Hi there

I have 7D with several primes which I use on occasion when I am keen to get a film like look.

I dont really know much about DSLR's and lenses etc as my knowledge and experience mainly centres around video cameras.

So my possibly dumb question is this... What zoom lenses dont extend forward and what ones do? My Tokina 11-16 doesnt appear to extend when adjusting zoom but I know some (most?) zooms do.

The reason I ask is that Im thinking about buying a zoom lens for when Im under the pump time wise and dont really have the time to change lenses. I do use a matte box regularly and dont want to lose the ability to use it if I end up with a lens that moves forward when I use the zoom.

Is there a specification I should look for when shopping for lenses that tells me how the zoom works (assuming some zooms dont extend)

If you're feeling extra helpful, It would be great if you had a suggestion or two around what might be a decent zoom lens I could buy (mid range price) that I can also use on the new Sony FS-100 when I get one later in the year.

Thanks

Jamie

Hi Jamie, I think the best way to approach this is to ask you what zoom range
are you considering. There are an awful lot of Canon and Canon-compatible
zoom lenses, so if you can narrow it down to a specific focal length range,
it would be a lot easier to answer your question.

For example, there are no less than five Canon EF 70-200mm L-series lenses
(two f/4's and three f/2.8's), and none of those extend. But there's a Canon EF
70-300mm L-series f/4-5.6 which does. And this is just the tip of the zoom lens
iceberg!

L-series (best quality, more expensive) or not?

EF-S (made specifically for crop-sensor cameras like the 7D) or not?

Short zoom (less than 100mm at full telephoto) or longer?

Hi Chris

I was thinking somewhere between 17mm and 70mm.

Id like to be able to use the lens on my 7D now and on the Sony FS100 down the track. Be going for a F2.8.

Im prepared to pay a bit more if it means I can use the lens on both cameras.

Will lenses made for crop sensor lenses (I have a EF 28mm) be OK with full sensor cameras?

Is there a specification that tells us whether the lens extends or not?

Thanks for your help (You've actually been helping me for years!) Much appreciated

Jamie

The Canon EF-S series, made for crop-sensor cameras, are *not* compatible
with full-frame cameras. But all of those zoom lenses extend (except for the
EF-S 10-22mm, which is out of your focal length and aperture range anyway),
so it doesn't really matter.

I think you have two choices, and both are L-series lenses. The first is the Canon
EF 16-35mm f/2.8L II USM, about $1700 (in USD, not sure how that converts to the
Aus. dollar): Canon EF 16-35mm f/2.8L II USM Autofocus Lens 1910B002 B&H Photo

-- it's expensive and a little short on telephoto but it has the constant f/2.8 aperture
that you want.

The other lens is similar in focal length, but slower and less expensive... the Canon
EF 17-40mm f/4L USM: Canon EF 17-40mm f/4L USM Lens 8806A002 B&H Photo Video

-- about $840 USD, a bit slower aperture than you want but still constant throughout
the zoom range and much more affordable.

There is no specification for a non-extending zoom, but the terminology often used for
it is "internal zoom" if you want to search for that (or internal zooming). You might want
to look into the now discontinued Sigma 50-150mm f/2.8 EX DC HSM APO -- it has
everything you want *except* it is crop-sensor only, and it had some mixed reviews.
For more details, see FM Reviews - Sigma 50-150mm F2.8 EX DC HSM APO (http://www.fredmiranda.com/reviews/showproduct.php?product=331) but you
might be limited to buying a used one -- hope this helps,

Thanks Chris

Clearly food for thought!

I will continue to investigate

Cheers

Jamie