Last week was, as usual, an exercise in refreshing my memory of photographic techniques and forcing me to follow those techniques to their ultimate conclusions. I am pleased to note that I ended up with several sequences of images that illustrate very nicely some of those processes, and as time allows, I hope to share those progressions to y'all, with pictures.

Case in point, backgrounds and depth of field. Pictures behind the cut to save your bandwidth )
Bracket your depth-of field. Throwing your aperture wide open might blur your background beautifully, but you may also lose important details in your subject. Closing it down all the way will give you more subject detail, but could resolve that pleasing blur back into distracting graphic elements. Sometimes, an endpoint is where you want to be. Other times, you want to live in the middle.

Case in point, this false hellebore leaf:
False Hellebore 1

which I shot at several f-stops, including f/3.5, which lost the curve of the back edge of the leaf, and f/32, which brought the background into far too sharp of focus, and in the end chose this instance at f/8, about the middle of the road.

ETA: The full set is here. I have this evening's shoot and tomorrow morning yet to go, so I may add some more over the weekend. Assuming I get any more shots I like.
georgmi: Camping on Shi Shi Beach, WA (Default)
( Apr. 7th, 2010 01:28 pm)
Depth of Field, or Why isn’t everything in focus?

So it’s been almost two years since my last “how photography works” post, and I know y’all have been waiting with bated breath, but Depth of Field is a much easier subject to talk about when there are examples to look at, and until recently, I didn’t have any useful examples. But now I do. I actually wrote most of this post two years ago, so if there are disjunctions, paragraphs dropped halfway through, or any other problems with the text, do let me know!

Long, and with images. )

Related topics (will add links when associated articles are written, or you can search on my “photography” tag):
Exposure
Focal lengths, f-stops, photon density, and autofocus
What the hell is "bokeh"?
Depth of Field
Camera shake and motion blur
Using the flash (Yeah, right! As soon as I figure it out myself…)
Film: Reciprocity failure
Expanding depth of field with Photoshop
Digital: The histogram is your friend

Feel free to suggest topics as well, though I make no commitment to address them in a timely manner. :)

Disclaimer/acknowledgments: Except as noted, all the above text is original to me, composed without direct reference to any other source. However, there are some people who have had a profound impact on my knowledge of photography, and it is possible that what came out of my head is very similar in language to what they tried so hard to put into it, so it would be remiss of me if I did not acknowledge their prior assistance.

I am deeply and directly indebted to Rod Barbee, Scott Bourne, Don Mammoser, and David Middleton for their in-person assistance and instruction. I have also been significantly influenced by the written works of Ansel Adams, Art Wolfe, David Gardner, and Galen Rowell. Years of articles in _Outdoor Photographer_ magazine provide some of my background as well.
georgmi: Camping on Shi Shi Beach, WA (Default)
( Dec. 30th, 2009 10:02 am)
Paul Burwell is a professional photographer up in Edmonton, Alberta. He and I (and a couple other guys) shared costs on a wildlife shoot outside Glacier NP a couple of years ago.

Anyway, living in Alberta, Paul sees a bit more snow than we do here in Seattle, and he's started taking pictures of individual snowflakes. He posted one to his blog this morning, and it's fabulous.

As to his technique, when I asked him, he said, "I let the snowflakes fall on my parka, and use a small paint brush to transfer individual, interesting looking flakes from there to a piece of glass where I photograph them."

Beyond that, I expect that he's using a strong, sharp macro lens and a tripod, that the glass is most likely clamped solidly to something so that the plane of the glass is parallel to the plane of the camera's sensor, and that the background color is a piece of cloth positioned several inches behind the glass. Probably a circular polarizer on the lens, and the flake itself is probably not in direct sunlight--note the soft light, and the suggestion of both front- and back-lighting. F-stop is whatever will render the flake in good focus, but throw the background into the land of bokeh.

If I lived somewhere where it actually got cold enough to capture individual snow crystals of a decent size, I would right now be on my way home to get my gear and try this out. Nobody else is here at work anyway.
...because I do not want you to know what happens inside my head except in the controlled circumstances under which I normally share. I don't need help "interpreting" my dreams, and the ones I remember generally explore aspects of my personality that you don't need to know about.

But this one was too weird not to say something about, and emotionally neutral enough that I can let it out. Not weird in the surreal sense, except to the extent that who thinks about that enough to dream about it all night long? Also it lets me put on my teacher hat, and I like showing off things that I know. :)

It was Monday night, after I got my new lens. Not too surprisingly, I dreamed about taking pictures with the new lens. But the dream did not focus (that there is a pun, you see immediately. What you do not see right off is that it is a pun *twice*) on the subject of my photography. Instead, it was about bokeh.

WTF is "bokeh"? you ask, and well you might. Bokeh is a Japanese term (alternately spelled boke, but adding the 'h' guides the reader closer to the correct pronunciation) which refers to the quality of the appearance of the unfocused area of a photograph. It does not, in my admittedly limited experience, get much attention in American teaching of the photographic arts.

Broadly, when a point source of light is not part of the area of sharp focus in a photograph, it is blurred into a small disc (we will discuss this as a "circle of confusion" in the Depth of Field article which I will someday write). The distribution of brightness in this disc determines bokeh. If the light is evenly distributed across the disc, this is considered "neutral" bokeh. If the light is concentrated toward the center of the disc, and fades away toward the edge of the disc, this is considered "good" bokeh. If the light is concentrated toward the edge of the disc and fades away toward the center, this is considered "bad" bokeh. These effects are going on with *every* unfocused point in the image, not just light sources, it's just that it's easier to see the effects with point sources of lights.

The reason why "good" bokeh is good is that the different points blend gently into their neighbors, providing smooth transitions between edges. "Bad" bokeh is bad because edges blend into each other discontinuously (because each edge appears as a double edge with a gap in between). At its worst, bad bokeh can make the out-of-focus areas of the image appear jagged and distract from the subject, just the opposite of the effect you're going for when you throw that area out of focus in the first place. The effects are generally very subtle, though, even if you are looking for them and know what you are about. I have never had a lens that allows for as much unfocused space in my images as my new lens will allow (also, as a shooter of landscapes, I tend to try to maximize the depth of field in my images and minimize the areas of unfocus), so I have never paid any attention at all to the bokeh in my images. I am aware of the phenomenon (obviously), but it's never been an issue or an interest for me.

So imagine my surprise when I dream me many dreams over the course of Monday night, all about me taking pictures in various situations with my new lens, and all focusing (and now you see why that is two puns for the price of one) on whether or not I was getting good bokeh out of the deal. Sometimes I was just holding the lens, with no camera attached, and evaluating the bokeh I was getting from it. Sometimes it was little fading-to-the-outside discs, and I was happy. Sometimes it looked like little rolled-up condoms, and I was annoyed.

I expect I will find out this weekend what kind of bokeh the lens actually has, and I will never have these dreams again. Though even for a given lens, bokeh can vary depending on whether the out-of-focus point is closer to or further from the camera than the field of sharp focus. I understand that some Nikon lenses, and formerly, some Minoltas (Minolta has gone bye-bye, and we are saddened), actually allow you to adjust the spherical aberration of the lens in order to change the bokeh effects, but boy, is *that* ever a topic for the Advanced Class. :)

ETA: Because spherical aberration in lenses is about the differential refraction of light waves, and while my math is probably up to it, my ability to *describe* the math is probably not, that's why.

Related topics (will add links when associated articles are written, or you can search on my “photography” tag):
Exposure
Focal lengths, f-stops, photon density, and autofocus
What the hell is "bokeh"?
Depth of Field
Camera shake and motion blur
Using the flash (Yeah, right! As soon as I figure it out myself…)
Film: Reciprocity failure
Expanding depth of field with Photoshop
Digital: The histogram is your friend
(Part 2 will have to wait until after the weekend.)

I knew it was going to be nice. I knew that, theoretically at least, the autofocus was going to be faster, quieter, and more accurate.

Digression the first: Focal lengths, f-stops, photon density, and autofocus.

This gets long, and there is a little math... )
The short story: Oh. My. God. What an *awesome* lens.

Related topics (will add links when associated articles are written, or you can search on my “photography” tag):
Exposure
Focal lengths, f-stops, photon density, and autofocus
What the hell is "bokeh"?
Depth of Field
Camera shake and motion blur
Using the flash (Yeah, right! As soon as I figure it out myself…)
Film: Reciprocity failure
Expanding depth of field with Photoshop
Digital: The histogram is your friend
georgmi: Camping on Shi Shi Beach, WA (Default)
( Sep. 13th, 2007 12:59 pm)
Been thinking about photography again, what with the trip to Yellowstone just past and the trip to Vermont coming up next month. Thinking about photography makes me think about the book(s) I want to write to help people get more out of their photography. I see so many people out there, taking pictures that I just *know* aren't going to turn out the way they could; I want to run up to them and tell them what they're doing wrong, and how they can do it better. But I am *positive* that this would be universally annoying and wouldn't do anybody any good. Also, it might lead to questions like, "How would you take this picture?" to which the answer is often, "I wouldn't," for a variety of reasons, and then it would seem like I'm condemning their taste *as well as* their competence.

But here, I have a (reasonably) friendly audience, and I'm not singling anybody out for a specific criticism. (As a rule, I don't criticize other people's pictures unless they specifically ask me to. I'll point out things that I think work particularly well in the image, but no negatives.) I do, however, believe that there are some common things that most people don't understand about photography and that a basic understanding of these things can make anyone a better photographer pretty quickly. I also believe (OK, I more than believe this--I know it for a fact) that the limiting factor in almost every photographer is in the head, not the camera. Once you know your gear and its limitations, great photographs can be taken with almost any camera, from your 1.5MP cell phone camera all the way up to the 8"x10" view cameras used by Ansel Adams and William Henry Jackson. (Your format may limit what you can *do* with your images, but that's another article.)

PS: Comments on the usefulness and understandability of the information presented below are encouraged, as are suggestions for topics of future, similar articles. I’m interested in comments from everybody—if you know what I’m talking about and I got it wrong or missed something, or if you don’t and all I did was confuse you, let me know. It’s often tough for me to pick a logical and useful path through a topic with breadth and depth and interconnections, given my penchant for digression and distraction. Questions, no matter how specific or general, are also welcome. I am here to help.

So, anyway. Exposure. )
What is exposure? )
Controlling exposure )
Cameras and eyes )
Handling exposure extremes )
Practical steps )
Example image )
Related topics )
.