split level shots / INON WAL

[Jolly 3]

Hello,

 

does anybody know if it is possible to make quiet good split level shots with an INON UWL 100 + Dome?

 

The manual says that the lens is usable in air and in water. Is there a need to have water between the lens and the housing for air photography? Or just for underwater?

 

If the lens requires always water between lens and housing it should work for top- and downside at the same time.

 

thank you in advance,

 

Julian

[JohnJohnsonIII 0]

Hi there! I started a similar thread a while back. I was using the UN WAL and had very poor results getting the above, below shot. I bought the Inon WAL and Dome Unit and have had much better results. Unfortunately, the last few weeks in Hawaii were so crappy weather-wise that I was unable to get very good shots, but I think the Inon WAL and Dome Unit are the way to go...

 

--John

[Peter Schulz 1]

I'm no expert. But here are a few shots I took on Saturday. The first and second pics are before and after correcting for the fish eye effect of the lens. For more on correcting for fish eye see the following thread.

 

http://www.wetpixel.com/PNphpBB2-viewtopic...ic-t-4722.phtml

 

The trick is to lift the camera into shooting position and shoot before the water beads on the lens --- easier said than done. Thus, the third pic, which is a result of not getting the camera above the water soon enough.

 

Others will recommend Rainex and other coatings. I'd rather not go there.

[Peter Schulz 1]

Adjusted Pic.

[Peter Schulz 1]

Pic 3.

[james 0]

While way cool (especially the last one, IMO) these are not true "split level" shots where some above water and some below water is included in each shot.

 

Or am I missing something?

 

True split-level under-over shots will probably require the dome port and a very calm day. Oh, and some spit helps...

 

Cheers

James

[Peter Schulz 1]

James, re "Or am I missing something? "

 

True, they are not split level. But they answer the question re can the lens be used above water. Answer, yes.

[JohnJohnsonIII 0]

I think that third pic was more spit level than split level

I have been trying them for a while in rough waters and have had trouble...I will include a picture or two...the first shows the theory...the second shows the (mal)practice.

[JohnJohnsonIII 0]

Well, I guess the order came out in reverse...the second is the theory, the first one is the practice...notice the beading line...very hard to take this shot...

[marpacifica 0]

I got very similar results using my PT-010/Inon UWL. The "beading line" comes from the water between the lens and the glass port, which doesn't drain or fill fast enough through the four "vents" to match the level of the water on the far side of the UWL.

[JohnJohnsonIII 0]

Yup...that's been my experience. I am thinking that the optimal conditions would be glass-like surface day when you can sit there with the lens half-submerged. Once the top half dries you'll be rid of the bead line. Of course, that limits you to working in protected bays and Neverland(not Michael's). It's do-able, I think. Just isn't the most practical thing in the world. But I am all for trying!

[JohnJohnsonIII 0]

Umm...I just re-read your article, marpacifica. I never thought about it...is the bead line from the drainage? I didn't think so. I thought it was just the wash of the water down the front side of the convex surface...I might be wrong, but I think I am right. Note the angle of the bead line. That alone tends to make me think it is external and not internal...

[Arnon_Ayal 1]

It’s possible even without the dome port.

It’s hard to get it and the biggest problem is the lack of ND filter.

[Arnon_Ayal 1]

And another sample.

[laz217 0]

Couple of ideas..

 

For the water drop issue on the lens... a little baby shampoo on the lens might resolve the water beading issue. I've seen some people use this method effectively. I don't have a dome lens (yet) so I haven't tried it.

 

For the water issue between the lens and housing.. How about plugging up the drain holes and a little silicon (or teflon tape) on the lens thread? Install the lens underwater and these little mods should help slow down the draining drastically.

 

I'll hopefully have a dome lens soon so I'll try to figure something out.

[Jolly 3]

Thank you for the input.

 

As I understood, the required water between the housing and WAL is draining out as soon as you hold the lens above the waterline?

 

@Alto: I've seen you have had aperture 8 with your Canon. Is it the smallest one (highest number) you can set on the camera? So the pictures show the maximum depth of field?

 

@John: Yes, I think you are right that the INON cmbination is the best way to go for compact digital cams. I think a bigger dome could increase depth of field and make capturing the waterline more easy. But a Seacam 240mm Dome costs 1600 $ + housing

I think your approach shows the way to get these shots.

 

Julian

[marpacifica 0]

Hmmm. In my oh-so-scientific (NOT!) field tests, I was trying to figure out where the darned line was coming from on my PT-010/4000, I lifted the housing completely out of the water and with the LCD watched the water drain very slowly from the vents. The opposite occurred when I took it underwater -- I initially would get the line at the very top of the frame. I unscrewed the WAL and out came some air bubbles that couldn't escape completely through the vents. JohnJ, I don't have the dome port with the convex surface, just the flat WAL, so I don't know if the beadline you've experienced is similar to the one I'm talking about.

 

As for using an ND filter to keep the top half of the shot from overexposing, that's definitely one way of doing it if you can figure out a good way. I got around the problem by exposing for the lighter top half and using strobes to fill the bottom half.

[Arnon_Ayal 1]

Julian: Yes F8 is the smallest I have I the S30.

As marpacifica wrote, I use the same, aimed the strobe inside the water but still the gradient is too big so a ND filter will help a lot

[Jolly 3]

Hello,

 

I suggest a ND filter would not help.

 

From absolutely black to complete white a digicam has a range of approx. 6 aperture steps. like slide film (by the the way neg film has about 12). a plit level shot with big brightness difference has to big amount of contrast for the cameras dynamic range.

 

A ND filter would just decrease the amount of light going into your camera. so the complete histogramm would just be moved to the left.

 

You would need a contrast decreaser. I've seen a filter like that from one small german manufacture. But didn't see it around somewhere.

 

Some guys have a filter where on half of it (for top side) has a ND filter. That could work. But hard to align it with the water line and pretty restricting.

 

I think just checking the histogram and correct it with manual exposure to fit the picture into the histogramm is the best way.

[Arnon_Ayal 1]

You are right of course, I meant the split ND filters.

I don't know about a way to attach it to the UW equipment but I used it above water with my SLR.

[Jolly 3]

ok. sorry, thought you meant a full nd filter.