T2i suddenly produces way over exposed images

[tinwhistle]

About four years ago my friend bought the T2i with the 100 to 400 lens and the 1.4 extender. Until recently he loved that rig, but it suddenly started producing way over exposed images. He adjusted the exposure comp to two stops under exposed but still way to light. I should mention that he is a wildlife photographer and his equipment takes quite a beating. The camera has probably produced tens of thousands of images. He also is not on line. Any ideas that you may have that I can pass along to him? Thanks

Chris

[Peter]

Dirt on the light meter?

[RobertTheFat]

He's not using a speedlite when this happens, is he? That's the symptom you get if you accidentally set a speedlite to TTL mode for a camera that expects E-TTL.

[ScottyP]

At least the old T2i is the least valuable piece in that trio with the 100-400 and the tele extender, and there is zero possibility the more valuable other two are at fault here.

[TCampbell]

Ask your friend to manually set the Av to f/16... then while looking through the viewfinder, press the depth-of-field preview button.  This is the small button located on the front of the camera body just slightly below the lens-release button.

If the lens and camera are working correctly, the aperture blades should be fully-retracted while looking through the camera, but when you press the DoF Preview button, the blades should constrict down to the f/16 aperture you dialed in.   The view through the viewfinder should suddenly become NOTICEABLY darker.

If your lens aperture blades are not working, then it could explain why you'd have heavily over-exposed images even when dialing in exposure compensation.

Try this with and without the extender.

If the lens works as long as the teleextender is not being used (lens direct attached to body) then you've got a problem with the extender.  It has electronic contacts that are supposed to pass communication through to the body.  Contacts on the body-facing side should be gold coated plates.  Contacts on the lens-facing side should be gold plated pins (which are springy -- make sure you can press them and they spring back out -- nothing should be jammed.)   You can try cleaning but do NOT use anything abrassive (dont' use a pencil eraser, for example... that gold plating is thin and you'll take the plating off.)  Clean only with a soft cloth.  You can lightly moisten it if you want.    It's also possible the fault is inside and not related to the contacts.

Also try a different lens.  If this only happens with this particular combination, then you've got a problem with the extender or lens or the extender.  If it happens regardless of what lens you use then you probably have a problem with the camera body.

[tinwhistle]

Thanks everybody. Lot of good ideas Tim. I'll be seeing him in a couple days, and pass along all these sugestions. Personally, I'd rather he (finally) upgrade to the 7DII !! I'll let ya all know what the outcome is...

Chris

[RobertTheFat]

---

@tinwhistle wrote:

Thanks everybody. Lot of good ideas Tim. I'll be seeing him in a couple days, and pass along all these sugestions. Personally, I'd rather he (finally) upgrade to the 7DII !! I'll let ya all know what the outcome is...

Chris

---

The T2i was (and is) such a good camera that it can be hard to get its users to switch. I have a spare 7D that I've been encouraging my wife to use. But she has back problems and likes that fact that her T2i is smaller and lighter.

[ebiggs1]

I believe it would be incredibly difficult to overexpose a picture when using a 100-400mm and a 1.4 tele converter on a T2i.  Actually I am surprised he gets that to work very well at all.  So, in that reguard I am going to suggest it is time to upgrade the camera.  Sounds like it has seen the best of its days.

Does the camera work as it should with other lenses?  Usually photographers that are dealing with a f8 lens, wide open, about not able to get enought light!

[TCampbell]

You ca

---

@ebiggs1 wrote:

I believe it would be incredibly difficult to overexpose a picture when using a 100-400mm and a 1.4 tele converter on a T2i.  Actually I am surprised he gets that to work very well at all. 

---

Given the abiliyt to either crank ISO or use a longer shutter exposure, you can always over-expose a shot -- even if the aperture doesn't function.  If the camera is in any semi-auto mode (aperture or shutter priority) then it's going to meter based on an assumption of aperture control it may not have.

e.g. if you use a Sunny 16 exposure as an example... f/16 and 1/100th sec if using ISO 100 would be a valid exposure for outdoor full-sun at mid-day.  If the lens is zoomed to 400mm then it's f/5.6.  Add the 1.4 multiplier and that gets you to f/8.  But the shot assumes f/16... making the lens 2 stops over-exposed.   If using manual exposure, one could compensate with shutter speed and shoot at 1/400th instead of 1/100th.

Unless his friend happens to be selecting f/8 as the desired aperture (or unless the camera does) a failure of the teleconverter to pass through aperture control signals would result in an over-exposed image.

And I do agree with you in that I am also surprised it would ever work reliably because a T2i doesn't have working auto-focus at f/8 and that's "wide open" for that particular combination.

At the end of the day... a 100-400mm with a 1.4x multiplier is not a supported combination on a T2i (even if everything is performing to spec.)

A 7D II does support auto-focus at f/8... but a T2i does not.

[ebiggs1]

But if you are starting with a f8 lens, max aperture (people don't shoot wildlife at 100mm), you need to set something else or even more things wrong to get that over-exposed (2-stop) picture.  

Yes, I can't believe it is working at all much less over-exposing.  I don't think I have ever heard of anybody complaining about over exposure with a combo like that.  Its usually, I don't have enough light (by 2-stops!).

He needs to try different lenses to see if it still over-exposes.