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Which strobe is the best for me ?

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Ike, I never gloated and I never contended in this thread or anywhere else that the DS-125 is not TTL.

 

What I did say is that it cannot work as a TTL hardwired strobe with certain cameras (Olympus and Canon come to mind) and certain housings.

 

Even Nikon cameras, where everything should be speaking the same language will have problems if the light sensor is hidden (as appears to be the case with the Aquatica 995 that has been discussed here).

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Hi Herb.

 

Well, on my G2, it is a back button, and I use compensation on the ttl quite frequently.

 

I find it fits the way I think, aperture for DOF, strobe comp for TTL exposure...

 

It has nothing to do with the strobes. Everything to do with the cameras.

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Don,

 

Can't argue with that. Sounds like a good way to do it. Too bad it won't work for my setup.

 

Now. Should I spend $2k and get the G2 and housing or spend around $5k and get a D60 or D100....

 

Herb

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Wow,

 

What a thread! I will contribute one more thing: From the DS-125 manual on use of the strobe chart:

 

"Full Power Manual mode example for 100 ISO film speed: If you select f-8, the subject should be 4' away for proper exposure . . ."

 

"1/4 Power manual Mode example for 100 ISO film speed: The difference between each power setting is one full f-stop; therefore, moving from Full to 1/4 power decreases the light output by two full f-stops. If you select f-8, then reference two less f-stops (two numbers greater) than f-8 in the chart, which is f-16. Subject should be 2' away for proper exposure."

 

I may not understand all the formulae, but I have finally figured out how to read my manual :) .

 

Mike Oelrich

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Herb, if Ikelite comes out with a housing for the d100, that combo should only run around $3k, plus ports if you don't have any...

 

Oh, plus lenses if you don't have any. Maybe that is where you came up with $5k...

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I have been diving for 3 days. Owners of an Ike 200, a pair of Nikonos 105's and a pair of S & S 90's all came up to drool over my D125s. Results show them to be the best on the boat. Secured 100$ with my shot of a wolf ell. They do exist south of Pt Conception (well, within site of Pt Conception though I have seen them at San Muguel Isd.)

 

Note, if Ike had his act together I would have been taking this images with my CP 5000. (i. e. where is my housing?)

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Maybe I can help clear up the confusion on the guide number math. As Ike says, 1/2 power is always one stop by definition. 1/2 power gives 1/2 the light, which is 1 stop. The error some were making was in the guide number math. The formula f=guide number/distance is correct. However, 1/2 power does NOT cut the guide number by 1/2. 1/2 power cuts the guide number by a factor of 1/sqrt(2), or exactly one stop. 1/4 power cuts the guide number by 1/2=(1/sqrt(2))^2, or two stops.

 

Message for Ike: I loved the DS-125 when I checked it out but, due mostly to the lack of control/poor TTL provided by digital cameras/housings, I felt that I *needed* to have finer manual control, so I bought two YS-90DX's and have been happy with them. If the DS-125 had finer manual control, I think we would all agree (well, maybe that's asking too much!) that it would be the flash of choice.

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for explaining the relationship between guide number and half power without abrasive comments and personal attacks.

 

I have edited all of the messages in this thread that involved the errant calculation.

 

Another issue of discrepancy in this thread is how much effect the 12 settings on the YS-90DX have. I did not quote the Sea and Sea manual (as rstark did) because an engineer from a competitive manufacturer told me it was impossible for the YS-90DX to have 7 stops of adjustment.

 

Both debates led away from the crux of the matter, which is if you are shooting manual, more control is better.

 

On another point...

 

Ike said...

The DS-125 is certainly a TTL strobe when hard wired unlike what Farris contends. No strobe can do TTL when hard wired to a Tetra housing. This is a housing deficiency.

 

Ike, if you're going to nail me to the wall for a mistake, you should expect it in return. This is not a deficiency in the housing. A hard-wired port in your housing would be no more successful at TTL with an Olympus camera than the Tetra. The camera doesn't speak "Nikon" and most strobes do. You can argue that your digital slave sensor provides TTL, and it can in transparent housings, but at that point the discussion was hardwired connections. As for TTL performance of your strobe, I did not anywhere in this thread say that your strobe is not TTL. I did say, and camera buyers should note, that TTL hardwired function is very dependent on camera brand and sensor placement. For digital hardwired TTL to work (on either Ikelite or Sea & Sea strobes) the camera has to be a Nikon and the sensor has to be in the open.

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I can't figure out how to quote previous messages, but in response to the discrepancies above about the YS-90DX's 12 power settings, I ran a test. I happen to have a very accurate flash meter for land photography that I used to measure the power output of the 12 settings for one of my YS-90DX's. (For those who are interested, the setup was YS-90DX on a tripod with fiber optic sensor hooked to a vivitar 283 flash which was in a dark bag, in a dark room. The 283 flash cord was hooked to the flash meter, which I operated manually in spot mode aimed at the same point across trials and held at approximately the same point. I popped 3-4 flashes per setting to be sure I had it right.)

 

Here are my results stated as stops relative to a full power burst. I think that they are accurate to 0.1 stops (they were *very* repeatable).

 

Full: 0.0

--: -0.5

-1: -0.8

--: -1.4

-2: -2.0

--: -2.3

-3: -3.1

--: -3.4

-4: -4.2

-5: -5.5

-6: -6.5

-7: couldn't measure

 

I couldn't measure the -7 setting because I have a short tie-wrap attached to the flash dial that makes it easy to set it with thick wetsuit gloves on (it's cold out here) but that makes it impossible for me to set the flash at -7. I didn't think it was worth removing the tie-wrap to measure a setting that I never use.

 

The bottom line is that there is some inaccuracy in the power settings, but they are basically as advertised. The lower settings are if anything lower than advertised. Other than that, on my flash the biggest variance was the -1 setting, which is supposed to be -1 but was actually -0.8. The "1/2" marking, which is near the -2 setting on my flash, seems to be completely wrong. BTW there could be variance across units so don't interpret these numbers as necessarily right for your flash.

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Lanier, do you find that you use the settings below -3 or so, underwater?

 

Thanks for doing the experiment!

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I use -5 @ f10 for my macro setup with a second strobe @ -6 if I want it less flat. I started to do a test that shows the settings on the 90DX are fairly accurate by shooting at each setting and adjusting my aperature 1 stop every time. I did the first four stops and they all produced consistant exposures. Every so often I will use the -6/7 setting on a reflective surface doing macro.

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Same for me. I use anywhere from -3 to -5 for macro, and sometimes -6 if its a really light colored subject like the white nudibranchs common around here.

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Oh, yeah. I keep thinking, "I always use f32+ for macro, and need lots of light." I haven't retrained my thinking to P&S yet.

 

Yeah, at f10, you sure would need to drop the light output. Since I use TTL, I just hadn't noticed.

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Will the CP5000 in the ikelite housing use TTL if you use ikelites ttl sync cord?

 

If I do not use the cord will the sensor work on the Ds-125 with this specific camera / housing? I have called ikelite and they are not admitting they have a problem with the ds-125 or the sensor.

 

Help..

 

 

[Edited on 5-1-2002 by Reefkeep]

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Yes to both.

 

If they have a problem, it is only in a couple of units, with bad parts or solder joints.

 

If you *ever* have a problem with any ikelite equipment, you can be sure it will be fixed, improved, or whatever, and gotten back to you with incredible speed and service. I've tried to talk them into accepting payment a few times, when I thought I was 50% likely to have been the cause! No luck!

 

This industry is so small, (in numbers of units per year), that many of the underwater manufacturers have problems with various products either when they first start selling them, (which is the case with the ds125 and ds sensor), or sometime down the road, when a batch of marginal parts come in, that barely squeak by testing, and fail during shipment...

 

This is an unavoidable consequence of the relatively small market. You can't afford to spend infinite time and resources testing, when you'll only ever sell so many per year.

 

From what I've heard and observed, most of the manufacturers do a good job of gracefully dealing with these issues, and keeping their customers happy.

 

From my own personal experience of using ikelite stuff for 10 years, they do a superlative job. Even if there are issues with a particular unit, you can bet they will be resolved to your total satisfaction.

 

Don

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Personally, I think you'll get better performance using the sync cord. If you can use a sync cord, why would you want to use the sensor?

 

It's a 5 pin sync cord afterall, and correct me if I'm wrong, but only 2 or 3 of those pins control, firing and TTL. The other two pass information back and forth between the camera.

 

For instance, my SB102 strobe tells the Coolpix5000 when it is recycled and ready to fire again. While the strobe is charging, I get the flashing "lightning bolt" on the Coolpix's LCD screen. I think there is a TTL ready signal as well. Ike and Larry would know - I believe they tested all of this while developing the CP5K housing.

 

Cheers

James Wiseman

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The cord seems like the way to go! Thank for the help. Any suggestions of were to buy a strobe at a good price?

 

 

Chris@reefkeep.com

www.jaxdivers.com

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So far I can find the Ds-125 kit for 650.00 best deal so far.

 

I can also find the sb104 new for 375.00.

 

Hmmmm

 

[Edited on 5-2-2002 by Reefkeep]

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The Ike strobe recycles in under one second. Don't know if that's important to you or not...

 

Cheers

James

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hi,

i am looking for advice on what strobes to purchase for diving in Ireland. my camera is a Nikon D90 with an ikelite housing.

any information would be appreciated.

Brian

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