DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   Under Water, Over Land (https://www.dvinfo.net/forum/under-water-over-land/)
-   -   White balance (https://www.dvinfo.net/forum/under-water-over-land/98459-white-balance.html)

Brendan Marnell July 8th, 2007 03:30 PM

White balance
 
Going back over clips of bird flight I notice that whenever I shoot with sky as background, especially bright grey sky, the bird remains in silhouette, showing no plumage detail or colour except perfect shape in black. Once the bird flies below the horizon plumage detail is revealed again. Sometimes, when the sky is blue and the sun is also shining on the bird the plumage detail and colour contrast can be quite good, even above the horizon.

Operating my XM2 (GL2) on auto I have never practised the use of white balance but I think it might be useful in this situation. But the XM2 Manual only advises the use of "Outdoor Mode" for close-ups and when the subject is of one dominant colour, otherwise it advises the auto setting.

Perhaps this problem is sort of inevitable and there's nothing white balance can do about it ...

Any advice please?

Kevin Railsback July 8th, 2007 03:39 PM

That's all exposure. Has nothing to do with white balance.

The only thing white balance will do is give the proper colors for the light you're shooting in.

Brendan Marnell July 8th, 2007 03:55 PM

Thanks Kevin. Now where's the section on exposure in my Manual ?? Oh, isn't this the AE Shift trick ? About which I know nothing ...

... Manual says, Levels are from -2 to +2 and the higher the setting the brighter the image. Does that mean that if I raise AE by +2 it will help counteract the brightness of the sky and accentuate the colours on the bird's plumage?

Kevin Railsback July 8th, 2007 04:38 PM

Yeah, AE shift you can use to overexpose or underexpose what the camera wants to do in auto mode.

The problem is that to likely expose the bird you blow out the sky.

Try shooting when the sun is low on the horizon and over your shoulder. You stand a better chance of getting a better exposure.

John M. McCloskey July 9th, 2007 07:21 AM

Put the sun at your back, that way your lens is facing away from the sun and the sun is lighting your subject,(the bird). Also a polarizer can be a huge help in that situation. Run your exposure manually and set it to your subject not the background also trust your viewfinder.

Yeo Wee Han July 9th, 2007 09:01 AM

John,

Why would a polarizer be useful when you are shooting opposite the direction of the sun? It has always been to my knowledge that there will be no effect at that level and the effect itself is maximized if we shoot at 90 deg to the sun. i.e aim at zenith if the sun is low on the horizon.

Cheers

WeeHan

John M. McCloskey July 9th, 2007 02:13 PM

Brenden has a GL2 which gathers light very good which makes the use of a polarizer in bright light effective, If he were shooting a HDV camera which is many stops slower than a DV or Mini DV a polarizer would be unusable. The polarizer zoomed in all the way on birds in flight lowers the bright backlight to where you can bump your iris up much more to bring the darker bird into better exposure. If you are shooting mid zoom to wide, a polarizer is not going to help since more than half of your frame is filled with sky, bird will be a sillouette no way around it. If you can get most of the sky out of your frame the polarizer will subtle the brights and allow you to bump iris up a good bit to lighten the bird up. Do it all the time and it works fairly well, in bright light,9:00 am to 3:00 pm.

Dale Guthormsen July 9th, 2007 10:33 PM

Brendan,

There are good points in the aforementioned.

for shooting in the sky I think it is important to manually white balance/

I was shooting commerants today with almost all sky background. In auto at first the sky was bleached or burnt out, more a grey instead of a subtle blue. I manual white balanced and it made the sky color better!! This also made the picture appear less of a silloutte.
Now, i did the shot with a the polizer as well as without out it. In General I totally agree with john's opinion!! At least with my gl2.

Also for shooting flying birds and such the better the depth of field you have the better your chances of having things in focus.

I totally avoid shooting toward the sun, that will always give you a sillioutte, unless of course that is the effect you want!!

Also, there is a reason early morning, evening and overcast days are most peopels favorite times to shoot!!

Yeo Wee Han July 10th, 2007 04:50 AM

Quote:

Originally Posted by John M. McCloskey (Post 709335)
Brenden has a GL2 which gathers light very good which makes the use of a polarizer in bright light effective, If he were shooting a HDV camera which is many stops slower than a DV or Mini DV a polarizer would be unusable. The polarizer zoomed in all the way on birds in flight lowers the bright backlight to where you can bump your iris up much more to bring the darker bird into better exposure. If you are shooting mid zoom to wide, a polarizer is not going to help since more than half of your frame is filled with sky, bird will be a sillouette no way around it. If you can get most of the sky out of your frame the polarizer will subtle the brights and allow you to bump iris up a good bit to lighten the bird up. Do it all the time and it works fairly well, in bright light,9:00 am to 3:00 pm.

John,

Have you tried this method before? In all my years of nature photography, I have not heard of this theory. The reason being the polarizer will lower the exposure of the entire scene (including the bird) by 1.5 to 2.5 stops and bringing back the exposure for the bird will also bring back light to the sky. The direction from where the sun is shining at will affect the usage of the polarizer and not the focal length of your lens....Although using too wide a lens will result in uneven polarization (that has to be with the Canon HD 6X or with a WA converter though).

What im trying to say is the polarizer does not help with contrast ratios. Its not a ND grad or softening or contrast-lowering filter.

Maybe im missing something?

Cheers.

WeeHan

John M. McCloskey July 10th, 2007 07:16 AM

I totally understand what you are saying but what I am saying is my subject is the bird flying, not the sky around the bird. My total interest is capturing the bird as well as I can. Now if you are trying to capture a realistic portait of what your eye is seeing you are involving all surrounding subjects along with the bird. A polarizer and many other filters are very helpful in picking a subject among many and keying in on it and making it something more vivid than what you eye sees, I call it shooting subjects not scenics. I always shoot wide scenics of areas then go in an pick many subjects within that scenic and use more of a EFP approach than an ENG approach. Filters, bounce boards, what ever it takes to make the subject vivid, then in post take the wide scenics and color correct as good as possible to make the tight subjects pop when intercut with the wides. Also drop in filters work much better than screwons.

Yeo Wee Han July 10th, 2007 09:08 AM

Sorry John, still not getting it here. The sky is overexposed while the subject is properly exposed. This either calls for more light on the subject so that I can bring down the overall exposure which makes the sky properly exposed....or shoot with a higher dynamic range medium. If I use a polarizer, I lower the overall exposure and bringing up the 2 stops by opening up the iris DOES NOT reduce the contrast ratio between the whites of the bird and the sky.

The polarizer just does not work at all angles....and when you are talking about drop-in filters, I presume you are talking about those for telephoto still lenses? I have never seen a difference between them and the screwons.

Cheers

WeeHan

Brendan Marnell July 10th, 2007 03:51 PM

1 Attachment(s)
This may help to identify my problem ....

.... here is one frame (from a clip) showing that even without flight to distract me I am not doing something I should be doing to show a bit of detail on the birds ... the cliff is 150 yards away and I'm at x20 on XM2 (GL2) on a tripod. Isn't two-thirds of this frame made up of solid greys? what am I failing to do to counteract the brightness of the sky? The sun is well clouded over and it's mid-afternoon facing approx. south in April in Spain ... I have done no editing at all in post ...

Yeo Wee Han July 10th, 2007 04:13 PM

Brendan,

The range from shadow to highlight is just too great for any sensor to handle. As the birds are at the very top of the cliff, there is not much a ND grad can do even though you may try using a 2 or 3 stop soft-grad to bring down the brightness of the sky. The jagged rock formations will however rule that out.

The only way I can think off at this time is to shoot when the sun is lower in the sky and with it behind you.

Cheers

WeeHan

Brendan Marnell July 10th, 2007 04:36 PM

1 Attachment(s)
I believe you WeeHan and thank you for explaining the difficulty ... here's another unedited frame, shot handheld from the same location within same half-hour ... please take a minute to describe why so much detail can be seen on this bird ... you are good at describing images, if you can find the time ?? And what settings would you try out to improve this sort of shot?

Kevin Railsback July 10th, 2007 04:49 PM

The 2nd one looks like you're shooting against the cliffs or a hill of some sort which is much, much darker than the sky. That's why you have detail on the bird because the background and the bird are closer together as far as exposure goes. Whereas the sky is dozens of times brighter than the bird and you're camera can't handle the range of both.


All times are GMT -6. The time now is 01:14 PM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2024 The Digital Video Information Network