Incense

by Bart Arondson

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I just bought a used Vivitar V3800N with a Vivitar 50mm 1.7 lens for an intro photography course. I'm coming from a fully-automatic D60, so this fully-manual camera feels really alien to me.

I'm trying to learn how to focus, and I understand that I should get the split image in the focusing screen to align.

focusing screen
Image: CC by rpmaxwell

But when I do so, the overal image is blurry. I can get the split image to be sharp (when unaligned), but then the outer areas are blurred. The distance of the subject is about 3 feet. Things get so small from further away, that I'm not really sure if things are really in focus when aligned; everything's just so tiny.

Is this normal? Is my approach correct, or should I be doing something different?

I bought it from B&H's flagship store, where it was rated an 8+.

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1 Answer 1

up vote 4 down vote accepted

The prism (neither the split in the middle nor the pyramid collar) is not a focusing screen; it's a focus aid. You'll notice that the image on the focusing screen is in focus when the image in the prism makes geometric sense (the two image halves in the split prism align, and the "dazzle" in the collar becomes a solid image).

Don't worry about the quality of the image in the prism, just the alignment. (The prism image can't be well-focused, otherwise you wouldn't be able to see the image halves to align them if you're out of focus by more than a little bit.) All of these focus aids act in a similar manner when focusing through the lens. It's only when the image you record on film is blurry when you focused properly on the ground glass/prism that you have to worry about there being alignment problems with the camera.

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Thanks for pointing out the correct terminology. Are you able to find a link to the prism or the pyramid collar? I'm still not sure what those are. I'm both relieved and confused by two things you said though: "the focusing screen is in focus when the image in the prism makes geometric sense" and "don't worry about the quality of the image in the prism, just the alignment", because when the split image makes geometric sense (is aligned), things are not in focus. Do you see my confusion? –  Louis Jul 5 '12 at 0:53
    
@Louis - Look at the picture you posted. The split prism is the bit in the middle where you try to align the two image halves; the pyramid collar is the ring around that with the sort of checkerboard pattern (the image becomes solid when you're in focus). The focusing screen is the rest of the viewfinder image (outside of the collar). –  user2719 Jul 5 '12 at 0:59
    
alright, I think your explanation just hit me. I will just shoot based on the alignment (even if the image doesn't appear to be in focus). Looking forward to developing a roll in the darkroom! –  Louis Jul 5 '12 at 1:18

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