70-200 F2.8 MK2 issue?

[Parsen66]

Advice please peeps. All day yesterday I used my brand new F2.8 lens on a photo shoot coupled with my 7D2. With the lens at its widest (70mm) and looking through the view finder (at 2.8) the focus locked and was sharp. When zoomed out to 200mm and viewing the same through the finder it locked focus but wasn't sharp. Not massively soft but soft non the less. I have adjusted the diopter to suit my eyes (I need glasses for reading) with the green LED detail sharp, I was advised this is the correct way to set this up. It cannot be adjusted any more which in itself is a worry.

I was concerned that all those images would be soft and after loading them to my Mac they are all sharp!!! Can anyone explain this or offer anything? I was so worried that I would lose all the shots and have to return the lens, but it seems OK. It cannot be right that they appear soft but come out sharp surely?

[Tigger]

Re: 70-200 F2.8 MK2 issue?

am I understanding this the lens is focusing and locking fine at short and long end but the issue is when zoomed out through the view finder only its soft?

[Parsen66]

Re: 70-200 F2.8 MK2 issue?

am I understanding this the lens is focusing and locking fine at short and long end but the issue is when zoomed out through the view finder only its soft?

Yes mate. When at full zoom, 200mm and looking through the view finder its locks but appears soft at that point.

[Tigger]

Re: 70-200 F2.8 MK2 issue?

thats really odd, I don't understand why the camera would do that - mine has no issues at all

can you use the lens with another body? I'm sure thats not the problem but it rules it out

[Parsen66]

Re: 70-200 F2.8 MK2 issue?

thats really odd, I don't understand why the camera would do that - mine has no issues at all

can you use the lens with another body? I'm sure thats not the problem but it rules it out

I didn't think that could be right. I'll see if Dave Stallard can take a look and compares his to mine

[Alan_H]

Re: 70-200 F2.8 MK2 issue?

Alan just a thought, perhaps an additional dioptre view finder on the camera could help if the adjustment you have made is not correct at both ends of the zoom, on the Canon magazine web site there are a number of these also they where covered in the Jan- March 2011 issue

Alan

[paul linton]

Re: 70-200 F2.8 MK2 issue?

Is it the whole Image that looks soft ,It's nothing to do with shallow DOF and only a small part of the image been sharp?
Do they look any sharper viewing on the rear screen or is it still looking all over blurry.

Paul

[Tigger]

Re: 70-200 F2.8 MK2 issue?

Do they look any sharper viewing on the rear screen or is it still looking all over blurry.

Paul

great idea

[Parsen66]

Re: 70-200 F2.8 MK2 issue?

Alan just a thought, perhaps an additional dioptre view finder on the camera could help if the adjustment you have made is not correct at both ends of the zoom, on the Canon magazine web site there are a number of these also they where covered in the Jan- March 2011 issue

Alan

Thanks for the reminder and info Alan, that may well help me out

Is it the whole Image that looks soft ,It's nothing to do with shallow DOF and only a small part of the image been sharp?
Do they look any sharper viewing on the rear screen or is it still looking all over blurry.

Paul

Its the point of focus that looked soft. They looked 'ok' on the LCD screen but to be honest it was a long day and I think my eyes were tired. Also the light was dropping and there was smoke bombs going off too!

Just tried a test in the garden and it look better than yesterday but I'm still not convinced. A second opinion needed I think.

[jimsphotography]

Re: 70-200 F2.8 MK2 issue?

It may need a micro adjustment - but first try a live view test.
1) put lens on tripod and set at 200mm with the aperture wide open - pick a stationary target that has no depth to it and easily stands out against the background.
2)take a shot using auto focus with a shutter speed of at least 1/1000 th second and with the IS off
3)now take a second shot but on manual focus via live view and expand the focus point on the screen and manually focus to get as sharp as possible - take the shot.
If they are both soft then you need to send the lens back for looking at.
However, if the manual focus image is fine compared to the auto focus one then you need to do a micro adjustment.
Hope that helps
James

[Parsen66]

Re: 70-200 F2.8 MK2 issue?

It may need a micro adjustment - but first try a live view test.
1) put lens on tripod and set at 200mm with the aperture wide open - pick a stationary target that has no depth to it and easily stands out against the background.
2)take a shot using auto focus with a shutter speed of at least 1/1000 th second and with the IS off
3)now take a second shot but on manual focus via live view and expand the focus point on the screen and manually focus to get as sharp as possible - take the shot.
If they are both soft then you need to send the lens back for looking at.
However, if the manual focus image is fine compared to the auto focus one then you need to do a micro adjustment.
Hope that helps
James

Thanks for the advice and suggestion for checking, really appreciate your comment

[El Sid]

Re: 70-200 F2.8 MK2 issue?

I note that the 7D2 has interchangable focusing screens, could it be that the screen isn't quite properly located? It wouldn't affect the camera's focusing but at the long end it might be enough to make things look a bit soft.

Also the Canon USA website say this about an alternative focusing screen...

Focusing Screen EH-S
The Super Precision Matte screen obtains sharp points of focus when using bright lenses with a maximum f/2.8 or higher aperture. The finer microlens structure provides optimum focusing for various scenes.

...which rather suggests that the standard screen may not always be optimal for more demanding lenses.

Probably worth checking the overall AF performance but if the images are actually sharp on the computer screen/in print it seems unlikely that the AF system is off.

[Parsen66]

Re: 70-200 F2.8 MK2 issue?

I note that the 7D2 has interchangable focusing screens, could it be that the screen isn't quite properly located? It wouldn't affect the camera's focusing but at the long end it might be enough to make things look a bit soft.

Also the Canon USA website say this about an alternative focusing screen...



...which rather suggests that the standard screen may not always be optimal for more demanding lenses.

Probably worth checking the overall AF performance but if the images are actually sharp on the computer screen/in print it seems unlikely that the AF system is off.

Sid, thanks for your thoughts. I shall check out the focus screens and carry out the AF test as mentioned by Jim earlier in the post.