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05-04-2011, 06:03 AM   #1
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Need help with flash portrait setup - K20D and Sigma EF-610 DG Super

I was hoping I could figure this out myself, but now I know I need serious help.

I am planning to take portraits of prom couples (my daughter and her friends and dates) this Friday. In preparation I bought two Sigma EF-610 DG Supers to go with my K20D. But reading through the Sigma manual has been little help, and my testing so far is hit and miss.

I plan to have the main flash off camera at 45 degrees to the couple through an umbrella. The second flash will be on or beside the camera bounced off the ceiling. Ambient window light will come in the side opposite to the main flash (I also bought gels to match the flash with ambient). I will be using optical wireless to control the flashes.

1) Should I use PTTL or go manual? What settings should I use on the flashes?

2) Would Av mode at f/5.6 make sense to blur the background?

3) Do I meter on ambient light? If so, shutter will be slow and I need to be on a tripod. How then do I set flashes so they don't overexpose?

4) Will I need high speed sync for this? If so, then one flash must be mounted on camera because popup does not support HSS.

What else do I need to know? In other words, I would love someone to give me a step by step tutorial so I get it right. Thanks!

05-04-2011, 06:54 AM - 1 Like   #2
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1)well firstly I would use manual mode on the flash and on the camera I never use AV mode when working with flash - with your flash in manual mode you can set up your lighting and keep it controlled and consistent. You are using more than one flash I recommend you use a ratio of 3:1 with your key light being in a prominent position and the auxiliary light being positioned to fill the shadows that the main light casts. Using a hair light to add specular highlights to the subject's hair is a popular technique with this kind of portraiture.

2) large subject to background distances are more effective at providing blurred backgrounds. Large subject to background distances also give you freedom to use an appropriate f/ value to keep the subject sharp while the background remains blurred. Lens selection will be critical for achieving shallow DOF effects.

3) If you use manual mode with the flash and you wish to incorporate ambient light I would gel the flash units and tweak their power levels to match the ambient light if possible (you are working with daylight so a 1/2 CTO filter should do nicely). As above I would be using the flash units in manual mode so PTTL doesn't spring any surprises.

4) If you are going to be using HSS which will mean you will be relying on PTTL which can produce decent results if you are aware of it's limits, personally I avoid using HSS if it is at all possible. Indoors HSS really isn't necessary anyway, HSS also severely limits the range of illumination from a flash unit, and any light modifiers you will use will also reduce the range of the flash.

Last edited by Digitalis; 05-04-2011 at 07:07 AM.
05-04-2011, 07:02 AM   #3
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Also to add to the above, test the set up in the area you're going to be taking the shots at, if possible, so you can see the results and be able to adjust for the conditions.

Don't forget to change the white balance for the type of lighting you'll be using.
05-04-2011, 07:49 AM   #4
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QuoteOriginally posted by Digitalis Quote
I never use AV mode when working with flash
So what mode do you use? How do you set your aperture to control DOF?

QuoteOriginally posted by Digitalis Quote
You are using more than one flash I recommend you use a ratio of 3:1 with your key light being in a prominent position and the auxiliary light being positioned to fill the shadows that the main light casts.
Any idea how to do that with the Sigma 610? The manual is not very helpful in understanding that. How do I know what power setting to use?

QuoteOriginally posted by Digitalis Quote
Using a hair light to add specular highlights to the subject's hair is a popular technique with this kind of portraiture.
I only have two flashes available, so was hoping that bouncing the fill flash beside the camera would help with that. Any other suggestions?

QuoteOriginally posted by Digitalis Quote
Lens selection will be critical for achieving shallow DOF effects.
I plan to use my Tamron 28-75/2.8. I have a variety of manual focus prime lenses, but I'd rather stick with this one for quick operation - the kids aren't going to be into waiting around much.

QuoteOriginally posted by chalion Quote
Don't forget to change the white balance for the type of lighting you'll be using.
Good reminder. I use RAW+ just to be on the safe side.

05-04-2011, 07:59 AM   #5
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QuoteOriginally posted by klh Quote
So what mode do you use? How do you set your aperture to control DOF?
I use manual for working with flash, it gives you all the control you need over aperture and shutter speed. If you need to overexpose/underexpose you simply change your aperture value and keep the shutter speed constant.

QuoteOriginally posted by klh Quote
ny idea how to do that with the Sigma 610? The manual is not very helpful in understanding that. How do I know what power setting to use?
Flash ratios are very important in portraiture, a simplified explanation of ratios goes like : 1:1 = equal power to both flashes 1:2 - with secondary flash at a power level one stop lower than the main light and 1:3 - secondary flash a one and a half stops lower than the main flash - 1:3 ratios are considered the ideal ratio for portraiture.

QuoteOriginally posted by klh Quote
I only have two flashes available, so was hoping that bouncing the fill flash beside the camera would help with that. Any other suggestions?
A silver or gold reflector should suit this purpose nicely. There are many ways to make them yourself, along with many different sizes available for purchase in photography stores.

QuoteOriginally posted by klh Quote
I plan to use my Tamron 28-75/2.8
That lens should suit your purposes nicely.

Last edited by Digitalis; 05-04-2011 at 08:05 AM.
05-04-2011, 10:22 AM   #6
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QuoteOriginally posted by Digitalis Quote
I use manual for working with flash, it gives you all the control you need over aperture and shutter speed.
Makes sense. Do you expose for the ambient light in the room?

QuoteOriginally posted by Digitalis Quote
Flash ratios are very important in portraiture, a simplified explanation of ratios goes like : 1:1 = equal power to both flashes 1:2 - with secondary flash at a power level one stop lower than the main light and 1:3 - secondary flash a one and a half stops lower than the main flash - 1:3 ratios are considered the ideal ratio for portraiture.
OK, I understand that. Now how do I do that on the flash itself? And what settings on the camera do I need to adjust? Sorry, but I'm really confused about what settings to adjust. How do I decide what power level to use in manual?

QuoteOriginally posted by Digitalis Quote
A silver or gold reflector should suit this purpose nicely. There are many ways to make them yourself, along with many different sizes available for purchase in photography stores.
Got one of those (use it for outdoors photos a lot). I can have someone hold it above and behind the couple.
05-04-2011, 02:09 PM   #7
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If it were me, I would setup ahead of time, get a test subject, and shoot. Make setting adjustments as needed until you get a good exposure. You have controlled lighting, so the settings shouldn't change.

To vary exposure you have several options:
1) ISO (but you probably want this at 100 in controlled lighting)
2) F-stop (you probably want to fix this based on your DOF requirements, or at least limit to a tight range)
3) Flash power (this is probably what you want to adjust mainly)

I would think a quick and dirty way to find the correct exposure would be to setup a f2.8 and decrease the aperture in steps until you get the correct exposure and then set your fixed aperture and adjust flash power accordingly. Example:

Start on f/2.8. Shoot. Overexposed, f/4. Shoot Overexposed, f/5.6 shoot. just right. Now lets say you want to shoot in f/4. Well, that was 1 stop to wide, so reduce the flash power by 50%. And then recheck.

BTW, I have played with my manual flash a bit, but I am no expert, but this might help you with the thought process. Also, I assume you are shooting at flash-sync speed (tv=180) and not taking ambient light into play. That might change the equation slightly.
05-05-2011, 02:11 AM   #8
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Don't be a hero. If you're not sure about it....use the ttl option on the flashes and shoot manual on the camera. It what its there for. check out this guys book or even his blog for some basics.
http://neilvn.com/tangents/

or...go to the strobist blog for some 101 on manual shooting. its not that hard. either way....set your sync speed to 1/180th FIRST and go from there. Want less ambient....start knocking down the shutter speed. ideally 1-2 stops below proper exposure then add light to taste. For flash, esp TTL you don't need to keep your ISO at 100. NvN uses 1200 all the time and his results are incredible....of course, it depends on the scene. I'm just trying to reinforce that 100 isn't a set number in flash photography.

05-05-2011, 05:13 AM   #9
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To continue what Digitalis had been said..

QuoteOriginally posted by klh Quote
Makes sense. Do you expose for the ambient light in the room?
I prefer ambient at 1 or 2 f-stops darker than the flash. I use to measure the ambient using the green button, then stop down 1-2 stops. Then adjust the power (and distance) of flashes. You also have iso to go, start with 400.

I also prefer 50mm or 70mm for couple portraits, half body or less. That implies enough space to shoot. You may need 10 feet from subject to background to have them blurred. Assume indoor, depends on subject's hair dark or light, I may switch on an indirect lamp for dark hair in background.

Your lens, f4 or f5.6, at 50mm or 70mm, flash power 1/4 and 1/16 would be ok. Reflection on white wall/door = reduce power 1/3-1/4. shutter speed = ambient then 1 or 2 stops less.

Regarding location in the house: I use to place the couple close to the door opening that I can use the other room to have enough space to shoot, and blurred background. White door blades=reflection - useful if you don't have umbrellas or reflector on location.

Flash gel = important to blend in ambient light.

Sigma flashes are not known for user interface. I have 2x 530 super.
- If you have radio triggers: Dial your flash to Manual mode, use Set button and [+]/[-] to set the power.
- If not, use the wireless build-in and use your pop-up on K20 to trigg these sigmas. K20 has an option to turn off your pop-up flash - not completely off - but that will reduce interference of the popup greatly. This case use wireless slave mode, and adjust flash EV directly for each.

Anyhow, you may need to testrun the setup. Stick to it when you have the settings.

and good luck.

Last edited by hoanpham; 05-05-2011 at 06:51 AM.
05-05-2011, 05:15 AM   #10
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klh,
practice, experiment, try it, decide, practice, practice, practice. Time is short, get busy!!!

Just to complicate matters, remember that the power of the flash on the subject(s) is also proportional to the distance between the flash and the subjects.

The main flash, shooting through an umbrella, JUST outside the frame of the picture, on FULL power.
The second flash near the camera bouncing off of the white ceiling at half power (adjust as necessary to fill shadows lightly).
The reflector held high and angled down somewhat, behind the subjects and to the side opposite the main light to bounce it down onto the subjects hair. (think straight line from main light, through subjects, and to reflector. again JUST outside the frame of the picture)
Forget the ambient light unless there is a lot of it.
Use X sync speed, flash white balance, keep your F stop open as much as possible (think minimum for sharpness) and adjust your ISO to control overall exposure.

P.S. Keep us informed of how it goes. Post a few pictures after your done. Write up what went right and what went wrong so we can all learn.

Please remember that I am not a pro and haven't got a clue about this, but this is where I would start from. Get busy and get ready. Prom shots are SUPER important to the girls and the parents (and some of the guys).
05-05-2011, 06:32 AM   #11
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QuoteOriginally posted by hoanpham Quote
K20 has an option to turn off your pop-up flash - not completely off - but that will reduce interference of the popup greatly.
Some good tips there hoanpham, but the above statement is not correct. With the pop-up set to Controller mode, it does not add to the exposure. I tested this by taking photos where the popup flash was visible as a reflection in my TV. In Controller mode the pop-up did not fire at all during the exposure. This was with a K20D, but I'm confident that's how it works on all wireless models.
05-05-2011, 06:49 AM   #12
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QuoteOriginally posted by audiobomber Quote
With the pop-up set to Controller mode, it does not add to the exposure
By default, the popup set to 'on'. So you will need to turn it off. Popup flash will then use as control unit. This option did save me when battery in the radio transmitter/reciever depleted.
05-05-2011, 10:57 AM   #13
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QuoteOriginally posted by hoanpham Quote
By default, the popup set to 'on'. So you will need to turn it off. Popup flash will then use as control unit. This option did save me when battery in the radio transmitter/reciever depleted.
Just to be sure, does this work with the flash in Manual mode (instead of PTTL mode)? I've actually been practicing with one Sigma mounted, but will try tonight with both as wireless slaves and using the onboard as the master.
05-05-2011, 11:06 AM   #14
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QuoteOriginally posted by calicojack Quote
practice, experiment, try it, decide, practice, practice, practice. Time is short, get busy!!!
Yep! I've been practicing every night this week. I'm starting to feel pretty comfortable, but still a bit overwhelmed by the options. I just wish the Sigma manual was more thorough in its explanation of all the features. The last time I thought much about flash it was with a bulb on my Brownie, and the only choices were none, clear, or blue.

QuoteOriginally posted by hoanpham Quote
Regarding location in the house: I use to place the couple close to the door opening that I can use the other room to have enough space to shoot, and blurred background. White door blades=reflection - useful if you don't have umbrellas or reflector on location.
Great ideas! Thanks.

QuoteOriginally posted by Deiberson Quote
If you're not sure about it....use the ttl option on the flashes and shoot manual on the camera.
That's my backup plan at this point. I do notice that the PTTL setting tends to give a lot of variability.

QuoteOriginally posted by hoanpham Quote
I prefer ambient at 1 or 2 f-stops darker than the flash.
QuoteOriginally posted by calicojack Quote
The main flash, shooting through an umbrella, JUST outside the frame of the picture, on FULL power.
The second flash near the camera bouncing off of the white ceiling at half power (adjust as necessary to fill shadows lightly).
The reflector held high and angled down somewhat, behind the subjects and to the side opposite the main light to bounce it down onto the subjects hair. (think straight line from main light, through subjects, and to reflector. again JUST outside the frame of the picture)
Forget the ambient light unless there is a lot of it.
Basically here's my plan at this point. Meter for ambient at f/5.6, then reduce about 2 stops in shutter. In practice that's been 1/180 or 1/120. Set up the main flash behind an umbrella at 45 degrees to the couple about six feet away on opposite side of ambient (window). Set fill flash next to camera (or on camera - haven't decided yet) eight to ten feet away and bounce off ceiling. Both flashes have a CTO gel attached (photos will be taken around 6-7PM). Have someone hold reflector above and behind couple opposite main flash for hair. Start with main at full power, fill at half, then adjust as necessary based on test shots. I will take both full body shots and half shots.

Any other suggestions?

Last edited by klh; 05-05-2011 at 11:21 AM.
05-05-2011, 01:25 PM   #15
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QuoteOriginally posted by klh Quote
Any other suggestions?
I would just say to be done with all of your experimenting and/or testing well before it's actually time to take the photos. Be set and confident in your method so you can concentrate on the moment and their poses.
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