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Thread: 70-200mm F2.8 L coupled to a 50D (Help please)

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    70-200mm F2.8 L coupled to a 50D (Help please)

    Hi,

    Has any one had an issue with slow or inaccurate focus with a 70-200mm F2.8 L NON IS lens.

    I purchased this lens second hand and rememberr reading in the manual that you can set micro adjustments to camera/lens set-ups.

    Could my soft/slow focus issues be from the previous owner setting the lens to his/her body?

    I have put several shots in the Sport forum under Rugby WA heading, all pics have EXIF data attached.

    Any help on this issue would be great.

    I was using AI servo mode, different types of metering (but not spot), center focus only, AV or M mode, ISO of 320 - 400, exp/shutter speed was chosen by the camera. Focus depth switch set to 3M.

    There seems to be a large difference to DOF/ motion blur and accurate focus pick-up. Also, other Rugby pics have been loaded into my Flicker site, but I think Flickr takes out EXIF, not sure. (Not trying to flog my Flickr site here)

    PP has been left to a minimal, as I am a novice with PS, I was shooting in WB Mode set to Sunny, so with some shoots WB and the green-magenta slide have been moved. WB set to 5400, and slide to +25.

    Thanks in advance.
    They call me "Blue" it's a red head thing.
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    I have not used that lens and body combination. However, I did have a similar problem with a 17-85 on a 400D. The auto focus would find the sweet spot, then at the last minute, shift to an out of focus position. It did this consistantly, every shot. It turned out to be a faulty lens focus motor (I think that is what they called it). Cost of repair was $200 including parts. Have not had that problem return after the repair.

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    Previous owner may have set micro-adjust, but all that does it set the body to the lens, not the other way round. You should read up on micro-adjustment and set this lens & your other lenses to your camera body. Quite interesting exercise seeing how much some lens are out. Generally I have found the L lenses to be pretty close on my body, only needing 1 or 2 points of adjustment, whereas another lens needed almost 10 points of adjustment.
    I had a look at your Flickr site and thought the footy pics look pretty sharp on there. EXIF data is there, go to Actions on the Menu tab.
    Remember also that using F 2.8 or 3.5 gives you a nice blurred background, but also gives you a shallow DOF so if your focus is off the target, then the pic may be soft. Use Canons Zoom Browser software you can see the focus points. Handy tool to check pics if using centre point only, eg, I have had shots I couldn't figure out why they are soft, but upon checking showed the focus point wasn't on what I thought I was aiming at.

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    The problems you're having in the last post are moving subjects and the first time using AI servo mode. How is the focus on stationary subjects ?

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    Suggest you have a look here.....(sorry if I knew how to link this I would )

    Forum...... Camera/lens/gear talk..... other.......This lens is soft...Read This First!.... posted by Etherial
    OR type in calibration in search.....one of the first threads to come up.

    In 50D manual there is a section under microadjustment which may help.

    I still believe few lenses are faulty........but a small percentage will be!

    I have a 50D and 70-200mm 2.8 IS II.........currently with Canon.
    Short story-....Asked for calibration - Canon thought unlikely a problem - reliable lens- no faulty ones reported to tha date.
    Technician did a quick check - kept lens (and camera) said AF and AF tracking not working.
    Will check Wednesday for progress- hopefully fixed- have been waiting 2 weeks so far.

    Canon were very helpful

    Cheers
    Lal
    Last edited by la lumiere; 04-04-2011 at 8:27pm.
    The Impressionists hoped to........" Capture the transient effect of light and colour"........ I wish I could!

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    Hey Roosta.

    A couple of things to be 'weary' of when you're trying to nut out any possible issues with gear.
    Any testing needs to be methodical and deliberate in scope and has to be easily reproducible, to have any meaning or relevance.

    That is, judging the performance of your 'new' lens, based on those Rugby images is not something that could be considered 'scientific'.
    There are more variables that come into play than simple back/front focusing lens problems! Subject movement, harshness of light(in those circumstances) and other variables.

    Those images are good samples for being suspicious of any possible performance issues with the lens, but not necessarily reason to think that there IS a problem with the lens.
    From those images, you would now need to do some proper testing to see if there is a focusing issue with the lens on your particular camera(body).

    You need a sturdy tripod, remote release, the guts to use Liveview(if you dare! ) and about an hours worth of boring stuffing around time.

    There are(apparently) half a million ways in which you could do this focus accuracy test, but I reckon for 100% surety and peace of mind, it should be done with a test subject that is at a distance is as close to the focus distance where you would use this lens for the majority of the time. That is, if you intend to shoot rugby from 10-20meters away most of the time with this lens, then your test target should be about 10 meters away(min) and up to 20meters away(max).. for the best results. Some lenses can have a habit of focusing slightly differently at different focusing distances. So if you do a test to confirm(or deny) any possible focusing accuracy problem with this lens, and the test target is only 2-3meters away, if you then calibrate the camera to tell the lens to focus differently(using micro adjust) there's the possibility that it may backfire at the 15meter(+- 5m range) and produce focusing problems in the opposite direction.

    The other really big problem, is that what you have here is a zoom lens. AND if you calibrate it at 200mm to (say) backfocus by -20, then you also have to remember that being a zoom lens, at 70mm it will also adjust focus by that same -20.. where it previously used to be perfect!
    I currently have this problem with my Tammy 28-75/2.8. At 75mm it back focuses slightly, and is more obvious at close range, and if I compensate with some micro adjust in the camera, at 75mm it's fine, but at all other focal lengths, it then backfires on me and they all front focus!
    So do this with lots of suspicion and doubt.

    My simple solution for now(to the Tammy problem) is basic and effective. Instead of stuffing around with setting camera micro focus adjustment, I measured the amount of focus inaccuracy the lens produces(at 75mm). As the lens is screw driven, and I only ever use the AF-On focus method, where I have to press the AF-On button on the camera body to focus, and not half press the shutter release, I focus and quickly give the focus collar on the lens a small tweak backwards to get my focus point 'about' spot on. There is a half a millimeter of play/slack in the screw driven focus drive and this allows a very small amount of focus play in the lens(they all seem to have a small amount of play, but some lenses don't).
    Alternatively if I'm continuously focusing on a target, I then take at least three images in succession and move myself back outwards(relative to the subject) as I rattle off multiple images.
    The idea is that I'm supposedly focus bracketing, once again in a kind of pseudo manner. FWIW, the focus accuracy problem I'm having with this lens, as an example of how minute it is, at about 2m focus distance, if I target the eye of a person, I get temple lobes or the front of an ear in focus instead, and slightly less sharpness in the eye itself. The error in distance is so small that it drives me bonkers sometimes, because it's so close .. yet not right on the money, and can ruin a shot that I felt important to get.
    Nikon D800E, D300, D70s
    {Nikon} -> 50/1.2 : 500/8(CPU'd) : 105/2.8VR Micro : 180/2.8ais : 105mm f/1.8ais : 24mm/2ais
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    {Tamron}; -> 17-50/2.8 : 28-75/2.8 : 70-200/2.8 : 300/2.8 SP MF : 24-70/2.8VC


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    I have the IS version and a 50D.

    I think in this instance at first glance I am going to back up the advice given by arthurking83. When I first got my lens (considering it is IS) I though I would nail this shot and that shot etc etc. I soon found out I needed to get better at taking the shots!! I was like you, ready to send the damn thing back but then I worked out that it was me and not the lens.

    You do not state how much experience you have with this type of shot although I am gonna take a leap of faith and say you probably know what you are doing. That make a lens issue more likely. How about you come over here one Sunday (yep, only day I get off) and marry your lens with my 50D and see what happens?? I am northern suburbs too so we will only be 10 mins apart.

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    Quote Originally Posted by Old Skool View Post
    Previous owner may have set micro-adjust, but all that does it set the body to the lens, not the other way round. You should read up on micro-adjustment and set this lens & your other lenses to your camera body. Quite interesting exercise seeing how much some lens are out. Generally I have found the L lenses to be pretty close on my body, only needing 1 or 2 points of adjustment, whereas another lens needed almost 10 points of adjustment.
    I had a look at your Flickr site and thought the footy pics look pretty sharp on there. EXIF data is there, go to Actions on the Menu tab.
    Remember also that using F 2.8 or 3.5 gives you a nice blurred background, but also gives you a shallow DOF so if your focus is off the target, then the pic may be soft. Use Canons Zoom Browser software you can see the focus points. Handy tool to check pics if using centre point only, eg, I have had shots I couldn't figure out why they are soft, but upon checking showed the focus point wasn't on what I thought I was aiming at.
    Thanks Russell, I will have to look at that, not blaming my tools, I appreciate it's probally me, or knowing how to use the tool properly. Will investigate. I take it (Zoom Browser) comes with DPP, not used DPP yet, so I'll have a look.
    Cheers

    Quote Originally Posted by Art Vandelay View Post
    The problems you're having in the last post are moving subjects and the first time using AI servo mode. How is the focus on stationary subjects ?
    Seems pretty good Art, though the user is a first timer with AI servor, deffently not blaming the tools here. I do suspect it's me not controlling it correctly. But want to be 100% sure,
    Cheers.

    Quote Originally Posted by la lumiere View Post
    Suggest you have a look here.....(sorry if I knew how to link this I would )

    Forum...... Camera/lens/gear talk..... other.......This lens is soft...Read This First!.... posted by Etherial
    OR type in calibration in search.....one of the first threads to come up.

    In 50D manual there is a section under microadjustment which may help.

    I still believe few lenses are faulty........but a small percentage will be!

    I have a 50D and 70-200mm 2.8 IS II.........currently with Canon.
    Short story-....Asked for calibration - Canon thought unlikely a problem - reliable lens- no faulty ones reported to tha date.
    Technician did a quick check - kept lens (and camera) said AF and AF tracking not working.
    Will check Wednesday for progress- hopefully fixed- have been waiting 2 weeks so far.

    Canon were very helpful

    Cheers
    Lal
    Will have a look and read into this, should Pm etherial dirrect, I know he has mentioned simillar before on another forum, thanks for the reminder la - lumiere.
    Cheers

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    Thanks Arthur, I will set some standard tests as you have suggested, I have used this lenses numerious times on stationary items (landscapes) with no problems, but never in AI mode, and trying to work the AEL as a focus lock (So to speak). I'm probally the error, but need to be certain, If lens needs pro shop attention, it'll get it. Thanks for the heads up on the specifics, I will do this and let you know, shall try it in all three modes and set as you say, see if the results vary at all (With-in reason). Makes sense when you bring up the micro adjustment s to both ends, probally easily overlooked. (Pardon the pun)

    Thanks again Arthur.

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    Quote Originally Posted by fess67 View Post
    I have the IS version and a 50D.

    I think in this instance at first glance I am going to back up the advice given by arthurking83. When I first got my lens (considering it is IS) I though I would nail this shot and that shot etc etc. I soon found out I needed to get better at taking the shots!! I was like you, ready to send the damn thing back but then I worked out that it was me and not the lens.

    You do not state how much experience you have with this type of shot although I am gonna take a leap of faith and say you probably know what you are doing. That make a lens issue more likely. How about you come over here one Sunday (yep, only day I get off) and marry your lens with my 50D and see what happens?? I am northern suburbs too so we will only be 10 mins apart.
    Thanks fess, might just do that, home this week. I have some experience, but not alot at shooting faster sports, This is my first season on the camera and not on the park. I have used this lens for birding and landscapes without to much problem, but not a user of the AI mode untill the other week, I hope and believe the problem is just my lack of experience with this style of photography. Will PM you for numbers.

    Cheers.

    P.S. Some very nice images on your smug site.
    Last edited by Roosta; 05-04-2011 at 12:25am.

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    Quote Originally Posted by Roosta View Post
    Thanks fess, might just do that, home this week. I have some experience, but not alot at shooting faster sports, This is my first season on the camera and not on the park. I have used this lens for birding and landscapes without to much problem, but not a user of the AI mode untill the other week, I hope and believe the problem is just my lack of experience with this style of photography. Will PM you for numbers.

    Cheers.

    P.S. Some very nice images on your smug site.
    Well I think maybe this is a practice issue then. I totally sucked (and stil do) at getting these shots until I convinced myself to concentrate and then the shots came in. PM me anytime, my cameras are mothballed due to over commitment to work - would be great to have someone give me an excuse to break away for a couple of hours

    Thanks for the feedback on my pics, it has to be said I have over 20,000 images and I am picky enough to only upload 40. It proves we all get lucky if we take enough shots

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    Quote Originally Posted by fess67 View Post
    Well I think maybe this is a practice issue then. I totally sucked (and stil do) at getting these shots until I convinced myself to concentrate and then the shots came in. PM me anytime, my cameras are mothballed due to over commitment to work - would be great to have someone give me an excuse to break away for a couple of hours

    Thanks for the feedback on my pics, it has to be said I have over 20,000 images and I am picky enough to only upload 40. It proves we all get lucky if we take enough shots
    if you need the encouragement, On the 9Th this Saturday, a whole bunch of us are heading out to East Perth for an evening shoot, see the WA forum, also there is an upcoming event/catch up in May. Might just entice you. Will look you up any way.

    Thanks again.

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