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Lens Problems??????

chrisgsimons
Apprentice

Hey guys,

 

I've been having problems with my 5D Mk ii and my 50mm 1.4 lens, and I think it has to do more than just a front/back focusing problem. My 50 1.4 works amazing with my 5D Classic and I've never had any issues with it. Super sharp wide open. This photo below was shot at 2.5 and I had them all on the same focal plane (I think!?).  Notice that the two guys on the left are fairly in focus and then 10-15 feet behind the guy on the right is also in focus. What the what!?

 

IMG_4259.jpg

 

Anyone have any ideas on this? Is it user error? Also I uploaded the image at 1800px wide but if you can't see the full size I can post it somewhere else and link to it.

 

Thanks in advance,

Chris

6 REPLIES 6

ebiggs1
Legend
Legend

Chris,

Sometimes how a photo comes out and how or what is in focus depends on how you held the camera. If you imagine a cone of light that comes into the lens, the optimum is to have it perfectly centered. Perhaps you were slightly off to one side or the camera was slightly canted.

Does this seem to show up in all the photos you take with this combo?

EB
EOS 1DX and 1D Mk IV and less lenses then before!

Thanks for the reply! I'm always pretty conscious about my placement with my subjects in that regard. I was pretty sure that I had myself straigt on to the middle person and shooting parallel to the line of them. I can't imagine that I was that far off.

 

That combo is pretty hit or miss for me right now. Half the time I'll just manual focus (i have precision screens installed) because I trust my eyes better. If I don't it seems to front-focus a lot and then I'll get a few like this one. I really need to send them both off to be calibrated, but I'm stuck in the middle of shooting for the next month so I can't just send it away. It sucks that focus is so much more reliable on my 5D Classic with this lens.

Well Chris, I would say if you can get good photos out of the 50mm f1.4 lens, it msut not be the lens itself.

I would say it must be in the camera or a combo of that lens and camera. Other than that I agree it is probably due for a tune up at CPS.

EB
EOS 1DX and 1D Mk IV and less lenses then before!

diverhank
Authority

At this magnification I couldn't tell if the guys on the right is in focus or not. They look like they are in focus to me.  If they are not, could it be everything is clear all the way to the trees behind the guys as far as DOF goes and any blurriness to any of the guys are due to the lens outer edges not being as sharp?

================================================
Diverhank's photos on Flickr

If you right-click the photo and hit "open image" or some variation of that you'll see a higher resolution image. I've attached another photo that shows what I think is the plane of focus in this particular shot. That can't be right! Right??? I'm pretty dang sure I wasn't that far from parallel with them.

 

IMG_4259edit.jpg

Do you own any other lenses?  Are you having this problem on everything on your 5D II?

 

If you want to test your focus, it's best to eliminate potential for error by carefully constructing a focus test.

 

Shooting an image where everything should be guaranteed to be at the same focus distance.  E.g. there's the cliche "brick wall" test -- camera on tripod.  Tripod and camera _carefully_ oriented to make sure it's absolutely perpendicular to the wall and not angled.  You can also hang a sheet of flat newsprint on a wall (e.g. indoors) to test because newprint is finely detailed and the black & white is pretty contrasty... so you get a pretty good idea of whether it's in good focus or not.

 

It's possible that there's a problem with a lens element.  This is basically how a tilt-shift lens works (they can angle the plane of focus so that it's not actually flat -- except a tilt shift lens lets you very precisely control the lens tilt.)  But as you say the same lens works great on your 5D classic, I'm wondering if you're not experiencing a sensor shimming problem.

 

The sensor inside your camera is mounted on shims.  They are adjustable... but only by service (a tremendous amount of disassembly is required to get to those sensor shims).  It's possible your sensor is not technically perpendicular to the lens axis (e.g. part of the sensor is technically closer than another part).    You'd have to send the camera in to Canon to have that serviced, but it would be well worth it as the 5D II is a fantastic camera.

 

Tim Campbell
5D III, 5D IV, 60Da
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