I'm getting better (I think) - Pics for C&C please..

I'm gradually getting used to my new camera, and although I only had it out for one dive, and six exposures on Sunday, all of them were good enough to keep

Here's a couple.

First some sponges and yellow zoanthids. I don't think this one is composed quite right. Its exposed for the sponge on the right, but focus point is more to the background. I wasn't trying to capture the zoanthids, but I think if I exposed for and focused on them, it might have been a better picture.

Pentax *istDS :: UK-Germany Housing :: Inon Z-240 :: 1/180 :: f6.7

There wasn't a huge amount of fish life on this dive, and my most interesting and co-operative subject was this magpie perch. I think the photo turned out okay, but looking at it after uploading it should probably be treated to some unsharp mask and a little more contrast.

Pentax *istDS :: UK-Germany Housing :: Inon Z-240 :: 1/180 :: f6.7

Please take a look at my gallery[/img] for some more.

Hi Mark,

Are you using Manual or Automatic?

Let me ask you this too... If you were shooting on land, would you use 1/180 shutter speed for a flash sync?

I think the first picture, you pretty much nailed your own review IMO

froop:

I don't think this one is composed quite right. Its exposed for the sponge on the right, but focus point is more to the background. I wasn't trying to capture the zoanthids, but I think if I exposed for and focused on them, it might have been a better picture

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The sponge is properly exposed on the right... I agree... but the left (the orange cup coral - or at least that's what it looks like) is blown out. I think this is a combination of strobe aiming, strobe power, and f-stop that caused this. 6.3 is very shallow DOF for underwater too.

If these are 2 out of 6 captures all day, that's pretty good. Take more pictures (LOTS), even if they're the same subject. Try different settings for each, and compare. I wonder how the first shot would have looked with a shutter speed of 1/60 and f 10?

Thanks for your comments Howard. I'm shooting manual, and you're right - I'm not sure why I dialled in 1/180. I think I was playing around from a previous a shot, and the current was picking up (which would have made getting the right focus at f6.7 even more difficult for me.

(The dive was in Port Phillip Bay here in Melbourne - dive was supposed to be at slack water, but since this dive site is right in a shipping channel, we had to wait until a container ship went through, and only caught a little bit of slack before the tide started to ebb on us. The second dive was supposed to be outside the bay, but the wind and swell was too strong to get out the heads, so it ended up being a drift dive. Not very camera friendly, so it stayed on the boat).

i like your shots, you have filled the frame nicely. what lens you using?

as for what howarde mentions about the shutter on the first shot, not necessarily true, that shot is pretty much a strictly flash exposed shot so the shutter not really in play there. If you were using a wider lens with more background then i agree with the shutter being important. What i think is missing from this shot is a strong focal point or subject.. like the second shot, a great fish portrait, you didn't bullseye it and have the lips all the way to the left, perfect.

so for the first shot i would have concentrated more on the sponge as your main subject and used a vertical orientation to give it prominence....

and yes, howarde is right about a higher fstop, f8 would give you better colour on that scene

definitely a stong image on the fish! i like it

Mike Veitch:

i like your shots, you have filled the frame nicely. what lens you using?

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Thanks Mike. Using an 18-55 with flat port. The first pic was at 28mm and the second at 55. I can't take all the credit for framing out of the camera. The first is virtually as is with minimal cropping. The second is cropped down from native 3008x2000 down to 1383x918.

and yes, howarde is right about a higher fstop, f8 would give you better colour on that scene

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I will definately stop it down a couple next time I'm out..

i think the first shot would benefit from a wider view at the 18 end of your lens. you could then get closer and it will therefore be sharper due to less water and have greater colour..

but.... you need to buy the dome port first...

Mike Veitch:

i think the first shot would benefit from a wider view at the 18 end of your lens. you could then get closer and it will therefore be sharper due to less water and have greater colour..

but.... you need to buy the dome port first...

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yeah... dome port

Mike types faster than I do...

Mike Veitch:

but.... you need to buy the dome port first...

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Mmmm... just tell my credit card that

I have the flat for the 18-55, and an extension for the 100mm macro (lens still on order, primarily for land photography). The idea was to get the dome for the 14mm when I could afford both the dome and the lens. But I'm not sure I can see myself getting my money's worth out of that investment, so maybe the 18-55 dome will do me..

Sorry to jump in (trying to learn), but what does the dome do versus the flat port?

Fastmarc:

Sorry to jump in (trying to learn), but what does the dome do versus the flat port?

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Hi Fastmarc,
I'm sure there's a better explanation somewhere, but here's my version.

A camera lens is designed to refract light from the subject through air, through the glass and back into air and onto the image plane (film or CCD). Light refracts differently in water than air, so when the light from the subject is refracted through the water instead of air, then a flat piece of glass (the lens port), then back to air before hitting the lens, it gets somewhat distorted.

Take a look at this picture from my album (click the picture to bring up the full size one to get a closer look) and although it is quite sharp in the centre, you will notice that the edges are a bit fuzzy. Not quite the same effect as being out-of-focus, but similar.

What has happened is that especially towards the edges of the image, the light refraction from water through the flat glass of the port has caused colours from the different parts of the colour spectrum to be bent ever so slightly differently. The effect is more noticable at wide angles than it is with longer lens. Eg, with a 12mm or 14mm lens the effect will be very noticable. With a 100mm it will be negligble.

The dome port acts as an additional lens to offset the refraction difference from water to air. They are generally more expensive that flat ports, because it is a lot more difficult to make an optically correct dome shaped piece of glass than it is to make a flat round one!