Tamron 17-50 f/2.8 or Canon 17-40 f/4L

Andy_S_T

Andy_S_T

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I'm looking for a good quality standard/wide angle lens for 40D. I have been thinking about the above 2, or even a Tokina similar to the Tamron. My question is are the lower priced lenses sharp at 2.8, or will I end up stopping it down to f/4 or even f/5.6 to get as sharp an image as the Canon is sharp at f/4?

I bet this has been asked many times before but my search didn't really turn up an answer.
 
both are great . the canon's build quality is better and its weather resistant . the Tamron however comes with a very attractive price tag,an extra reach of 10mm and its 2.8 . i,d say the Tamron ...
 
Another vote for the Tamron... and non VC all the way!!
 
How about the Canon 17-55 f/2.8 IS

Think I keep mentioning this lens because I was surprised at just how good it is
 
As already stated, the Tamron is excellent value for money plus it's a constant 2.8
Loved mine, but sold it last when I upgraded to a 24-105 F4 L (and yes, I do miss being able to shoot at 2.8!)
 
Knowing absolutely nothing about the Tamron range - Is the 17-50 you are looking at designed for a crop sensor camera? If so, this throws up another issue.
 
swag72 said:
Knowing absolutely nothing about the Tamron range - Is the 17-50 you are looking at designed for a crop sensor camera? If so, this throws up another issue.
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Only if he's planning to go full frame in the future. I don't think this is a good enough reason to not consider it personally, but that's just me. Even then if you buy second hand you're not going to lose much money, if any at all when you come to sell it on.

Tamron all the way.
 
My issue wasn't anything to do with full frame, more the focal length of the 17-40 on a crop sensor. If the Tamron is made for the crop sensor (similar to the EFS Cannon range), then the Tamron will give a 17-50 focal length on the 40D. The OP will end up with something a little different with the 17-40 on a cropper.

That was my point - If I'm wrong please do correct me :thumbs:
 
swag72 said:
My issue wasn't anything to do with full frame, more the focal length of the 17-40 on a crop sensor. If the Tamron is made for the crop sensor (similar to the EFS Cannon range), then the Tamron will give a 17-50 focal length on the 40D. The OP will end up with something a little different with the 17-40 on a cropper.

That was my point - If I'm wrong please do correct me :thumbs:
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Sorry, I just get annoyed when people say "are you going full frame blahblah blah" it just bugs me. :)

The focal length is still 17-50 on the tamron, and the same is for the 17-40. The field of view of both lenses are multiplied by 1.6. The focal length is a bit out of date nowadays imo, but I suppose it's easy to remember.

There is a difference though, but it has nothing to do with focal length. As the Tamron's designed for a crop sensor the whole of the lens is used, right up to the edges, rather than just the centre as it would be on a lens designed for full frame. There's a reason for this, something to do with how close the lens is to the sensor, but I can't put it into words. Friday afternoon brain drain :bonk:

Edit: It's come to me now! Image circle. The full frame lens has a larger image circle compared to a crop sensor lens. The crop sensor can only use a certain amount, a lot of the extra from the full frame lens is wasted. But to produce a bigger image circle you need a bigger diameter, which in turn means a heavier and bigger lens to lug around.

http://www.bobatkins.com/photography/tutorials/crop_sensor_cameras_and_lenses.html

Scroll down to the bit about image circle, it explains it a lot better than I can!
 
If the Tamron is designed specifically for a crop sensor then gives you a 17-50 focal length, whereas the 17-40 on a crop sensor will give an equivalent focal length (field of view if you prefer) of 27-64 - Isn't that right?
 
No, the 17-50 focal length is still measured by full frame standards. It gives you the equivalent of 27-80 on a crop camera. If you wanted the same field of view on a full frame you'd need a 27-80 lens.

I think the focal lengths are measured by full frame standards so people don't get confused.
 
Well you learn something new everyday - Thanks Ben :thumbs:

Here was me thinking that my 17-55 EF-S was actually equivalent to what it said on the tin.
:bonk:
Anyway, I digress. To the OP, the Canon 17-55/2.8 EF-S is well worth a look. It is a great lens that fits the cropper nicely.

Hang on though, if what you say is right Ben and it is really equivalent to 27-64 ................ :thinking::thinking: Then why is there posts that say that the 17-55 on a cropper is far wider than a 17-40?
 
No problem, it's nice to actually know something for once!

I think the post you're referring to means the tamron is 10mm longer.
 
The Tamron 17-50 f/2.8 is one of my most fav. lens I've ever used, it's cheap but it feels great and the image quality is very good :thumbs:
Just make sure you don't get the VC one :)
 
So I assume from what you are all saying, the Tamron is sharp at 2.8. Not bothered about the weight, most of the time I have an Canon 80-200 2.8 strapped to the front, and that weighs a ton!

You've got me interested with this image circle lark though, might have a read about that.
 
no it's not very sharp at 2.8. It perform acceptably at f/2.8 and best at f/4 :thumbs:
 
it's pretty sharp at f3.5
 
swag72 said:
Hang on though, if what you say is right Ben and it is really equivalent to 27-64 ................ :thinking::thinking: Then why is there posts that say that the 17-55 on a cropper is far wider than a 17-40?
Click to expand...

Well they're wrong...
 
Tamron for me, heard nothing but good great things about it and always is sharp to the tee.
 
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