Custom White Balance without a Gray Card

This article assumes that the reader is familiar with:

- Concept of White Balance (WB)
- Concept of how camera reads color temperature.
- Usage of cameras built in white balance settings

This entry describes my experiments with in-built white balance settings and custom white balance setting. So here we go…

I have read in various articles that a photographer should always select white balance depending on the subject lighting to get the best results.

All digital cameras (consumer and professional range) have the option to select from multiple white balance modes depending on the lighting of subject.

Daylight, Cloudy, Sunny, Flash, Florescent, Tungsten are some of the options available. These presets work well for most of scene types. However, there are some situations where automatic and preset white balance would not yield natural colors. So what’s the solution? Read on….

One option available in the advance segments – high end compacts and DSLR’s is the selection of “Custom WB” instead of the preset options.

I use a Canon 350D/Rebel XT Digital SLR and it has the option to select “Custom WB”.

The most common method is to use a “Grey Card” and use it to set the Custom WB. Basically you take a picture of the Grey card at the same angle as falling on the subject and get a correct exposure. Then set that image as the base for custom white balance and take the shot.

My problem: I do not have a Grey card.
Possible Solutions: 1) Use a pure white paper instead of a grey card or 2) Use the front of my hand (palm) instead of a Grey card.

The second option was worth exploring as there would be many places where I may not be having Grey card or white paper handy when shooting.

I experimented with the second option and took a shot of my palm in similar lighting conditions in a shaded area of my room and here are the results:

Experiment #1: Single Subject – Single Color

Shot #1: WB – Auto

Shot #2: WB - Shade

Shot #3: WB - Cloudy

Shot #4: WB - Flash (-2EV)

Shot #5: WB - Custom

Experiment # 2: Multiple Subjects – 3 Prominent Colors

Shot #1: WB – Auto

Shot #2: WB – Custom

Conclusion:

Experiment #1
WB Auto and Presets did not work well when I had only grapes in the scene. The color of grapes was pale and washed out. High degree of yellow cast was seen in the result. The custom WB worked very well here – I got rich and accurate reproduction of colors seen by eyes.

Experiment #2
WB Auto and Custom WB, both did very well here. The results from Auto WB and Custom WB were comparable. The addition of colors in the scene contributed to camera selecting accurate WB automatically.

Conclusion:
Use custom WB when one color dominates the scene – snow, sky, diamonds, gold, a model dressed in a red garment etc…..

It is safe to rely on Auto WB when you have multiple colors in the scene and camera has the chance to set the auto WB by judging other areas of scene as well.

There are other situations when you would want to try custom WB like multiple light source and many more which is not covered by the experiment in this post.

Bookeh results from Canon 50mm 1.8

The 50mm prime lens is one of the best prime lens available today and most of the lens manufacturers have this on offering. Canon provides three flavors for the 50mm:

50mm f/1.0 50mm f/1.4 50mm f/1.8

I have the 50mm f/1.8 which in terms of the price is the cheapest. However, it is no cheap performer. The results are quite impressive and professional.

The major difference in all the three variants is the lens construction and not the speed as some of us may feel. 50mm f/1.0 is less than 0ne stop faster than 1/8 and around half stop faster than f/1.2, but costs way more than the other two lenses. Apart from photographers who shoot in severe low light conditions, f/1.0 would not have many takers.

One major difference worth noting down here is that 50mm f/1.8 has 5 blade diaphragm versus the 8 blades of 50mm f/1.0 and therefore it is way cheaper than the f/1.0.

The effect for which you will be shelling out almost a 1500+ USD is called the "Bookeh". It is the soft blur of out of focus areas in the picture.

I wanted to see how good or bad the 50mm f/1.8 gets. It was Christmas time and I wanted to check how this lens captures the out of focus Christmas lights. So here is what I did....

1) Set the lens to MF and intentionally made it totally out of focus for the Christmas lights
2) Camera to Manual Mode
3) Set the Tv / Shutter Speed to 1/10s
4) Set the Av / Aperture to f/1.8, f/2.0, f/2.2, f/2.8 and took shots of the Christmas lights from the same place (distance to subject is constant)


Here are the observations:

Experiment 1: Subject to Camera Distance Fixed with Av changing


f/1.8
The out of focus Christmas lights / bookeh was rendered as perfect circles. I was not able to make out the 5 diaphragm blades. This is as good as it gets with the more expensive 50mm f/1.0. The results are comparable.

f/2.0

Here we start to see the shape of diaphragm slightly.

f/2.2 - f/2.8

The shape is very obvious and instead of a circle we see a 5 sided blur shape.



Experiment 2: Subject to Camera Distance changing with Av fixed

I had expected that as the subject to camera distance increases, the lights will gradually come in focus. I tried upto a 15 feet from the subject and all I got was the lights getting even more blurred and dull.




@ 4 Feet

@15 Feet

Experiment 3: Custom bookeh shape

I learnt about this method on the DIYPhotography.net site. This needs a fast lens which can open up to a minimum of f/1.8. Custom cutout was made in star shape and placed infront of the lens. The results were very nice with ample scope of experiments.



Consulsion:

50mm f1.8 provides a very good bookeh for the price you pay for it. It is sharp as it gets and worth every penny you spend.

Happy clickin ;-)