[popo]

On a recent trip out in persistent rain, my fave long lens the 100-400L got condensation inside which reduced contrast and reduced AF accuracy that I had to give up using it. The lens was unprotected and I have used it in rain before without ill effect, but I think given enough exposure it built up to significance. That was the second time it happened and I don't think it would be the last, as I can't choose the weather when I'm out.



I'm now wondering if the 70-300L is much better in that regard? Anyone have experience of it in persisting rain conditions or similar comment? The weak point of the 100-400L is of course the extension, which is present in the 70-300L too. But is it better sealed enough such that the zooming action wont draw in water?



Thinking more, should I even consider the 70-200 f/2.8 II with teleconverter(s)? The aperture is not important at all, but 280mm is even shorter than 300mm however slightly, and I'm not sure on the quality at up to 400mm. Plus how's AF speed under those conditions? I don't foresee using it as a 70-200 in itself. The short zoom range is also a concern.



I'd consider the 100-400L as the reference optical condition to match where possible. Primary application is wildlife. A 300mm zoom would be adequate. 200mm definitely isn't. I'll only be using these on APS-C body.



Is there any other non-lens related workaround I might have overlooked? I'm really not keen on rain covers and I'm really not sure they'll work that great on extending lenses anyway.

[Brightcolours]

Both the 70-200mm f2.8 L IS USM II and 70-300mm f4-5.6 L IS USM are well sealed.



The 70-300mm is the lighter and cheaper option, but only reaches 300mm, obviously.

The 70-200mm f2.8 has the edge there, with the new 2x extender III it still is nicely sharp and will give you 400mm at f5.6, like you have with the 100-400mm.



With the 2x extender, the AF will be slowed down by the camera to about half the speed. I know the lens is very speedy in AF, not sure how big the speed hit will feel like in practice.



Any chance of trying out a 70-20mm f2.8 IS MK II + 2x TCIII extender to test the AF speed? Of course, a TC II would do the job too, to test the speed.



I'd go for the 70-300 for its weight <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />... you probably should go for the 140-400mm f5.6 L IS USM II.. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />

[popo]

I know testing it first hand is the best solution but I don't have ready access to any of these short of arranging a rental.



My only concern for the 70-300L was if the extending zoom was a weakness for water ingress. It is my first choice if that is not an issue. Got a reference to the level of water resistance? I know it is supposed to have some, but I'd want to know it is significantly better than the 100-400L for it to be worth considering.



The 70-200 II unfortunately is much bigger, heavier, more expensive, requires a TC, has shorter zoom for the only minor plus side of not extending during zoom. As I'm not sure about the 2x performance, I wonder if the f/4 IS with 1.4x might be a cheaper option for the middle ground.

[Brightcolours]

[quote name='popo' timestamp='1308697971' post='9393']

I know testing it first hand is the best solution but I don't have ready access to any of these short of arranging a rental.



My only concern for the 70-300L was if the extending zoom was a weakness for water ingress. It is my first choice if that is not an issue. Got a reference to the level of water resistance? I know it is supposed to have some, but I'd want to know it is significantly better than the 100-400L for it to be worth considering.



The 70-200 II unfortunately is much bigger, heavier, more expensive, requires a TC, has shorter zoom for the only minor plus side of not extending during zoom. As I'm not sure about the 2x performance, I wonder if the f/4 IS with 1.4x might be a cheaper option for the middle ground.

[/quote]

http://forums.dpreview.com/forums/read.asp?forum=1029&message=38712022

If you can make total sense of the crops... I can't, yet. But the new 70-200 is great even with 2x TC.



About the level of weather sealing... nothing is ever really brought out about that, or put in numbers. Just that the lens is well sealed against moisture and dust, and than owners have has it getting rained on heavily and the lens being fine after that. How it exactly deals with extending and sucking air in, while keeping moisture and dust out, that is not documented.



What Canon said about it is:

"The lens includes environmental protection, allowing photographers to shoot in harsh conditions - even in the extremes of the desert or rainforest. Canon’s new Fluorine Coating also makes cleaning the lens easier, preventing smears or streaking. "

[miro]

Cotton cloth works fine for me.

[popo]

On the level of sealing, that's why I'm particularly interesting in actual experiences. I have now go one owner reference elsewhere which was positive.



Thanks for the link, I'll have to pixel peep that later, although now it is looking less likely I'll spring for the 70-200 family and pick the more flexible 70-300L instead. I just need to decide how to finance it... think it is time to say goodbye to the 70-300 DO for starters...

[popo]

[quote name='miro' timestamp='1308734394' post='9397']

Cotton cloth works fine for me.

[/quote]



Can you reach inside the front element with it in field conditions? I don't think I can. My problem is moisture getting INSIDE the lens. I'm not concerned about the water on the outside.

[mst]

I don't think that any zoom lens that changes its length during zooming will behave better in this regard ... or at least those conditions. Tha volume of the lens changes with zooming, so does the volume of air inside the lens, of course. It will suck in moisture saturated air, that condensates on the inner lenses.



So, I guess the only real solution would be a zoom length with constant length. Which would translate to the 70-200 IS w/ TC. Or a Sigma 100-300/4. Maybe a 100-300/4 OS, if that ever happens.



-- Markus

[miro]

I have never had problem with moisture inside of my lenses.

As far as understand you have problem with moisture getting INSIDE the lens.



I'm afraid that there is no single photographic lens that can classify in this category.

Technically seen the moisture gets easier than liquid water. If you throw your trusty L prime lens in water it will suck it immediately, despite what the marketing brochure says. Am I right?



I have chosen different approach.

“Prophylactic is better than cure.”

- for short trips in the Netherlands. Cotton cloth is enough.

- For long trekking trips in wilderness /sleeping in tent /. No dry place for about 2 weeks. Plastic package and cotton cloth works fine for me. In the rest time I prefer to take care for drying of my boots and cloths instead of my camera lens and tripod. BTW tripod sucks water which annoys me.



Sorry that I cannot give you advice. I have never experienced such problem.



Greetings,

Miro

[popo]

I'm not sure it is simply external moist air that is causing it. The lens would generally be same temperature or warmer than the air so condensation from simply having it in the wet environment shouldn't affect it. Other lenses used similarly but kept externally dry-ish don't have the same problem. I suspect the 100-400L, due to its extension allows surface water on the zoom section to enter the lens, where it then evaporates and saturates more so than ambient. That is also a concern I have of the 70-300L but as said I now have one owner reference that suggests this isn't the case. Coincidently that user also has the same issue I have with the 7D joystick in wet weather, so I think our usage is quite similar. I find the 7D joystick can become unreliable after prolonged exposure to water.