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Old Oct 14, 2006, 10:48 AM   #11
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That firs tlink seems self expanatory. But are there any details I need to be aware of before i go in and attempt home adjustments (anything associated with the internal mirror, like unlocking it or something)? Or is simply turning a set screw? I can't read french. . . .i think it's in french. . . :-)
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Old Oct 14, 2006, 10:57 AM   #12
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Roughly translated:
The test card being used for the adjustment is a tilted slide caliper. The points of the rule move away here from the objective when the graduations decrease. One wishes to hang the central collimator on a contrasted black mark, carried out with an end of adhesive. The blue square indicates the approximate size of the central collimator projected on the rule. The camera is posed on a robust foot. To be able to modify autofocus (AF), it is necessary to permanently raise the mirror reflex camera by activating the cleaning mode of sensor (and by checking that the battery is charged). The adjustable tangent is located at the bottom of a hollow tube, not far from the plan of the sensor

The screw in question is of the type with 6 hollow sides (hexagonal), that one can turn with a key allen. This screw little to be seen by placing a small mirror with 45° in the room reflex camera. I used a small key in the US standard, which correctly returns in housing 6 hollow sides (enough deep). Can be that a European key also functions taking into account the plays (approximately 1.3x1.3 mm between two parallel plans of the hexagon)? It should be stressed that the swing angle authorized by the size of the cavity is weak. To be able to insert the key in the print of the screw it can be necessary to fold slightly the key allen in vices (it is what arrived to me). One sees this folding of key in the sight above. The ideal is in fact to have two keys allen, one folded in a direction, one folded in the other direction. They are used according to the direction of rotation and make it possible to work more comfortably. The key allen must return well in the screw, which is hollow 5 good millimetres (it is well quidée).

The key allen is well places from there in the adjustable tangent. There is no more which has it to turn, with delicacy. Once the committed key and once adjusted for wear its in housing, the screw is rather hard. Is necessary to insist while forcing a little. As of which moved, one stops and one checks the result while assembling the objective test and by checking the effect on the AF. The process is iterative. One should not be pressed and to proceed by stage, by small keys, while returning possibly behind.
The objective which is used for to fix the autofocus must be regarded as a reference, i.e. are clean optical pulling is characteristic of the optical range. It is the condition so that the point, once regulated, is correct for a maximum of objectives. With the end, the cleaning of the sensor is required bus well on a little dust fall into the cavity reflex camera. This cleaning is in any case a routine operation for any user of numerical reflex camera! It should be noticed that of a catch of sight to the other the point is not strictly identical. The autofocus is sensitive to a noise. This one of as much is highlighted better than optics is opened, because then the depth of development is reduced. Gun EOS350D is clearly with the sorrow with an objective such as the 135 mm f/2. The views presented above are characteristic of the average point obtained on 10 to 20 successive stereotypes, by taking care to demolish focusing before each release. The test carried out on a EOS 20D shows a rate of failure significantly lower (and not of defect of systematic AF as on the 350D on the model tested), though not completely no one. The difference in price between a 20D and a 350D this also does not justify these details.
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Old Oct 14, 2006, 11:03 AM   #13
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Uh. . .does anyone not recommend i try this at home? Or is this a relatively simple self adjust? Sounds like the set screw might be loctited in place (hence the need to break the set screw free). I wonder if this will only create long term focus issues if the set screw is no longer locked in position but now suceptible to movement. has anyone else done this at home before?

I'm a mechanical engineer by trade. So mechanically, this is a no brainer. But my concern is if the screw is locked in place (which would seem to be the best thing to do to maintain proper focus adjustment) and i break that seal am i opening myself up to focus problems and having to readjust on a routine basis.

I'm ready to operate. . . . my confidence may exceeds my abilities. . . :-)

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Old Oct 14, 2006, 3:49 PM   #14
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There's no lock...

It could be held by friction (you probably know better I'm only a EE :G), but it's tight. My Canon MrkII has two eccentric screws (#1, and #2), but the 10D (probably 20D, 30D the same) only have the#1 stopper screw (#2 is a fixed rubber stop). If you complete a full 360 degree rotation on theses screws they should moved back to their original position(s):






FYI:
http://forums.dpreview.com/forums/re...ssage=20008393
http://forums.dpreview.com/forums/re...ssage=16962790
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Old Oct 15, 2006, 7:49 AM   #15
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I went ahead and made the adjustments myself last night. With very good results i think!

Need to use a .050" allen wrench. CW rotation.

Based on my before and after. I had to rotate about 5° CW to bring the focus back in line. The biggest problem I had was that the 90° allen wrench would only go in at an angle (handle touching edge of cavity wall. But a quick bend in a vise fixed that.

Here are the after photos. i was focusing on the #18 on the right hand side. I went with a steel scale instead of a tape measure this time. The first photo was taken with the Sigma 70-200 f/2.8 and the second with the Canon 85 f/1.8, Tripod mounted camera, self timer, yada, yada, yada.

I adjusted as best as my eyes would allow. 20/20 and I have long since parted ways :-)

But I'm much happier with the photos also. But being an engineer. . I'm constantly thinking. . . "could I adjust it even better...hmmmmm"

But i think it's much better than before.
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Old Oct 15, 2006, 7:51 AM   #16
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85 f/1.8 Both photos are 100% crop
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Old Oct 15, 2006, 7:53 AM   #17
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NHL thanks for info and links. I would have been lost without them.
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