Dark Banding in Macro Daylight Shooting Nikon D200 w/ 2x Ikelite DS-125

[mikepalo]

Ok I have been shooting underwater with point and clicks for some time, but I am new to shooting underwater with

a semi-professional set up, and am having a slight bit of an equipment issue. <br>

<p>

First I guess my equip:<br>

<p>

Nikon D200<br>

Micro-Nikkor 60mm Macro lens<br>

Sea&Sea DX200 housing<br>

Flat port <br>

2x Ikelite DS-125 Sub strobes <br>

<p>

I took them down on my first day time dive with them today and noticed an issue with some of the shots i got

back. Ignore the subject it doesnt matter in this shot, this is just a good clear example of the issue im having.

I am getting black bands of varying intensity on either the top or bottom of the picture or as in this picture on

both.<br>

<p>

<a href="http://s448.photobucket.com/albums/qq208/mpalozzola/?action=view&current=DSC_3865copy.jpg"

target="_blank"><img src="http://i448.photobucket.com/albums/qq208/mpalozzola/DSC_3865copy.jpg" border="0"

alt="Dark Banding"></a>

<p>

Was shooting on <br>

ISO: 100<br>

F/: 4<br>

Shutter: 1/640s<br>

WB: Fluorescent (I know it was wrong but that would only effect the color not this banding issue)<br><br>

Strobe power 1/8th<br>

Strobes were softened by white plastic covers<br>

<p>

Anything else you need just ask.<br>

<p>

Thanks for your help<br>

-Mike Palozzola

[2Oceans]

Mike,

I shoot a D2X in an Aquatica and have a D200 that I use topside. Sync speed for any underwater strobe used with the D200 should not exceed 250th of a second. Your setting is much faster than that. The D200 uses a vertical travel focal plane shutter that is probably catching the strobe illumination in the middle of its travel. Good hunting. Andy

[leicaglow]

I've also found with some flashes and the D200, you should use 1/200th second. You clearly are capturing the shutter in your image.

[mikepalo]

I cant belive I didnt think of taht. I am so sorry for wasting anyones time the max sync shutter speed on the 200 is 1/250s i was shooting double/triple/Quadrupal that...the shutter was closing too fast...hence I was getting the inside edges of the shutter as the strobe fired. The faster I had the speed the thicker the bands were and of stronger intensity.<br>

<p>

So to solve this problem I'd lower the shutter speed to 1/250s but then my shots were whitewashing from too much light if i stop down farther that should fix it, but what if i stop down all the way and still whitewash? If I turn the strobes off I lose the color underwater so what do I do about bright scenes where the strobes are too bright? <br>

<p>

-Mike

[blueviews]

As Ed pointed out, you are capturing the shutter. For macro, I always try to shoot at f16 to f22 with the canon equivalent of

the lens. You were shooting at f4. For macro, you typically want good DOF which means small (high number) f stops. If

you still get blown out highlights at 1/200 and f22 dial down the strobes, or put big thick diffusers (I use milk bottles) on

them. In general though, don't worry too much, stop down and you should be fine.

 

Bill

[mats nilson photography]

Like everybody says, you've probably synced at too fast a shutter speed. However, shutter speed does not affect

exposure, unless you have enough natural light around to do the over exposure - and that, I'd imagine, is rarely the case

under water. The flash duration itself is so short, that only the aperture has an effect, regardless of shutter speed. In

other words: f/4 would yield the same exposure regardless.

 

I do find it a bit strange, though, that you get bands in both the top and bottom of the frame. Normally, the flash fires

when the first curtain has opened up completely. If your sync speed is too fast, the trailing curtain blocks the light, but

the first curtain shouldn't. So there should only be a dark band along either the upper or the lower edge, depending on

which way the curtains travel. Could it be that some part of the equipment intrudes either in the field of view of the lens,

or in the light-path of the strobes..?

[mats nilson photography]

<p>Actually, when I look closer at the picture, it doesn't seem like the problem is caused by the sync speed after

all. Yes, 1/640s <b><em>is</em></b> too short (unless the Ikelites are capble of FP-high speed sync which I

doubt). But

the image is just vignetted, not blocked, as it would be if the shutter obscured the image (being so close to the

sensor). One can still see the whole image, but it's darkened top and bottom. This makes it even more likely that

there's something in the way, obscuring the field of view. And, like I said, too short a sync speed would just block

one side.<p>

[mikepalo]

Well there are other shots in the series of shots from this specific dive that came out perfect. There are also shots with only the top blacked out and others with only the bottom. It was not specific to one or the other. I did change the shutterspeed throughout the dive up to even 1/2000s which makes complete sence that some of the pictures werent even just darkened but BLACK bars through the top and or bottom.<p>

 

-Mike

[mikepalo]

Also from the design of the housing/port something would have to be OBVIOUSLY outta place to be hanging infront of the lens. I do not have anything free hanging on the housing that could possibly hang down that low. Also the banding was in PERFECT lines. I think the others are right that it was a simple case of the sync speed. But if you do think it was something else I can test or look at please let me know I dont want to lose a perfect picture because of this in the future.<p>-Mike

[2Oceans]

Michael, There is a nice explanation and example of what I mentioned regarding the slit caused by a focal plane

shutter at shutter speeds greater than the sync speed of the camera on pages 63 and 64 of "The Manual of

Underwater Photography” by Heinz-Gert De Couet and Andrew Green. It’s a somewhat dated book from 1989 but

still has a great deal of useful information. On a different note, how did you create your sequences of the wake

boarder and the diving bird? Andy

[mikepalo]

<b>Edward</b> I will take a look at that book if i can get my hands on it from a library or something as for the sequence shots.. They are all rapid succession shots which I later compiled in Photoshop CS 3, you dont need CS3 to do it any photoshop will do it fine. Its just time consuming to combine the images. its a combonation of overlaying, matching up, making fit, and erasing. The more images u have the more complicated it becomes obviously :) I use the same method to make panaramics. <p> -Mike

[2Oceans]

Thanks. Andy

[mikepalo]

I just wanted to let anyone who checks in on this post again know. I have since shot on 2 more dives, over 150 pics keeping my speed under 1/250s and my F/ up around 8-16 and have not since had a problem with the black bars. So it was definitely the shutter speed issue. I will be posting some of those new shots soon actually. Thanks all for your help<br>

<p>

-Mike