Which ISO setting do you use for UW?

[f3nikon]

Well I guess the answer to your question would be, whatever ISO I have to shoot at dependant on conditions. Maybe as low as possible, maybe much faster.

I mean no offence but could you please be more specific on the conditions that you speak of? With or without a strobe, low light, action stopping conditions maybe?

 

[f3nikon]

The obvious answer is to use the setting you need to get the picture. If you have the light to shoot at ISO100 all day long, by all means do it, less you want to make a grainy B&W(I love those). If you need more light and can't make it up with shutterspeed, useable aperture, strobes, ect - make it up with a faster ISO. D'uh?.

Its foolish to think you have to keep the ISO at the lowest possible ISO no matter conditions. Just about any current dSLR will make medium sized prints without much noticable noise at ISO400 if it was exposed correctly. Even if you gotta push it further, a grainy shot is better than none at all.

Could you not achieve the grainy look from post process? Is it not better to get the best image (resolution and correct color) possible first, then change or downgrade the image later? Because once you shoot the image at a downgraded or less than optimal settings its next to impossible to go to the optimal high res. image.

"A grainy shot is better than none at all" this I agree, for example if my strobe goes dead, the shutter or aperture gets stuck to yeild an underexposed image. And out of the blue I see a whale shark with Paris Hilton riding on the shark's back...you bet I'll be turning up that ISO! Short of this I'll keep the ISO on low.

 

[f3nikon]

Depending on depth and topside conditions using ambient light by shooting up will not give you enough light to properly expose and image. Even if there is a lot of light coming from the surface, your subject will be dark against the surface without a strobe. Why do you think that the Hammerheads in that link were shot with a strobe?

Yes, its called silhouette when the subject is dark against a lighter back ground. Yes, you would need a strobe to properly light the dark areas, increasing the ISO to correct the the dark subject only overexposes the background to the overexposure round file.

Underwater is like turning on a high power blue light coming from above, at that depth everything has a blue cast. The questions is how did the under belly of the lead hammerhead shark come out as pure white, without artificial light? Plus I have seen Mr. Hall's video on TV, as I recall he was using rebreathers and taking those pictures at a depth of 100ft or more. The light from the strobe did not reach the sharks in the background.

 

[f3nikon]

Since the friends I was referring to are multiple international award winners, I'm certain they're aware that in general you want to get low and shoot upwards. But since they actually dive and photograph regularly, they also know that sometimes isn't enough depending on conditions. Sometimes you have to boost the ISO as well, and many times use of a strobe isn't the effect they're looking for.

True artists are willing to explore many ways of achieving the desired effect. That means experimenting. And sometimes breaking the rules. They're the ones who expand the art.

I know which people to rely upon when looking for advice on shooting techniques... and who just quote others without demonstrating their own acquired knowledge.

Well, if your friends are indeed multiple international award winners, I will not fault them for making such an amateurish mistake, seeing that they being multiple international award winners and all. Again I ask, what are the conditions are you speaking of? What time of the “sometimes” do you have to boost the ISO?

“Use of a strobe isn't the effect they're looking for.” So are they looking for the blue cast effect or is it really that theirs and all strobes cannot properly illuminate distance or far away subjects?

You can be a “true artist” all you want, my goal is to achieve the highest resolution, color and composition possible then do the artist thing during post process.

Oh now I see… its disregard all fundamental, sound photographic principals because “multiple international award winners” who invented U/W photography and photography in general says so. And no fair quoting others (which I did not) but for the record Mr. Hall is one of the most highly regarded pioneer in U/W photography in both video and stills. Mr. Hall invented “close focus wide angle” he coined the phrase. And I stopped logging in (meaning writing in a log book) about 500 dives ago.

 

[HowardE]

I would like to know - from the people who claim that "boosting the ISO would be appropriate" in any situation, Do you actually change the ISO setting while on a dive?

What I've noticed from my experiments, is that on WA shots... You really can't see noise at ISO 100 or 200 (lowest on my camera is 100) But in Macro shots - noise can definitely be seen when in ISO 200, but no noise in 100.

 

[f3nikon]

I would like to know - from the people who claim that "boosting the ISO would be appropriate" in any situation, Do you actually change the ISO setting while on a dive?

What I've noticed from my experiments, is that on WA shots... You really can't see noise at ISO 100 or 200 (lowest on my camera is 100) But in Macro shots - noise can definitely be seen when in ISO 200, but no noise in 100.

I believe you did an outstanding job on your experiments and answered your own question. The answer I am waiting for from the posters are the conditions of which to use the higher ISO. I guessing one of the answers is for faster shutter speeds to stop the action. With water being 600 times denser than air most everything moves very slow when compared to air a shutter speed of 1/125 is enough to stop the action underwater and I am fixed a ISO 50 (Velvia film). And on your wide angle shots just because you cannot notice the noise at 200 does not mean its is not there.

cont.

 

[SuPrBuGmAn]

I mean no offence but could you please be more specific on the conditions that you speak of? With or without a strobe, low light, action stopping conditions maybe?

I often dive in low visibility with current and surge. The shutterspeed often has to sit relatively high to stop action, like you stated. If I want WA, the aperture can't be opened up too much. I'll also dive through our summer storms, which really kill ambient light in the first place. My shutterspeeds, especially WA, often lie under 1/20" in the waters we dive.

I don't own a strobe.

Could you not achieve the grainy look from post process? Is it not better to get the best image (resolution and correct color) possible first, then change or downgrade the image later? Because once you shoot the image at a downgraded or less than optimal settings its next to impossible to go to the optimal high res. image.

Adding grain post process often ends up looking artificial, aside from that, I agree with you.

I would like to know - from the people who claim that "boosting the ISO would be appropriate" in any situation, Do you actually change the ISO setting while on a dive?

I have no qualms with changing ISO UW. Its a menu driven option on my UW rig(PnS), but I know the camera well enough to do it without hesitation. Even easier on my dSLRs...

 

[f3nikon]

I often dive in low visibility with current and surge. The shutterspeed often has to sit relatively high to stop action, like you stated. If I want WA, the aperture can't be opened up too much. I'll also dive through our summer storms, which really kill ambient light in the first place. My shutterspeeds, especially WA, often lie under 1/20" in the waters we dive.

I don't own a strobe.

Thanks for the response, now lets list the guidelines:

Higher shutter speeds to stop the action.
Smaller aperture openings for longer depth of field. ? (“Aperture can't be opened up too much.&#8221

So the ISO is increased to satisfy these settings…oh and the most important factor, low visibility.

http://en.wikipedia.org/wiki/Depth_of_field#Hyperfocal_distance

After reading the link the article mention hyperfocal distance, wide-angle lenses are the hyperfocus kings. At f 22 and above, 2ft to infinity is in focus, the key word is INFINITY…now why would we need such a large area of focus when, as you stated, we are in waters with Low Visibility!

That extremely huge depth of field is wasted in what…5 to 10 feet of visibility! So instead of increasing the ISO to add some noise to the degraded image (due to poor vis.), why not open up the aperture to f 5.6 or even f 2.8 to lower the hyper focal distance and not waste it on the low visibility.

At the lower (wider) aperture settings we should now be able to increase the shutter speed to lets say 1/125 or 1/500sec. And quoting Alcina: “there is more than one way to skin a cat.”

PS. It works the opposite for good visibility, use smaller apertures and decrease the shutter speed, but then with good vis. the lighting is a bit more intense anyway, so again I ask why do we want to increase the ISO just to have a noisy image. And please get a strobe, ebay is a great place for one or two.

 

[SuPrBuGmAn]

F22?

I'm running a PnS with a minimum aperture of F8, hardly infinite focal distance. No matter what internet dictionary you'd like to pull the info from I find f2.8 to have far too shallow a DOF to pull any sharpness from a WA shot. F5.6 is a bit better, f7.1, even more so, and f8 being the best I can pull. An out of focus shot is not better than a grainy shot.

I don't think I've ever been able to use a 1/500 shutter speed in our waters(including spring water with 200' visibility - albeit lots of shadows from surrounding forest), WA or not, wide open aperture or not, internal flash or not. Not an option for this area in available light. I'm lucky to get 1/125 on any occasion.

Increasing the ISO isn't my first choice to gather light, but its a viable one. If I can't reduce the shutter speed enough and a larger aperture isn't conducive to the shot I want, why not raise the ISO? It gets the shot done! I'm using a PnS. A PnS thats horrendous with noise anything greater than ISO100. Reduced size images significantly decrease visible noise. There are quite a few programs available to reduce noise. Noise isn't as noticable when printed.

DSLRs handle noise MUCH better. Talk to a wedding photographer, ask if they shoot at the lowest ISO in dark churches, with or without external lighting. There job is dependant on quality pictures and includes large prints. I just don't see why the big fuss, quit pixel peeping and look at the big picture.

I'm not too worried about a strobe, I have plenty of others things for my money to goto(lenses for my dSLRs which are not housed, a new car, ect) and I'm not positively convinced I want to tote that much camera around with me UW.

There certainly IS more than one way to skin a cat.

 

[victor]

Saving in RAW should be an image of the output from the CCR without any internal correction, amplification, loss compression, etc.

If you are saving in RAW format does setting a different ISO rating do anything more than allow you to con the camera into taking a picture with the aperture and shutter speed that you want to use.

The comparison with film would be using different CCR’s for different ISO settings, e.g a CCR with only 4 megapixels rather than 8 when switching from ISO 100 to 400 but the same physical dimensions, the larger area collecting more light. As we are not doing that I suspect that with RAW it should not matter what ISO you are using.

Someone who knows the internal hardware/software of the camera may need to comment on this.