Resistance to Larger Filter Size, Kills Great Lenses?

[pwp]

I personally still don't see the usefulness of IS on a lens like that and I personally would always chose the non-IS version over the IS. It's really more an amateur gadget unless were talking much longer focal lengths.

You may have steadier hands than average. I certainly don't have a case of the "trembles" but do achieve a clear benefit from IS on my 24-105 f/4is and of course the 70-200 f/2.8isII. A 24-70 f/2.8is would be a very useful bit if kit for me. I just ache for IS on my 135 f/2.

Some people have the gift of steady hands. For the rest of us, IS = more keepers.

-PW

 

[Meh]

Seriously Neuro, what's with your obsession with evidence, logic, and reasoning? Frankly, it's getting old and tiresome.

Yeah, it's Canon Rumors and not Canon Facts for a reason

What do facts have to do with anything, people don't want facts interfering with their opinions.

 

[Radiating]

A google search led me back here to another post mentioning the 24-70 and a 95mm filter size. OP was the same that mentioned it in the other thread. Not sure where the info is from. Radiating, where did you hear about the 95mm filter size?

Canon experimented with 2 different possible image stabilized f/2.8 zooms. There are patents for them available on both Canonwatch.com and egami.com, and canonrumors.com

The first of these two lenses is a 28-70mm f/2.8 IS, with a filter size of 86mm. The second was a 24-70mm f/2.8 IS with a filter size of 95mm, (although it could have used 90mm filters, if anyone made those).

The 24-70mm II uses I beleive (don't quote me on the precise number) a 68mm front element with an 82mm filter size. The 24-70mm f/2.8 IS used a 77.29mm front element!

Other sources, such as Canonrumors themselves do add that it's not strictly the sheer size of the lens that was an issue (or it's resulting filter size) but that as a result of it's size it also weighed a ton and the lens elements were expensive due to their size. Though this thread is focusing more on the filter size issue being serious enough to be partly responsible for killing a lens, and if that's justified. I'm sure there are tons of other threads that cover whether the size and weight of a lens are an issue people care about.

 

[RMC33]

A google search led me back here to another post mentioning the 24-70 and a 95mm filter size. OP was the same that mentioned it in the other thread. Not sure where the info is from. Radiating, where did you hear about the 95mm filter size?

Canon experimented with 2 different possible image stabilized f/2.8 zooms. There are patents for them available on both Canonwatch.com and egami.com, and canonrumors.com

The first of these two lenses is a 28-70mm f/2.8 IS, with a filter size of 86mm. The second was a 24-70mm f/2.8 IS with a filter size of 95mm, (although it could have used 90mm filters, if anyone made those).

The 24-70mm II uses I beleive (don't quote me on the precise number) a 68mm front element with an 82mm filter size. The 24-70mm f/2.8 IS used a 77.29mm front element!

Other sources, such as Canonrumors themselves do add that it's not strictly the sheer size of the lens that was an issue (or it's resulting filter size) but that as a result of it's size it also weighed a ton and the lens elements were expensive due to their size. Though this thread is focusing more on the filter size issue being serious enough to be partly responsible for killing a lens, and if that's justified. I'm sure there are tons of other threads that cover whether the size and weight of a lens are an issue people care about.

Just did a search on the USPTO/google patent and there are no patents for anything related to a 24-70 f/2.8 IS. Loads of references to the 24-70 f/2.8 MKII and 24-70 f/4 IS. It could not be published yet, but I want to see the source material from the websites as nothing shows up in searching on them.

 

[Marsu42]

General comment: If this rumor is true, it seems to me there won't be a 24-70IS at all?! Not that it would matter to me, a €3000+ price tag is not in my budget region for a standard zoom anymore.

What do facts have to do with anything, people don't want facts interfering with their opinions.

Most people of course are open to interfering facts - but in my experience it is often discovered that these facts, after due inspection, either aren't really proven/applicable or even magically validate the seemingly contradicting opinion as the exception to the rule

The 24-70mm II uses I beleive (don't quote me on the precise number) a 68mm front element with an 82mm filter size. The 24-70mm f/2.8 IS used a 77.29mm front element!

So in simple layman's terms a Canon 24-70/2.8IS needs larger glass elements to be sharper than the 82mm Tamron 24-70vc, or does the Canon IS have another construction that is larger than Tamron VC?

I have to admit I don't quite understand it yet because I imagined the IS being build *around* the lens, but now it seems like the IS needs some glass "headroom", at least in the front element, to work because the angle of the lens changes slightly when IS is at work?

 

[Loswr]

Canon experimented with 2 different possible image stabilized f/2.8 zooms. There are patents for them available on both Canonwatch.com and egami.com, and canonrumors.com

Just did a search on the USPTO/google patent and there are no patents for anything related to a 24-70 f/2.8 IS. Loads of references to the 24-70 f/2.8 MKII and 24-70 f/4 IS. It could not be published yet, but I want to see the source material from the websites as nothing shows up in searching on them.

RMC33 - Your Google-fu is weak, Grasshopper.

Radiating - Thanks, although a link would have been helpful.

http://www.canonrumors.com/2012/07/patent-canon-ef-24-70-f2-8l-is/

 

[RMC33]

Canon experimented with 2 different possible image stabilized f/2.8 zooms. There are patents for them available on both Canonwatch.com and egami.com, and canonrumors.com

Just did a search on the USPTO/google patent and there are no patents for anything related to a 24-70 f/2.8 IS. Loads of references to the 24-70 f/2.8 MKII and 24-70 f/4 IS. It could not be published yet, but I want to see the source material from the websites as nothing shows up in searching on them.

RMC33 - Your Google-fu is weak, Grasshopper.

Radiating - Thanks, although a link would have been helpful.

http://www.canonrumors.com/2012/07/patent-canon-ef-24-70-f2-8l-is/

Thats the one. Upon searching it again it shows up in tandem with the MKII, f/4 IS and a few others. ~

 

[Rat]

Could someone explain why these specs indicate a need for 95mm filters? As far as I can tell, a 82mm thread would be enough...

 

[Loswr]

Could someone explain why these specs indicate a need for 95mm filters? As far as I can tell, a 82mm thread would be enough...

They don't, necessarily. But if you look at the 24-70 (both verisons), the front of the lens has a ring of reasonable diameter (sufficient to print the lens ID info) around the front element, meaning the filter diameter is a fair bit larger than the front element. Not all lens designs have that much space (and some have a lot more).

Does Canon have a reason for designing it that way? Probably. Note that a quick comparison of this image suggests that the front element of both versions of the 24-70L is pretty close to the same size, but the MkII uses an 82mm vs. a 77mm filter. Reasons could be to reduce chances of mechanical vignetting with a filter in place, to allow space for a more robust bracket setup to hold the front element, etc.

 

[helpful]

Image quality is affected by filters depending on the quality of the filter and on the surface area of the filter.

The larger the surface area of the filter, the greater the reduction in image quality. (You can see this with a softening filter--when your lens is stopped down, the effective diameter and surface area of the filter are reduced. When the surface area goes down, the image quality goes up, and hence there is less of a "softening" effect from the softening filter at smaller apertures (large f numbers).)

A filter with twice the diameter has four times the area. Large filters are bad in this way.

But ultimately, it is due to the expense--the larger the filter, the more expensive it is to make one the same quality as a smaller filter.

In fact, achieving that same level of filter quality isn't enough because even at the same level of filter quality the image quality will still be worse because of the larger area.