fredlee70x7 Posted February 23, 2007 Share Posted February 23, 2007 I'm thinking of getting the 24-105/4 L IS to use on a 5D. Does the camera's high speed/high precision centre focusing point work on this lens that has a maximum aperture of F4 only? Link to comment Share on other sites More sharing options...
mark u Posted February 23, 2007 Share Posted February 23, 2007 See p 78 of the manual: http://www.eosdoc.com/manuals?q=EOS5D High precision is only available with f/2.8 or faster lenses. However, the centre sensor would be cross type. Link to comment Share on other sites More sharing options...
rainer_t Posted February 23, 2007 Share Posted February 23, 2007 According to ... http://web.canon.jp/Imaging/eos5d/index.html and http://www.digitalcamerainfo.com/content/Canon-Makes-it-Official-Announces-Full-Frame-EOS-5D-.htm the center focus point will take advantage of an f/2.8 lens and work better with it than with an f/4-only lens. Rainer Link to comment Share on other sites More sharing options...
fredlee70x7 Posted February 23, 2007 Author Share Posted February 23, 2007 Thanks. Link to comment Share on other sites More sharing options...
bob_osullivan Posted February 23, 2007 Share Posted February 23, 2007 Canon marketing people are smart. They always find a way to get us to buy "just one more lens" ;-) My zooms are all F4 only my primes are faster. Now it looks like we both NEED a 24-70 2.8. Cheers. Link to comment Share on other sites More sharing options...
sgpix Posted February 23, 2007 Share Posted February 23, 2007 Hmmm... I know I'm guilty of NOT RTFM, but I've been using a 5D set to centre point focus with 24-105/4L and 17-40/4L, as well as some faster lenses for about 6 months... I've not had any more off-focus shots than usual... So what does it use when set to centre-point with 2.8 or above? Link to comment Share on other sites More sharing options...
sgpix Posted February 23, 2007 Share Posted February 23, 2007 PS. Having reviewed some shots in last 6 mths, I note that about 80% of 'bad focus' ones are with 50mm/1.4 (which is the worst focusing lens I have ever come across)! Link to comment Share on other sites More sharing options...
fredlee70x7 Posted February 23, 2007 Author Share Posted February 23, 2007 Exactly, I'm confused. I have been using the 70-200/4 L (non-IS) and centre focus point on 5D for my kids' sooccer game and have not experienced any difficutly (or at leaset I am not yet aware of any). Mind you that I usually use it outdoor with reasonable sunlight. What are the real world differences of using F2.8 and F4 with center focus? Under what situation will the differences be big enough? Link to comment Share on other sites More sharing options...
jurigab Posted February 23, 2007 Share Posted February 23, 2007 I'm getting confused! I know that usually the center focus point is the most accurate point! Isn't it? For example, on eos 3 and eos 1 series it is the only point that you can use on f/8 lens... isn't it? Link to comment Share on other sites More sharing options...
sgpix Posted February 23, 2007 Share Posted February 23, 2007 OK - I've now RTFM... and am no clearer! It needs to be explained in English (or French would be be better than what Canon have written), for a 'normal' kinda guy... Link to comment Share on other sites More sharing options...
andrew robertson Posted February 23, 2007 Share Posted February 23, 2007 It needs f/2.8 to work because of the narrower DOF, not some magic conspiracy. Link to comment Share on other sites More sharing options...
andy_jones2 Posted February 23, 2007 Share Posted February 23, 2007 It only exhibits its "high precision" if the lens is f/2.8 or faster. Normally, the AF will get your focus plane with the expected DoF. The high precision sensors will get you within 1/3 of the DoF, hence the designation high precision. The centre point will always work, no matter what lens as long as it's f/5.6 or faster (or f/8 on the 1 series) but it works better for an f/2.8 (more light to work with!) Link to comment Share on other sites More sharing options...
sgpix Posted February 24, 2007 Share Posted February 24, 2007 So now I'm really learning somthing - thanks, all! Looks like I need toi brush up on some articles and learn to start using manual focus in some instances (I never do at the moment!)... Link to comment Share on other sites More sharing options...
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