Canon 24-105mm is L series lens
 

Hi all, after a bit of advice here, I have several lenses and by far my all round favourite is the above, recently I'm having focus issues with the lens whereby when using spot on eyes etc I manage to get a nasty blur when I download the images to PC, The lens is very clean, I have tried high ISO, tried flash etc etc but cannot seem to get a good AF.

The lens is on my Canon 5D MKII and has been used for approx 3500 shots.

I know there is a micro adjustment in camera but don't want to touch this not knowing what the hell I am doing with it..

I'm still reasonably new to DSLR this being my first one and purchased a year ago..

Any help would be muchly appreciated.. Tar

Does this happen with any of your other lenses.



This is very easy and straighforward to do, but is rather labourious.

As John says "does this happen with any of your other lenses"?

As for MA-ing your lens this is very simple, download a focus test chart.

http://www.dphotojournal.com/downloa...us-test-chart/

however this will only adjust the camera/lens for front or back focus.

I guess you need to check whether indeed this is front/back focussing.

I assume you have switched to manual focus and used Liveview at full 10x magnification, if only as a test.

Harry

Can you upload a sample, possibly with the exif still intact!

Hi All

Thanks for advice, will try to upload a sample in a short while..

Does this lens have a UV filter fitted ?
If so have you tried it without ?

Yep tried without, Just looking at some of the images that were ruined, when you half depress the shutter on the eyes and re compose, press the shutter and take the pic, in DPP will it always just show where the centre AF point (Highlighted Red) was when you took the pic rather than where you metered from?

Right I fired off some test shots and it seems to be not completely sharp across all three of my lenses, with auto focus, with manual focus I can get pretty much what I want..
In Canon settings, what is the default setting for AF is it stop or start as I used to have no problems with this beast, it has never been dropped or knocked I have taken much care with my lenses...

Image from test sheet

EXIF Data from camera

Well, looking at the test shot above Lee, I would say that your lens was front focusing. A really quick guide to Micro-Adjusting is as follows:

First you need you need to set the camera on a tripod and place the target (black print on white paper) a minimum distance of 50 x the focal length, from the camera. (For a 50mm lens you would need a distance of 2.5 meters and a 500mm lens would require 25 metres). If you are calibrating a zoom, set the lens to the focal length you use most often. The target also needs to be parallel to the camera sensor.

Set the camera to aperture priority and set the lens to its maximum aperture. Also switch off any image stabilisation.

For front focusing lenses take a series of shots at 0, +5, and +10 and then examine the images to see which gives the sharpest result. If +5 gives the best result, take another series of shots at +3, +5 and +7. Again examine the results for the sharpest image. Assuming +7 was the sharpest, take another set of shots at +6, +7 and +8. If the +6 image is the sharpest then set the micro adjustment to +6 for that particular lens.

NOTE: this is just a rough guide to micro-adjusting a lens. The actual amount of compensation and the number of test shots you take is entirely up to you.

Cheers for that all, I think I may have cracked it by doing a settings reset on the body, no idea what i had set but it seemed to have knocked everything out....