Author Topic: White Balance and Cokin Filters  (Read 5154 times)

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Offline zekewhipper

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White Balance and Cokin Filters
« on: January 09, 2010, 06:58:37 AM »
I am a recent owner of a Minolta Maxxum 7D.  In the course of testing out the camera I have determined that its ability to render accurate colors when shooting in natural daylight is excellent with very little adjustment ever needed.

However, when it comes to shooting under fluorescent lighting it is very "hit or miss" and with tungsten it is not great in my opinion.  This is all of course based on testing done with AWB, Preset WB options, Custom WB experiments, and even manually adjusting the Kelvins.  Therefore, I started to wonder.  What sort of results could I get if I used the Cokin fliters I had that I use for shooting under those lighting conditions with my film SLR's?  Wonder of wonders, I found that I could get more accurate color rendition using them.

To make a long story short, I started out doing the testing with the camera set manually to 5500K.  That is often sited as the default Kelvins measurement for daylight, which of course is what the filters are geared to compensate for when  daylight film is used under the other two types of light source.  (Bear in mind, I am a person who likes "cooler" images more than "warmer" ones.) 

What I discovered (based on the lighting in my home as obviously opposed to that in your's) was that if the Kelvins were set to 4600, and the applicable filter was in place, that I got better color rendition accuracy than if I used the camera's own built-in means for compensation for the given light sourses. 

The 4600 number was the best compromise between the 4900 that seemed best for tungsten and the 4300 that seemed best suited for fluorescent.  (I wanted to find a compromise Kelvins number because I wanted a default setting to use for Register No. 3 which was going to be allocated to indoor non-flash photography.)  (For those who don't understand what a "register" is in this discussion, it refers to a collection of camera settings that can be memorized and recalled in the camera for ease of convenience.  Not all D/SLR's have this option.)

With the filter for tungsten light, I am losing at least 1EV because of its use.  However, since my default ISO setting for this register is 1600, I am not too badly affected.

I am pleased to have discovered that using filters made for film photography may actually make my digital shots better.

Has anyone else experimented in this use of filters too on DSLR's, or seen the same sort of benefits I have by doing this?
« Last Edit: January 09, 2010, 07:03:18 AM by zekewhipper »
DSLR's
Pentax K-5
Olympus E-520
Sony A100

SLR's
Minolta: Maxxum 600si
Zeiss Ikon: Contaflex Super BC

P&S's
Nikon: P7100

lenses: various AF zooms and M42 primes

Offline winjeel

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Re: White Balance and Cokin Filters
« Reply #1 on: January 23, 2010, 08:32:26 AM »
I didn't see this thread until today, sorry for the (very) slow reply. I think the cokin filters for white balance adjustment work very well with film, as film is usually balanced for 5,500k (I think). So, I think you won't get accurate results by sticking on a Cokin (unless perhaps you've set the sensor to 5,500k, but...). If you can get a hold of an on-line manual (via the KM website, I think), you'll find that there's a way to adjust your white balance using nothing more than a white sheet of paper and a test shot. I've tried it a few times on my old camera, but haven't been pleased with the results. The only other option is to use an Expo Disc, if you can't get a sheet of paper to work. I didn't get an Expo Disc, so I can't say how well that works.
JapanesePhotos.Asia; Some basic photographic how to's.
Sony the200, Minolta 28mm 2.8, 50mm 1.4, 70-300mm Gregarious, 100mm 2.8 macro.

Offline zekewhipper

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Re: White Balance and Cokin Filters
« Reply #2 on: January 24, 2010, 04:35:36 AM »
Winjeel: I find that I definately get more accurate results using the old Cokin filters.  The surprising thing is though that on another website another photographer was doing the same thing except he was still using AWB with the filters and getting good results.  I tried it, and found that I too got even more accurate results doing it that way.  My experience with my Maxxum 7D has shown that doing Kelvin adjustments or doing custom WB settings just doesn't cut it.

It was explained to me that: "The WB correcting filter can have a genuine advantage in some extreme situations, e.g. where an individual colour channel would otherwise be boosted several stops from the sensor's native WB (as this would introduce noise similar to underexposing and compensating in post processing, and the noise can cause colour shifting). The filter acts as sort of a selective ND filter, which allows for better exposure for each colour channel."

Now, I have to point out that I am speaking about my Maxxum 7D.  In reviews, it has been repeatedly mentioned that color rendition was generally poor for tungsten and fluorescent lit shots with the 7D.  My wife's A100 seems to deal WB-wise with the aforementioned lighting situations much more accurately than my 7D. Therefore, the use of filters may not be necessary at all with that body or other Alphas. 
DSLR's
Pentax K-5
Olympus E-520
Sony A100

SLR's
Minolta: Maxxum 600si
Zeiss Ikon: Contaflex Super BC

P&S's
Nikon: P7100

lenses: various AF zooms and M42 primes

Offline winjeel

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Re: White Balance and Cokin Filters
« Reply #3 on: January 25, 2010, 09:25:48 AM »
Hmm... I'm not convinced. It'd be interesting to see some comparison shots. I've got a fluorescent filter somewhere. I'll give it a go when I get the chance sometime. However, I'm sure the AWB would be compensating for the colour cast, which it does already, so I'm not sure that there'd be any special advantage over manually selecting Sunny, Cloudy, or custom.
JapanesePhotos.Asia; Some basic photographic how to's.
Sony the200, Minolta 28mm 2.8, 50mm 1.4, 70-300mm Gregarious, 100mm 2.8 macro.

Offline zekewhipper

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Re: White Balance and Cokin Filters
« Reply #4 on: January 25, 2010, 08:36:35 PM »
Winjeel: I'm not trying to convince you.  I don't care if you believe me or not.  I'm just telling you what my experimenting has demonstrated as giving better results IN MY OPINION for my Maxxum 7D.

If you want to see some comparison shots, drop me an e-mail, and I'll send some off to you with explanations as to their settings at the time they were taken.

dandukro@nc.rr.com
DSLR's
Pentax K-5
Olympus E-520
Sony A100

SLR's
Minolta: Maxxum 600si
Zeiss Ikon: Contaflex Super BC

P&S's
Nikon: P7100

lenses: various AF zooms and M42 primes

Offline winjeel

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Re: White Balance and Cokin Filters
« Reply #5 on: January 26, 2010, 07:32:15 AM »
...

It was explained to me that: "The WB correcting filter can have a genuine advantage in some extreme situations, e.g. where an individual colour channel would otherwise be boosted several stops from the sensor's native WB (as this would introduce noise similar to underexposing and compensating in post processing, and the noise can cause colour shifting). The filter acts as sort of a selective ND filter, which allows for better exposure for each colour channel."

...

Ahh... I probably scanned over this bit too quickly. I was also thinking that in most situations you used the wb filter, not in specific situations. It's the scientific sceptic in me that has me relying on other knowledge, like when you're standing with the lens slightly angled to the sun, light from the sun refracts through the filter, which creates sun spots across an image. Having an extra layer of glass reduces the sharpness, albeit by a small margin. It also means you lose one or two f-stops. Also, I assumed the Auto part of AWB would cancel out the presence of the filter in normal situations, which I still expect it would. As for tungsten, I don't know. It would still be interesting to see how it looks, though I don't have any tungsten lights, so I'd have to wait until I find a place that has some.
JapanesePhotos.Asia; Some basic photographic how to's.
Sony the200, Minolta 28mm 2.8, 50mm 1.4, 70-300mm Gregarious, 100mm 2.8 macro.

Offline zekewhipper

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Re: White Balance and Cokin Filters
« Reply #6 on: January 26, 2010, 10:07:02 PM »
No, I don't just put the filters on and leave them on.  They are only used when I am doing indoor ambient light (meaning no flash or studio lighting) photography.

Yes, with the tungsten filter I do lose at least one stop exposure, but since I have no issue with shooting at ISO 1600 or 3200, that is no great loss to me.

Why would you assume the AWB would cancel out the presence of the filter?  One, the AWB doesn't know there is even a filter there (meaning there is no communication between the two).  And two, the filter only affects, in a strong way, a few particular color bands of light and the others are only affected in a very minor way.  Therefore, the AWB is still seeing most of the light as it is coming to it.  The filter just seems do a better job at adjusting color cast than what the camera's computer program can do.  (Remember again, this is on my 7D and under the lighting conditions in my home.)  I have not yet tried this while indoors in the evening in someone else's home.  I may not get the same results.

As for tungsten lighting, don't your home lights use regular old light bulbs?  If they do, there is your tungsten lighting.
DSLR's
Pentax K-5
Olympus E-520
Sony A100

SLR's
Minolta: Maxxum 600si
Zeiss Ikon: Contaflex Super BC

P&S's
Nikon: P7100

lenses: various AF zooms and M42 primes

Offline winjeel

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Re: White Balance and Cokin Filters
« Reply #7 on: January 26, 2010, 11:11:57 PM »
...

As for tungsten lighting, don't your home lights use regular old light bulbs?  If they do, there is your tungsten lighting.

Nope. Japan has got past that quite some time ago. They are still available, but very rare. Otherwise this house, at least, uses only the energy efficient bulbs and fluorescent tubes.
JapanesePhotos.Asia; Some basic photographic how to's.
Sony the200, Minolta 28mm 2.8, 50mm 1.4, 70-300mm Gregarious, 100mm 2.8 macro.

Offline acemclynch

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Re: White Balance and Cokin Filters
« Reply #8 on: January 26, 2010, 11:45:35 PM »
Just tried it with my A900, 80B and on auto WB I'm getting a much nicer shot with a cooler more accurate colour. Nice tip!
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Offline zekewhipper

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Re: White Balance and Cokin Filters
« Reply #9 on: January 27, 2010, 04:17:27 AM »
Winjeel: What filament do your "energy efficent" bulbs use?

Acemclynch: "Just tried it with my A900, 80B and on auto WB I'm getting a much nicer shot with a cooler more accurate colour. Nice tip!"  Yea!  I'm glad to hear that!  It just goes to show I'm not crazy.  :) 

I believe my filter is an 80A, which as I just researched, is the most blue inducing one.  That's good for me, because I tend to think all the digital cameras make everything, especially caucasian faces too red.  I don't like white folks like myself to all look like they have spray-on tans. hahaha I like my photographs "cooler" instead of "warmer", which is the whole reason I have been hammering away at WB with this new DSLR of mine.

As for the use of the tungsten filters like your 80B, (and the ones for fluorescent too), tell all your DSLR buddies to try it if they can, and let me know in this thread what they think.
DSLR's
Pentax K-5
Olympus E-520
Sony A100

SLR's
Minolta: Maxxum 600si
Zeiss Ikon: Contaflex Super BC

P&S's
Nikon: P7100

lenses: various AF zooms and M42 primes

Offline zekewhipper

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Re: White Balance and Cokin Filters
« Reply #10 on: February 13, 2010, 05:53:53 AM »
Winjeel & Acemclynch: Have either of you or your photog pals done any more experimenting with what were discussing here?
DSLR's
Pentax K-5
Olympus E-520
Sony A100

SLR's
Minolta: Maxxum 600si
Zeiss Ikon: Contaflex Super BC

P&S's
Nikon: P7100

lenses: various AF zooms and M42 primes