Long Exposures and the Pentax 645D

I spent about three hours on New Year’s Day wandering around Cliff Gilker Park in Roberts Creek, BC. On the way back, a spectacular sunset greeted my arrival into Davis Bay. After working in a few photolabs for a combined total of nearly seven years, I thought I more than had my fill of sunset photos. Mother Nature still has some surprises!

The Pentax 645D has very low noise images in general, but I haven’t had the opportunity to really push it to the limits of the marked shutter speeds. The lowest user-selectable speed is 30 seconds. The image below was shot at 25 seconds f/11. I was pretty much tripping over the rocks at that point. It was dark! The subtle fill light in the rocks was from a single street light located at least 50 feet behind me. Fortunately for me, it was sodium vapor so the color matched the sunset quite nicely. This image was shot about 30 minutes after the sun dipped below the mountains on Vancouver Island. The city lights in the distance are Nanaimo.

As an aside, white balance can be an easy tool to altering the appearance and mood of an image. A cool white balance for images of people is seldom attractive unless going to a particular style. Warm it up a bit and the skintones look attractive.

For the image above, I played with the white balance setting on the camera then tweaked it further in Lightroom. The fluorescent setting can give quite an attractive appearance to this sort of image. As is standard on most DSLRs these days, the 645D offers further tuning on the cyan/blue versus yellow/red axis as well as the magenta versus green axis. Very handy!

Back to noise characteristics… I mentioned there was a street light behind me and to my right. It provided some fill on the rocks in the foreground, however the sky was changing quickly and the light was fading. To wait for better balance between the street light fill and the sky wasn’t going to happen. Plus it was cold. After a half hour crouched over the tripod I was done. No suffering for my art. Adjust in post.

Below is a 100% crop from the rocks near the waterline in the center of the image.

Bringing more detail into this area can be accomplished via a number of methods in Lightroom / Camera Raw or later in Photoshop. While I don’t favor the extreme brightening in the image below, it shows what lies in the shadows of a 645D image.

The Fill Light slider was moved to a setting of 50 from its default of zero. Noise reduction is at zero for Luminance and 10 for Color. Reducing the Color slider to zero shows some noise, however if you consider that the default setting is 25, I don’t feel zero is a realistic setting.

I think the engineers at Pentax should be lauded for the excellent long exposure noise characteristics of the 645D. (Kodak too, since they manufacture the sensor) Compared to some other cameras on the market, this looks great. To top it off, the long exposure noise reduction (dark frame subtraction) didn’t even kick in at 25 seconds. In other words, there was no waiting after each exposure before taking another. Wow.