JoJo by Paul Sager, on Flickr


JoJo, Brookfield Zoo’s silverback western lowland gorilla, suffered a fatal cardiac arrest Sunday during an emergency procedure. He had an acute illness, according to a Facebook post from the zoo. The 42-year-old gorilla was considered "geriatric," the zoo wrote. He lived 10 years beyond the typical life span of a male gorilla in managed care.

JoJo was brought to Brookfield in 2012 as a part of a breeding program aimed at bolstering the species. He moved into the Tropic World habitat and quickly got to work. "Let’s just say he hasn’t been hesitant to respond to the females," zoo primate curator Craig Demitros said when JoJo arrived.

The animal sired three gorillas: Nora in 2013, Zachary in 2015, and Ali in 2018. He fathered two more gorillas before he came to the park, including one at Lincoln Park Zoo and another at the Louisville Zoo.

The offspring were consequential: Western lowland gorillas are critically endangered, the World Wildlife Foundation says. The species’ central African native populations have been hit hard by poaching and disease in the last 20 years, the WWF said.

"The loss of JoJo is great, but his legacy will live on in the overall zoo population for this critically endangered species," according to the post.

JoJo was as popular as he was prolific. Chicagoans responded to the news of JoJo’s passing by posting dozens of their own photos of the lionized gorilla on the zoo’s Facebook page, offering one last glimpse at the awe the animal inspired.

First, I'm assuming "The Gasket" you refer to is the one on the bayonet mount.

If that's the case, you can just leave it alone and not worry about it. The weather seal on my 70-200mm wore out long ago and I never bothered to replace it. Never had any trouble shooting with it that way.

However, if you want to do something about it, you have choice of...

- Send the lens to Canon for replacement. It will cost about $40 for the part and labor, plus shipping both ways. (Might be more, that price is from an older quote.)

- Or take the lens to a local camera repair person and have them replace it. They can order the part from Canon and install if for you. It will cost less and, if you can do it locally, will save on shipping.

- Or buy the part and replace it yourself. It's really pretty simple.

Replacement procedure:

1. Remove the lens from the camera or the rear cap from the lens.
2. Use a marker and make a registration mark on the bayonet mount and barrel of the lens, so that you know how it's oriented on the lens and can return it to the same position.
3. Use a good fitting screwdriver to remove the bayonet mounting screws. Probably the screws are "JIS" (Japanese Industry Standard). Be very careful to not slip. (It may be a good idea to cover the optical element with "dental dam" or similar.)
4. After all the screws have been removed, slowly and carefully lift the bayonet mount while looking to see if there are any shims under it at the screw holes. If there are any, the shims will be very thin, small, metal "washers". Also check the back of the bayonet mount to see if any shims are stuck there. If you find any shims you MUST carefully set them aside in an organized way so that you can put them back under the bayonet mount exactly where they came from. There may not be any, but some lenses use shims to precisely align the lens on the camera. If shims were used on your lens, failing to replace them in exactly the same places would mis-align the lens once it's mounted on the camera.
5. Remove whatever remains of the old, damaged rubber ring.
6. Fit the new weather seal ring in place. The newest ones are now made of silicone for better durability than the old rubber ones.
7. Replace any shims as they were originally.
8. Replace the bayonet mount in it's original orientation (which you marked earlier).
9. Put a very small amount of blue Locktite on the threads, then carefully re-install the screws that hold the bayonet mount onto the lens.
10. See the following link to one source of the replacement weather seals (you also can buy directly from Canon... they might even be cheaper that way).

https://www.ebay.com/itm/322477736280

Ignore the trolls...

There can be only a few different contexts.

Insurance

Repair

Lubricant

He probably means Canon Repair Services...since it sounds like you are past using a dry silicone.
I do apply some every year or so...then let them dry out a few days before using them...do some I'm not planning on using...then swap out. Just part of good maintenance.

You'll have to get it replaced...any decent repair shop can do it. You'll pay more if Canon does it...but at that point...tell them to give it the once over...clean it inside and out.

In for a penny...in for a pound.

Details vary from camera to camera but all advanced cameras have some sort of AI auto exposure mode that can detect strong back lighting and other "fool the meter" scenes.

Youll hafta figger out your particular camera but heres two hints about finding the controls you need. There are two areas that address "difficult scenes":

1. Metering patterns, especially if one is called Matrix or Multi-Zone.
2. AE Modes, look for controls about Scene or Subject Recognition, possibly claiming AI.

Also, learn when to shoot raw+jpeg files as "insurance", if not always, at least in tricky situations. Raw is not just for geeks. Its also for CYA. Newish cameras can procees raw to jpeg in-camera without a PC yet allow you to repair some degree of exposure error and WB error, and to crop a bit if needed.

Examples of in-camera raw to jpeg processing menus, showing some of the corrections menus: