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Old Jan 29, 2006, 4:21 PM   #11
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Sorry - I sent twice.
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Old Jan 29, 2006, 4:30 PM   #12
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Dear John,

Cool, how often does one get to write a Dear John letter?:-)

I'm curious what you mean by "constant" and "lights that cycle"? I.E. fluorescent lights flicker or cycle that's why they come in pairs, while one is 'off' the other is 'on'.

But what I don't understand is why you say the white balance won't work? I would think that as long as the light is on long enough to make an exposure on a white or grey card then the custom white balance should work. Is there some science/technical thing going on that I'm not aware of? There is no explanation in my instruction book as to when it won't work, even in the often technical footnotes.

My understanding is that when a camera company uses the word "constant" light it means it won't work with electronic flash. That applies to light meters but as far as I know, not the WB function in my camera. The custom WB is not reading the light under which I'm shooting it's evaulating an exposure I've made on a white or grey card.

The one thing that strikes me about the Barbarians photo is that it's very green and yellow. It's not even close to being correctly balanced, therefore I think a Custom WB (under even the most mixed lighting) would get him very close to normal coloration.

I just have to giggle at how aptly he describes how "greenish" one shoulder is while the other is "pinkish". I can't see it, which doesn't mean it's not there, because the entire color balance is soooooo far off. Get the green and yellow out first, then tell me you see some pink. Besides, unless you're the Jolly Green Giant, a pink skin tone is much preferable to a green one.:G

Africa
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Old Jan 30, 2006, 6:46 AM   #13
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Africa,

Let's say the light in question cycles at 120 per second. Now as that light cycles and you take a 5 shot burst, the color temperature of the light is going to change depending on where in the 'cycle' it is - there are a dozen different possible combinations of light temperature. Now, with the florescent tubes like you mention this is not so much of an issue - but I believe that is because they cycle faster. Better lights will cycle at say 3000 istead of 120 which means a more constant, uniform light. But with other bulb types it is definitely an issue. Not being a light expert unfortunately I can't tell you what type of lights will do this and what types wont. Maybe try a google and see what you find. The gymnastics meet I photographed a few weeks ago provided a perfect example. I set a custom WB, took a couple of test pics and everything was looking great. Then I shot a few bursts and you could see the dramatic change in WB from shot to shot within the burst. I'll have to see if I still have any of those shots - they were just test shots during warmups and I likely deleted them. If not, I'll be going back this upcoming Saturday and I'll take a series with a custom WB to illustrate the point.


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Old Jan 31, 2006, 1:24 AM   #14
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John,

Let's take your example of shooting a five-burst sequence, let me guarantee you and anyone reading this post that the number of burst makes NO differenct in light temperature or exposure as it pertains to a light cycling - NONE. What will make a difference is the shutter speed being used, whether it's a single shot or five.

If the light cycles at 120 cycles per second (cps) then when you shoot above 1/125 of a second there is chance you will be taking a picture between cycles and could get a poor exposure. BTW most fluorsecent lights cycle at 60 cps, per bulb, faster than the human eye can distinguish. So when a pair of FL lights are on they are "flickering" at 120 CPS. However like almost every light we use, FL's glow when in the off cycle. The glow is created by the white phospor that coates the inside of the bulb, or in tungsten bulbs by the filament which glows even when not charged - that's why we don't get bad exposures - the cylcling light is actually constant, - a fast on-off cycle with a glow in between, equals a CONSTANT light.

In addition to that a gym has multiple lights whose light-spead crosses over into the path of adjoining lights. It's not as thought each light is a laser beam whose spread is so narow it would light only one spot on the floor.

While the color temperature of a light could change as it powers up and down (flickers) every light in a gym would have to be cycling at exactly the same time and same rate. If this was a real problem I think we would have postings every day wonderng what is going on. Televsion would never go live because they would be consatntly getting color shifts and flickering - this just doesn't happen.

So as far as photgraphy is concerned, tungsten theater lights, the light bulbs in your house, fluorescent lights in corporate headquarters and libraries are all CONASANT light sources and light meters and custom white balance can read them with the consistancy and accuracy we need to take great photographs.

Africa

I'll be looking forward to your next shoot and corresponding posts to see the color shift you have encountered. Please do me a favor, point the camera skyward and take a picture of the lights. Also let me know what all your camera settings are: ISO, SS, f-stop and exposure mode (M, S, A, P or M Tv, Av, P). I'll bet we can figure out what's going on.

From a high school game this past season: Canon 20D, Sigma 70=200mm - ISO 3200, SS 400, f-3.2.
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Old Jan 31, 2006, 6:42 AM   #15
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Africa,

I'll be glad to post some pics. Take a look at any forum where pro sports shooters hang out - like Fred Miranda Sports Corner or even places like DPREVIEW which have more sportsshooter representation than we do here and you'll find this is a known and accepted issue. Again, I'm not going to argue the technical reasons because I admit, I'm not an expert on how lights work. I merely state that I've encountered the situation personally and accept the explanation I've received from professional shooters with considerable experience in different venues. I did check and I don't have any of the shots with manual WB and a seriessaved. So, I'll have to take a series this weekend. I'll post the results so you can see what I'm talking about.

As to what my EXIF info was - I can already tell you, I shot Manual mode, 1/320 @ f2.8 ISO 3200

By the way nice pic - not sure what it has to do with Basketball though
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Old Jan 31, 2006, 11:58 PM   #16
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You wrote that you perfer the "explantion I've received from professional shooters with considerable experience in different venues." Allow me a response to the velvet glove I felt on my cheek upon reading that.

I believe your post has been edited since I read it earlier today at work. I distinctly remember a sentence that effectively said, "Africa I think you'll have to admit you're wrong on this one." Now that's gone? Wha' happen'?" That was my inspiration for my diatribe!!! You've taken the wind out of my sail. Oh well, read on if you like.

You suggested ‘googling' to find out about this flickering problem. I took your advice, what more do you want? It's where I read about flickering and how it is NOT a problem for all the reason I put in my previous responce.
Now I will admit I only read five sources but they were getting repetitive. I'll be going back to check out some more because I'm curious and I really want to know if this is a problem but until then I have to, based on experience, education and my "professional" references assume flickering is NOT the problem.

Here are my three "professional" sources.

1. The first has a MS (that's Master of SCIENCE) degree from the Brooks Institute of Photography. He was the first photog in El Paso, Texas to shoot digital. That was more than 15 years ago when EACH picture required him to make three different exposures with a primary colored filter over the lens. This guy knows digital and he knows lighting. He's the "tech weenie" I go to when I can't figure out something or just don't know. He's been commercial photographer since 1988 and unversity Instructor since 1999. I'll admit I'm always impressd with someone that has a master of science degree.
Professional enough for you?

2. The other guy got a BA degree in photojournalism, then spent eight years as photojournalist working on four different newspapers before returning to school to work on his MA (Master of Arts) where he studied visual communication. While shooting for those newspapers he also freelanced for Associated Press and United Press International and won three AP photo awards. He was a corporate photog for three years then began teaching at the University of Texas at El Paso for eight years. He is currently teaching PT and on the university photo staff PT. He began his photography education/experience in 1978 and has been a photog or teacher since then. He's the type of guy you see on Fred's web site, a working photojournalist.
Professional enough for you?

3. The last guy is in charge of the lighting and sound for the 52,000 seat Sun Bowl and 12,000 seat Haskins center at UTEP. He doesn't have an university degree but has had to learn on the job (more than 20 years) to end up being the man in charge of the entire operation at UTEP.
Professional enough for you?

So my answer is a combination of info I got from each of those four sources.
It doesn't mean I've got the definitive answer, I'm open to finding THE truth, but until I get THE answer I, like you, have to work (take pictures) with what I DO KNOW.

BTW. I went to Fred Miranda's site and after checking back five pages of posts I had only covered 24 hours, so that's going to take awhile. If you have specific listings I can check out to make my search easier let me know. I'll also search DP Review. I'm curious to see who posts those problems and how they came to the conclusions they did.

Africa

I know the picture I posted was out of context but a couple of guys prodded me about wanting to see my stuff to go along with the confident/arrogant answers I've posted. Since then I decided to include a picture with every post I make.

Oh, I almost forgot, my second "professional" source is ME, so if you want to check my credentials...:|
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Old Feb 1, 2006, 6:44 AM   #17
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Now, let's not get so defensive here. As for my comment about 'professional' - I believe you mentioned you had only recently been offered a job at your college after doing freelance work for them. So, I assumed - maybe eroneously you didn't have years or decades of sports shooting experience. This is not a pi$$ing match and I don't want it to become one. I merely state that I have experienced a certain phenomenon and it coincides with my research on other forums with more sports shooter participation and experience that this is a problem with the lights cycling. I took it at face value. As I know how to set a custom WB and have used it in gyms and buildings before - when I see a big temp shift from frame to frame and I'm shooting in manual I feel confident it's not a set-up mistake. I'm open to other explanations for what causes it. But, I am certainly not the only one to have found it.

Here is one link, and one of the posters has a nice time-lapse affect showing the color shift:

http://www.fredmiranda.com/forum/topic/341635/0#2902557

Anotherwhere Scott Sewell, the moderator of the Sports Corner mentions this affect:

http://www.fredmiranda.com/forum/topic/341377/0#2900207

And yet another thread discussing it:

http://www.fredmiranda.com/forum/top...3473/0#1577986

Again this isn't a contest. I've seen these people's work so I trust their wisdom. Just like I trust people's wisdom here who have demonstrated knowledge and experience. Yours may, in time, become a trusted source for me as well. Again these guys could all be wrong and you could be right (which is why I removed that comment). But since my own experiences coincide with their explanaition I'm inclined to believe them over your assertion that such a thing is not possible. If you'd like to continue the discussion, please PM me so we don't waste everyone elses time. Otherwise let's get back to the business of posting pictures and helping each other become better sports shooters.
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Old Feb 1, 2006, 8:32 AM   #18
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Nicely stated John.

I come here to learn, to solicit ideas and opinions and apply advice to my situation. Ultimately, I, like every other person I know, will use a mix of advice and experience and devise a standard that works for them.

Some people offer advice based on their experience. It doesnt make them right or wrong, it makes them someone who offered a solution that worked for them. It may or may not work for someone else in a different setting. Even when someone makes a post that says "try this" and I think when I read it "wow, thats way out there" I do at least try it. Even if it doesnt work, I learned someting.

Photography is very subjective. What one person sees as a terrific shot, another sees as mediocre. I take pictures that ultimately are pleasing to me. I want to capture that moment in time and be able to look at it later and say to myself, "that looks nice" Nothing more, nothing less.

I learn and sharpen my skills by visiting forums such as this and reading everything I can, asking questions and taking what I have learned and applying it. That is the essence of this forum. It isnt about who is right and who is wrong or having the need to prove your position.

I respect the both of you immensly but I agree with John, lets get back to what this is really all about .....
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Old Feb 7, 2006, 7:24 AM   #19
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For what it's worth, I've found "sweet spots" on that floor, where color is much better. Apparently the different lighting balances out there somehow. There are other places that are horrible. Changing the WB doesn't seem to help much.

Not being a professional, I'll now leave the clearing, and let the elephants fight.


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Old Feb 7, 2006, 7:28 AM   #20
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Barbarian - very sesible solution. Improvise, adapt, overcome


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