Figure 1: The DoF (Depth of Field/Focus) equation.
Depth of Field ain’t so tuff.
Recently I needed to take some photographs of the antique glassware that my spouse collects. This is easy with a point n’ shoot, since its depth of field is pretty good thanks to the short focal length that most point ‘n shoots have in their built-in lenses. The point ‘n shoots usually have a wide angle (anywhere from 6 to 15 mm – but sometimes variable up to higher focal lenghs with fixed zoom offsets).
Read more about my DoF
Figure 1: My Pentax K5 probably isn’t under warranty now.
So … I guess my K5 has long been out of warranty anyway. About a year ago the mirror-box went out of calibration. Anyway – I think that’s what happened, and I thought about sending it in for a re-cal. Subsequently the LED/Live-View screen went belly up, and finally the main board. The cost trade-offs seemed to imply that fixing the K5 was no longer an option, so I decided I may as well take it apart and see what makes it tick. After a dozen or so tiny little screw removals …
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Have you ever asked yourself why those photoless days – the cloudy ones, are so diffused and blue?” Probably not, because it seems to not be an important question to ask yourself. Unless you’re me. I love deep-diving the trivial things, it seems.
Blue light scatters, and red light is absorbed. Actually, some blue light is absorbed, and some red light scatters, but it’s more often the other way around. So, on a bright sunny day, all the light comes from one spot in the sky, right? But on a cloudy day, it seems to come from every direction. That’s because it IS coming from every direction, as a result of scattering. When you take the red and yellow out of the color spectrum, what is left? Well, green and blue are what remains – but it’s the blue we mostly see, because there’s not much in the clouds to reflect green light. Water reflects blue light pretty well. So, now you know the answer, and I’m sure you feel much more fulfilled.
Photographers hate cloudy days. With the red and yellow all being absorbed, what is left is mostly scattered blue, and only 1/3 of the pixels in the photographer’s camera can catch blue light. So, the camera sees 1/3 of what it could see on a sunny day. No wonder the cloudy day pictures are dull and uninteresting.
An overcast day is the worst sort of day for a photo guy. The IR and the red tones are obliterated by the water vapor in the sky, and what’s left is a mono-tonish blue that uses only about a third of the pixels in your shiny new camera. The result is often boring, but I’ll admit that creative photographers sometimes manage special photos in spite of the clouds and blue light.
Read More Gimp tricks …
Figure 1: Nature made a surrealistic sculpture, awaiting my lens
The photo in figure 1 is of water swept grasses. Click it to see it in full size. Nature makes some very pretty stuff by accident sometimes. Lovely to be there to catch it.
For those wanting to see my smugmug collection of similar photos, the link can be followed by clicking this :
Figure 1 : Bee shot taken with K5, Pentax 50mm /f1.4 vintage lens
Recently I started to take macro tube shots of bees in my area. This is quite an addicting facet of photography, I must say. I’m a rank beginner at this task, but so far have managed a few semi-interesting shots. The picture in figure 1 is one of my favorites thus far (clicking on the photo will show it enlarged on smugmug).
Read more about the bees …
Figure 1: Should I go mirrorless?
When I first used my K5, I was enthralled. It was easily the most solid feeling camera I’ve ever owned. Most cameras give me the feeling that I have glass in my hand (smile) – and that I have to be careful. The K5 made me feel like I had a hatchet in my hand and that tossing it into a spiraling arc that ended on a cleaved tree trunk would do it absolutely no harm.
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