can you please help with advice with bad canon 100-400 is lens
Discussion
7 replies
Posted by chris jones on December 10, 2009 at 4:03 PM
Hi
I have had this lens for six monthes but have only just started to use it now on my bird feeding station. The trouble with the lens is its giving me sharp and soft images, iv taken it back to a canon service shop who have said that is fine and thay cant find what the trouble is with it. I have done a lens test my self and the imagies speek for them selves what do you think.
test info
tripod used
flash used man
shutter 200
apeture 5.6
self timer used
subject focused on each time after taking the lens out of focus
hope you can understand what i am trying to explain.
chris
link to pics
http://www.flickr.com/photos/csjones/sets/72157622975584568/show/
Posted by Ian Butler on December 10, 2009 at 5:20 PM
Looks similar to the results I was getting on my 7D and that went back to the shops. Did you send the 1D mk2 back to canon to have it calibrated with the lens? Apart from that I cant help, im afraid. maybe one of the more technically minded people on this forum will be able to help. Hope you get it sorted soon though.
Posted by chris jones on December 10, 2009 at 5:40 PM
yes the technician used my own body and still said all was ok.
Chris the lens is renowned for being 'soft' beyond 370mm. Not sure about having it calibrated, but it might be worth a punt as Canon can do more (Elstree). I might be tempted at some point to sell the 100-400 and invest in a 70-200 & 300mm IS which are beter lenses and would give you better results, especially with a 1.4x. F4 are good unless you have a surplus of cash and go for the 2.8 versions
Posted by Mike Smith on December 11, 2009 at 2:52 AM
Which Canon body are we talking about?
Are these FF or crops?
Is AF set to SAF rather than CAF?
Is IS off if using on a tripod?
Are you using single point AF or 45 point AF mode?
I didn't scroll through the entire presentation, but at least one of the images is acceptably sharp so I doubt it is a back focus issue if all the parameters when taking the shots are a constant, without knowing more about your test set up it looks more like an issue of using CAF on a static subject; or IS being used on the tripod; or (if using a 1 series etc) using 45 AF points on a static subject, or if a 1DIII just that the body is from the batch that gave all the AF problems as discussed a year or so ago, or you have a poor copy of the 100-400 (but if these are FF shots I doubt it is that bad....)
Still too many ambiguities to pin down your issue!
I asume these shots are taken indoors as you mention the use of flash. The light and subject are quite low contrast which doesn't help with fast and accurate auto focus.
Try some further testing outdoors. Choose a cloudy day with consistent lighting and head to a large outdoor car park and shoot a variety of subjects. Buildings, car number plates, the writing on various sign posts, all make very good, sharp, contrasty and well defined subjects.
Take any filters off of the front of the lens. Shooting at maximum aperture will confirm focus accuracy, shooting at all other apertures is useful for comparing image quality throughout the range. Manually turn the focus ring to infinity each time before auto focusing on your subject. Use mirror lock-up for every shot and a cable release and a solid tripod. Keep I.S. switched off.
Check the diopter is adjusted accurately and take some manually focused and auto focused shots for comparison.
Ensure the tripod foot on the lens is done up very tightly, this can often work itself loose.
Shoot at a variety of distances.
Posted by chris jones on December 11, 2009 at 7:28 AM
thanks for your help so far, i have some more info for you in the test the IS was off on the tripod and the centre focus spot was used on my 1dmk2 . I am going to to the test again out side and try to get a shutter speed of at least 400 plus i will keep you up to date.
thanks
Posted by Phil Shaw on December 11, 2009 at 10:03 AM
The 100-400/f4.5-5.6L IS lens is probably the weakest "L" lens in the Canon line-up. As Stephen has said, image sharpness declines at maximum zoom extension, but it is also pretty soft wide open. So wide open and at maximum extension is going to produce shots that are not that sharp. When I had this lens, I never used it at an aperture wider than f8 and always backed-off a bit from maximum extension. Having said that, it is a very versatile lens and I got plenty of shots that I was happy with.
I don't think that the subject that you've used is a particularly good one for testing. As Justin has pointed out, the contrast in the scene isn't very high and using an f5.6 lens, the AF sensors, including the centre AF point is only horizontal line sensitive and may not be picking up the contrast in this subject which is mainly in the vertical plane.
When re-testing make sure that you only have the central AF point selected, the camera is set to manual AF point selection and the AF-mode is set to One Shot. This means checking that you do not have any AF expansion points selected in Custon Function (CFn 17?), and if you are shooting with flash, that you have the custom function for AF assist beam disabled. If you are shooting test shots at relatively low shutter speeds, you should also enable mirror lock-up CFn12. Make sure that your subject is somewhat beyond the minimum focusing distance of your lens - say 2m, and select a test subject with good sharp edges - a bank note taped to a wall makes a good test subject, but don't be tempted to print the shots
Discussion
7 repliesI have had this lens for six monthes but have only just started to use it now on my bird feeding station. The trouble with the lens is its giving me sharp and soft images, iv taken it back to a canon service shop who have said that is fine and thay cant find what the trouble is with it. I have done a lens test my self and the imagies speek for them selves what do you think.
test info
tripod used
flash used man
shutter 200
apeture 5.6
self timer used
subject focused on each time after taking the lens out of focus
hope you can understand what i am trying to explain.
chris
link to pics
http://www.flickr.com/photos/csjones/sets/72157622975584568/show/
Are these FF or crops?
Is AF set to SAF rather than CAF?
Is IS off if using on a tripod?
Are you using single point AF or 45 point AF mode?
I didn't scroll through the entire presentation, but at least one of the images is acceptably sharp so I doubt it is a back focus issue if all the parameters when taking the shots are a constant, without knowing more about your test set up it looks more like an issue of using CAF on a static subject; or IS being used on the tripod; or (if using a 1 series etc) using 45 AF points on a static subject, or if a 1DIII just that the body is from the batch that gave all the AF problems as discussed a year or so ago, or you have a poor copy of the 100-400 (but if these are FF shots I doubt it is that bad....)
Still too many ambiguities to pin down your issue!
Try some further testing outdoors. Choose a cloudy day with consistent lighting and head to a large outdoor car park and shoot a variety of subjects. Buildings, car number plates, the writing on various sign posts, all make very good, sharp, contrasty and well defined subjects.
Take any filters off of the front of the lens. Shooting at maximum aperture will confirm focus accuracy, shooting at all other apertures is useful for comparing image quality throughout the range. Manually turn the focus ring to infinity each time before auto focusing on your subject. Use mirror lock-up for every shot and a cable release and a solid tripod. Keep I.S. switched off.
Check the diopter is adjusted accurately and take some manually focused and auto focused shots for comparison.
Ensure the tripod foot on the lens is done up very tightly, this can often work itself loose.
Shoot at a variety of distances.
thanks
I don't think that the subject that you've used is a particularly good one for testing. As Justin has pointed out, the contrast in the scene isn't very high and using an f5.6 lens, the AF sensors, including the centre AF point is only horizontal line sensitive and may not be picking up the contrast in this subject which is mainly in the vertical plane.
When re-testing make sure that you only have the central AF point selected, the camera is set to manual AF point selection and the AF-mode is set to One Shot. This means checking that you do not have any AF expansion points selected in Custon Function (CFn 17?), and if you are shooting with flash, that you have the custom function for AF assist beam disabled. If you are shooting test shots at relatively low shutter speeds, you should also enable mirror lock-up CFn12. Make sure that your subject is somewhat beyond the minimum focusing distance of your lens - say 2m, and select a test subject with good sharp edges - a bank note taped to a wall makes a good test subject, but don't be tempted to print the shots
Hope this helps.