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Old Jan 24, 2003, 4:12 PM   #1
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Default MF distance correct?

Does anyone know how accurate the ft/m scale in the MF mode is? I need to use the MF for supermacro with my 5050 and wonder if i can go by those, and physically measure the lens distance . The lcd even zooming in for the focus just isn't clear enough.:?:

thanks in advance
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Old Jan 25, 2003, 6:56 AM   #2
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I don't think it is very accurate - certainly not on mine.
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Old Jan 25, 2003, 7:30 AM   #3
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It's not accurate on the D7's either, initially may be but not after the zoom ring is adjusted...

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The lcd even zooming in for the focus just isn't clear enough.
Can you magnify the LCD? Manual focus works really well on the magnified D7's EVF for macro shots, which is a tiny LCD.
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Old Jan 25, 2003, 8:27 AM   #4
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Regarding magnifying the LCD, that's what was meant by zooming...when you're in manual focus mode on an Oly, when you push the focus adjust button the LCD automatically magnifies/zooms-in so you can see it better.

As for accuracy, unlike better SLRs which have a measurement mark on the camera body to show you the film plane, there's no such mark on most digitals so you don't know where to measure from...is it measured from the end of the lens, beginning, where the CCD is? Until you know that, you can't use the measurement fully.
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Old Jan 25, 2003, 10:55 AM   #5
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... Even if you know what the distance is, how would you input this to the camera, since the camera distance scale is not accurate in the 1st place? ops:

I guess we have to live with WYSIWYG!
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Old Jan 27, 2003, 12:45 PM   #6
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... Even if you know what the distance is, how would you input this to the camera, since the camera distance scale is not accurate in the 1st place?
NHL, I am using a custiom rig with my oly: an old manual belows rail off my canon FD line. With macro so precise, I will not focus the camera to the distance, but move the whole camera in relation to the subject. I found that the enlarged view in manual focus has too much noise to clearly identify correct focus; which is the same i found with the nikon 5700. With olympus' supermacro on, coupled with a macro lens infront, its a trial and error most of the time.
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Old Jan 28, 2003, 4:54 AM   #7
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Default Manual Focus Correct?

The german manual of my C4000Z calls the figures of the MF scale "approximations". There is a possible reason.

With a regular SLR Zoom you expect the focus to stay correct at the set distance over the whole zoom range. Designing a zoom lens like this takes a lot of extra correction and effort. With the full time use of autofocus with digital cameras this extra effort is dispensable, because the autofocus does a calibration for every individual picture.

I wanted to have an idea what my camera does with MF. I took test pictures only with maximum aperture F=2.8 and maximum focal length. I do not know wether all C4000s act similar. As a reference point I took the front side of the camera body. I did not try super macro. For super macro I totally rely on auto focus.

At a range up to 3 feet the scale seemed correct (you should be aware that the figures and the spaces inbetween are non-linear).

Beyond a distance of 5 feet I had to add 30% to the real distance.

This means, that there was no way to manually set the distance to infinity with F=2.8 and maximum tele; how can you add 30% to infinity? With this setting the camera was focused for 15 feet.

I do not complain. Once I know the limitations, I still appreciate the possibilities of this feature.
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Old Jan 28, 2003, 6:36 AM   #8
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Quote:
With a regular SLR Zoom you expect the focus to stay correct at the set distance over the whole zoom range. Designing a zoom lens like this takes a lot of extra correction and effort. With the full time use of autofocus with digital cameras this extra effort is dispensable, because the autofocus does a calibration for every individual picture.
'Zoom' is a misnomer, they are really called Varifocal the more exact term! It's also why one can't zoom-in, manual focus on the detail (like on a true zoom), and zoom-out and expect the picture to stay in focus ops:

It's has been like this for a while with the advance of Auto Focus, and the quest of consumers for smaller lens/affordable cost... remember the fix aperture at all focal point? that also went with the advance of auto metering! ops: ops: ops:

True zoom with fixed aperture lenses still exist, but usually are also very expensive (and if I recalled cost more than some cameras)
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