300mm rear filter?

[carmo]

I have the Canon 70-200 2.8 IS and absolutely love it (also 24-70L 2.8 love it

too but not quite as much). I'm now thinking about the 300 2.8L IS. Most of

what I do is sports- swimming, lacrosse, soccer...indoor and out.

 

I've searched and read much about this lens (all good) but I'm new to

the "rear" filter concept. Could someone please describe or point me to a

link that shows exactly what this is?

 

Does this rear filter afford any protection or is it just a slot for "effect"

filters (i.e. polarizing...)?

 

Also, there doesn't seem to be a front filter option due in part to "the cost"

of such a filter- from what I've read (hard to believe considering the price

of this lens). I also read that a front filter is "not necessary" due to the

fairly low cost to replace the front lens glass (I'm sure they used a

different term to describe this but it escapes me).

 

I'm excited about the purchase but would like to make sure that if I need a

filter, I understand it's purpose and order one with my lens.

 

Also- the "Wimberly Sidekick" seems to be a popular option for these

telephotos on most posts and articles. Recommended?

 

I know I'm asking a lot of questions here so thanks in advance for your

consideration.

 

Other equipment I have: 30D and 1.4x extender

 

Jim

[franklin_polk]

The rear filter is solely for effects filters, like polarizers, gels, ND, etc. There has to always be a filter in the rear filter slot, otherwise you will get worse images as the lens is designed with the rear filter in mind.

 

The front element of the lens is specifically designed to be easily replaceable (by Canon), it is just an optical flat (it is actually slightly curved to minimize flare, but isn't made of special materials, or anything of the like). It costs about the same as a filter that size would cost anyways (about $200). All Canon teles (except the 100-400 and 400/5.6) have this 'protective' filter. You can see the front element and its shape in the block diagram: http://tinyurl.com/53gyng .

[zml]

If you do sports, you need a monopod: you'll quickly chuck a tripod as its lack of mobility will hinder your photography.

 

 

Also, the rear filter holder has a clear glass built-in so dust won't get into the exposed rear elements (AFAIK this is just that - clear glass, just pulled out mine to check.) Canon makes a pola filter to fit the holder. As an aside, the 300/2.8 works great with the 1.4x extender.

[don_wilkie]

<i>" There has to always be a filter in the rear filter slot, otherwise you will get worse images as the lens is designed with the rear filter in mind."</i><br><br>

 

I have never heard of that being an issue. I have a couple lenses that can utilize drop in filters and the image quality seems just fine without a filter in place.

[zml]

Don: Some lenses use a screw-in rear filter which is indeed a part of the lens' optical path (a good example is 16/2.8 Zenitar fish-eye) hence the confusion. Not the case with the 300/2.8 of course.

[neil_everitt]

Agree with all the above posts. Have had three 300 2.8s in the last 20-odd years. Never any

problem with the front element which, as others have pointed out is flat, replaceable glass -

but I've never managed to scratch one or need it to be replaced.

 

With this lens and the sports you mention there is no need to use a tripod. Sitting at football

I never use a monopod either - it is unnecessary and just limits your mobility. The only time I

might use one is when using two cameras behind the goal - the 300 on a monopod enables

you to quickly drop it against your shoulder when switching to a camera with shorter lens.

[neil_everitt]

Apologies, for benefit of our American friends, when I say football I of course mean soccer:-)

[lester_wareham]

"Some lenses use a screw-in rear filter which is indeed a part of the lens' optical path (a good example is 16/2.8 Zenitar fish-eye) hence the confusion. Not the case with the 300/2.8 of course."

 

Are you sure about that. In the EF Lens works book Canon shows a plane glass final element and states "Lens construction: 17 elements in 13 groups (protective glass and drop-in filter included)"

 

For the drop-in filter accessories Canon state:

 

"52mm Drop-in Screw Filter

Holder

(with protect filter)

A holder for the 52mm screw-type

filters available on the market. Use by

replacing the filter with the protect

filter provided.

Compatible with the EF 300mm f/2.8L IS USM,

EF 400mm f/2.8L IS USM, EF 400mm f/4 DO IS USM,

EF 500mm f/4L IS USM, EF 600mm f/4L IS USM."

 

There is also a Drop-in Circular Polarizing Filter PL-C 52.

 

These sound like part of the optical formula. Not to be confused however with:

 

"52mm Drop-in Gelatin Filter Holder

Up to three gelatin filters can be

placed in this holder. To use, insert a

cut piece of gelatin film between the

holder?s filter frame and pressure clip,

and screw on to the lens.

Available for both 48mm-compatible

and 52mm-compatible lenses.

* Compatible lenses: EF 300mm f/2.8L IS USM,

EF 400mm f/2.8L IS USM, EF 400mm f/4 DO IS USM,

EF 500mm f/4L IS USM, EF 600mm f/4L IS USM."

 

These don't look like part of the optical formula.

 

http://www.canon-europe.com/Support/Documents/digital_slr_educational_tools/ef_lens_work_iii.asp

[mark u]

A rear flat/filter will affect focus:

 

http://doug.kerr.home.att.net/pumpkin/Glass_Plate.pdf

 

and may also affect corrections for other aberrations such as CA.

[neil_everitt]

Jim, forget all the filter concerns. Buy the lens, you won't regret it but be prepared for the

fact that when you do you will rarely, if ever, pick up the 70-200 again.

[carmo]

Everyone- thanks for the great dialogue and input.

 

I guess my take away is that "for protection" of the glass I'm all set out of the box. As for "optical clarity" and "focus concerns" I'm still a bit confused but from Michael's post above it sounds like a "clear glass" element, in the rear drop in slot, comes with the lens when you buy it, so again I think I'm good out of the box. My only concern is Neil's last response about "rarely, if ever picking up" my beloved 70-200 :(

 

I guess only time will tell. Thanks again for the feedback.

[zml]

<i>beloved 70-200</i>

<br><br>

The 300/2.8 runs circles around my 70-200/2.8 IS in terms of image quality (sharpness, contrast, light fall-off, use with a TC) but you cannot zoom the 300/2.8 :)

[thomas_nolan]

Niel Everitt,

My name is Tom and I have just being reading all the above,one thing is I have bought a EOS

1D Mark11N and a canon 300 f2.8 I took it out this evening to photograph a football game

and most of the photos were blur, could you give me some idea as to what I was doing wrong

or which is the best setting to use while doing sports,like mode TV,AV,M,OR P. All info would

be very greatful.

 

Cheers Tom

[neil_everitt]

Hi Tom. If your photos are blurred we would need further details on how you were shooting,

exposure, focus points, etc.

 

Evening suggests you were shooting under lights which, depending on how bright they were,

might suggest camera shake or subject movement for the blurriness.

 

Please supply as much detail as you can.

[bob_osullivan]

Tom, what matters most is what shutter speed you used. For night football, you'd want at least 250, preferably 500th sec sutter. If you don't have a monopod then I'd have IS turned on as well, or at least IS in mode 2 for panning.

 

I prefer M mode so exposure is consitent and the meter doesn't get fooled by changing backgrounds. But Tv mode should work ok for you if you're not comfortale using M.

 

This will probalby require using ISO 1600 or 3200.