fredmiranda.com
Login

Moderated by: Fred Miranda
  New fredmiranda.com Mobile Site
  New Feature: SMS Notification alert
  New Feature: Buy & Sell Watchlist
  

FM Forums | Lighting & Studio Techniques | Join Upload & Sell

  

Archive 2006 · Flash Color Temp Variations

  
 
pwcphoto
Offline
• • •
Upload & Sell: Off
p.1 #1 · Flash Color Temp Variations


I was shooting some high key portraits in the studio today and noticed that there was a pink tint to all of the images. Previously I had shot with a Fuji S1 Pro and have just upgraded to the D200, this is only the second time I have used it so still getting familiar with it.

I had the D200 set to the flash color temp setting, for this session so it was constant. With the Fuji I had set it to daylight as it didn't have a flash setting for color temperature and it gave pretty accurate colors.

To try and figure out what was going on I used my Minolta colormeter and started measuring the various flash heads. Man there were pretty much all over the place. some were 4400k others were almost 6000k. This I attributed to the fact that they were set to different power settings. So I ran a few tests to confirm this.

The flash equipment is Speedotron Blackline the pack is a 4803 and the head tested was a 102 with a new bulb. I realize that this is old stuff but that will be part of my question.

I first plugged the head into one of the 800 ws connectors and set the power level to 0 which is full power, I triggered the flash with the color meter 1 foot away from the head and allowed 10 seconds for the flash to recover which should pretty much give it 100% charge each time. I set the power level to -1 -2 and -3 and measured each color and watched the color shift as the power went down. I then moved the head to the 2400 ws connector and went through the same procedure and plotted the color temp. Below are my recordings and the variance.

800 Watt Seconds
0 6070K
-1 5900K
-2 5770K
-3 5640K

2400 Watt Seconds
0 6320K
-1 6020K
-2 5930K
-3 5790K

My question is, do the newer strobe systems control color temperature more closely or do they vary as the power level changes? How do you folks handle the color temp change while shooting, do you compensate with CC filters on the heads as you lower the power keeping a chart so you know how much to add or subtract to bring it to some standardized color? Or do you all just wing it and try to adjust it in Photoshop after the fact? If this was transparency film it would really be a mess although a few hundred K may not show there is almost 700 k difference between the high and low, not to mention differences between other heads which have their own color temp range.

Any one else taken the time to look into this or measure their stuff?

Phil



Aug 07, 2006 at 01:01 AM
mmurph
Offline
• • • •
Upload & Sell: On
p.1 #2 · Flash Color Temp Variations



Phil,

That was a big problem when digital first came along. Your numbers match some of the figures I saw quoted by Broncolor in 2002 or so, about a 100 degree variation per stop.

That was one of the big "selling points" for Broncolor and then Profoto around that time. They go to all kinds of lengths to ensure consistent color temperature, especially on their high end packs.

That is also one reason why some quality monolights were limited to a 3 stop adjustment range. Of course it is easy to put in a "pot" to allow you to reduce the power more, but at what cost in color temperature stability?

I'll try to find a link to some of those articles, one was from the old PEI - Photo Elecectronic Imaging - magazine.

That said, others have reported more consistent results from their testing of low end systems. There was one detailed test posted in the Lighting forum at the old RobGalbraith about 1 year ago that had color meter tests of a bunch of lights at different power settings.

I'll try to do some searches for these things when I get a chance.

Best,
Michael



Aug 07, 2006 at 01:04 PM
shatterkiss
Offline
• • • •
Upload & Sell: Off
p.1 #3 · Flash Color Temp Variations


I think Michael's totally right, and color consistency has been a big selling point for Bron, Profoto and Elinchrom gear. I've noticed a bit of a warming trend when cranking down my Dynalite stuff, but not as dramatically as when I owned Photogenic monolights. And I barely notice it at all with the Profoto rental equipment I'll sometimes use.

As for how I deal with it: once my lighting is pretty much set, I shoot off a couple frames of my model holding a black/white/grey card in front of her. If it's a portrait subject, I'll just prop the card up or have an assistant hold it or clip it to a stand. When I go to batch-process the RAW files I'll just do a quickie eyedropper white-balance selection on the card, then season to taste from there. I'm often not looking for "correct" white balance, as opposed to one that gives the look I want, so I haven't had to be much more stringent about it than that.



Aug 07, 2006 at 01:27 PM
mmurph
Offline
• • • •
Upload & Sell: On
p.1 #4 · Flash Color Temp Variations



Here is the PEI article, from 2001. Interesting reading, if a bit dated:

http://www.peimag.com/pdf/pei01/pei1201/sholikpei1201.pdf

Best,
Michael



Aug 07, 2006 at 01:34 PM
RDKirk
Offline
• • • • •
Upload & Sell: Off
p.1 #5 · Flash Color Temp Variations


Unless it's one of the models specifically advertised as color constant, don't expect it. My use is pretty much like Simon's.


Aug 07, 2006 at 08:58 PM
pwcphoto
Offline
• • •
Upload & Sell: Off
p.1 #6 · Flash Color Temp Variations


Thanks for the info guys. I suspected this was a problem with older equipment. Guess it is finally time to upgrade to something a bit newer and better.

I am really curious how the newer units keep the color constant if the power is varied, or is it they vary the duration and keep the power the same. Will have to check into this and see who does what.

Thanks again for the info.

Phil



Aug 07, 2006 at 11:00 PM
RDKirk
Offline
• • • • •
Upload & Sell: Off
p.1 #7 · Flash Color Temp Variations


pwcphoto wrote:
Thanks for the info guys. I suspected this was a problem with older equipment. Guess it is finally time to upgrade to something a bit newer and better.

I am really curious how the newer units keep the color constant if the power is varied, or is it they vary the duration and keep the power the same. Will have to check into this and see who does what.



As I said before, if it does not specifically advertise being color consistent, don't count on it, regardless of brand, regardless of date.



Aug 08, 2006 at 08:29 AM
ajmichael
Offline
• • •
Upload & Sell: Off
p.1 #8 · Flash Color Temp Variations


I'm in agreement with Simon. I always white balance on a WhiBal once I've set the lighting for the shoot and use that as the RAW capture white balance in C1 Pro. WIth my Elinchroms I find that the modifiers have a much greater effect on colour temperature than the power level.

Andy




Aug 09, 2006 at 08:03 AM
mmurph
Offline
• • • •
Upload & Sell: On
p.1 #9 · Flash Color Temp Variations


Part 1:

I agree too. I use the WhiteBal to set my color balance.

Because I shoot RAW+JPEG, I also get in close to capture just the WhiteBal. Then I set a custom white balance (I'm using Canon.) That usually gets me pretty good color on the JPEGS out of the camera. Also saves some time in RAW processing.

The problem that drove me to better equipment - from older Speedotron - was the mix of color temperatures in a scene when you have one light cranked up and one turned down! Then you have local color problems, like a hair light with a color cast, which are much harder to edit than global.

Don't overdo it chasing the problem though. As mentioned, softboxes, beauty dishes, etc., also influence temperature. The folks that really have problems are the product and catalog photogs. Personally, I have *way* too much money invested in lighting equipment.


Part 2:

How do they do it? I'm not sure

I know bits and pieces. They use separate capacitors for each channel to isolate the influence between channels. Of course you can still combine channels to get full power.

I don't really know what they do technically. Here is some text from Broncolor that gives some hints. Looks like these things are starting to get firmware updates like the cameras that improve their function!

*********************************************************************************

Within the scope of its ongoing product enhancement drive, the Swiss lighting specialist has announced a new software (Release 20.10) for its Topas A2 and A4 power packs. The new software improves colour temperature control (CTC) and makes both power packs even more suitable for delicate digital work.

Also, the newly developed software provides an additional “Sequence” function that allows the photographer to program up to eight flashes for special effects and multiflash exposures. Moreover, Release 20.10 expands the control range to 6 f-stops with the Topas A2 and to 6.5 f-stops with Topas A4.

****************************************************************************************

All that from new firmware?

Best,
Michael



Aug 09, 2006 at 09:41 AM
pwcphoto
Offline
• • •
Upload & Sell: Off
p.1 #10 · Flash Color Temp Variations


Michael,

Thanks for the info.Time to empty the water bottle full of pennies and see what kind of strobe system I can afford. I have always drooled over Broncolor so I am leaning that way.

I shoot a lot of product stuff so I am running into the problem of localized color shifts which takes extra time in Photoshop so I need to get serious about this stuff I guess.

Any of the folks out there have pointers on a new high end flash systems like Broncolor, Elinchrom, Profoto etc

Thanks again for the input,

Phil



Aug 09, 2006 at 12:27 PM
Verdi
Offline

Upload & Sell: Off
p.1 #11 · Flash Color Temp Variations


pwcphoto wrote:
I shoot a lot of product stuff so I am running into the problem of localized color shifts which takes extra time in Photoshop


Exactly that problem made me do some research. It looks like the following packs are the only ones seriously promising constant colour temperature. Be prepared for a hefty price tag.

Bron Grafit/ Topas (all packs with 'CTC')
Hensel Tria 3000 AS (using the Bron CTC patent)
Profoto D4






Aug 09, 2006 at 03:11 PM
mmurph
Offline
• • • •
Upload & Sell: On
p.1 #12 · Flash Color Temp Variations


Yeah, those localized color shifts can drive you nuts!

I picked up 3 Topas A2's (1600 w/s) used at $1,800 each. I love those packs! Digital display for each channel, dial up or down by .1 stop, 6 stop range, fully asymetrical, with two channels (heads) each.

Two were older, backup packs that a photog had in his studio. One was a Helix demo that had a 2 year warranty. They have counters so that you can see how many pops they have on them, when they were manufactured, what firmware is installed, etc.

I also have some other packs, both current and older (Nano A4 2400 w/s, 2 Pulso 4 3200 w/s, Opus A4 3200 w/s.) It is still great equipment, I use those for specialzed lights, backgrounds, etc.

The Broncolor Pulso heads are fairly expensive, but great heads. They run around $550-$600 used. I got a demo Unilite head, which I like a lot, from Helix for about $600. Smaller and lighter than the Pulso. So the same general ballpark as the Profoto Acute's when used, but they are $950 new.

I also have some Bron Pico and Mobilite heads which are small, cute, and great for location, hair lights, etc. But they require a $200 adapter to use regular reflectors.

The older Primo heads can be decent if they are low use/clean tubes. There is one eBay seller I can warn you about if you go that route, the stuff he is selling came out of rental, so not "pristine."

I would not push Bron, as they are more niche than Profoto, but it is great equipment. They sometimes have great 20%-30% off sales, or else you really need to find good used stuff at 40%-50% off new.

With *any* of the high priced systems, the trick is to figure out which Profoto/Bron/Elinchrom, etc. way overpriced accessories you need, like reflectors, and where you can substitute Mola or Chimera or even Speedotron (grids, etc.)

For example, a set of 3 Broncolor grids for their standard P70 reflector are $318 at B&H!!! Same for Profoto, their regular grids are $85 to $107 each. But I think the Speedotron fit the Profoto perfectly - a used set of 3 Speedotron runs like $25

Good luck, have fun - and post here as you work through what you are going to do, we can save you some $$$ !

Best,
Michael






Aug 09, 2006 at 06:35 PM
pwcphoto
Offline
• • •
Upload & Sell: Off
p.1 #13 · Flash Color Temp Variations


Sheesh, high priced, no kidding! What are these people thinking? They must have developed their price list based on the petroleum industry!

Well I will look around and see what I can find, there are so many different models of packs it will take a bit of research to figure which ones have the features I need or will use. With the old Speedotrons you either had Brownline or Blackline at various wattage ratings, not a lot of options.

I cannot fathom paying between $6000 and $9000 for a pack, I just don't see it.
Maybe I will just keep my old speedos and buy a ton of CC gels and forget it

Will let you know what I am thinking about getting, may have to crack open the piggy bank for this one.

Phil



Aug 09, 2006 at 07:27 PM
mmurph
Offline
• • • •
Upload & Sell: On
p.1 #14 · Flash Color Temp Variations



Look at intermediate options, and used.

Just talked to my dealer today, he said he may be getting some used Grafit A2. Don't know about price.

Profoto Acute would probably be better than what you have too, more moderately priced. Not sure how variable they are though.

Good luck!

Best,
Michael



Aug 11, 2006 at 12:18 PM





FM Forums | Lighting & Studio Techniques | Join Upload & Sell

    
 

Welcome back
Log in to your account