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Importance of TTL underwater


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#21 tshepherd

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Posted 06 February 2003 - 10:30 AM

Or you could go with the D60 @ ISO100, half the noise of the S2... ;)

#22 james

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Posted 06 February 2003 - 10:34 AM

See my other thread called ISO Comparison where I noted this.

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#23 scorpio_fish

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Posted 06 February 2003 - 10:57 AM

First, I do not believe TTL is a crutch. It is a tool. There were a lot of naysayers years ago when in camera metering first came out. Just a crutch. Use your own meter to evaluate the exposure, blah, blah, blah. Sorry, the Nikon in camera meter does a better job than me and it's really fast compared to me pointing a light meter all over the place.

Under the right circumstances, TTL does a better job than manual controls, because the manual controls are in discrete increments of full power, in the case of the SS200 full stops of light, whereas TTL allows a theoretical infinite number of power settings.

Using manual power requires understanding guide numbers and accurately estimating strobe to subject distance, otherwise you are just guessing. TTL is better at it than our brains.

The key is to understand when TTL won't do what we want it to do and to not use it in those circumstances. If TTL works for macro, then it works. Using manual control can only hope to replicate the results and it's more difficult since you've only got whole stop increments of power. Adding manual controllers just makes it easier to dial in correct exposure, perhaps the same as what we would have got on TTL.

I use TTL for macro and it works 95% of the time. The other 5% is due to unusual background or super dark/super light subject. In these cases one should dial in some EV. Franklin Viola uses TTL for all shots and uses EV compensation to adjust for the scene, wide angle and macro.

Back to the original question:

Prioritize.

I went through the same decision process that Marriard went through and chose a D100 over the S2. Some of the reasons that swayed me to the D100 are no longer valid, but the decision was made when both had just hit the shelves. I've got an MD100 battery pack, which I prefer to the two battery system of the S2. I prefer the way the histogram displays on the D100. I prefer the D100 plastic LCD cover to the S2's. I prefer Nikon's RAW editor. I prefer the color rendering of the S2 better. The biggest factor was housing availability. The same criterion that made Marriard choose the S2 was the same one that swayed me to the D100. The S2 had and has one housing available and it was available early. I did not want an Ikelite housing. There is nothing wrong with it, but I wanted a more compact custom solution with better port options. While he's been shooting 1000's of underwater images, I've been waiting. He's been diving more, well, unless you count my local quarry. But I've only missed out on one trip from using my D100 underwater. I plan on buying a housing once, so I've been willing to wait. It's been killing me, I must admit.

Back to priorities:

If using Subal ports is very important, then the Titan is the answer. The digital ROC should take care of most of the TTL issue.

If absolute image quality is paramount, the S2 has an edge on the D100.

Take a CF card to a dealer and shoot both cameras. Take card home at look at the results. Decide if the image quality difference is worth tossing your beautiful Subal glass ports off on e-bay.

Better yet, buy both and report back to us on the results. (I love spending other people's money)
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#24 craig

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Posted 06 February 2003 - 12:40 PM

Regarding the noise graphs, it is important to understand what the units are being displayed. Numbers like 1.0 and 2.0 are meaningless otherwise. How much is considered acceptable? Without knowing that, you can't say "the S2 has MUCH LESS noise". Half of nothing would not be much less than nothing, for example.

The original author didn't do a very good job explaining this so the reader was left to decide whether 1.0 was good or 1.5 or 2.0. You have to read the article yourself. The author did say "Overall noise levels are very low (compared to what we've seen in the past)." The D100 is not considered to have bad noise performance, but appearently it is bested by both the Fuji and Canon.

Interestingly, in the raw comparisons, the raw files used default processing rather than no processing which I believe would have been a better choice. I suspect the author didn't have a choice in the matter. When it gets down to it, I'd like to know about noise in the sensors only. Turn off the white balance and sharpening please.

I think the S2/Ike owners are happy that they have the advantage of the best available body in the class. They should be, but really these three cameras are competitive with one another. Overall performance underwater is not just a function of which body you have but which ports you use.

If Subal ports are important, you might want to consider the Subal housing!
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#25 james

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Posted 06 February 2003 - 12:46 PM

I agree 100% about the ports Craig. The optics for the Ike ports are very good - but I would LOOOOOVE a nice big dome port so that I can try some over-unders (they're free, right?).

I tried some over-unders of the Sea-Lions at the Coronados but couldn't get a good one. If you want to see a REALLY good one, check out Eric's recent pix w/ the Sea and Sea 8" port taken at Monterrey.

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#26 craig

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Posted 06 February 2003 - 01:48 PM

You'll need one of those inflatable cradles with the wings on the sides to control the surface waves, though. Sometimes you see one of those shots and think "how in the world did they get that?"

I wish I could put an S2 in the Nexus housing. I hope the Aquatica S2 is good, too.
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#27 Alex_Mustard

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Posted 10 February 2003 - 12:46 AM

I am using an SB80DX in an old plastic SB26 housing. It DTTLs fine with my Subal clad D100 and TTLs fine with my F100.

I intend to only use this gun for macro. And will probably use my subtronics on manual for wide angle when not using filters and grey card (which I am far more interested in than flash lit wide angle because this is something I just can't do with film).

I think that the TTL/DTTL is essential for getting the best possible macro shots and therefore if one does not plan to house a DTTL gun then the S2 must be favoured over the D100.

Good subject matter is a key ingredient in successful macro photography. Just about every macro subject commonly encountered underwater has been shot from every conceivable angle. One of the few areas where you can get fresh macro images is to shoot animal behaviour and for these sorts of shots you often only get one chance - exactly when you need TTL.

If you just want to do macro abstracts of static subjects or posed wide angle then manual flash is fine, possibly even preferable. And tools like ROC are fantastic. But not having TTL or DTTL is a serious limitation for macro and standard lens (28-70) photography of more ephemeral subject matter such as behaviour.

Alex

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#28 Alex_Mustard

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Posted 10 February 2003 - 02:44 AM

I have put one of my D100 SB80DX trial shots on the following page.

Its the fluorescence photograph of an anemone at the bottom.

Of course this is one of the sorts of static subjects ideally suited to manual flash(!) but I am pleased with the TTL performance.

http://www.soton.ac..../D100/d100.html

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#29 wetpixel

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Posted 10 February 2003 - 03:09 AM

Fantastic fluorescence! I really love your photos, Alex.:D
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#30 marriard

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Posted 10 February 2003 - 05:13 AM

which I prefer to the two battery system of the S2. 

I have been meaning to bring this up here for the S2 users - you SHOULD NOT be using the two battery system in the S2. You should be leaving the CR123a batteries out of the camera when you are diving underwater.

In fact I do not use the CR123A batteries at all as they only serve two purposes:
1. Power the onboard flash (which is not very good)
2. Shut down the camera when low (which generally happens when you are underwater)

They are annoying because they drain quickly, as I am told they are also used with the autofocus system, but if they are not in, the autofocus still works fine.

So leave them out, buy a nice Speedlight (all the Nikon DX/D100 users are selling their old SB28's and SB26's) and enjoy. I don't even own any batteries that would fit in the CR123 slots.

M

#31 james

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Posted 10 February 2003 - 05:50 AM

Paul's right.

As far as the S2 is concerned - for us underwater photographers - it runs on 4 AA batteries.

That sure is nice because it means we don't have to carry yet ANOTHER charger...:-)

Cheers
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#32 davephdv

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Posted 10 February 2003 - 09:49 PM

Some people sure are spending a lot of time telling us how great the S2 is. Sounds like their trying to compensate for other inadequacies. Do you guys own Corvettes as well?
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#33 james

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Posted 11 February 2003 - 06:02 AM

Hehe! Not only am I the president of the hair club for men - I'm also a member! :-)

Cheers
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#34 MrFish

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Posted 21 February 2003 - 09:56 AM

i come to this debate as very much a novice user having only recently returned from a 40 dive trip round asia using the S2/ike combo with my principle interest being macro. (although i have tried a few dives with wide angle and got some nice shots of a 4m leopard shark)

My main deciding factor was the final quality of image and after comparing images on both the D100 and S2 the S2 stole the show. It produces better colour tones and handled the lighting better.

I hadn't tried not fitting the CR123 batteries and did come unstuck a couple of times when the damn thing died on me (losing me the chance of a really good shot of a sun fish.. aaargh!).

Because my previous camera experience was all using an older fuji digital things like TTL and lighting were all a bit of a mystery to me and so i was glad to find out just how well the S2 handled the TTL.

What is irritating with the S2 is the max sync speed of 1/125.

As far as the housing goes it is very well made indeed, b ut if i had had the choice at the time i would have preffered a more compact aluminium housing with better levels of control.

I do find it difficult to judge just how well a photo will come out by looking at the LCD screen. It is especially difficult to determine just how good my depth of field is.

As a newcomer i have ruined a hell of a lot of what could have been good shots by not using the right F stop. But that is the beauty of digital, you just keep on shooting, getting a lot more shots than i could do in one dive using a film camera.

How does not fitting the CR123 batteries effect sync speed and autofocus speeds?
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