1. First I had noticed that the green of trees and grass sometimes appears a bit yellow when shooting with default settings – that includes using Auto White Balance. So I studied the various color settings that are available in the FX7, and came up with a proposed picture profile tweak in Part 1 – Improving the color green with custom Picture Profiles.
2. Then I tested different picture profiles with AWB in Part 2 – Tweaking Auto White Balance. This showed that picture profiles like WB Shift -1 / Color Level +1 do improve the color green a bit with a color balance closer to neutral. As a side tip, I also showed how a Gray Scale can help equalize colors between shots in adverse conditions. But in the end, it appeared that picture profile tweaks are no match for the wild behavior of Auto White Balance, which can cause random yellow casts to various extents – sometimes slight, sometimes quite severe – and a nightmare when trying to match colors in post. A better, repeatable solution was needed.
3. How about Manual White Balance? Part 3 – Unreliable Manual White Balance showed that it also causes random red casts, and therefore cannot be trusted. Too bad for such a costly, sophisticated, 3-sensor camcorder.
4. Part 4 – Testing the OUTDOOR White Balance preset finally showed that the OUTDOOR WB preset is the best candidate for securing faithful colors and a neutral outdoors color balance.
5. On to a real-life test in the countryside: Part 5 – Comparison of OUTDOOR preset vs. Auto White Balance demonstrates the superiority of OUTDOOR WB over Auto WB. I also show that changing the ‘AWB SENS’ menu setting from the default ‘Intelligent’ to the value ‘Low’ seems to improve AWB behavior by reducing yellow color cast when that happens.
6. And for anyone who would need further convincing, Part 6 – More AWB yellow evil examples!

Many thanks to klenkfilm and 2mnyHCs of Sony HDV Info .com who gave this OUTDOOR preset tip and warned against using AWB (thread: FX7 and white balance: what is your opinion?). After all, AWB did a fair job on the HDR-HC3, and choosing a fixed preset instead seemed to go against the very nature of outdoors shooting where the color of light always seems to change ever so subtly. So why try to outsmart the machine’s auto program in the first place, that’s what I had first thought!

Anyway, whatever the cause of this AWB behavior, whatever the reason for that wicked ‘AWB SENS’ feature, there’s now a simple solution for best colors when shooting outdoors.

So here is my final complete recommendation for shooting outdoors with the HDR-FX7E (custom picture profile and other settings):

• Regarding colors: OUTDOOR WB preset, WB Shift -1, Color Level +1. Maybe also set ‘AWB SENS’ to ‘Low’ in case you would still need an emergency temporary switch to AWB.
• Regarding sharpness: Sharpness 6, ‘AT IRIS LMT’ set to f5.6 while trying to keep iris around f4 as much as possible, and avoid full zoom-out (keep a slight zoom-in instead).

End of this quest, summer is vacation time – everybody move out there and record great memories!

Here comes an illustrated demonstration of the superiority of OUTDOOR WB over Auto WB.

First test: the unpredicable yellow cast from AWB

The first series of frame grabs shows the typical situation when AWB goes awry: on the right is AWB with the 4 possible values for the ‘AWB SENS‘ menu setting; on the left is Outdoor WB preset (repeated 4 times to facilitate the comparison).

For some reason, the colors appear a bit dull here once converted to JPEG stills (colorspace issues maybe?), compared to viewing on the TV or in EDIUS where the yellow cast is significantly stronger. Anyway the conclusions are already quite obvious:

• Outdoor WB shows deep greens, slightly cold maybe due to WB Shift -1, but basically in line with the colors one should expect in early spring.
• AWB with ‘AWB SENS’ set to ‘Intelligent’ or ‘High’ shows a strong yellow cast instead, which decreases every step of the way when changing ‘AWB SENS’ to ‘Middle’ or to ‘Low’. The difference with Outdoor WB is much more obvious with ‘Intelligent’ or ‘High’, than with ‘Low’.

Second test: accurate colors (for no reason)

The second series of frame grabs was taken shortly after the first one. Here again is a comparison between Outdoor WB and Auto WB, with saturation (Color Level) increased to +3 to outline color differences even more. But now instead it is nearly impossible to spot any difference between Outdoor WB and AWB!

Final recommendations for shooting outdoors

So this final outdoors test brings some very important confirmations and conclusions:

• Auto WB is unpredictable and can cause random color casts. The color cast can change any minute or even disappear, which will cause an intense nightmare in post and unbearable workload when trying to edit and match colors between shots.
• Outdoor WB is much more predictable, much more likely to produce repeatable results and stable, neutral colors.
• If you should keep using AWB despite the severe danger to picture quality and to your satisfaction, at least don’t leave ‘AWB SENS‘ to the default ‘Intelligent’ value; set it to ‘Low’ which seems to cause lower impact.

This last point is interesting in light of what Sony writes in the FX7 Operating Guide (quote):

[AWB SENS] is not effective under a clear sky or the sun.

Haha, it does seem quite effective instead in causing that random yellow cast!

I’ll take that with a little bit of humor, because the one WB feature that was brought by the FX7 and did not previously exist (e.g. in the HC3) is apparently the one that rampaged and ruined random parts of the footage I took during my trip to Rome. More examples in my next, final post about colors when shooting outdoors with the FX7.

The bottom-line is:

• Setting a Picture Profile with WB Shift -1 and Color Level +1 or even -2/+1 gives much nicer colors.
• Using a 3-step gray card also seems a quick and handy way to help secure the capture of consistent, reliable colors. However further caution and adjustments may be necessary because – a surprising observation – aiming at fully neutral white would be incorrect, yielding a noticeable overall yellow cast whereas the consumer’s eye instead seems to prefer some measure of blue in the color white.
• In the end however, AWB turns out to be too unpredictable on the HDR-FX7 and a big No-No unless you’re ready to spend considerable time color-correcting in post.

Equipment and tools for this test:

• Sony HDR-FX7E camcorder,
• X-Rite ColorChecker Gray Scale (3-step, mini or full size),
• EDIUS Pro with vectorscope and 3-way White Balance correction tool,
• Sony Bravia KDL-40X2000 Full HD LCD TV,
• Eizo FlexScan M1950 monitor,
• X-Rite Eye One Display 2 monitor calibrator and profiler.

Testing HDR-FX7 color settings with Auto White Balance

Here is the same scene with different settings for WB Shift and Color Level, and two frame grabs for each scene (with or without the 3-step gray card in front of the lens). This way I can present the vectorscope output for the whole image or for the gray target area alone. I also get a subjective impression by viewing the images both on the high-end Bravia or on my computer monitor (fully calibrated and profiled) with the colorspace-aware EDIUS Pro.

Here are my observations:

• With WB Shift 0 / Color Level 0, the image has a yellow cast and the stone floor appears reddish. However the neutral gray scale is slightly on the blue side already – that’s a surprise.
• Iterating through these values makes the image every step a bit bluer.
• With WB Shift -1 / Color Level +1, the image is more neutral and better in line with my recollection; the stone is close to neutral gray, the grass is a bit greener (although it is too early in the season to have nice vegetation here).
• But then, WB Shift -2 / Color Level +1 is really nice too.
• The grass is greenest with WB Shift -2 / Color Level +2, but here the image is getting too blue overall.

Now, it seems that the objective of improving the color green has been met here. I can’t really make up my mind between -1/+1 and -2/+1, I’d wish for something in-between. I’ll probably choose -2/+1 but more practice should tell, especially under sunlight…

One could oppose that the neutral gray target isn’t really neutral and introduces some color bias. But it is manufactured and sold for this very purpose – being neutral – and I tried with 2 different targets (mini size and full size) with similar results.

Securing predictable colors with an X-Rite ColorChecker Gray Scale

On to another test now, specifically focused on how the gray scale can help secure color balance:

• Hereafter, column A recaps the original raw images from the HDR-FX7E, for the 4 sets of values.
• Then for each scene, I applied the 3-way White Balance correction tool to the 3-step color target, to determine automatic color correction across the full luminance range. As a result, all pictures with different WB settings were corrected to a similar look & feel (column B). I won’t provide individual vectorscope screenshots here, but after correction each of them for the color target alone shows a perfectly centered position (i.e. color-neutral). So the 3-step color target seems quite effective in capturing a reference and bringing the image consistently back in line with that reference.
• However for a consumer’s taste, this looks even more yellowish than the camera’s default WB 0 CL 0, so this requires additional color correction towards the blue – by a fixed amount regardless of camera settings. In column C, I applied the exact same reverse correction to all four of them, to bring them all back to a look similar to WB Shift -2 / Color Level +1.

This is all a bit cumbersome all right, but it is apparently reliable and reproducible. That’s the point! In adverse conditions, a quick shot with the gray scale should bring some peace of mind, much appreciated when later you’ve left the field location and are facing the computer. It only takes a couple of seconds to show the mini gray scale in front of the lens to capture a reference shot, and it fits into a shirt pocket with a nice protection sleeve so you can conveniently carry it with you. The only, very important constraint is, the color target must be receiving the same incident light as the subject you’ll be shooting.

For future reference and use, here are the color corrections values in EDIUS:

An additional thought: this white reference anomaly (yielding a yellowish image) is really odd, but after all, it is a known fact that white copy paper, or white T-shirts, or even white cloth detergent, have some dose of blue dye to make them look ‘more white’ – see Optical brightener or Bluing. Maybe we’re culturally inclined towards whites that are ‘whiter than white’ – heck, why not.

Beware of the unpredictable colors of Auto White Balance

Finally, here are a few different shots under sunlight (raw frame grabs), with AWB / WB Shift 0 / Color Level 0.

The obvious observation is that the yellow-reddish cast is different in every shot, sometimes quite severe, and therefore these shots will require different corrections to give pleasant colors. Indeed, this is the nature of Auto White Balance: it can be off by various measures – a nightmare when editing because you just can’t apply similar correction across the whole footage, it’s specific work per segment.

But why is it so unpredictable on the HDR-FX7?!? Could it be due to the ‘Intelligent AWB Sensitivity’ feature (AWB SENS)?

So this calls for another test (and another blog post): using fixed white balance (instead of auto), either with the OUTDOORS preset or setting WB manually with a white card.

So I investigated the color settings that are available within custom Picture Profiles, with the purpose of fixing the color green – or as some might say, making green closer to consumerish tastes.

I took the following approach:

1. Make practical tests with the color settings,
2. Make a theory of how the color settings would roughly equate to geometrical transformations in the color space,
3. Use the geometrical approach to determine methods that would make greens greener,
4. Simulate the settings with NLE color corrections,
5. Come up with a proposed recommendation which is based on combined WB Shift and Color Level, so as to build a custom Picture Profile.

Practical tests

I shot the same target (green and red folders / binders on a white wall cast with strong incandescent yellowish light), adjusting various color settings on the FX7. Pay close attention to how the green dot moves on the vectorscope…

Fig.1: screenshots of the vectorscope for White Balance Shift = -7/0/+7, Color Phase = -7/0/+7, Color Level = +2.

Fig.2: screenshots of the vectorscope for Color Level = 0/+2/+7, WB Shift and Color Phase = 0.

Interpretation of color settings

Then I put together, on the same picture using 50% transparency, the vectorscope screenshots for the extreme values of each setting. The purpose is to show how the image moves on the vectorscope as you change the values for each color setting. This way it appears that:

• WB Shift behaves roughly like some vector translation, i.e. the whole vectorscope shifts,
• Color Phase (hue) behaves like some rotation, i.e. the whole vectorcope rotates,
• Color Level (saturation) behaves like a scalar multiplication, i.e. the whole vectorscope expands or contracts.

Fig.3: geometrical interpretation of color settings.

Proposed methods to improve greens

Using the geometrical approach, I therefore determine that I want to try & make greens greener with 2 different methods:

1. WB Shift the whole image away from yellow, then use Color Level to put the reds and saturated yellows right back where they were in the first place, so that only the greens and blues steer away from yellow.
2. Or rotate the image towards the greens (Color Phase) while WB Shifting the whole image away from yellow beforehand, to avoid getting greenish yellows.

Simulations through color correction

Here are the simulations that I did with the color correction tools in EDIUS (White Balance and Color Wheel):

• WB Shift combined with Color Level give the best results: greener green, bluer sky, less yellow cast on the whole image while keeping the red building about right.
• WB Shift combined with Color Phase produce the greenest grass (so the geometrical approach did meet its objective), but at the expense of making the building unpleasantly greenish.

Note – you need a carefully calibrated monitor to see the differences in colors.

Fig.4: simulations.

Conclusion and proposed custom Picture Profile

Therefore, to achieve better greens with the FX7 and less yellow cast, I would recommend to decrease White Balance Shift and increase Color Level.

By how much do we want to do that, are WB Shift -1 and Color Level +1 enough? Next part will address this question through practical tests.