Lens calibration and autofocus problems

[chad]

Hi you might know about me having focus problems!!! (I put another post up on it)

Here are some photos all on a tripod and focused using back button.

Camera is

Canon 7D
Lens

70-200 F4 L
50mm F1.4 usm

I am just not happy with them!! (espeserly at 100% crop)

They dont seem as sharp as they could?

What do you think?


Or is it me just being funny.

Any Ideas

Do I need to collaborate them to my camera or have my AF optimised?

Or anything else??

Please help I’m doing my nut in lol.

70-200 @70mm


test image 1 by Digital SLRschad189, on Flickr

70-200 @200m


test image 2 by Digital SLRschad189, on Flickr

50mm 1.4 usm


test image 3 by Digital SLRschad189, on Flickr

 

[andybeach]

Images aren't really big enough to have a good look (1,024 pixels only).

EXIF data shows you're shooting wide open (f4.0 / f1.4) so not at either lens 'sweet spot' I would suggest - images should be a lot sharper at around f8 - my 100-400L is transformed from 'slightly soft' at f5.6 to 'super sharp' at f8 - not much help if you need to shoot wide open!

I have calibrated my 7D to each lens though can't say it's made a big difference, but they weren't spot on.

 

[HoppyUK]

If you're looking to test for AF accuracy, then you need to do it properly.

Check out a few recent threads on AF microadjustment.

 

[TCR4x4]

If you're looking to test for AF accuracy, then you need to do it properly.

Check out a few recent threads on AF microadjustment.

One of those threads is his, where there was lots of info on what to do to test properly.

 

[chad]

Been looking and Google a lot about it and thought it you should do it with aperture wide open that's why I had lens wide open

I might just get one of them lens calibration devices.

Can any one point me to a good clear step by step easy to understand guide please

 

[chad]

One of those threads is his, where there was lots of info on what to do to test properly.

Well I done that got a tape and a ruler and took photos of it thought I was doing it right god knows what distance to be away or what to set aperture to.

 

[HoppyUK]

Well I done that got a tape and a ruler and took photos of it thought I was doing it right god knows what distance to be away or what to set aperture to.

Have you seen the pic of a cerial box and ruler I put up? It's been posted a few times, including today.

Set the camera up square to it, use centre point AF on the flat face of the box, in good light, at lowest f/number, and at a sensible distance, ie not too close or you'll end up making a correction that could throw the focus out at normal shooting range.

See where the lens has actually focused on the angled ruler by zooming in on the LCD. Adjust if necessary and retest until perfect. The lens probably won't need much adjustment, if anything, unless you're unlucky. If you do see a problem, de-focus the lens and check again, and then again, to make sure it is consistent and not user error.

 

[chad]

Yea just been looking at that

It dose not help I am leaning problems dyslexic thanks

 

[chad]

I'll have a go I think I understand it now I seen a photo when using a zoom lenses do you zoom in or out?

Or dose that not matter

Thanks for your patience

Jamie

 

[jm2]

Test the zoom lens at the focal length mostly used with the lens.

 

[HoppyUK]

Test the zoom lens at the focal length mostly used with the lens.

Yes, good starting point. Or if in doubt, somewhere around the middle. If you're fanatical, and it is very easy to get far too obsessive about this, test at min, mid and max focal lengths and select the best compromise.

All AF systems are a compromise, and none are absolutely 100% perfect at all focal lengths and all shooting distances. However, good quality lenses on a decent camera - like the OP's - are usually pretty damn good and the weakest link in the chain, in actual picture taking, is almost always the photographer.

 

[chad]

However, good quality lenses on a decent camera - like the OP's - are usually pretty damn good and the weakest link in the chain, in actual picture taking, is almost always the photographer.

Yea that's what I'm thinking that its me. But just want to be sure.

I noticed that the picture style was set to landscape with a sharpening of 4... so I have set that to neutral to see if that makes a difference. Might of been over sharpening the image?

I am going to have another play tonight and see if I can crack it.

Once again thanks and thanks for the help. From swapping the enlarges for a computer. Has turned into a mine field lol

 

[jm2]

Yea that's what I'm thinking that its me. But just want to be sure.

I noticed that the picture style was set to landscape with a sharpening of 4... so I have set that to neutral to see if that makes a difference. Might of been over sharpening the image?

Even if you set sharpening to 7, it will not be over sharpened. If you can. do the test in good daylight

 

[chad]

Yea I will might have to wait till the weekend tho see what time I get done

 

[chad]

Ok you can all shoot me... it looks like the problem was because lens wide open I have been shooting at f8 today and all the pic are nice and sharp

So looks like it was me... sorry its the way my head works.... backwards..

But at least its all good and sorted..

Thanks

 

[HoppyUK]

Ok you can all shoot me... it looks like the problem was because lens wide open I have been shooting at f8 today and all the pic are nice and sharp

So looks like it was me... sorry its the way my head works.... backwards..

But at least its all good and sorted..

Thanks

No. The depth of field will just pulling everything sharp at f/8, whether it's in perfect focus or not. See below.

Have you seen the pic of a cerial box and ruler I put up? It's been posted a few times, including today.

Set the camera up square to it, use centre point AF on the flat face of the box, in good light, at lowest f/number, and at a sensible distance, ie not too close or you'll end up making a correction that could throw the focus out at normal shooting range.

See where the lens has actually focused on the angled ruler by zooming in on the LCD. Adjust if necessary and retest until perfect. The lens probably won't need much adjustment, if anything, unless you're unlucky. If you do see a problem, de-focus the lens and check again, and then again, to make sure it is consistent and not user error.