Crop Circles: Part Three

The Unexpected Circles…

Greetings Holy Crop Readers. It has been a while since I posted due to a three-week excursion in Costa Rica teaching a Worldesigns Photo adventure. Internet is still spotty in the rainforest and time was limited.  I am back now and ready to resume some crop discussions.

This is an unexpected turn in the Crop Circle series as I was faced with an actual circular capture in the field.

Sloth through the scope via iPhone – Costa Rica

When working with a guide’s spotting scope the possibility of a circular capture is present-especially when shooting through the eyepiece. Like the lens on your DSLR, the spotting scope throws a circular image. Shooting through this lens’ eyepiece yields a smaller-than-full-frame image circle on my iPhone 4. 

The guide composed the image in the spotting scope and I was left to capture it as framed with only the choice to get the maximum circle possible. The circular offset in the 4:3 frame was unintentional.  Had I my choice, I would have framed the sloth in-scope  a little lower and a little right moving the face downward and off center.

It is getting time to have that circular composition discussion, isn’t it?

These circular images are starting to crop up everywhere, if you will forgive the pun.

Rikk Flohr © 2012

Crop Circles: Part Two

In the previous iteration of Crop Circles, I discussed, primarily for the sake of argument, the concept of the circular image.  Though our lens casts a circular image we tend to capture a rectangular subset of that image circle.  For now, I am going to drop the pretense of a film discussion and focus (pardon the pun) on digital capture. In an ancient Holy Crop! article, I discussed this in-depth and there is no need to rehash it here.  Images, on computer at least, are rectangular. Even the circular crop  above is bounded by a nice rectangular box specified in the PNG file format.

The impetus of this article is a casual email from a friend, Mark Sirota. Mark is a regular on Holy Crop! and a former victim in our Sharecropping Series.  Mark, ever on the look out for another cropping article to shovel into my salivating grin, sent me this rather brief email:

An interesting topic for the Cropist?

<http://photo.net/casual-conversations-forum/00ZoDd>

Mark

Apparently there is a world of circular cropists out there-at least a small band of intrepid corner-haters. I would encourage you to take a look at this link and see what the concept of circularity (is that a word?) does to your sensibility.  In fact, reading this series of posts is your homework and must be done before I can write the next installment. I will wait…

Like many of you, my grandmother had those old-fashioned portraits hanging in oval frames under curved glass. Any nice gift shop has an assortment of frames with oval or circular frames (more likely oval as that better matches the typical camera’s aspect ratio than does a circle).  But we are just cutting circles out of squares or ovals out of rectangles to use the more inclusive term. (after all, all circles are ovals just as all squares are rectangles.)

While I still maintain that with the exception of a lens’ image circle that the circular crop is a phantom (at least as it relates to a digital file), there may be some of you out there who want to create an ‘analog’ (read print) and trim it circularly, and display it.  What happens to composition when there are no corners?

Part Three of Crop Circles is going to explore just that. Is there still a Rule of Thirds? What about Grounding? Diagonals?

It will all have to wait for the next edition of Crop Circles in Holy Crop!

Rikk Flohr © 2012

Crop Circles: Part One

…from a topic suggested by Mark Sirota

The Crop You Forgot You Made

Every picture is a crop but likely not in the way you might be thinking. We all make viewfinder framing decisions where ever we decide to point our lens.  We slice out the rest of the world for that rectangular vision we desire. What we likely knew, but have forgotten, is that our camera, specifically our sensor is performing a crop of all the light gathered by our lens.

Lenses are round. They cast circular images. But our digital sensors, like sheets and rolls of film before them, only capture rectangular images. Shutters (talking in-lens shutters) could be round or rectangular but ultimately, modern cameras take a rectangular image to the emulsion or the memory card.  Our digital files, slides and negatives all reside in a rectangular format.

Math Time

Lenses: Focusable area of a standard 35MM format lens is roughly 1520 MM² at minimum to cover the shutter/sensor. The image circle of lenses varies slightly so this is an inexact number.

Sensors: Full Frame are 864 MM²

Cropping: The cropping which occurs in taking the rectangular ‘meat’ out of the lens’ image circle is about 44%. Only 56% of the focused image by the lens actually falls through the shutter and onto the sensor.

In the example I’ve mocked up above, you can see how the sensor effectively crops off much of the image circle. And, in this case, most of that lopped off detail is meaningless.  Nonetheless, we have lost part of the image rendered by our optics. There isn’t much we can do to get it back either.

“What is the point of all this, Rikk?” you might be asking yourself. We are, after all, stuck in a raster world where image formats are defined by an array of pixels that is always rectangular. It turns out, thanks to Mark Sirota’s pointing me to an interesting web community there is a small but determined band of circular croppers out there. Originally I dismissed Mark’s suggestion as being simply a group of matte-ers – sticking a rectangle with a hole on top of every image. But, as I thought about the origin of all our images being circular, it became less peripheral to me and I decided to take this topic on.

In Part 2 of this Crop Circles Series, we are going to dive deeper into this rogue group of croppers. Part 3 is going to talk about compositional considerations for the ‘circular crop’.

Stay tuned.

Rikk Flohr © 2012