Canon 24-85 Filter pressing on first element

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Hi, I have a canon 24-85mm usm lens and put a Toko 67mm skylight filter on this lens to protect it....

It turns out the filter was hitting the front element of the lens and has left a circle about 3mm across with scratchs.

Has this happened to anyone else?

Is like canon have stuffed up with the clearances ?

At the time I didn't think to check if the filter was touching the front of the lens element.

Rgds Leif

-- Leif Pigott (leifpigott@hotmail.com), March 16, 2002

Answers

Unfortunately, I know people that have had the same accident as you with the EF24-85 USM, EF28-105 USM and several other wide angle lenses.

There's nothing wrong with your lens. However, you should know that filters are built to widely varying specs and you must select and install the right one. For example, some filters have more threads or fewer threads, thicker or thinner rims, the filter glass may be placed forward of center or centered, the glass may be thicker or thinner, etc.

Wide angle lenses have a very concave and protruding front element. You must be careful when installing filters. Not only is it easy to slip and scratch the front element while installing a filter, but the wrong filter type will damage the front element by abrasion. I always make sure the filter does not contact the front element before I screw it all the way down.

A standard B&H filter has one of the safest designs for lenses with protruding elements. Why? The rim is thick and the glass has more space between it and the front element than a Hoya HMC Super or Nikon L37c.

-- Puppy Face (doggieface@aol.com), March 17, 2002.


Sorry, I meant to say that a standard B&W filter has one of the safest designs for lenses with protruding elements.

-- Puppy Face (doggieface@aol.com), March 17, 2002.

That said, my 24-85 is fine with a Hoya HMC.

-- Isaac Sibson (isibson@hotmail.com), March 17, 2002.

Yeah, my Hoya HMC is close but otherwise works great on my EF28-105 USM. The front element of that lens is extremely close to the filter threads and edge of the barrel. One advantage of close filter glass and small rims--but not touching-- is you may be able to get away with stacking filters without vignetting.

-- Puppy Face (doggieface@aol.com), March 17, 2002.

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