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Archive 2014 · Tips on more accurate focus with the 5d mk1?

  
 
jvphotos
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p.1 #1 · p.1 #1 · Tips on more accurate focus with the 5d mk1?


I got my 5d a little over a year ago, and I love it (though I don't get the chance to use it nearly often enough these days). After I had it for a while I noticed the center AF point seemed to be a little bit "low" compared to the dead center of the picture when viewing it in cs6. Since I got it from KEH I sent it back for them to look at it, and they forwarded it on to canon to get calibrated. I got it back with a clean bill of health, but despite that I'm still having some trouble getting shots that are consistently in focus. I recently started using back button focus and that doesn't seem to make a whole lot of difference. I'm getting a number of shots that seem to be back-focused (although some are front focused, with the same lens!), and I'm starting to think there's a problem with the person pressing the shutter. I did some googling and some of the tips I saw for accurate AF with the 5d1 were to use single shot when possible (already do), use the center focus point whenever possible (already do), try to make sure the center focus box is squarely targeting an area with a lot of contrast (haven't tried that yet) and try to make sure the box is filled with an object that's uniformly distant from you/occupies the same focal plane (ie, on a distant person don't let the face fill half the box with the rest of the box filled by a wall 20 ft behind them, because that could cause back-focusing.)

Does anyone have any tips in addition to these ideas (or any thoughts on the validity of them?) I really love this camera and what it can do, and my inability to use it to it's full potential drives me nuts!



Oct 30, 2014 at 12:55 PM
Blake.Kinder
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p.1 #2 · p.1 #2 · Tips on more accurate focus with the 5d mk1?


What kind of lenses are you using? Have you tried anything that's on a tripod and not hand held to see if that makes any difference? I'm by no means an expert, just tossing around some ideas that I can think of.


Oct 30, 2014 at 01:07 PM
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p.1 #3 · p.1 #3 · Tips on more accurate focus with the 5d mk1?


I don't know if it's possible in the 5d, but if it is, replace the focus screen with one that is better for checking focus, even at the cost of viewfinder brightness. I never had a 5d but did this for the 5d2 and it really helped.

And if possible use back button focus even in one-shot mode to keep the camera as steady as possible.



Oct 30, 2014 at 01:35 PM
jcolwell
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p.1 #4 · p.1 #4 · Tips on more accurate focus with the 5d mk1?


I think trying that third suggerstion (area with contrast) is worth a shot.

Focus on an area with high contrast; a sharp border between dark and light is really good for this. I often used "focus and recompose" with the 5D (still do with the 6D), and got reasonable results even with fast f/1.2 lenses. The trick is to find an appropriate 'target' that's at the right distance for the majority of subject matter that will be in the composition. Stopping down to get deeper DOF is often helps, but it might be contrary to your intention for the photograph.

If there is no reasonable AF target, then try manual focus assist. Use the 'old school' manual focus technique where you "rock" back and forth, through the point of sharp focus. You can sometimes tell better where sharp focus is located by examining the OOF image on "either side" of it.

I used a lot of manual focus "Alt" lenses with the standard focus screen in my 5D, and never had much difficulty (still do with the 6D). OTOH, when I used manual focus with a 1.6x CF body (20D), I needed a third-party 'prism' focus screen to get anything right.

P.S. I prefer back button focus as it lets me separate the point of focus from the exposure and composition when the shutter button gets pushed all the way it. It doesn't provide faster AF than shutter button AF. Also, back button AF allows you to "pump" the AF without firing off all kinds of bogus shots.



Oct 30, 2014 at 02:51 PM
jvphotos
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p.1 #5 · p.1 #5 · Tips on more accurate focus with the 5d mk1?


Blake.Kinder wrote:
What kind of lenses are you using? Have you tried anything that's on a tripod and not hand held to see if that makes any difference? I'm by no means an expert, just tossing around some ideas that I can think of.




I mostly notice it with my 85 1.8 and my 35 f2 IS, but only because those are usually the only lenses I get fairly depths of field. I haven't tried it with a tripod just because I never shoot with one (I'm not even sure id trust the old one I have with the weight of the 5d + lens!), although I have tried it at different shutter speeds to try to reduce the possibility that it's shaky hands.



Oct 30, 2014 at 04:05 PM
scalesusa
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p.1 #6 · p.1 #6 · Tips on more accurate focus with the 5d mk1?


jvphotos wrote:
I got my 5d a little over a year ago, and I love it (though I don't get the chance to use it nearly often enough these days). After I had it for a while I noticed the center AF point seemed to be a little bit "low" compared to the dead center of the picture when viewing it in cs6. Since I got it from KEH I sent it back for them to look at it, and they forwarded it on to canon to get calibrated. I got it back with a clean bill of health, but despite that
...Show more

Its entirely possible that the AF of the camera is off a little. Canon would not have adjusted it when it was returned unless you had complained.

Since two lenses have focus errors, sending it for adjustment is the best option, and that may cost more than buying a different camera.

BTW, the focus screen has nothing to do with autofocus, only manual focus, and when replacing it, it must be calibrated and shims added or removed.




Oct 30, 2014 at 05:36 PM
jvphotos
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p.1 #7 · p.1 #7 · Tips on more accurate focus with the 5d mk1?


scalesusa wrote:
Its entirely possible that the AF of the camera is off a little. Canon would not have adjusted it when it was returned unless you had complained.

Since two lenses have focus errors, sending it for adjustment is the best option, and that may cost more than buying a different camera.

BTW, the focus screen has nothing to do with autofocus, only manual focus, and when replacing it, it must be calibrated and shims added or removed.



I dunno, I'm usually big on blaming the equipment, but when I sent it in to keh and they sent it in to canon, it was to have the focus adjusted/corrected (specifically). Keh got it back with a clean bill of health and forwarded it on to me. And it's not like it consistently front/back focuses, because sometimes it's dead on with all lenses. It's just that my keeper rate is lower than I feel like it should be. I was wondering about this the other day while shooting my t3i, and realized that the rebels I first learned on had focus dots instead of boxes, and it made me think even more that I've got a part to play in this error. If it was consistently missing focus with one or two lenses, then I would love to blame the body, but it does get a bunch right. The failures are too random/inconsistent for me to rule out bad form on my part.



Oct 30, 2014 at 07:34 PM
kzoockof
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p.1 #8 · p.1 #8 · Tips on more accurate focus with the 5d mk1?


Are you focusing and then recomposing? Since you indicate you mostly use the center point for focus, it would not be too surprising if you are focusing and then recomposing for composition.

You say you have the camera set to One Shot (do you mean single shooting vs. multiple shots, OR do you mean One Shot focus)?

Also, you said you got the camera for Keh, was it used? Can you MA a lens on the 5DC/1 (I never had one)? I guess, though it is probably unlikely, that you are using a lens that perhaps the previous owner had MA'd. But the variance between front and back would seem to indicate that is not the case.

Finally, I am assuming you are shooting stationary objects and that you, yourself, are also remaining stationary, at least once you engage the back-button focus.

You also suggest the problem may be the person pressing the shutter button, you could always just replace that person



Oct 30, 2014 at 08:19 PM
jcolwell
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p.1 #9 · p.1 #9 · Tips on more accurate focus with the 5d mk1?


kzoockof wrote:
...Can you MA a lens on the 5DC/1 (I never had one)?


Nope.




Oct 30, 2014 at 08:20 PM