D7100 and 10 24 - long exposure

Started Apr 29, 2013 | Discussions thread
OP Nepentanova Forum Member • Posts: 68
Re: D7100 and 10 24 - long exposure

mosswings wrote:

engbert wrote:

Thank you for the interesting picture.  I  do not have any extra wide angle lenses, so please would you explain the 92 seconds at f22, iso 100?

At 10mm on this camera, everything from about 3 feet to infinity would be in focus at f4.  At f4, as far as I can tell from an Android App, "Photo Tools",  you could have used 1/30th second.  At iso 200 1/60th, very roughly.

This would have been much easier, hand held.

How would the result have been different?

Blurring out any movement on the water would be a possibility - was this the main intention?

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pbase & dpreview supporter

Convert the given exposure to an effective EV number and you'll have your answer.

ISO 100:f4:1/30 is EV 9, or skylight just after sunset. Barely handheld if you've got a very steady hand.

ISO 100:f22:92 with a 2 stop ND filter is EV 2-3 at the sensor, two stops less light than a candlelit scene - deep into tripod territory, with the absolute light levels at the scene a lot darker than it appears in the image.

The image was captured with the very last rays of the already-set sun, with the foreground light already strongly dusky blue. This creates a strong contrast between the red of the sky and the blue of the shore and clouds. A 2 stop ND filter was chosen to balance the skylight and ground light and to slow the shutter speed down so as to blur away the detail in the surf, turning it misty and cloudlike.  The lack of wind at low and high levels kept the clouds roughly in place, lending a surreal quality to the image.  A tripod was absolutely essential to keep the foreground and midground details free of motion blur.  Had the photographer a 5 or 6 stop ND filter, he could have used a smaller aperture which would have avoided some diffraction limiting in the foreground detail but would have minimized depth of field.

Attempting to shoot this scene handheld as you propose would not only have resulted in handholding motion blur - especially with such a high resolution camera - but would not have produced the ethereal effect you see.

Spot on!

It was getting quite dark when that picture was taken, over 30 minutes after sunset. The reason for the small aperture and long exposure was not for the waves, but for the cloud movement. I have to say i was thankful for the dr of the d7100 as the exposure time (an educated guess!) came close to blowing the highlights in the sky, particularly the red channel.

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