math focul ff stuff

[KIPAX]

Not every good with this sort of math...so will ask.. probably nominal is the answer but here goes..

I ahve a 1.3 crop and a full frame camera. both canon

Am looking for a wide angle and would prefer on ff... best I can find is the canon 17-40

But I like the look of sigma 10-20 however doesnt work on FF

What the difference as in wide.. not quality or owt else.. just wide..... ff 17mm and 1.3 crop 10mm big or nominal?

 

[Little John]

17mm on a FF is 17mm
17mm on a 1.3 crop is equvilent of 22.1mm
on a 1.6 crop (7d, X0D, X00D etc is equivilent of a 27.2mm

Hence the canon 10-22mm is an EFs giving an effective focal length of 16mm-35.2mm

if you want to try the 16-35 or the 10-22 let me know I have them both

 

[Phil V]

The 10-20 won't go all the way to 10 on your 1.3 crop, there are tests on the web - probably starts about 14mm.

The 12-24 gets plenty of recommendations and would be wide on both bodies, though obviously wider on ff.

 

[Nod]

A good copy of the 12-24 works great on FF (it's crazy wide though!!! ) and at 12mm should equate to about 15.5 on a 1.3x crop. Sharper than the 10-20 too (or at least my 12-24 is sharper than Yv's 10-20!)

 

[KIPAX]

cheers guys.. dont think i heard of a 12-24 ..is that sigma as well ? gonna go google and ebay it now for info and prices

 

[Nod]

Yup, it's one of their EX range.

 

[KIPAX]

Yup, it's one of their EX range.

been reading up.. reviews seem to say f8 + for best results and the most worrying is the good/bad copies.. i wasnt going to buy new where you could send back until right... so i need a private seller who can show me pics or i can test.. ebay no good for that.. might be a long wait

its not a lens i would use a lot.. but it is a lens i would definitely use and want.. but usage doesnt warrent new ..erk

 

[MatBin]

Without wishing to be pedantic, its field of view that changes when lenses are discussed in terms of ff or crop, not focal length. We just express it that way.

 

[KIPAX]

Without wishing to be pedantic, its field of view that changes when lenses are discussed in terms of ff or crop, not focal length. We just express it that way.

So long as we know what I meant.. that will do me

 

[Nod]

I know what you mean about wanting to be sure of a lens. I've not had any problems with any lens I've bought (apart from an older superzoom that was a bit crap - but that was common to all of them at the time!) but still always buy locally and try before I buy (not had to reject any either). Most of the reputable shops with a bricks'n'mortar presence will take returns. IIRC, one of the advantages of the EX range is the extra level of QC they go through - might pick up dodgy copies?