What's the fastest shutter speed with Rebel XT and

Might be as simple as the ol Nikonos days, you could set your shutter to 125 or 250 or 500 or whatever BUT...the camera would override and the shutter would still only synch at 90.  So yours might still be going off at 200, you just don't know it.  But i certainly could be wrong about that.

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This is definely not the case. At 1/400 you will always have the lower ~1/3 of the pic cut off from the strobe light.

This is definely not the case. At 1/400 you will always have the lower ~1/3 of the pic cut off from the strobe light.

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And if you turn your rig upside down you use these speeds and have blue water (where you don't need flash at the top of the frame). I did this quite a bit with my D100.

Alex

And if you turn your rig upside down you use these speeds and have blue water (where you don't need flash at the top of the frame).

now THAT is clever!

that's cool. Should gain about one stop against sunlight with my 10D. Good hint.

Julian

I still haven't found an appropriate replacement setting to my old 5050 to get  black background when shooting kelp in the daylight, a la: [very nice image snipped from quote]

Chris,

The minimum aperture on the 5050 is f/10 and max shutter speed is 1/1000. This combination is (approximately) equivalent in EV to f/22 at 1/200, which is available with flash sync on every single DSLR produced and 99% of DSLR lenses (a very few specialty lenses go only to f/16). Thus, the same exact black background is easily achieved. The only difference would be that f/22 requires a more powerful strobe burst to light the kelp. Is that the problem? If so, you could try using a wider lens and getting a little closer to the kelp.

[As an aside note that the 5050's sensor is roughly 1/3 the size of the average DSLR and hence f/22 on a DSLR should be sharper -- have less diffraction -- than f/10 on the 5050 so the DLSR is also better on that front. f/22 on a DSLR should be roughly equivalent in diffraction limited sharpness to f/7 on a 5050.]

Thanks lanierb, I'll have to check out the settings I've used recently and see if they are similar to that.

And Alex, pure genius

After reviewing many photos and their EXIF settings it DOES APPEAR that even when I set the camera at 1/250 or 1/320 in M mode, using Ikelite's eTTL2 the camera and strobe were smart enough to limit the shutter speed to the Canon Rebel XT's 1/200 max synch speed.

Only thing I can think of that made successive photos darker is pushing past the max strobe output for a particluar f-stop in essence underexposing the complete photo.

Example, if 1/200 at f 8 is still too bright for my taste, a combination of dialing in more negative flash comensation plus going to a smaller f-stop than the strobe can put out for my camera to subject distance, resulted in an underexposed but maybe more pleasing photo.

Will have to try MANUAL camera mode and MANUAL FLASH in FLA next week. After checking EXIF to see if this will allow a true 1/250 or 1/320 shutter speed with flash I'll report back.

Still won't likely be usable as Nikon D70 shutter speeds of 1/500, but all cameras have limitations. I still love the Canon CMOS color and smooth pics even at higher ISO.

dhaas

Will have to try MANUAL camera mode and MANUAL FLASH in FLA next week.

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350D doesn't support manual flash from the camera's side. M does only mean shutter speed and aperture being set manually. If an E-TTL strobe is connected, the camera operates the strobe in E-TTL mode. Shutter speed is still bound to fastest sync speed (1/200).

I don't know the Ikelite converter. But I assume the unit is fully responsible for manual strobe control. I would guess the camera still thinks there is an E-TTL strobe connected but the Ikelite unit ignores camera’s strobe power signal and overrides it with the manual setting? Or does the unit cut down the conversion with the camera as if a manual strobe is connected with just two wires? If not (what I assume), max. 1/200 would still apply.

Julian

Ok, David, you have confirmed the XT works just like the 300D and the 10D.

If you set the eTTL conversion circuitry to manual, it will let you do faster exposures - but at 1/320 there will be a slight darking in the bottom of the frame.

William,

thanks for pointing this out. That means the Ikelite conversion unit is bypassed when set to manual power control and the camera doesn't know anymore that a strobe is attached?

Julian

No the camera still knows the flash is there. The camera for some reason assumes the attatched strobe is capible of high speed sync when the eTTL circuitry is set to manual.

The <lightning bold>H shows up in the viewfinder. And the camera records "flash fired" in the EXIF.

I agree with Bill that Ikelite's eTTL and eTTL2 systems KNOW there is still a strobe attached but makes no effort when switched to manual settings to limit a maximum shutter speed.

Being the lazy, give me the automated systems type of photographer I am (after spending WAY too many vacations trying to "override" what light meters, TTL strobe systems, etc. were designed to do) I will still likely use eTTL2 99% of the time.

I just aim down a few degress if blowing out surface highlights

YMMV

dhaas