Protect filter and lens sealing

[loosecanon]

Reading the small instruction book that came with my new EF 16-35 IS f4 lens I see Canon say one needs to fit a protect filter in order to weatherseal the lens. This because the elements move on focusing and so not sealed.
This being so I suppose the flourine coating on the front element (to assist in keeping the element clean) seems a bit pointless!

[William W]

Reading the small instruction book that came with my new EF 16-35 IS f4 lens I see Canon say one needs to fit a protect filter in order to weatherseal the lens. This because the elements move on focusing and so not sealed.
This being so I suppose the flourine coating on the front element (to assist in keeping the element clean) seems a bit pointless!

Maybe your post is basically a light-hearted comment, but if it isn't: the coating really is not so pointless.

The Flourine Coating's specific purpose is to allow any gunk to be (more) easily removed, than what it would be if there were no Flourine Coating. It's good, especially on the outside of the REAR element when dust bunnies jump out of the camera.

Anyway, some examples of why Flourine is useful on the the outside of the Front Element of the lens: even if you were to use a Canon "Protect Filter" there would likely be times when you might want to remove that 'Protect Filter' to don a CPL or ND, and at those times little dust bunnies might just jump in, especially on dry days. so if cleaning them off is easier, so much the better.

On the other hand any gunk on the FRONT o the lens has to be serious GUNK to make much difference - so we return to the OP - maybe the Flourine Coating is mostly pointless . . . ?

Nice lens (apparently, I haven't used one) - congratulations on your purchase. Have fun with it.

WW

[Ken MT]

I think that it is Fluorine.

[William W]

Sure is.

[tao2]

Or.....ye could just breathe on the lens then wipe it with a microfibre cloth..saving money on a Ffluorinated lens.

Fluorinated gases are, of course, greenhouse gases so mebbe the EU will ban Canon/Nikon cameras under its new legislation?

[IzzieK]

Or........ so mebbe the EU will ban Canon/Nikon cameras under its new legislation?

You wish too much...think of something else apart from brand bashing...

[MrB]

If you lick the front element to clean it, you will be helping to protect your teeth.

Cheers.
Philip

[William W]

[tao2]

The use of fluorine, is not new in optics or camera lenses. Ah have a near 60yo Helios 50mm lens...



As ye can see below, age has not withered it, nor custom made stale its infinite variety...



Coatings are still intact. Coated with, fluoric magnesium, silicon and titanium oxides. Coatings are approximately 0.1 micron thick. Which is why the surfaces show as violet, purple or light blue in reflected light.

I quote...

Care and Protection

It is recommended that the coated surfaces should be cleaned as follows...

1) Remove dust with a clean, soft brush, a clean (well-washed) flannel, calico or cambric cloth.

2) Greasy stains and other foulings - fingerprints, fogging etc. can be removed with a cloth lightly soaked in rectified alcohol, and petroleum or sulfuric ether.

3) Use may also be made of of toilette Eau de Cologne. No excessive effort should be applied in any of these cases.

Tough folk , those Soviets...

[Tringa]

I'm puzzled by Canon'w statement about your lens. I can't see how fitting a filter can weatherseal a lens.

Dave

[Ken MT]

Built to function even in unfavorable weather conditions, the EF 16-35mm f/4L IS USM is dust-resistant and water-resistant (when used with an optional Canon PROTECT filter) for professional caliber ultra-wide performance, everywhere.

http://www.usa.canon.com/cusa/consum...mm_f_4l_is_usm

[William W]

I'm puzzled by Canon'w statement about your lens. I can't see how fitting a filter can weatherseal a lens.

There are a few considerations and perhaps all are toward the pedantic, but all are necessary to mention to address your question.

Firstly, I don’t think that there is any official Canon Document that uses the word/phrases such as “weather sealed” or “weather proof” or “water proof” - instead “dust resistant” and “dust and water resistant” etc, will be used, occasionally “dust proof” and “drip proof”.

Secondly the 'Protect Filter' is necessary to COMPLETE the dust and water resistant seal of the lens because it is a ZOOM LENS and the front element rotates when the lens is zoomed. (key word is 'complete')

Similarly, at the Bayonet Mount end of the lens, there is a RUBBER RING SEAL, which will wear out. When that ring becomes worn, then the lens is NOT 'water and dust resistant', any more.

Also, not for this lens particularly, but for example a Canon telephoto lens which is classified as ‘dust and weather resistant’,- if that lens is attached to a Tele-Extender which is NOT ‘dust and weather resistant, then the Lens also is NOT ‘dust and weather resistant’ any more.

Really pedantically, there are specific EOS Cameras which are classified as ‘dust and weather resistant’ and, it follows that if a lens so classified is attached to a Camera body which is not, then the Lens fails to be ‘dust and weather resistant’, also.

I am not aware of any dispute regarding a warranty claim about ‘weather and dust resistance’ concerning the what camera body was attached to the lens, but I can note reports that without the use of the ‘Protect Filter’ warranty has been voided – also the rear seal on a ‘dust and weather resistant lens, is usually one of the first parts which is inspected for wear when the lens is serviced. Attending to the service of the rear seal is the owner’s responsibility.

‘Protect Filters’ are not required on all lenses designated ‘dust and weather resistant’. As far as I know, such filters are only required on Zoom Lenses, but not all Zoom Lenses; for example the EF 70 to 200 L Series has five lenses: of those five lenses not all are ‘dust and weather resistant’, but those which are, do not require the “Protect Filter” to complete the seal at the front of the lens, because the Front Element performs that duty and the Front Element does not move during the zooming function.

WW

[Ken MT]

Weather sealed Canon products are not completely sealed from the environment, they are merely more resistant than non-sealed versions. Wikipedia