I am pleased with my Canon 400d and currently use my older lenses. One result is that the digital makes the lenses more powerful by a factor of 1.5.  Which is great for my  75 to 300 zoom but means I have lost the wider angle on my 28 to 90 zoom. Am i correct in thinking that  17 to 40 is the equivalent ? 
This would be a good chance to get a specific wide angle zoom  but I am not sure what would fit besides Canon lenses,
thanks confused of Scotland !

Hello Garlor,

i'm using a sigma DC EX 18-55 f/2.8 on my canon eos 20d (yes it's equivalent 28-80mm)

It's really excellent when you work from f4 to f8, but he is yet great full open.

The price is around 400$ i think....

hope this help,

Olivier

I use a Sigma 10 - 20 on my Nikon D100 - well pleased with it.
Comes with different mounts,good value in my humble opion.Worth checking it out.
Eddie

Yeah you will get something more like wide angle to standard lens... It is in fact a 1.6 crop so 27.2- 64mm for the Canon 17-40mm L f4 which is a wonderful lens you will find others like the Sigma to provide good value, but I  know a few have been disappointed when compared to the Canon... So if you can afford the Canon you wont be disappointed.. 

For a wider view on the 1.6 Crop the The Sigma AF 10-20mm f/4-5.6 EX HSM DC is good but a bit slow at the 5.6 end while the Canon retains f4 througout the zoom range ..

As with all lens choices it depends what you want to shoot with it, and how.

Some very good lenses mentioned and they all have different features and strengths, if they suit you, and the type of shot you want to make is another question.

The Canon 17-40 that you mentioned is a great lens and has a reputation for quality.  I would say it is more of a general walk about lens than a specific wide angle lens when used on a camera like the 400d with it's 1.6 crop factor.  It has the advantage of fitting all Canon cameras if you should ever upgrade to one with a larger sensor, and as Danny has pointed out is F4 at all focal lengths. 

The Sigma 18-50 also has a good reputation and is F2.8 all the way this may an advantage in some situations eg indoors or poor light.  It is slightly less money than the Canon but probably not as weather proof and will only fit cameras with a smaller sensor eg 400d, 30d etc. Again more a walk about lens than a specific wide angle lens.

The Sigma 10-20 is a true wide angle lens on a crop sensor camera. Consider carefully though if you want a specific wide angle lens. It is a specialist, and therefore requires specialist technique to get the best out of it.   Results from this lens can be stunning if this is the type of shot you are after, it is in my opinion the pick of the wide angle lenses available for your camera the quality is second to none.  The fact that is F5.6 at 20mm is of no consequence to most users as they would be using a much smaller aperture  in practice when shooting wide angle landscapes. 

Thanks to all, I am planning more ground based photo work. There are times when I feel the need for an increase in the Wow factor and 28mm is just not wide enough. Also I will be working with large structures such as ships,cranes,docks. (already done the air views of the location)
So its looking like the Sigma 10...20 which includes the equal to my original 28 mm plus the ability to go even wider.
While I am not  fixated on believing that a pro photographer has to have lots of kit , I do believe that I need to keep re investing  some of the profits into expanding what I have as tools of my trade. I aim to deliver exciting and unusual images and not just from the air !

Talk to Zacko or Mayda about the Sigma 10- 20....or, just look at their work...Stunning!

OK, OK....it's not the lens alone....LOL!!!!

hello,

just one more word : my last pics (flowers) were done with a Zeiss Flektogon 35mm f2,4 - Manual focus with an adaptator ..
On my canon 20d, i work in raw and diaphragm priority... The contrast is awesome !!! it's very sharp at full opening, on the center and on the edge ...The bokeh is so great !!!!! it's like a 50mm in 24x36.

But it's a fix focus.. not a zoom... I bought it 130€ on ebay (+- 100$)

Olivier