[JJ_SO]

He's applying for a position in da test-lab  ^_^

[toni-a]

Interesting ? Maybe not much more than their already existing line of superzooms, however a 15-200 would have made much more sense, I found my 15-85 range more handy than that of 18-200 I used for a while.

[JJ_SO]

Given that you are thinking about buying a 17-55 again, your comment is a little bit nitpicking. Never thought about there's a reason that superzooms - none of them AFAIK - start at 18mm? With two lenses like 8-16 or 10-24 and this 18-400 I could cover a set for lightweight travel.

 

Or in other words: It's not Tamron's fault that Canon uses smaller sensors than other APS-C candidates and therefore would benefit from shorter FL for wide-angle - and on the other side it gives you a "longer" tele equivalence. It's not Tamron's fault and Canon themselves might see reasons to not go for a 22× zoom for DSLRs. It has yet to be proven these 400 mm can be used with satisfying results.

 

Btw., a 1.5× instead of 1.6× sensor would give 18 × 1.5 = 27 ÷ 1.6 = 16.875 

[Brightcolours]

Given that you are thinking about buying a 17-55 again, your comment is a little bit nitpicking. Never thought about there's a reason that superzooms - none of them AFAIK - start at 18mm? With two lenses like 8-16 or 10-24 and this 18-400 I could cover a set for lightweight travel.

 

Or in other words: It's not Tamron's fault that Canon uses smaller sensors than other APS-C candidates and therefore would benefit from shorter FL for wide-angle - and on the other side it gives you a "longer" tele equivalence. It's not Tamron's fault and Canon themselves might see reasons to not go for a 22× zoom for DSLRs. It has yet to be proven these 400 mm can be used with satisfying results.

 

Btw., a 1.5× instead of 1.6× sensor would give 18 × 1.5 = 27 ÷ 1.6 = 16.875 

And a 1.53x crop sensor?

[JJ_SO]

Higher math (more than 1 digit on the right side) I leave to people who dedicated their life to the religion of eqivalencism  :lol:

[Brightcolours]

That puts into question your 16.875 result  :lol:  :ph34r:

[JJ_SO]

Result and input are two things. One I have to type, the other to read. Or paste...

[Brightcolours]

So in other words, you don't want to use exact figures in a calculation, but you have no issue reading a too exact result? 

 

18 x 1.53 = 27.54 / 1.61= 17.1

 

Just for optics 17mm looks better than 16mm  :lol:

[JJ_SO]

Don't you get it?

 

I was making fun out of toni's ridiculous 15-200 idea. And I do agree very much with Rover's "da wide", "da tele" and "da whatever" categories as these are precise enough.

 

Meaning, your equivalence calculatuions with 4 digits behind the comma are the best indicator to "not care about THAT post". I really don't give a sh_t about calculations which imply to show a truth which is simply depending on much other factors without lots of high resolved numbers.

[davidmanze]

 As we are talking precision focal equivalents, (probably the most tedious process known to man), just for kicks and giggles I decided to resurrect my brain and verify the crop factor figures.....using the Pythagoras's theory (for the diagonal dimension).

 

  The crop factor for the D500 (23.5 X 15.7mm) as 1.53067 so 1.53 is near enough.

 

  For the 80D  (22.3 X 14.9mm)* I have it at 1.6156 so 1.615 will do!

 

 

  *Dimensions from Canon's official site for the 80D. ...

 

  http://www.canon.co.uk/for_home/product_finder/cameras/digital_slr/eos-80d/specification.aspx 

 

 

   So, 18 X 1.53067= 27.55206/  1.6156 = 17.05376 mm!