This photo is approx 2X life size:
Wolf Spider
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Wolf Spider
This little guy came home on our granddaughter's picnic blanket the other day. 14 image stack, Canon MP-E 65 lens at 3X life size, each exposure 1/250 f8 combined in Helicon. I would have done additional images to get more of those front legs in focus, but was concerned about alignment.
This photo is approx 2X life size:
This photo is approx 2X life size:
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rjlittlefield
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Re: Wolf Spider
Nice pictures!Tom Stack wrote:I would have done additional images to get more of those front legs in focus, but was concerned about alignment.
I am curious about your alignment concerns. Was the camera at risk of moving sideways, or the spider? Have you gotten bad results before? This sort of image is not usually a problem for any of the stacking packages, so I am interested to know what might be different here.
--Rik
Rik,
The spider was mounted on a macro focusing stage and at 3X life size there was movement over quite a bit of distance as I focused, so much so that I could see the edges of the legs disappearing out of the frame when I did a rapid image series playback on the camera LCD. Really concerned me...
My alignment must have pretty good as I don't see much ghosting in any of the stacks I did...
Tom
The spider was mounted on a macro focusing stage and at 3X life size there was movement over quite a bit of distance as I focused, so much so that I could see the edges of the legs disappearing out of the frame when I did a rapid image series playback on the camera LCD. Really concerned me...
My alignment must have pretty good as I don't see much ghosting in any of the stacks I did...
Tom
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rjlittlefield
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Ah, "legs disappearing out of the frame"!
Yes, they will certainly do that. What's happening is that the camera has a fixed view cone, with its apex at the entrance pupil of the lens. When the camera is positioned to focus on the front legs, the cone is relatively wide at the front legs (and even wider farther back). But as you move the camera or subject closer, to focus farther back on the spider, the cone at the front legs gets narrower and narrower. Replayed as a movie, the front legs get bigger, wider, and may move out of the frame as the camera moves closer.
The usual way of handling this issue is to process the stack from back to front. That restricts the output image to cover only areas that were within the view cone at all focus positions. Recent versions of Helicon do this by default; in some other packages you have to explicitly set the order.
This issue is minimized by using longer lenses, which will place the entrance pupil farther away from the subject and produce a narrower cone.
--Rik
Yes, they will certainly do that. What's happening is that the camera has a fixed view cone, with its apex at the entrance pupil of the lens. When the camera is positioned to focus on the front legs, the cone is relatively wide at the front legs (and even wider farther back). But as you move the camera or subject closer, to focus farther back on the spider, the cone at the front legs gets narrower and narrower. Replayed as a movie, the front legs get bigger, wider, and may move out of the frame as the camera moves closer.
The usual way of handling this issue is to process the stack from back to front. That restricts the output image to cover only areas that were within the view cone at all focus positions. Recent versions of Helicon do this by default; in some other packages you have to explicitly set the order.
This issue is minimized by using longer lenses, which will place the entrance pupil farther away from the subject and produce a narrower cone.
--Rik