Tips for D200 manual WB with Magic Filter?

I intend to use a Magic Filter whilst snorkelling with a fisheye zoom (for the first time). Going by the MF instructions, manual white balance is the recommended method. However, playing around with the camera and fisheye lens I'm having trouble getting a good reading. Assuming I'm using center weighted or matrix metering, how would you all recommend doing this? I guess I'll be taking a white slate with me to use but will it need to be virtually full frame to get a decent reading? And if not, will the WB be affected by the area that's not covered by the slate? Anyone been in this situation and can comment - am I better ignoring the manual WB advice in this case - I certainly wont be adverse to the idea as I'll likely be more interested in composition than messing around getting a good reading and missing the action. Similarly, I'd rather be shooting aperture priority so spot metering and shooting manual, if that helped, wouldn't be a preferred method.

Any advice appreciated.

Andy

I was going to post the same question. I tried in vain on my trip to the Galapagos to get a good read. I ended up picking tungsten or fluorescent, which was pretty close.

Hi Andy

i was reading an article in issue 38 of UWP magazine all about white balance and filters yesterday it would be worth you reading it

you can download it from

www.uwpmag.com

written by alex mustard and peter rowlands , who make/sell magic filters (i think)

its worth reading the whole mag but this item on Page 52

vinny

First of all try to use RAW, so if all else fails you can recover your WB later.

When I have had problems with manual WB it is usually down to not getting a good enough exposure (I.E underexposing the WB shot). If it is easy on your camera try taking the WB shot on Auto then flipping back to a manual exposure (if that is where you want to be).

As for the subject to WB on the back of your bare hand works pretty good, it does not need to fill the entire frame just get as much as is practical - if you want to use a slate then that also works well.

Keep at it, as it is well worth getting it 'right'.

Paul C

P.S Alex and Peter do make the Magic filter.

Hi Andy,

I believe that setting white balance underwater is an important part of shooting with filters. It is not essential because it can be done in RAW afterwards, but without it, you don't see which images are really working and which are not and therefore don't hone your techniques or really work the best photo opportunities.

If you are planning to use the filter while snorkelling then you probably only need to set the WB once and most of the time you will be at the same depth. If you are snorkelling near the seabed/rock etc then this is easy. If you are snorkelling in the blue (looking for big creatures) this is more of a challenge. If it is the later than you may want to use a grey card (you could borrow mine, considering you don't live far from me). Even if you use the grey card, you probably only want to set WB once. It is best to do this straight away before the subjects show up by diving down two or three metres or so.

On the D200 you can store at least 5 manual WB - so you could always save a few in camera for reference - done by diving to different depth.

The article referenced above has much more info on the details of setting WB.

Alex

Alex,

What temperature range usually works in raw processing for general blue water diving?

It depends entirely on how deep you are.

But I can give some examples if it helps, with numbers in terms of Colour Temp and Tint from a Raw Converter. All these images are taken with the Magic Filter. This image, for example, from the Wetpixel column in Sport Diver Magazine has the following settings:

Temp 5950, Tint +100.

While this shallow wreck shot, had the following settings:

Temp 4300, Tint +26.

Basically the deeper you go and also the further from the subject you are, the more you need to push the Temp and Tint. This wreck shot is one of my deepest filter shots - about 18-20m - below the published depth range we say for our filter:

Temp 10000, Tint + 150

The last two wreck shots are actually from the same dive. The final MF recipe was defined as that which gave use the wide depth range of operation, while stilll maintaining high image quality and not introducing too much noise. When designing the MF I tried many different combinations of CT (warming filters) and CC filters (both red and magenta) - the three constituents filters for the MF - until the best combination was found for real world shooting with a digital camera.

The resulting recipe is then made for us not far from where Andy H and I live in Hampshire! Combining the three ingredients in one gel is important as stacking three gels together does degrade image quality (and it is at least three times more fiddly than using one gel!).

Hope that this helps.

Alex

I've been very lazy and used Matrix metering and Shutter Priority with -1 exposure compensation when snorkelling with a Magic Filter. Manual White Balance works against the bottom if there isn't too much shade or colour contrast, but the camera doesn't see things the same way as the eye, and I've been surprised by what works and what doesn't. Manual White Balance fails when the sun goes in, it seems, and the camera has to be in focus (I have trouble with the simple things, sometimes).

Maldives, D200/10.5mm/Magic Filter/Nexus small dome, and I admit to cropping

Tim

B)

Thanks all.

I will be shooting raw and for the reasons Alex mentioned in his post so not want to leave it to later correction in PS. I'm downloading the latest UWP now so that's extremely convenient.

Alex, thanks for the offer of the loan of your grey card. Will a manual WB from a white slate make much difference i.e. will the reflectivity affect anything? I need to do some testing later with my slate and non waterproof grey card I think.

I'd also better read up on saving WB settings......

Andy:

I gave up on using Aperture Priority because it's very easy to get low shutter speeds and unwanted blurring if you don't keep an eagle eye on the meter. Since the filters like a lot of light, and shots with low illumination aren't very colourful, I found that the good shots had a decent depth of field, anyway.

1/60, f6

1/60, f11

RAW conversion of filtered images seems, to me, to be even more dependent on having a good image to start with than in strobe or unfiltered ambient light photography.

Tim

B)

Thanks for the advice Tim. I was thinking of going with Shutter priority for that reason and maybe shooting ISO 200 or 400 for an extra stop or two. Quite looking forward to trying it out now. thanks to all of the responses I have a far better idea of how I want to approach it - which always helps.

Andy