164 replies to this topic

[Alex_Mustard]

One technique I am starting to explore with digital is shooting without flash, getting colour using a combination of a colour correction (red/magenta) filter on the lens and calibrating my D100's white balance using a grey card.

I have only done 3 dives with this technique - which works best in the top 10m of the water column. And below is an image from each of the dives. I wanted to really put this technique into action on my last trip to the Red Sea - but the fact that my housing spent most of the week in Gatwick (London) scuppered those plans! All are shot with D100 and 16mm, ISO 200 aperture priority, matrix metering (top and bottom EE G. Cayman, middle Sinai, Egypt).

Compositionally these are not that great. The ray and diver is the most pleasing to my eyes. I am interested in whether people think that this is a lighting technique that is worth perservering with? Or are we so used to flash lit pictures that coloured available light doesn't look right?

What the technique does well is is allows me to colour large areas that I couldn't light with on camera strobe. The wreck is the best example of this - with good colour extending away from the camera.

[Arnon_Ayal]

Good shots with pleasant colors.

I have few questions:
- Do you have to calibrate it again on changing the deep you are? (cause the changes of the light)
- Did you tried to calibrate by using white board? If yes what is the different?
- Does it work also without the filters?
- Did you tried to set WB after the dive by using RAW mode? What the difference?

[Alex_Mustard]

Thanks for the response, Alto. Here are some quick answers to your insightful questions:

Q1) Yes - although if you just change the light path a bit you can correct it in Photoshop. On a flat seabed I just did one calib a dive. On a wall or pinnacle I recalibrated for most shots.
Q2) The D100 electronics are set up for a grey card. Other cameras use a White card (e.g. the Coolpix 5000). You can use a white card with the D100, but it means you have to underexpose the white balance calibtration.
Q3) Not well. If the processing has to add too much colour - you quickly get noise.
Q4) I always shoot RAW. The preset white balance (calibrated with the grey card) is always much better than any of the other settings. A good RAW converted (better than Nikon's RAW Plugin) that let you subtly adjust colour temp might overcome the need for the grey card - but would be very time consuming in post processing. The grey card calibration takes about 15 seconds to do in situ - and the pictures look like this straight from the camera.

[craig]

I sure think colored available light looks right! The middle photo looks great. I'm not sure if I've seen it before.

The wreck shot is a testament to the strength of the technique. At best it yields a photo that much more of the character of a land shot. We really have grown comfortable with the limitations of strobe-based uw photography and allow it to define how things should look.

More, more!

[Kasey]

I guess I'm so used to strong color in the foreground, and dull beyond the strobe range, that I find this technique uncomfortable - except for the 1st photo for which I think it works very well in the bright sunlight. I think what I don't like is the tone of the blue - it just isn't right to my eyes. The wreck photo is interesting, but I'm just not sure where my eyes should focus - a well lit foreground subject usually leads my eye. To each his own, I guess :freak:

[Alex_Mustard]

Craig, thanks for the support - I already know that you are a big filter fan.

Kasey, I really appreciate your feedback. I will certainly take your comments on board when I am using this technique in the future. I think this technique needs to be used carefully because the underwater world doesn't look like it usually does in pictures.

I entered the ray in competition at the weekend (BSOUP annual overseas prints) - it didn't win anything - and while some people liked it and told me it was their favourite others criticised it saying I had stuck the diver and ray on in Photoshop. Which I hadn't.

Not sure what to do about the blues. I think part of the reason they are different is that they are shallow and on all the dives the Viz was not wonderful (10-15m)? For comparison here is a flash lit shot of a gang of jacks I also took in the Red Sea (with flash and 17-35mm) on the dive before I did the Anthias reef shot. I think the blues are pretty similar?

[Alex_Mustard]

Thinking about it a bit more. I think the lack of a main subject in the reef and wreck shots are major weaknesses and may not be the best adverts for this technique.

I do think the unpleasing blues may result from the poor Viz.

But on top of this the wreck shot is taken in shallow water (~5m) and I was shooting slightly upwards. In the reef shot which has a more pleasing blue I was able to get a decent blue by shooting down into the water column (where the scattered light has a longer light path and therefore has a much richer blue).
Peter Rowlands took a picture of me while I was taking the Red Sea shot - and his flash lit shot (below) was taken with a more upward camera angle - showing the poor viz on that dive and also how upward camera angles in shallow water shorten the light path and give more greeny backgrounds.

Am I making sense?

[craig]

I entered the ray in competition at the weekend (BSOUP annual overseas prints) - it didn't win anything - and while some people liked it and told me it was their favourite others criticised it saying I had stuck the diver and ray on in Photoshop. Which I hadn't.

That's very discouraging.

I like the blues in the second two. The first looks a little dirty so I expected it was the viz. Otherwise the color looks very natural to me.

I tend to like images with no clear subject and like the wreck shot very much. I also like abstract art totally devoid of imagery and I suspect those go together.

[Arnon_Ayal]

In response to what Kasey wrote: The problem is that usually we use the strobe to illuminate the main close subject and the blue background stay under exposed and more dark then in reality, there is also a lot of times we try to make it dark and deep blue on purpose.
I found the blue color in thus shots very close to reality.

[Rob Esaw]

I am amazed at how realistic the colors are in the shots. One of the most interesting things I get from this is the example of how changing the composition can affect the blue water background. I never knew this tecnique.

After seeing the image of you shooting the reef, I can see your interest in available light photography. The lack of strobes and arms makes your rig look really comfortable, instead of unwieldy.

What filters are you using?? I would like to try this with my Nik5000, but if I put a 46mm filter between my WE-68 and adapter, I think it will screw up my focus???

[Alex_Mustard]

Hi Rob,

The accepted way to shoot wide angle UW is to shoot upwards so you get lots of light into the camera, then stop down and use flash to fill the silhouetted foreground. As Alto states above this allows us to control the background exposure with the shutter speed.

With available light you have less control because you don't have flash to give you an exposure difference between foreground and background. To underexpose the background you have to under expose the foreground! The way I try to get richer/darker blue backgrounds is to shoot slightly downwards in to darker richer blue water.

I stumbled into the advantages of doing this because I was relying on the sun to illuminated the foreground - and in a typical land technique I wanted the sun to some over my shoulder to light the scene!

My experience with this technique is still pretty limited. But I think there is quite a lot of flexibility with filters so long as it is a strong red because by calibrating the camera's white balance this corrects for any slight inaccuracies in the filters correction.

I use Kodak wratten gels (40CC and 50CC Red) because they can easily slid onto the front or rear of a lens or in your case between lens and adaptor. UR-Pro make great filters that are popular. Craig has lots of experience with filters and will have some good suggestions.

Alex

Craig, I'm not discouraged by the comp, especially 'cause BSoUP ones are voted for by the audience and safe pictures tend to be successful. Not that I say that when I win the odd one! I will try the picture again in some of the image festivals later in the year.

[craig]

I meant discouraged by the accusations! I'm never discouraged by comps especially if I've entered a shot as beautiful as you ray shot.

Nikon apparently sells a red filter (30 or 40 CC I believe) for underwater so that reinforces Alex's suggestion. I like the magenta ones because they effect the violets less, but I believe the difference between them is primarily in the second 30'/10m of depth. I also combine my magenta gel with an 81EF, but if you do that it can become strong. If you're very shallow you'd probably not do that.

For screwon filters I use the flourescents. There are three main types: FL-B, FL-D, and FL-W. FL-B is the most powerful and FL-D the least. FL-W filters are rare and are almost the same as powerful magenta filters.

Each filter manufacturer uses a different recipe for flourescent filters so they're not interchangable. For FL-B I like Singh-Ray. This one is useful for deeper depths (20-70 feet) and is very difficult to use with any additional light. For FL-D I like Hoya. It's not too strong; much like a 30 CC magenta but warmer. B+W makes a nice FL-D but, at half the strength of the Hoya, it's not really useful for ambient light photography. I avoid Tiffens because of their sandwich construction.

UR Pro filters are fine but essentially identical to the flourescents recommended above. If you can only get a UR Pro in the size you need then by all means get one. Otherwise you can save money by buying the Singh-Ray FL-B (UR Pro CY) or Hoya (UR Pro GR) instead. Avoid the UR Pro VLF. As best I can tell it's the same as the CY filter. Try to get the resin UR Pros rather than the glass. The glass ones are sandwich construction like Tiffen.

I do technical measurements of all the filters I find that are suitable and can provide the specific numbers to anyone interested. I keep a spreadsheet and someday hope to post it permanently on wetpixel.

[wetpixel]

I'm going to move this thread to the tips and techniques category and pin it. Great information here!

[scorpio_fish]

I find all three shots visually pleasing. Compositionally, the 3rd one is a little off due to the positioning of the diver. I think the technique works well.

It takes me about 15 seconds to adjust color temp and tint in ACR and I'm not breathing compressed air.

Also, what's everyone's take on using white to calibrate color temp? I always believed it to less reliable than gray because most white objects are not perfectly white.

[ReyeR]

Interesting technique and discussion.

It takes me about 15 seconds to adjust color temp and tint in ACR and I'm not breathing compressed air

scorpio_fish, what does ACR stand for? Adobe Raw Convertor? Are you saying you use this with pictures taken with filters or without?

Thanks.

[MrFish]

Thanks for the info guys. This is a technique i definately want to try out. Ideally on Mantas.
I have just purchased a Hoya FL-D and shall be giving it a try, but unfortuneately i cannot do a white balance underwater on my S2 with the Ikelite housing (can't wait for the new aluminium back to come out.)

Any suggestions on how i can overcome this? What would you suggest i set the white balance too? i.e. Flourescent, tungsten, auto, day

[craig]

Shoot RAW. White balance can be changed after the fact when shooting RAW.

Alex uses custom white balance to make sure his settings are correct. You could accomplish the same thing by shooting a test frame with a white reference, then shooting your subject. When converting, white balance your test shot then use those settings for the real thing.

I like to leave my camera set to auto to see what the camera will do. I know I'll override it anyway. In Stephen Frink's recent article he suggests cloudy. That might produce a more pleasing image on the review screen.

[Andi Voeltz]

One technique I am starting to explore with digital is shooting without flash, getting colour using a combination of a colour correction (red/magenta) filter on the lens and calibrating my D100's white balance using a grey card.

Hey Alex,

really great shots! I have been thinking to explore this for a long time too, but options were quite limited as we never
had access to the WB-balance button in our old Coolpix housing. However Uwe is just upgrading our old housing. The
DSLR will offer even more...

I have one question: Can give a precise Item No. and Brand of the filter? I want to buy a similar one for one
of our 10D lenses. Thanks! Andi

[Andi Voeltz]

[quote] [quote name='Alex_Mustard' date='Jul 10 2003, 10:59 AM']I have one question: Can give a precise Item No. and Brand of the filter? I want to buy a similar one for one
of our 10D lenses. Thanks! Andi [/quote]
Mhhh.. was so exited of this thread, that I overlooked the answer
Anyway, with the SIGMA 15-30mm lens, I'll only be able to slide a "foil-filter"
(urghs, my english?!?! - what's the correct word for that?) into the rear of
the lense, because the front glass is bulb-shaped. Craig, I'd love to get a
hint from your spread-sheet...

Thanxx guyz,... Andi

[craig]

For the rear gelatin holders you buy the red or magenta color correcting gels and cut them to fit. If you also want warming you add a warming gel. I haven't had any trouble putting two gels in the holder although it's a little fussy. There are no flourescent gels to my knowledge but I'll explain how to make one below..

Red and magenta gels are specified by their strength (usually in increments of 10) and either an "R" or an "M" Alex recommends a "CC 30 R" or "CC 40 R" I believe (CC means color correcting). I've used the "CC 40 M". The M filters pass more blues and violets but attenuate yellows more than the R filters. M filters are definitely better between 30-70 feet. From 30 feet to the surface I don't know, but you've seen Alex's results and they're hard to argue with. Apparently Nikon sells a CC R filter for underwater use if that helps you choose.

The warming gels are the 81 series and the 85 series and are used to lower color temps. Their values are specified in "mireds" and their effect is given by the following formula:

CCT(new) = 1 / (1 / CCT(old) + mireds/10^6)

Mireds are much handier than Kelvin when talking about color temps and filters since you just add them up. Instead of saying daylight is 5500K you say it's 182 mireds. Halogen lights are 313 mireds. If you want to convert halogen to daylight you need a -131 mired filter. The 80A is just that. Easy, eh?

The 81 series filters consist of the 81, 81A, 81B, 81C, 81D, and 81EF with values of 9, 18, 27, 35, 42, and 53 mireds.
The 85 series is stronger and consists of the 85C, 85, and 85B with values of 81, 112, and 131 mireds.

A Singh-Ray FL-B is 147 mireds plus CC 50 M. A Hoya FL-D is 34 mireds plus CC 30 M. These are my measurements. You can see that a variety of flourescent class filters are easily constructed with a combination of two gels. That's what you do with a rear holder.

The filtering behavior of water varies with quality and time of day, but I believe that blue water at noon on a clear day acts like a -5 mired + CC 2 G (green) filter PER foot. Some believe that a higher value of CC 4 G per foot is closer. Since an M filter is the direct opposite of green, a Singh-Ray FL-B is a nearly perfect blue water filter at 30 feet.

As if this wasn't enough to think about already, I'll mention that in Adobe Camara Raw you have two controls that adjust white point, color temperaturre and tint. Color temperature corresponds to mireds and tint corresponds to the magenta/green balance. Moving left on tint is like adding a CC G filter. Moving right is like adding a CC M filter. Since filters modify light before the sensor they are actually better than digital adjustments since they balance exposure beween R, G, and B more evenly. If anyone using ACR is noticing that they are consistently at +20 or more on tint they should consider trying a B+W FL-D. It'll move your tint 20 points left I promise.