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Old Dec 6, 2007, 10:29 PM   #1
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It says in the Challenge instructions that we're supposed to learn from the experiences here...

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...We are all winners in that we can learn something from every photo posted
and this current 'fabric' topic has taught me some technique I should probably have known already after all these years. I've done macro close-ups in my time, occasionally as a scientist), but always with 35mm SLR, and I'd forgotten one of the basics.

I find it frustrating how far away the point of nearest focus is on my Kodak Z712, and it occurred to me that my little Casio EX-Z750 (with only a 3x zoom) might do better than my 12x superzoom lens so I tried it. The largest size of sharp image I can get optically is little different if I go further away and zoom in.

In fact, at shortest focal length, and as close as the focusing mechanims would go, there was no difference either in the size of imageI could get from the two cameras. But for obscure softwaredesign reasons, with the Casio it was necessary to go further away and zoom into persuade it to provide me with a smaller stop than f/4 when in aperture priority mode. This made me realise that I could, (doh!), of course get a greater apparent depth of field anyway, by simply by moving further away. For simple geometric reasons, everything is apparently closer together the further away you are.

So on going back to the Kodak, simply by going further away and zooming in I managed to add another fabric (a silk bow tie) to the shot of the sheep, and gain more depth of field at the same time. The greater distance improves the distribution of the on-camera flash as well.

(Tiny bit of USM after resizing the original whole frame, 116mm equiv instead of 36mm, both f/8; earlier one cropped a bit).

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Old Dec 6, 2007, 11:13 PM   #2
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Thanks for your lesson, Alan. It reminds me of a photo series commissioned by my father. At the time he was a token (e.g. bus tokens, trade tokens, etc.) collector. He had a set of tokens he wanted photographed for a brochure he was producing. At the time, I had a Minolta SRT-101A and three prime lenses, 35mm, 55mm, and 135mm. I ended up putting the tokens on a paper background on the floor using a high-intensity desk lamp for light and mounting the camera on a tripod about 3 ft above the floor. I used the 135mm lens and the tokens filled the frame and were in sharp focus. My dad was elated with the results.

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Old Dec 12, 2007, 11:25 PM   #3
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That's one great thing about taking on these challenges...we always learn something new....good for you!! :-)

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Old Dec 13, 2007, 9:34 AM   #4
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Alan, after reading your comments again, I see that you have illustrated the difference between zooming and moving the camera. Zooming in or out does not change the perspective of the shot but merely the size of the image. Moving the camera definitely changes the perspective. Perhaps we'll do a challenge in the future on this topic. If you really want to see the difference, put some tape on the zoom ring to keep it from moving. Now, move the camera in closer to your subject and shoot. Next, go back to your original location, remove the tape, and zoom in so the subject is the same size in the viewfinder as when you moved the camera. You will see a definite difference, especially if there are peripheral objects on either side of the field of view between the camera and subject.

Note--This example assumes DSLR with manual zoom. If shooting a P&S with electric zoom control, you can do the experiment by simply not touching the zoom control when moving the camera in toward the subject.

Happy shooting and Holidays.

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Old Dec 16, 2007, 9:45 AM   #5
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calr wrote:
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three prime lenses, 35mm, 55mm, and 135mm....tokens onthe floor...using a camera...about 3 ft above the floor. I used the 135mm lens and the tokens filled the frame and were in sharp focus.
I did some experiments recentlyto help someone in the Kodak forum photograph coins with his Z712is like mine. I zoomed to 432mm equiv., set minimum focus and moved the camera to & fro to focus a ruler about 25 inches away against my monitor.
As you can see I got a field71mm wide, so really macro photography is not for me. Doing the same at 36mm equiv. gave 76mm width, so for my enormously complicated zoom, it made little difference.
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