient light handheld, fair enough. In which case then you just look to have only flash light in your images. Switch off Slow Speed Sync (back to normal flash mode) and the shutter speeds should jump back to faster ones ok for handholding.

Last edited by mcgregni; 12-06-2017 at 07:16 AM.
12-06-2017, 08:46 AM   #7
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Unless you post pictures, it's very hard for anyone to diagnose what you're doing wrong, AWS.

One thing to try to eliminate variables is to begin with manual exposure settings on the camera (say ISO 800) and manual power on the flash - starting from 1/8.

Smoothly chimp test shots and adjust up or down to taste.

Until you leave that room for a new setup, if the subjects are framed the same way you know the settings are right for all the future shots, too.


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