Manual WB idea

[Bob Ross]

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Manual WB requires a white/gray card or an Expo Disk/Pringle Lid and if you have a sqare lens hood using an Expo Disk is inconvenient and slow. It occured to me that something like a pop-up flash diffuser that I use might work, so I put it on an took a picture. Now, this is untested and I will test it against the Expo-Disk and suspect that I have to go searching for better material. Those with color meters will have the advantage here. It is made from a split translucent lab squeeze bottle and when not in use stores around the camera strap. The original idea as a flash diffuser is not mine and the credit goes to a KateRK on DPR forums. Given the price and convenience potential it may be worth it for those who manually WB, be it for JPEG or DNG.

Bob

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[dhoelscher]

Very cool idea, Bob! Thanks very much for posting.

 

The weird problem that I had (with firmware 1.092) with manual white balancing the camera (using an ExpoDisc) was that when I photographed a WhiBal card in the same light right after manual WB - then brought the image into any of my Raw converters and used the WB tool to click on the image of the WhiBal - the image WB changed significantly.

 

Because of that experience, I now don't bother at all with manual WB - I just set "daylight" manually for daylight (etc.), and shoot a grey card at the beginning, and whenever I change lenses or the light changes significantly (unless of course I want a sunset to look warm for example) ...

 

I haven't yet had a chance to redo all my WB testing with firmware 1.102, so I don't know if it's any different.

 

YMMV

 

DH

[Jamie Roberts]

Hey David--

 

What you're reporting is exactly what I see too with the WhiBal. Which is why I now only use the new neutral expodisc.

 

In all honesty, I find the WhiBal way too warm most of the time. I have one of the very first ones made, but it's too warm on the Canons and the DMR and the M8 to be neutral.

 

I also don't usually want to balance for multiple lights, usually only for the key light. If I am in truly mixed light I'll take an expodisc shot off a reflector (eg white paper). That still gets me closer than the WhiBal.

 

Just IMO (and shock--I've been using a WhiBal for years now).

 

@ Bob--huh? The large Expodisc (77mm maybe?) works really quickly with both the square and round lens hoods. It doesn't need to fit all that accurately to give an excellent white balance. So buy the largest one you need and use it on your smaller lenses too. Way faster than sliding a bottle over the hood, though the price difference is enormous

[Bob Ross]

@ Bob--huh? The large Expodisc (77mm maybe?) works really quickly with both the square and round lens hoods. It doesn't need to fit all that accurately to give an excellent white balance. So buy the largest one you need and use it on your smaller lenses too. Way faster than sliding a bottle over the hood, though the price difference is enormous

Hi Jamie,

My Expo/disc is a 55mm from back when they were first on the market and I used it for incident light readings. It works as you describe, but is a bit inconvenient without a third hand. I am wondering if the curved bottle would not be as specific with mixed lighting. I also think some of the less translucent bottle plastics might be better, so I am eyeing various pill bottles. Something to do in my spare time....

Bob

[Bob Ross]

Very cool idea, Bob! Thanks very much for posting.

 

The weird problem that I had (with firmware 1.092) with manual white balancing the camera (using an ExpoDisc) was that when I photographed a WhiBal card in the same light right after manual WB - then brought the image into any of my Raw converters and used the WB tool to click on the image of the WhiBal - the image WB changed significantly.

 

Because of that experience, I now don't bother at all with manual WB - I just set "daylight" manually for daylight (etc.), and shoot a grey card at the beginning, and whenever I change lenses or the light changes significantly (unless of course I want a sunset to look warm for example) ...

 

DH

Hi David,

My first experience with a DNG>C1>AWB was so far off that I wondered what I had gotten into with the M8. At that point I hadn't noticed the Kelvin readout, being new to C1. I tend to do like you do and use daylight, but getting closer to the actual balance can be useful, where accurate colors are important.

The warm look seems appropriate for Texas...LOL

Bob

[gennfiks]

Hi Bob, the idea of a diffuser is pretty good, but a word of caution: We don't know how the plastic "treats" the visible light spectrum. In order for it to be used as a WB reference it has to be wavelenght independent. We really don't know whether it is the case, and surely it is not. If you take different plastic bottle it could look a bit blueish or a bit warmer than the one you are using, and that's exactely the effect of wavelength dependence. WhiBal is proved to treat all the colors equally, but the plastic bottle not, at least not yet. The WhiBal should be wavelenght independent as a reflector, the diffuser - as a transmitter.

 

Cheers,

Gennady

[Bob Ross]

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Hi Bob, the idea of a diffuser is pretty good, but a word of caution: We don't know how the plastic "treats" the visible light spectrum. In order for it to be used as a WB reference it has to be wavelenght independent. We really don't know whether it is the case, and surely it is not. If you take different plastic bottle it could look a bit blueish or a bit warmer than the one you are using, and that's exactely the effect of wavelength dependence. WhiBal is proved to treat all the colors equally, but the plastic bottle not, at least not yet. The WhiBal should be wavelenght independent as a reflector, the diffuser - as a transmitter.

 

Cheers,

Gennady

Hi Gennady,

You are 100% correct and finding a plastic that is accurate may be futile and some plastics yellow or discolor over time as well. You have also put into words what I have wanted to say to some comments about the Pringle lid substitue. On the other hand, if I can find a readily available, inexpensive product material, it could be good when I don't have my Expo/Disc handy.

Bob

[hammam]

Manual WB requires a white/gray card or an Expo Disk/Pringle Lid and if you have a sqare lens hood using an Expo Disk is inconvenient and slow. It occured to me that something like a pop-up flash diffuser that I use might work, so I put it on an took a picture. Now, this is untested and I will test it against the Expo-Disk and suspect that I have to go searching for better material. Those with color meters will have the advantage here. It is made from a split translucent lab squeeze bottle and when not in use stores around the camera strap. The original idea as a flash diffuser is not mine and the credit goes to a KateRK on DPR forums. Given the price and convenience potential it may be worth it for those who manually WB, be it for JPEG or DNG.

Bob

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Thanks for the tip, Bob. Since I almost always shoot DNG (like most M8 users, I guess), I finally realized that guesstimating the color temperature is almost as good as any preset WB the M8 offers, and that's what I find myself doing more and more. At least in «normal» conditions. It just takes a little longer than choosing a preset, but certainly much less long than doing a manual WB.

[divory]

Do you really have to WB for Raw files? I can understand the need where jpegs are concerned, but surely the point of Raw is that you can adjust the colour temperature later as you can almost everything else.

[gennfiks]

Sure you can adjust color T in RAW processing, as well as in Jpeg if you want to, but what you need is a reference, something that you can say is neutral (R=G=. That reference is a WhiBal, Expodisc, etc.

 

Gennady