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Author Topic: How do you choose the right flash?  (Read 9882 times)

gibbsphoto

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How do you choose the right flash?
« Reply #20 on: September 12, 2007, 12:45:23 pm »

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Thanks, DiaAzul.

I think I want to stay mobile and only use one flash.

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You may also want to have a look at:

[a href=\"http://www.onelightworkshop.com/OneLight/Welcome.html]http://www.onelightworkshop.com/OneLight/Welcome.html[/url]

Joe
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Hank

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How do you choose the right flash?
« Reply #21 on: September 12, 2007, 01:00:55 pm »

"As to the post-processing time, I knew that was going to be an issue, and bid that into the job. There was no way around dealing with multiple light sources with wildly varying color temps; even filtering all the lights in the restaurant somehow (which was out of the question budgetwise and schedulewise) would have still left me with 3 disparate color temps of light to deal with. If you can't bill what you need to make the job worthwhile, you have no business being in business as a photographer."

My point exactly.
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Jonathan Wienke

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How do you choose the right flash?
« Reply #22 on: September 12, 2007, 03:18:16 pm »

If you have only one kind of ambient light, (tungsten, fluorescent, or whatever) then gelling the flash is an easy way to avoid lots of post-processing work. But if you're shooting in a room with mixed fluorescent and tungsten and sunlight, manually blending multiple developments of a RAW with different WB settings is your only option, unless you can avoid the whole mess by converting to B&W. Each approach as its advantages and disadvantages. The multiproccess/manual blend technique will work in any combination of lighting, but requires a lot of post work. Flash gel requires minimal or no extra post work but is not usable in mixed ambient lighting. So you need to know both, and when to use (and charge for) each.
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The View

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How do you choose the right flash?
« Reply #23 on: September 12, 2007, 07:00:41 pm »

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Yes the 283 is smaller than the 285

I dont like the 285 cos the zoom head kind of flops about

I AM NOT SURE THE 283 IS SAFE TO USE ON A DIGICAM

(...)

you really just need something that light comes out of with an auto setting and a few manual poer levels

strobist also mentions nikon sb28 they have manual and auto mode and full diectional movement

but they dont work on my blad - dont know about pentax

(...)

FYI I actually use a sb28 on my nikons, quatum q flashes for off camera work,  and a metz54  on my blad

I also have a few 283 that I use off camera with pocket wizards taped to the side

I did have a time of using a Quantum Qflash on the side of my camera mounted on a Metz bracket - latterly fired by pocket wizards - I could slip it off the bracket and hand it to someone for fast off camera work

This is proably the ultimate walkaround flash - but very heavy and I needed to donor a Metz45 to get the Qflash to attach to the Metz bracket

My second Qflash is now bust so it will be back to the 283 and wizard as a secondary flash for a while - those things are sturdy

----

In terms of colour temp set your camera on cloudy take a shot - look a the scene and you can get an idea of the colour temp of the light you are under - no $900

I think there was a product 'stofen omnibounce' that was available in different colours tungsten and flouro

I am still not conviced you cant make acceptable changes in post unless you have very specialised requirements YOU MUST SHOOT RAW

Say a tungsten scene with a flashed foreground just kind of looks funky

I have never seen a pro with colour over thier flash exept a slight warming gell in softboxes (shooting tranny) or when shooting for wild effects

If you are inexperienced with flash you will learn a lot with just using direct flash for a while and conquering those horrible shadows by longer shutter times that fill the shadow or picing backgrounds like sutably distant where you wont get a shadow - like the sky

www.DG28.com also has some tutorials

S
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Thank you. Your advice is great and very helpful.

PS: the strobist warns against all Vivtar 283 and 285, except the 285HV (both old and new - sells new for 90$)
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The View

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How do you choose the right flash?
« Reply #24 on: September 12, 2007, 07:10:10 pm »

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A single RAW exposure is sufficient, all you have to do is process it once for each light source. So if you're mixing flash and tungsten, develop the RAW once with WB set for the tuingsten-lit areas, and again with WB set for flash-lit areas. Paste the flash-WB as a new layer on top of the tungsten-WB, make a layer mask, and airbrush the layer mask to blend to taste. I used this technique on this exterior where there were 5 light sources with different color temps:



You have:
1. Incandescent light inside the restaurant upstairs. (warm)
2. Fluorescent light inside downstairs. (green)
3. Sodium vapor streetlights. (magenta-brown)
4. Tiki torches on the patio. (very warm)
5. After-dusk sky light. (very cool)

So I developed the RAW 5 times, each with WB set for a particular light source, and then stacked the exposures in a 5-layer PSD file. I used the sky layer as background, since it had the greatest area of correct color. Then I used the brush tool to paint in other layers as needed where the color was wrong. I spent some time on this image in post, but everything you see came from 1 RAW.
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And regarding going around the need of a color temperature meter:

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I make my own, using this technique:

1. Shoot a neutral object (WhiBal card, Color Checker, etc) with no flash in the ambient lighting condition you're trying to match. Use RAW mode.

2. Shoot the same neutral reference with flash-only lighting, ISO 100, f/16, X-sync shutter speed. Use RAW again.

3. Open both RAWs in ACR. Do a click white balance on your neutral reference in the flash-only shot. Write down the white balance settings you get as a result.

4. Open the ambient-only shot and give it the same white balance temperature/tint settings as the flash-only shot. It should take on a yellow or orange color cast if the light you're trying to match is sunlight or incandescent, or a greenish cast if you're trying to match fluorescent. Click the Open button to bring the image into Photoshop.

5. Apply a 5-pixel Gaussian blur to the image, and then click on the neutral reference with the eyedropper to sample its color. Double-click the color to edit it, and change the L value in the LAB section to 95. You now have the exact color you need to make your flash gel.

6. Change the canvas size to 8x10 inches and 100DPI, and then fill the image with the color from step 5. Print the resulting document on a transparency, and you have a gel sheet that will exactly match your flash color temp to the ambient lighting encountered in step 1.

You can use this technique to match any flash to any ambient lighting, or match one flash to another flash with different color characteristics.
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This are very interesting techniques.

Technique nr.2 looks more suitable for a studio shoot,  except when you have time to work on a laptop on location, and not too many setups. An event photographer or a real life photographer would possibly not have the time to do all those steps.

I also have to check if I can use this for on location headshot and portrait work.

But it all shows there is a lot of fascinating things to do with flashes, and cause all kinds of surreal   effects.

One thing I wonder is how many photographers actually use a color temperature meter.
« Last Edit: September 12, 2007, 07:21:24 pm by The View »
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Jonathan Wienke

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How do you choose the right flash?
« Reply #25 on: September 13, 2007, 07:09:17 am »

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Technique nr.2 looks more suitable for a studio shoot,  except when you have time to work on a laptop on location, and not too many setups. An event photographer or a real life photographer would possibly not have the time to do all those steps.

An approach that works well is to scout the location before the shoot, and take an ambient light reference shot for each type of ambient light you encounter. Then you can go back and make the gels you need for that location. But once you have gels for incandescent and fluorescent lighting, you'll often find that gels you already have work just fine. Incandescent doesn't usually vary much from place to place, and there are maybe 3 common flavors of fluorescent lights. Throw in gels for mercury vapor and sodium vapor streetlights, and you have about half a dozen gels that cover the majority of lighting you'll encounter even if you can't make a true custom gel.

In studio the main reason to use gels (other than for deliberate colored lighting effects) is to match 2 different brands of strobes together. For example, I made gels for my Canon 550EX and 420EX flashes to color match them to my Alien Bee studio strobes. This comes in handy if you want to use them together.
« Last Edit: September 13, 2007, 07:21:01 am by Jonathan Wienke »
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