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#175966 - 11/16/18 08:27 AM Re: Oh..You "Canon" guys... [Re: Captain Chris Stanaback]
thevalueman Offline
Knife Enthusiast

Registered: 02/04/08
Posts: 2828
Loc: Georgia
Capt,
While this may not fit here....I needed to catch your, or anyone's attention...I need to know about "focus shift" and how it occurs. I sold that Leica camera body, as well as some lenses...and appears that one byer is claiming "focus shift"....from what I read, it's something that needs both pieces to come into play, the camera body, and the camera lens, however, I my be incorrect....can anyone help me understand this phenomenon??
Thanks
:-)Rocky
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Rocky Whitaker
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#175967 - 11/16/18 08:38 AM Re: Oh..You "Canon" guys... [Re: thevalueman]
W Polidori Offline
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Registered: 02/09/16
Posts: 5791
Loc: Central New York
Google it Rocky.
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#175982 - 11/16/18 11:30 AM Re: Oh..You "Canon" guys... [Re: W Polidori]
thevalueman Offline
Knife Enthusiast

Registered: 02/04/08
Posts: 2828
Loc: Georgia
I have, but I trust the folks here for a more layman's understanding...

:-)Rocky
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#175990 - 11/16/18 01:33 PM Re: Oh..You "Canon" guys... [Re: thevalueman]
Captain Chris Stanaback Offline
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Registered: 09/14/05
Posts: 12664
Loc: Central Florida
Rocky,
The more "open" (aperture) your lens is, the more problems will occur with (lens) focus shift. In other words, a subject shot at F8 will have less turmoil than one shot at F2.8. Many lenses, even high-end ones exhibit this problem. On some cameras the issue can be resolved by focusing with a more open aperture and then re-adjusting to a more closed one, similar to "depth-of-field".
I am no photography expert but I try to eliminate problems like this by:
* Backing up
* Moving my image farther away from the camera
* Closing down a few F stops...
....&....
* Shooting at a higher ASA.
Good luck, Capt. Chris
PS: Where's "Litch" when we need him??
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Capt.Chris Stanaback
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RKS #016
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#175991 - 11/16/18 02:11 PM Re: Oh..You "Canon" guys... [Re: Captain Chris Stanaback]
Litch Offline
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Registered: 11/11/08
Posts: 1273
Loc: Rhein/Main
Rocky,

if I understand it correctly, this is an optical problem that occurs due to spherical aberration and that can only be eliminated when constructing the lens. But it only occurs with SLRs - not with a viewfinder camera like the Leica M3...

Depth of field is something different. It can be quite narrow if you are really close. Backing up helps but you'll lose a lot of your precious high-res wink
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Peter

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#175993 - 11/16/18 02:29 PM Re: Oh..You "Canon" guys... [Re: Captain Chris Stanaback]
Captain Chris Stanaback Offline
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Registered: 09/14/05
Posts: 12664
Loc: Central Florida
Rocky,
Almost all of the old viewfinders have focus shift issues, i.e. the "fixed" focal point intersects at 2 separate points, making only a portion of the subject totally in focus. This is nothing new and completely normal, given the specifics of a particular shot! I think Litch will agree. As for someone complaining about this?
Dunno'!
Hope this helps, Capt. Chris
PS: Focus shift also occurs on Canon DSLR's...(at least, according to the "You-Tube-Gurus"...CCS
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Capt.Chris Stanaback
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#175995 - 11/16/18 02:42 PM Re: Oh..You "Canon" guys... [Re: Captain Chris Stanaback]
Windsor Offline
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Registered: 08/12/15
Posts: 1861
Loc: Texas!
Also, you can run a higher f-stop if you slow down the shutter speed (a side effect of running higher ASA film).

I believe the rule of thumb was to never go below 1/60 if you're holding it by hand. If you're mounting the camera on a tripod and using a remote trigger, you can run some awfully low shutter speeds.
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#176001 - 11/16/18 06:24 PM Re: Oh..You "Canon" guys... [Re: Windsor]
thevalueman Offline
Knife Enthusiast

Registered: 02/04/08
Posts: 2828
Loc: Georgia
Thanks guys!!!
This is the ammo I was looking for...I guess the fellow that bought my lens, and either used it for what he wanted, lacks experience, or simply decided that they did not want the lens after all
eBay/PayPal...you just gotta love um...all in favor of the buyer, screw the seller
sorry to hijack the thread

:-)Rocky


Edited by thevalueman (11/16/18 06:25 PM)
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