Camera Body & Lens Calibration

[MarkLamble]

Hmmm..... IE died after I'd typed this all out the first time round - Can't wait for the Mac to arrive

Anyway, I thought I'd share the story of my recent purchase with you folks...

As part of a medium term plan to leave the rat race, I treated myself to a Canon 1D MkII and a 24-70 f2.8L. Having heard good things about both the camera and lens I wasn't really expecting what happened next.....

After the usual 'new toy' period had expired and I got down to the task of taking some 'serious' pictures, I became concerned that all was not well with my new kit. The pictures were at best, soft, and at worst, not in focus !

There followed a series of conversations with the camera shop, friends, other photographers, and countless nights spent digging deeper into the joys of internet photography forums such as dpreview. The consensus was that it was me....... probably..... either not using the camera correctly, not post-processing correctly or simply expecting too much

So I persevered..... started getting to grips with PS (still heaps more to learn there....), took more photos, downloaded test charts, took more photos. Nothing I did made it any better - the final straw was when my 70-200 f2.8L IS arrived, and it was no better !

So either I was really stoopid and should give up my dream of becoming a photographer, or there are such things as bad bodies and lenses, even at this price......

In the end, I did what I should have done at the beginning and went to the 'horses mouth'. After an unsatisfactory response from the shop (I'd had it 7 weeks by this time due to work getting in the way) I finally spoke to someone who knew what he was doing. He gave me the number for Canon Professional Services at Elstree and suggested I phoned them - it was either that or they could ship it back for a warranty repair but that could take up to 3 weeks and I needed it for the following weekend.

So one phone call to CPS later and I'm driving to Elstree with the body and both lenses - despite not qualifying for CPS membership, and inspite of a sudden influx of work, they managed to turn it all round in 3 days for which I'm extremely grateful !

The difference between the images before & after calibration/adjustment of the kit is amazing - I'm finally beginning to see the quality that this kit can deliver.

I've read many posts on many different forums about the poor quality of both Canon & Nikon gear lately, and as many if not more people denying it. From my own experience I can safely say that it does exist - but I'd also give them a chance to fix the problem before giving up on a particular lens/body. One of the US forum posters suggested that I should take my kit into the shop and try every lens & body they had until I found a good combination ! That may work in the US but I don't know many shops here that have that amount of stock and I certainly don't have the time to spare - besides, what do I do if I ever get the money for another body or lens ?

So.... if you have any niggling doubts about your new toy get it checked out by the manufacturer.

Here's some links to some example before and after photos - all have full EXIF info for those interested (the 70-200 after was actually taken with the 1.4x converter on as well, so should be even sharper without it). All pictures are 100% crops taken from in camera JPGs with no processing.

1DMkII & 24-70 Before Calibration
1DMkII & 24-70 After Calibration
1DMkII & 70-200 Before Calibration
1DMkII & 70-200 & 1.4x Converter After Calibration

[fraggle]

Did they say what they had actually calibrated?

Did you try taking test pics pre-calibration using manual focus?

What did the pics of the test charts show up?

I thought that my D70 had bad auto focus, apparently quite a few of the early ones did, so I got the test chart, did the tests and it showed up bang on. And after some playing round in the garden I found that minor distance changes were sometimes not picked up by the auto focus so I always force the focus out before letting the auto focus do its thing, or use manual.

[kenlynch]

You can't compare those photos - they are so totally different, different exposure, different iso, different focal length and different subject distance from what I can tell.

The before images are out of focus, the after images aren't.

The thing that was out of kilter is the correspondence between the autofocus sensor plane and the picture sensor plane. Typically, this might be adjusted by altering the resting position of the reflex mirror by a tiny tiny amount, or some other mirror in the autofocus path. Since it was probably adjusted in the factory, it may be that a minute dirt deposit is preventing the mirror returning to its exact correct position after each shot.

There are three separate things that can be out of registration with each other:

the image sensor plane (the important one to be in focus)
the viewfinder screen plane (manual focus)
the autofocus sensor plane (autofocus)

Unless all three are precisely the same distance from the lens, you're going to get out of focus pictures.

You can check this as I have just done. Here's the central part of a test shot of a steel rule with my new D70, using a 50mm lens at f1.8. Camera on a tripod, flat autofocus target (in this case a compactflash card) precisely at right angles to the line from the lens, precisely lined up with the 10cm mark on the ruler. Autofocus on the target, and the 10cm line should be the sharpest. In this example, just one hundredth of a millimetre error inthe position of the autofocus sensor would put the sharpest point on the next millimetre division of the ruler. Looks about right to me. phew.

[seany]

What were the odds of both the camera and two lenses needing calibrating. If it's not user error it has to be camera error.

When ever a test is done it has to be same subject same settings. Many things can lead to an out of focus shot. that's why a like for like test needs to be done.