50mm 1.8 focus problem

[JacoMedia0113]

Whenever I focus automatically with the viewfinder, it doesnt actually focus where it says it will. For example, I tested this out with a roof and focused on the chimney and saw the red flashes indicating where the camera is focusing. It also looked perfectly in focus in the veiwfinder. When I took the shot and saw where the focus point was, it was about 10 feet closer to me than the chimney. Then I went to the lcd screen and focused the same way on the chimney and it focused perfectly. I tried this on other lenses and its only the canon 50 1.8. Its really not that expensive so I might get a new one or if you recommend a better 50mm lens. I use a canon 6d btw if that helps. Thanks.

[TTMartin]

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@JacoMedia0113 wrote:

Yes its the stm. I would never put a bad set of glass in front of a 6d lol

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I agree 10 feet is a lot, and would seem to indicate something other than a lens issue. But, if it is a lens issue it needs to be sent into Canon for repair.

Some things to eliminate on the use side.

Make sure you are in 'One shot' focus mode.

Make sure you are in single center AF point selection mode.

Do not use Auto AF point selection, AIServo or AIFocus for your test.

Here is a more recent and in my opinion better Microadjustment Guidebook.

Canon EOS AF Microadjustment Guidebook

[RobertTheFat]

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@JacoMedia0113 wrote:

This may sound weird but Im actually in Boston right now visiting. Im hoping to go to the leica store. Do you have any recommendation as to where to go with family and for photography. Id like to take unique photos not just the ones you see on google images. Im thinking acorn street or the outdoor library but idk. Thanks

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If you have school-age kids, I suppose you might want to visit Concord Bridge, "Old Ironsides", the Bunker Hill monument, the Freedom Trail, etc. But of course everybody has photographed those. Cambridge has a lot of interesting and photogenic locations: Harvard, MIT, sailboats on the Charles River, etc. It can be difficult to park in Cambridge, but it's easy to get around by foot, bus, and subway. North Point Park (accessible from the Science Park and Lechmere Square subway stations, is the only place I've found to photograph the cable-stayed Zakim Bridge, an architectural icon since it was built 15 or 20 years ago. There are footpaths along the river on both the Boston and Cambridge sides, with a lot of good scenery, depending on the time of day and the angle of the light. One of the best pictures I ever took was of the skyline of Kendall Square in Cambridge from the footpath on the Boston side, a bit upstream of the Longfellow Bridge.

Out in the suburbs where I am, it's a bit hazy and overcast today, but maybe you'll have better luck downtown. Boston weather is very fickle, but my feeling is that you have to play the cards you're dealt. And often a white shy can be a good background if you don't let it get out of control.

Good luck and enjoy your visit.

[JacoMedia0113]

The subject I was testing was far away so that may have had a difference. it goes up 20 and -20. I did fix it and it works now.

[RobertTheFat]

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@TTMartin wrote:

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@JacoMedia0113 wrote:

Yes its the stm. I would never put a bad set of glass in front of a 6d lol

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I agree 10 feet is a lot, and would seem to indicate something other than a lens issue. But, if it is a lens issue it needs to be sent into Canon for repair.

Some things to eliminate on the use side.

Make sure you are in 'One shot' focus mode.

Make sure you are in single center AF point selection mode.

Do not use Auto AF point selection, AIServo or AIFocus for your test.

Here is a more recent and in my opinion better Microadjustment Guidebook.

Canon EOS AF Microadjustment Guidebook

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It's hard to see it as a lens issue. Note that the OP told us it focuses fine in live view, so the problem must be with the viewfinder's AF. AFMA should be the first thing to try.

[TTMartin]

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@RobertTheFat wrote:

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@TTMartin wrote:

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@JacoMedia0113 wrote:

Yes its the stm. I would never put a bad set of glass in front of a 6d lol

---

I agree 10 feet is a lot, and would seem to indicate something other than a lens issue. But, if it is a lens issue it needs to be sent into Canon for repair.

Some things to eliminate on the use side.

Make sure you are in 'One shot' focus mode.

Make sure you are in single center AF point selection mode.

Do not use Auto AF point selection, AIServo or AIFocus for your test.

Here is a more recent and in my opinion better Microadjustment Guidebook.

Canon EOS AF Microadjustment Guidebook

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It's hard to see it as a lens issue. Note that the OP told us it focuses fine in live view, so the problem must be with the viewfinder's AF. AFMA should be the first thing to try.

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Elimitating user error as a factor is the first thing the OP should try.

AFMA won't correct for a 10' error.

Liveview and viewfinder PDAF focus systems work completely differently.

I doubt it is a lens issue, but, at 10' it is also not a microfocus adjustment problem. And if it is user error, AFMA will just compound the problem. 

[ebiggs1]

"Elimitating user error as a factor is the first thing the OP should try.

AFMA won't correct for a 10' error."

"I doubt it is a lens issue, but, at 10' it is also not a microfocus adjustment problem. And if it is user error, AFMA will just compound the problem."

I ditto that. 

[RobertTheFat]

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@ebiggs1 wrote:

"Elimitating user error as a factor is the first thing the OP should try.

AFMA won't correct for a 10' error."

"I doubt it is a lens issue, but, at 10' it is also not a microfocus adjustment problem. And if it is user error, AFMA will just compound the problem."

I ditto that. 

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Whether AFMA will correct a 10-ft discrepancy probably depends on how far away the object is. Think of it as a DOF-related issue.

[jrhoffman75]

Message #13 - OP says it is fixed via AFMA.

[ebiggs1]

Robert, 

Let's think!

It's normal for AFMA to vary with distance of course. At longer subject distances, the delta becomes very small, this is why the usual recommendation is to do the test at 25x to 50x the focal length.  Let's use a 50mm f1.8 lens x 25 = 1250mm or about 4 feet.  Even at 50x it is a tad over 8 feet.  Depth of focus is actually what we are working with here.  Let's assume an adjustment of +5 on the f1.8 lens.  This might be fairly noticeable but at f5.6 or f8 hardly noticeable. Tiny corrections, right? 10 feet is a lot. Whether it is the OP's problem or not, I still think it not likely an AFMA issue..

[RobertTheFat]

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@ebiggs1 wrote:

Robert, 

Let's think!

It's normal for AFMA to vary with distance of course. At longer subject distances, the delta becomes very small, this is why the usual recommendation is to do the test at 25x to 50x the focal length.  Let's use a 50mm f1.8 lens x 25 = 1250mm or about 4 feet.  Even at 50x it is a tad over 8 feet.  Depth of focus is actually what we are working with here.  Let's assume an adjustment of +5 on the f1.8 lens.  This might be fairly noticeable but at f5.6 or f8 hardly noticeable. Tiny corrections, right? 10 feet is a lot. Whether it is the OP's problem or not, I still think it not likely an AFMA issue..

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Except that, as John points out, AFMA apparently did fix the OP's problem.