It should be kept in mind that these are extreme closeups, taken with my 90mm macro lens. The greatest challenge with such closeups is depth of field. This optical limitation poses problems as it is simply not possible to keep everything in sharp focus when the subject has depth, as with this bromeliad. (The only other option would be to try to take a series of shots at different points of focus and combine them in a composite image. There is software to handle such projects, but my success with such attempts has been not so good.)
My lens allows me to use an extremely small aperture, in the case of this first shot, f/64, as small as the lens is capable of. Even so, much of the image is out of focus. For example, the orange leaf in the upper right of the image is quite out of focus. That and other more distant leaves do not bother me. However, my goal was to keep in focus the edges of cluster of small leaves in the lower left. However, when I focused on them the tips of those leaves, which have browned out and which were closest to the lens went out of focus. In my experience it is OK to have more distant features go out of focus, but when the closest features (the tips in this case) are out of focus, it becomes a distraction to the viewer who assumes the photographer made a mistake. So in the end I set the focus on the tips and let the focus on the edges of the small leaves go soft. For the record, the exposure for this shot was 2.0 seconds at an ISO of 200.
The next shot was taken from a slightly greater distance to include (almost) the tips of leaves in the lower portion of the image. The shot was cropped a bit on the top and right side.
The metadata for this shot were f/57 for 1.6 seconds at ISO 200. This is my favorite of the shots. I actually like the fact that the leaf tip in the lower left is just off the edge, creating a bit of a tantalizing effect.
The final shot was taken from a bit further away at f/51 for 1.6 seconds at ISO 200. Perhaps a bit too much extraneous stuff?
John
I enjoy your discussion of the technical side of things John, even though I mostly don't understand it all. It's interesting to read your analysis of your photos too - the good and the not-so-good (mind you it ALL looks pretty good to my untrained eye!!).
ReplyDeleteYou make a good point that the discussion was a bit technical but probably without adequate explanation. Depth of field refers to the fact that a lens can only focus on one distance from the lens. Everything closer to or further from the lens from that plane of focus are going to be out of focus However, you can control the extent to which objects not in the plane of focus are out of focus. If the lens aperture (size of the opening of the lens) is narrow, then the band of relatively good focus both in front of and behind the plane of best focus can be quite wide (high depth of field). If the lens aperture is large (wide open), then the depth of field is quite narrow. This is more of a problem for closeup photography than for photos where everything is at a substantial distance from the camera, such as a distant landscape. Aperture is rated by "f-stops." The higher the number in the denominator, the narrower the aperture and the greater the depth of field. So f/4 is relatively wide open, while f/36 is very narrow.
ReplyDeleteI have a little Canon Power Shot digital camera that's probably almost ten years old, so no opportunity to fiddle with the technical side of things. I've heard all the terms and have a vague idea but obviously a tad out of my league. I enjoy your explanations and discussion anyway - who knows maybe some of it will sink in!
DeleteOne of the great advantages in a more versatile camera is that one often can choose what parts of the image are in or out of focus. That's the essence of depth of field. Think of a portrait of an individual where subject is in focus but the background is out of focus, eliminating elements that might otherwise distract from the primary subject.
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