Here's another early morning test photo, this one taken of my next door neighbors' houses with my camera setup in my driveway:
I was testing my latest modification to my present camera project (the curious among you can see it here:
http://www.canyonero.com/files/1499805687.jpg) wherein I am adding a fixed amount of front tilt to allow me to achieve slightly more DoF without stopping-down the aperture, so as keep my exposure lengths as short as possible while using the A7R's base ISO setting to achieve maximum image quality. (Yes, I know that astrophotographers, who also take long-exposure photos at night, prefer to use much higher ISO settings than that when using their A7R bodies, but my testing has shown that, for
my purposes, ISO 100 is clearly the way to go.)
The result of this is that I was able to keep the gravel at the very bottom of the frame sharply focused simultaneously with the roof tiles at the very top of the frame. This isn't possible using just DoF alone, by stopping down as far as I can while still maintaining an exposure length of 30 seconds or less (which is the upper limit for the A7R, beyond which its firmware automatically drops one bit's worth of exposure range from its files, and thereby significantly reduces my ability to recover detail from the shadow areas during post-processing.) Unfortunately, the A7R is a less than ideal camera for the type of photography I do. However, it's also the best camera available to me and surprisingly, I find it to be a better performer overall -- for
my purposes, as YMMV! -- than the A7RII that replaced it. I would love to get my hands on a QHY367 astrophotography camera to compare to my A7R -- they share the same sensor, but have different firmware, so no issues with changing the file's bit depth for exposures longer than 30 seconds, plus, it actively cools the sensor to reduce thermal noise, a feature that will come in
very handy here in the Arizona desert, especially during our five months of summer, where the ambient temp when I'm photographing late at night is often higher than 100 degrees -- but I haven't been able to find anywhere I can rent one to test and at $4,395 MSRP, I can't afford to gamble and buy one just to satisfy my curiosity. <sigh>
Although I also own a Cambo Actus, which incorporates a front-tilt feature directly from the factory, I've found that keeping the plane of focus otherwise perfectly aligned with the sensor is difficult in the field, especially since I carry the camera around mounted on my tripod, which in turn is slung over my shoulder and bounces around a lot. I already had the Cambo WDS body on hand, leftover from my film days, so I thought I'd modify it a bit and see how well it fares for my purposes.
While the modified Cambo WDS does indeed work well, it turns out the amount of front tilt I can apply as a default (
i.e., for
every photo I take with it) isn't very large. So I've been experimenting with using different amounts of tilt to photograph a variety of typical scenes and it appears that using .024" shims (which in turn provide a fixed .34 degrees of tilt) is roughly the upper limit. Any more than that and I risk the roofs of houses or tops of trees going soft in some situations; any less than that and there is no benefit. And even with .34 degrees of tilt, the benefits are still fairly small -- it appears I gain only 1/3 to 1/2 of a stop's worth of additional DoF -- but helpful nonetheless.
We shall see...