I need to know if its my lens or my camera??

[engephotography]

Hi all! I have an equipment issue and I am trying to narrow it down. So I have a Canon 5D Mark II with a Tamron 28-75 mm F/2.8 lens, both are bought used and I have had them for a about a year and a half. I just noticed when I am taking pictures sometimes the view finder gets a bit dark and does a weird clicking noise for a few seconds whenever I am trying to take a picture (it wont take it the pic until it goes back to normal) 

So basically I am trying to figure out if this is a lens issue or a camera issue, so that I can figure out which one to replace first. I just went freelance so it is pretty important that these are both working as I dont have a backup! If its the camera I will probably buy a new camera and send this one to get repairs and use as a back up in the future. 

I dont have a whole lot of funds to buy both brand new right now, so it would really help to be able to narrow down to one. 

Thanks!

[TCampbell]

Consider why a viewfinder could get dark.  

There's the mirror.  And there's the aperture blades.  There's really nothing else that should be able to get into the light-path to block light from the viewfinder.

If this was the mirror, then things would likely go totally black.  But if it is the aperture blades, things would just get dim.

The 5D II has a depth-of-field preview button.  It's the small button located below the lens-release button on the front of the camera body.

e.g.  set the camera to use f/11... look through the viewinder and press the button. 

Normally the aperture blades are fully retracted to the "wide open" position when you compose & focus, but constrict just before the shutter opens to whatever f-stop you set, then retract again as soon as the shot is complete.

Press the DOF preview button and it'll constrict the aperture blades to whatever will be used during the shot.

You should be able to push the DOF preview button a few times and see it get dim, release and it gets bright, and cycle that a few times.

If you bump the button and don't realize it, it could explain what you are seeing.

If you are SURE you aren't gripping the camera in a way that is bumping the button... then there is some fault in the system that makes either the camera or the lens constrict the aperture blades when it should not.

The easiest way to sort that out... is to try a different lens.

[amfoto1]

You might try cleaning the electronic contacts on the rear of the lens. Sometimes with handling they get oily or dirty and that interrupts communication between the camera and lens.

Simply wipe those contacts on the rear of the lens with a clean rag, slightly dampened with a a few drops of isopropyl alcohol (cheap & widely available "rubbing alcohol" works fine).

If that doesn't solve the problem, my first suspicion would be the lens aperture is hanging up... as has already been suggested. And the best way to tell would be to try using a different lens on the camera. If you don't have a second lens yourself... maybe a friend or visit a store with lenses and ask to borrow one of theirs.

If it turns out to be the lens is at fault, it may or may not be repairable or practical to repair. You might check with the manufacturer or a local camera repair shop.

If not practical to repair, a replacement doesn't need to be expensive. on a tight budget I'd recommend looking for a Canon EF 28-135mm IS USM lens. It's not f/2.8 (has variable f/3.5-5.6 aperture instead), but it does have image stabilization, so with reasonable care can be used at 2 to 3 stop slower shutter speeds. The 28-135 is an older model that was just recently discontinued, but a lot of them were sold over the years so it's pretty easy to find a nice, clean used copy for $around $200. Might even include the lens hood that's normally sold separately (also still widely avail., if needed). The 28-135mm has pretty darned good image quality, rivaling a lot of considerably more expensive lenses from 28 to 105mm. It gets slightly soft wide open (f/5.6) at the 135mm end. Stopping it down to f/8 sharpens that up pretty well. It's reasonably close focusing, has fast USM focus drive and, as mentioned, helpful IS.

Hope this helps!

***********

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

[StanNH]

Does the body exhibit the same behavior with a different lens?  Conversely, does another body malfunction with your lens?

[ebiggs1]

No advise is going to help until you do as Stan suggests, "Does the body exhibit the same behavior with a different lens?  Conversely, does another body malfunction with your lens?"

This is the only way for you to eliminate either the lens or camera.  Try a different lens on your camera or try your lens on a different camera.  You can forget cleaning the contacts unless you just don't have anything to do sometime.

I am sorry to say but the Tamron 28-75mm f/2.8 XR Di LD is not a 'stellar' lens in the first place.  Certainly not in your case, " I just went freelance so it is pretty important  ...". If you are serious you might look for a better lens and a back-up camera.

[engephotography]

Yes I’m currently trying out switching the lenses to see what happens, so thanks!
The tamron lens isn’t amazing but it has provided me some beautiful images through this past year almost comparable to the canon version in my opinion (I have Worked with both) , but it might be really reaching its limit haha. And yes I am Aware of having a backup, this is what I’m working towards I just Wanted to know which should I replace first at this moment. Looks to be the lens.
Thanks!