Canon Mark II 5D Focus Problem.

<p>Hello i am an owner of a canon mark II 5d and i am a portrait photographer. I realize some issues with my camera in edit process. <br /><br />I used to have some high shutter speed but in some of my photos the subject is out of focus completely. I dodnt understand the focus spot of this Photo. <br />I use a 85 1.8mm canon <br />In this photo i used the following settings <br />1/2000 f2,5 iso 100 <br />Take o Look at the photos , you will realize the difference if you see the actual size.<br>

Thanks for the support here is a link with some of them <br /><br />https://www.dropbox.com/s/1420zkc0yrbw9s1/leoforio-153.jpg<br /><br />The second is <br /><br />1/3200 f2,5 the same problem the face is out of focus and i cant see the focus point <br /><br />https://www.dropbox.com/s/fi5k84pshpd0cm3/leoforio-162.jpg</p>

 

<p>Jo, the problem is the f/2.5 aperture. At f/2.5, the depth of field is very narrow, maybe a fraction of an inch. That means that wherever you focus on the face or elsewhere, everything else will be out of focus.</p>

<p>Why do you need to shoot at 1/2000 second when your subject isn't moving at all? If you're shooting handheld, try 1/250 or even 1/500, with an aperture somewhere close to f/11, for a start. That will probably solve the problem...</p>

<p>i think that 2.5 is ok. I have a good distance to take the model full body shot. Also i want to make the background out of focus. Its so difficult to do that at f11 . i am not so close to the model. Its not a head shot. </p>

<p>As William pointed out the problem is not focus but DOF. In the first example the shadow on her nose from her eyelash is sharp, in the second the fingers on her left hand are sharp - that is where the focus point was.</p>

<p>The rest of each image is soft due to DOF. Stop down to f5.6 or f8 and you will see an improvement.</p>

<p>Focus on the eyes, and if the eyes are at different distances from the camera, focus on the nearest eye.</p>

<p>DOF with an 85mm lens on full frame at f2.5 at 3m is about 20cm. At 5m it's about 50cm, it's not "a fraction of an inch" unless you are shooting macro. I doubt the problem is just DOF. It's could be the lens focus that's off, but you'll have to shoot a flat target to see that. You might also be focusing on the wrong part of the subject.</p>

<p>Of course within the DOF doesn't mean absolutely sharp. It just means "acceptably" sharp. Still, whatever you have the focus point over should be the sharpest part of the image.</p>

<p>I think Bob has it covered. Unless you have a model who isn't moving at all, in order to get acceptable sharpness for those shots, something like f4 would be my suggestion. I've had some good results at f1.8, but not a huge number, I'll usually stop down a little.</p>

<p>is there any possibility that in portrait shots i used to focus with a non center point ?</p>

<p>Jo, the outer AF points on the 5D MkII are a complete joke. They are nowhere near accurate enough for shooting with a wide aperture lens. You will get focus errors like this all the time. Use the centre AF point and recompose carefully. </p>

<p>Technically it could be an AF micro-adjust problem but I doubt it. Use the centre AF point to focus on a flat subject like a brick wall. Check to see if it focuses correctly. If it does, there is no need to adjust the AF.</p>

<p>I've used the 5D MkII since it first came out and the only time I would use an outer AF point is if I'm photographing the moon with a 12mm lens at f/22 ;-)</p>

 

<p>a lot of people said to me that with the recompose your item will be out of the focus most of time. It is so difficult to use the wide apertures</p>

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<p>a lot of people said to me that with the recompose your item will be out of the focus most of time. <br>

</p>

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<p>That is also true. But... you will have more success that way. The outer AF points are totally useless on the 5D MkII.</p>

<p>I rarely have problems with the outer AF points of my 5D2. As long as there is reasonable light and contrast my 5D2s lock the side points very accurately. I use it all the time at F1.2 to F2.8 with several fast primes (35 2.0 IS, 40 2.8, 50 1.2L & 200 2.8L). On the other hand, it is a bit slow compared to 7D AF. The cameras that gave me side points problems were the 10D and 20D...</p>

<p>One important thing for AF success is to place the AF rectangle on a point of contrast, e,g,, eye rather than smooth forehead. So even with the outer AF points you still need to preform slight lock and recompose. I only limit myself to the center point in really low light.</p>

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<p>...a lot of people said to me that with the recompose your item will be out of the focus most of time...</p>

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<p> <br>

That's pretty much a myth if you mean by out of focus outside the DOF limits. It's often quoted as "conventional wisdom", but if you do the math and you actually do tests, you'll see it's generally not correct. There is a focus shift but under most conditions it's much less then the DOF. And don't forget the stated accuracy of most AF systems is "within the DOF" with normal accuracy focus points and "within 1/3 the DOF" for the highest accuracy focus point when used with fast lenses. The recomposition error is typically less than 1/3 DOF, often much less.<br>

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See <a href="http://bobatkins.com/photography/technical/focus_recompose.html">http://bobatkins.com/photography/technical/focus_recompose.html</a> for the technical details and some sample images.<br>

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There are some situations in which focusing and recomposing will give an out of focus image, but it's typically when using a wideangle lens wide open at short focusing distances, like a 20mm lens at f2.8 focused at 1m with one focus point in the center and the other at the edge of the image. <br>

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Maximum focus error with an 85mm lens focused at 4m on a full frame camera is just under 9cm. That's focusing at the extreme edge of the image and recomposing with that point in the center. Since the DOF is around 33cm at f2.5, you can see that even extreme recomposition shouldn't have much effect on focus. Focusing 1/2 way to the edge and recomposing to center will give a focus error of only 2cm (less than 1") and the DOF is still +/- 16cm (about 6"). Even wide open at f1.8 the DOF is +/- 12cm</p>

<p>The main reason for out of focus shots when using the focus and recompose method is subject movement. As Bob says, the slight movement of the camera and lens itself when recomposing makes little difference as it is well within the DoF. The problem is when you are photographing a fidgety subject like a child or an animal. They can move outside of that DoF boundary in the time it takes you to recompose and take the shot. If you are photographing compliant subjects it is a rarely a problem.</p>

<p>Focus and recompose is my default way of working for portraits. I always use the center AF zone and I typically focus on the nearest eye of the subject before adjusting composition. I've never had a problem with my focus point being out of focus due to recomposition, even with fast lenses (typically 85/1.8 or 50/1.4) used wide open. Typically with portraits you aren't moving the camera through much of an angle when you recompose anyway. If you want to chose your exact composition you'll probably have to recompose anyway since it's rare that one of the AF zones, even the outer zones, will cover the <em>exact</em> area you want to focus on.</p>

<p>I'd agree though that it's not a technique to use with a moving subject. Under those conditions I'd use one of the outer focus zones if I didn't want my subject centered.</p>

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<p>i think that 2.5 is ok. I have a good distance to take the model full body shot. Also i want to make the background out of focus. Its so difficult to do that at f11 .</p>

 

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<p>You mention f/2.5 and f/11 as if they were your only options. I agree with whoever said to try f/4 or even f/5.6. One of those is likely to put the entire model in acceptable focus, with the background out of focus.</p>

<p>--Lannie</p>

<p>I shoot fast primes all the time. Anytime I shoot with my 85 1.2L, 50 1.8, 35 1.4 Zeiss, 28 1.8 then I know I will be shooting in manual focus mode. Some of my primes will only do manual focus as that is the sure shot way of knowing what will be in sharp focus. Auto-focus points can change at anytime between composing and clicking the shutter. <br>

Also, when I shoot F2.8 or larger I use live view and zoom in 100% to verify focus is where I want it and I use a tripod because you moving can also cause focus issues. As someone said on full frame camera DOP is very small.<br>

Also, if you really want to blur background I generally get better results with my Tamron 70-300 at F4 - 5.6 or Sigma 70-200 F2.8 as both auto-focus better than my primes. Primes, mean slow down, open wide, stabilize with tripod and manual focus. Under those circumstances primes can get better shots than zoom.</p>

<p>i also read that with a full frame body the 85 1.8 most of time needs some micro adjustments. Do you have a good guide to make some tests ?</p>

<p>Info is here: <a href="

to Adjust Your Autofocus </a><a href=" /></a></p>

<p>Don't bother buying the silly chart, just use a ruler propped up at roughly a 45 degree angle and focus on one of the numbers. </p>

<p>You can download a chart from <a href="http://bobatkins.com/photography/technical/focus_testing.html">http://bobatkins.com/photography/technical/focus_testing.html</a> It's much the same as a ruler, but the calibration marks are adjusted for a 45 degree chart angle if you want to measure just how far off your focus is.</p>

<p>I think this will help you... Canon 5D Mk II Micro-focus Calibration