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gatherlight Nov 13, 2002 5:32 PM

D7s - Time Exposures?
Considering a D7 i or Hi to make the move to digital from 35.

I see great info and interesting commentary in the various forums but I don't see any info regarding the "bulb" setting and the spec that indicates a 30 second max. Is the true max even under manual settings still 30 seconds?

If so is this limitation the nature of the digital beast?

Thanks in advance for any comments or feedback.

NHL Nov 13, 2002 8:14 PM

All D7's have bulb setting. The only thing is when you go to the bulb setting, you'll lose the What You See Is What You Get feature (WYSIWYG) of the camera in manual.

For example when you're at a hypothetical 4s speed for night shot (ie really, quite dark) you can see what you are getting in the final picture by opening up or closing the aperture (or keep the aperture fix and varying the speed up or down), the exposure value will change accordingly in manual. Once you go to the bulb setting the camera revert back to its auto-EVF mode and doesn't reflect the real exposure of the final shot anymore (ie the intensity of the EVF varies automatically with the scene lighting, even turning to B&W, and is uncoupled from the aperture settings)! The real-time histogram still works in the bulb setting but I would rather rely on an external exposure meter at this point, just MHO.

In the bulb setting the camera automatically captures a second exposure without opening the shutter. It then uses the noise information gathered from the dark current to eliminate most of the noise in the first exposure. You can see this by the time delay (same as how long you held the shutter down in bulb) it takes the camera to take the 2nd exposure after the shutter is released before the picture is written to flash (or microdrive)!

JimHunt Nov 15, 2002 7:51 PM

Yes, 30 seconds is the true max. Bryan Biggers has constructed a timer to take a series of 30 second exposures. He then stacks them to get low-noise, high resolution photos:

With digital as well as film, noise (grain) is going to increase with longer exposures and high ISO's. The noise must be dealt with electronically and Minolta apparently decided that 30 seconds was the max they wanted to deal with in a "prosumer" camera.

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