EX3 dramatic focus event

[Kieran McConville]

On the offchance that anyone has any idea. The lens fell off my EX3 yesterday from about two feet onto soft ground with longish grass. When I put it back on it worked fine until about 20 minutes and several shots later when the focus just packed in with a click in the middle of a shot. Attached is the event. Also attached is what it looks like now after I've tried everything I can think of. I've had the usual focus issues with this camera before but this is different.

[Alastair Traill]

Hi Kieran.

I assume that when you say it “fell off” that the lens somehow became detached from the mount as distinct from screws working loose or similar. It is hard to imagine that if the lens was fully inserted in its mount with the locking lever in about the “4 o’clock” position that the lens would just fall out. In addition to the locking lever there is another mechanism on the EX3’s right side that makes it harder to unlock the lens. Was that in use?

I also assume that you did not mistake the locking lever for the zoom lever.

If the lens lever was not tight the lens would have been hanging slightly forward in its mount. This would have upset the back focus distance and any wide angle shots would have been soft and the front focus would have been closer to the camera than you intended.

As far as the failure of the focus mechanism is concerned the first thing I would check is whether the fall bent or damaged any of the contacts on the back of the lens.

[Kieran McConville]

The locking lever for the lens was obviously loose and caught in my belt as I was taking the camera strap from my shoulder. Hence the falling off. I probably had not tightened it sufficiently when last taking the lens off to deal with my other focus issues (which has been the only solution). So that's not really the issue.

Alastair thank you but I do know what all the levers are for. There is no visible damage anywhere on the lens so it may well be an internal element.

[Luc De Wandel]

I do not know how the locking mechanism on an EX3 works, but I do know that the bayonet system on my PMW320 - and on any pro video camera for that matter- sucks. As a professional stills photographer, I have used Nikon as well as Canon camera's over the last 40 years, and they both use a simple and intelligent bayonet system, with positive locking: once the bayonet is turned to it's stopping stud, there's no way the lens will come loose, unless you press the 'unlatch' button.

I have never understood how videocameras with lenses that cost a fortune can rely on such a ridiculous bayonet without a locking device, as they have been doing for centuries. If the locking lever goes up, for some reason, the lens falls off. Unless someone would call the silly rubber cap that one has to put on to prevent the lever from moving 'state of the art'. Changing lenses on a videocamera is a nightmare, compared to the same action on a still camera. When I shoot concerts with my 5DmkII - or any other pro DSLR - I change lenses at least 20 times an hour. Can you imagine doing that with any video camera...?

Do engineers who work for firms that make videocams - or lenses - as well as DSLR's, never talk to each other? One would start to think so...

[Alastair Traill]

Hi Luc,

I have made a few lens mounts in my time from “C” mount to PL (perfect lock) and a few in between. The EX3 works on the same principle as the PL and it has a lot to recommend it. The locking ring draws the lens flange tightly onto its seat. Unlike the Nikon or “C” mount there is no rotation involved in seating the lens and so little opportunity for wear. My criticism of the EX3 mount would be that relatively soft materials are used for its construction compared to the hardened stainless steel used in the better PL mounts. Another criticism is that it uses a relatively long locking lever that can catch on things. The lever is needed because it is hard to grip the locking ring otherwise. Sony have tried to reduce the chance of the lens being inadvertently released by installing a secondary lock.

As the SLR cameras use relatively long focal length lenses there is less need for a very high degree of accuracy in the manufacture of their mounts. Personally I do not like the twisting action needed to install and remove a Nikon lens. If there is a bit of grit around, as can happen in dusty conditions, 20 lens changes an hour would soon wear the mating surfaces. In the PL type mount main problem is keeping the mount clean, only a small build up of foreign matter can upset a wide angle lens.

[Luc De Wandel]

I agree that a twisting motion would not work well on a videocamera, considering the bulky lenses with their attached zoom handles and so on. But what I fail to understand is that there is no firm locking system for the ring (+ handle) when it is turned to it's end. That must not be hard to design and it would add an important safety margin.

[Dana Kupper]

OK, I'll jump in.

I am going to ask some obvious questions, since you didn't say what you tried. The first thing I would do is the automatic backfocus adjustment that the camera does.

Here are the steps:

1. Put the camera on tripod or a stable surface that won't move.
2. Point the camera at a focus chart or a flat surface with a lot of contrast, like a newspaper taped to the wall about 5 - 10 feet away. (Make sure you are perpendicular as possible to this.) (Also, it should be fairly well lit.)
3. Make sure you are in servo(mechanical) zoom and the iris in auto.
4. Hit the menu button.
5. Go to the Lens menu - it's the sixth one that looks like a little lens, and go to AUTO FB ADJ.
6. Choose EXECUTE.
7. Let the camera do it's thing. Don't move it.
8. If it says error, then try more light, or move the card.

Have you tried this? What happens?

Also, there is a 'lock' for the lens on the wrong side of the camera, under the hand grip. I have found it to be dubious at best. I guess you should make sure it is set to locked, for what it is worth. (I think the design is flawed as well, having pulled an EX3 out of the bag, and having the lens almost fall off after the lever caught on the edge of the bag.)

[Kieran McConville]

So it's definitely the lens itself. I've borrowed a replacement and everything works fine. Went to EC Electronics in New York and they say my lens is junk and to buy a new one. That's a little tough. Thank you all for your help.

[Vincent Oliver]

I know how you feel, take a look here

http://www.dvinfo.net/forum/sony-xdc...3-useless.html

I posted a picture on post #7

Managed to sort it all out in the end - with a new lens.