Brand New 5D mkIII Bizarre viewfinder issue

[Kenan171]

I have a brand new 5d MKIII, that arrived today. I took it out of the box, and put my (also) brand new 24-70 L series on it. Looking thru the viewfinder, I cannot get the lens to manually focus. I try the lens on a different body, it's working properly. I try adjusting the diopter of the viewfinder. It makes no difference.

Ok, I think, I'll try autofocus. I put a battery in the camera and boom!, everything is pin sharp. Great, I think, so I adjust the viewfinder using the focus points then take the battery out to continue charging it. Instantly, the problem returns.

Does anyone have any idea what's going on?

Thanks!

[TCampbell]

The lens has a zoom ring and a focus ring. The focus ring has a clutch and is designed to slip if you hit the limit of focus travel OR if the motors are focusing the lens... this allows the lens to have full-time manual focus even when in auto-focus mode without harming the lens. This is typical of Canon lenses that have the USM focus motors.

If you look at the lens, you'll see a window indicating the focus distance. If you rotate the focus ring while looking at the window, you should see the distance changing (unless you hit the focus limit in either direction... at which point the clutch on the flcus ring will allow it to slip without harming the lens).

Are you able to see the focus distance indicator move when you rotate the focus ring? I'm wondering if perhaps the clutch on your lens is excessively loose.

[Kenan171]

It's not a lens issue. It's a viewfinder issue.

I've since discovered that there is an LCD overlay in the Viewfinder, and without a battery in the camera it causes the VF to go dark and soft. Annoying, but not a major problem.

Thanks.

[hsbn]

It's the same for 7D also. But I don't think why it should be annoying since I don't think there is any point of focus adjusting f when there is no battery in the camera. How can you take photo?

[TCampbell]

Much of what is displayed on the focusing screen is LCD and wont appear if the camera is off. If my 5D III is off I only see the dashed circle in the center -- but it is in clear focus as long as the the focus knob in the upper right corner of the viewfinder is properly adjusted. To focus that, I prefer to point at something with no contrast -- like a plain white wall -- this allows me to get the viewfinder focused tack sharp (the lens does not need to be focused when you do this and it's almost better that it be deliberately out of focus as it makes the background less distracting and easier to see the details on the focus screen itself.)

[Kenan171]

Thanks Tim. On my 5D, I don't get even the dashed circle without the battery.

This morning I set the camera (with a battery in it) up on a tripod and framed up on the garden. Perfectly sharp. Then while looking the VF, I removed the battery. Instantly the VF gets about 2 stops darker and goes totally soft. The manual warns about the VF getting darker, but says nothing about the softness.

@hsbn There is no point focusing a camera without a battery if you are taking stills, but if you are shooting video, it is often useful to be able to see your frame without the camera being powered.

[amfoto1]

There is no point in removing the battery. Without it, you can't shoot stills or video or do anything with the camera at all.

There is nothing bizarre about the viewfinder in your camera.

The 7D, 70D, 5DIII and 1DX all use a transmissive, active matrix LCD as a focus screen. This is what allows the AF system to be displayed in different configurations, allows a composition grid to be turned on and off when wanted, etc.

When the camera has power - i.e. the battery installed - even if it's "turned off" at the power switch, the screen stays bright and in focus. The only time it dims down and blurs is when you remove the battery.

But, without a battery the camera is little more than an expensive paperweight. You can't do anything with it, without the battery installed. It's fully electronic and completely battery dependent. So you really just need to stop removing the battery. In fact you might want to consider getting a spare batt to have charged up and ready to swap out when needed. 

***********
Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM  

[cale_kat]

To the OP, You might want to reconsider "popping out" the battery if you don't first turn off the camera. It could corrupt the memory card or worse.

[amfoto1]

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@cale_kat wrote:

To the OP, You might want to reconsider "popping out" the battery if you don't first turn off the camera. It could corrupt the memory card or worse.

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Nah, I've done hundreds of battery changes, lens changes, memory card changes without turning the camera off first. It's not a problem. In fact, the moment you open the battery door, the camera is completely powered down... There's a microswitch on the battery cover door that shuts it off. There's a similar microswitch on the memory card door. So it really doesn't matter if you turn the camera off at the switch or not.

I hardly ever turn my cameras off... have to conciously make myself do it from time to time, in order to run the automatic sensor cleaning.

***********
Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM 

[cale_kat]

@amfoto 1, With all due respect to your experiences, Canon warns that removing the battery while the camera is writing to the card could result in corruption of data.

To the OP, Canon describes the dimming of the viewfinder on page 30 of your manual.