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08-11-2011, 10:48 AM   #16
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QuoteOriginally posted by po-jama people Quote
unless i'm completely misunderstanding, you're saying that it doesn't really matter how much i turn the focus ring on my fisheye because it's not even noticeable and everything will just be in focus whether i mess with it or not. so...why have it at all? or am i missing something?
Not dumb, not missing much, but there's a basic of optics: The shorter the focal length, the thicker the depth-of-field (DOF). Some little point-and-shoot and CCTV cameras have 2mm to 5mm fixed lenses set so everything from a few inches out is sharp. On our SLRs, some slow fisheye lenses are fixed-focus -- my Vemar 12mm f/8 works that way, no focus ring.

But a faster fisheye, even though it has huge DOF, still needs to focus if you want to shoot stuff that's fairly close. And the wider the aperture, the thinner the DOF. Let's say I have my DA10-17 at 10/3.5 and focused closest to 14cm. DOF is from just under 13cm to a little over 15cm, about 2.5cm (one inch) total. I certainly need a focus ring to work that close! If I focus to 1m, my DOF is 60cm to 3m -- I still need to focus to have any control over the image.

Here's a DOF calculator; play with the numbers: Online Depth of Field Calculator

When an ultrawide is stopped down to f/8 or f/11 and aimed at a subject over 1m away, the focus ring doesn't do much. You won't see much difference. But working faster or closer, it's another story.

08-11-2011, 11:13 AM   #17
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QuoteOriginally posted by RioRico Quote
Not dumb, not missing much, but there's a basic of optics: The shorter the focal length, the thicker the depth-of-field (DOF). Some little point-and-shoot and CCTV cameras have 2mm to 5mm fixed lenses set so everything from a few inches out is sharp. On our SLRs, some slow fisheye lenses are fixed-focus -- my Vemar 12mm f/8 works that way, no focus ring.

But a faster fisheye, even though it has huge DOF, still needs to focus if you want to shoot stuff that's fairly close. And the wider the aperture, the thinner the DOF. Let's say I have my DA10-17 at 10/3.5 and focused closest to 14cm. DOF is from just under 13cm to a little over 15cm, about 2.5cm (one inch) total. I certainly need a focus ring to work that close! If I focus to 1m, my DOF is 60cm to 3m -- I still need to focus to have any control over the image.

Here's a DOF calculator; play with the numbers: Online Depth of Field Calculator

When an ultrawide is stopped down to f/8 or f/11 and aimed at a subject over 1m away, the focus ring doesn't do much. You won't see much difference. But working faster or closer, it's another story.
ahhh ok i gotcha. thank you. photography has been a casual (with emphasis on the casual) hobby for me up til this point. but i want to start taking it more seriously and all this info has been very helpful.
08-11-2011, 11:14 AM   #18
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thanks to everyone who responded! i am pumped to go take some pictures
08-11-2011, 12:35 PM   #19
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QuoteOriginally posted by po-jama people Quote
thanks to everyone who responded! i am pumped to go take some pictures
Well, that's the point of all this, isn't it?!?!?

I'm reminded of Tom Lehrer's HUNTING SONG:
You just stand there, looking cute
And when something moves, you shoot!
The next couplet could be about snapshooters:
Well, there's ten stuffed heads in my trophy room right now:
Two game wardens, seven hunters, and a cow.
But I digress. Have fun!

08-12-2011, 08:45 AM   #20
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I'm a little late in the reply as it's been a busy week. You won't likely see a big difference in focus on the fisheye. I have a pretty good collection of manual lenses and on several occasions I have forgot to switch my camera back to AF when mounting my DA 10-17 or DA 15 and most of the shots came out just fine. I never noticed the lens wasn't focusing although on the large computer screen, some were a little soft but still usable. Ultra wides are almost "stupid photographer proof".
08-15-2011, 08:50 AM   #21
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Fisheye lens:

08-16-2011, 09:35 AM   #22
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QuoteOriginally posted by Sakura Quote
I own the same fisheye lens, and indeed it's really great fun.

I'm not sure or the K200d can also shoot movies, but if so, you really should try making a movie while standing on rolling stairs
The k200d can not make videos nor can the K20d. That started with the K-x/K-7 and K-r/K-5.
08-16-2011, 09:58 AM   #23
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QuoteOriginally posted by Blue Quote
The k200d can not make videos nor can the K20d.
Well, sort of. The K20D in Burst mode shoots 23fps at 1536x1024px JPG, but no sound. It ain't HD but it ain't bad. Pretend you're DW Griffiith or Spike Jonez; then overdub a theatre organ or techno track.

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