

Easy stuff
Center crop from both lenses at 50mm. Tamron on left, Canon on right.
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The Canon lens doesn't open to f 2.8, so there is no comparison here |
| Tamron f2.8, 50mm, ISO 200 | |
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| Tamron f4.0, 50mm, ISO 200 | Canon f4.0, 50mm, ISO200 |
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| Tamron @ f8 | Canon @ f8 |
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| Tamron @ f11 | Canon @ f11 |
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| Tamron @ f16 | Canon @ f16 |
Both Lenses at their widest angle and low aperture. Shows field of view (full frame body) / Light falloff / General sharpness & quality.
Tamron on left, Canon on right.
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| Tamron @ 28mm, f2.8, ISO 200 (as wide and open as it goes) | Canon @ 24mm, f4, ISO 200 (as wide and open as it gets) |
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| Tamron @ 28mm, f5.6, ISO 200 | Canon @ 24mm, f5.6, ISO 200 |
So, what can you see? I'm on the extreme wide end of both lenses here with the aperture open and again with the aperture a little stopped down. This isn't a test for sharpness, as you can see from the 50mm tests, the lenses are about equally sharp in the center. What I see here is the Tamron and Canon lenses both vignetting wide open on full frame bodies at their widest aperture. As you can also see, The vignette on the Tamron is mostly gone by f5.6, whereas the Canon is still showing light falloff. This can be fixed in photoshop, but a lot of newbies worry about light falloff on their 5D's and are surprised to find it, even with top quality glass. It's normal and not necessarily a bad thing. Under many circumstances, you'll not even notice it.
What you'll also notice is the difference in maximum field of view. The extra 4mm of width on the Canon is a lot. You can work closer with the Canon lens. Also notice, if you cropped the Canon lens down to a 28mm field of view, the light falloff would be less than the Tamron at that focal length. You get wider with the Canon, but you get more vignette too. Above f5.6, you'll not really see an issue with either lens.
- The long end -
Here's a 2:1 Lightroom crop at 75mm/f4
Tamron on the left, Canon on the right.

At f4, the Tamron is as good as the Canon with center sharpness, maybe better.
Below is a 100% crop at 75mm/f8.
Tamron left, Canon right.

So, what can you see? I see the Canon being a little sharper at f8 with a little more contrast. The Tamron is a hair brighter. Not a big difference though. Both lenses do a good job at 75mm. Obviously, the Canon has a length advantage of an additional 30mm. I can live with the results of either.
- Edge/Corner performance -
This is where good lenses run away from average lenses.
Again, Tamron on the left, Canon on the Right
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The Canon lens doesn't open to f 2.8, so there is no comparison here |
| Tamron Corner @ f2.8 | |
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| Tamron Corner @ f4 | Canon Corner @ f4 |
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| Tamron Corner @ f8 | Canon Corner @ f8 |
In order to provide you a little closer inspection of the corner performance between these lenses, here's a 4:1 crop from Adobe Lightroom.
The Tamron is on the left, the Canon is on the right.
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So, what can you see? What I see is the Tamron holds up pretty good for a budget lens. The Canon is a bit sharper at f4, but the Tamron isn't that bad and by f8 it is even closer. On the 30 inch Mac display in my studio, I can see that the Canon lens has better corner sharpness and less chromatic aberration. If you examine these crops closely, you can see a small difference, but trust me, it is small. On prints up to 8x10, you won't tell them apart. You'd have to be printing up to 24 inches to really notice.
Well, that's all I'm going to do with photos. Are they perfect examples of what these lenses can or can't do? Nope, but they are good representations of the differences between these two lenses in a real world environment (my back yard.)
My conclusion is this. The Tamron 28-75 f2.8 XR Di LD IF Aspherical AF lens at a cost of $360 will compete optically (and in some cases out perform) the Canon EF 24-105 L IS lens. Keep in mind, both lenses were tested on the Canon 1DsMKII, which is about as tough a camera to make happy as there is. This camera will expose a bad lens quicker than you can drop one on concrete. All that said and done, I can highly recommend the Tamron for anyone looking for a great budget lens that will produce top quality results.
Myself, if I need a lens for money work, I'll use the Canon. The Image Stabilization, extra focal length, weather sealing and rugged build make it a pro grade lens that can handle rough work. When I need a lens for the beach or back yard BBQ with the kids throwing baseballs or rocks or the dogs jumping on everything, I'll put the Tamron on my camera because I can afford to replace it. I've taken hundreds of shots with both lenses and I can tell you that I have no qualms using either on any camera body I own.
Happy shooting.
- Edge/Corner performance -
This is where good lenses run away from average lenses.
Again, Tamron on the left, Canon on the Right
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The Canon lens doesn't open to f 2.8, so there is no comparison here |
| Tamron Corner @ f2.8 | |
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| Tamron Corner @ f4 | Canon Corner @ f4 |
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| Tamron Corner @ f8 | Canon Corner @ f8 |
In order to provide you a little closer inspection of the corner performance between these lenses, here's a 4:1 crop from Adobe Lightroom.
The Tamron is on the left, the Canon is on the right.
![]() |
So, what can you see? What I see is the Tamron holds up pretty good for a budget lens. The Canon is a bit sharper at f4, but the Tamron isn't that bad and by f8 it is even closer. On the 30 inch Mac display in my studio, I can see that the Canon lens has better corner sharpness and less chromatic aberration. If you examine these crops closely, you can see a small difference, but trust me, it is small. On prints up to 8x10, you won't tell them apart. You'd have to be printing up to 24 inches to really notice.
Well, that's all I'm going to do with photos. Are they perfect examples of what these lenses can or can't do? Nope, but they are good representations of the differences between these two lenses in a real world environment (my back yard.)
My conclusion is this. The Tamron 28-75 f2.8 XR Di LD IF Aspherical AF lens at a cost of $360 will compete optically (and in some cases out perform) the Canon EF 24-105 L IS lens. Keep in mind, both lenses were tested on the Canon 1DsMKII, which is about as tough a camera to make happy as there is. This camera will expose a bad lens quicker than you can drop one on concrete. All that said and done, I can highly recommend the Tamron for anyone looking for a great budget lens that will produce top quality results.
Myself, if I need a lens for money work, I'll use the Canon. The Image Stabilization, extra focal length, weather sealing and rugged build make it a pro grade lens that can handle rough work. When I need a lens for the beach or back yard BBQ with the kids throwing baseballs or rocks or the dogs jumping on everything, I'll put the Tamron on my camera because I can afford to replace it. I've taken hundreds of shots with both lenses and I can tell you that I have no qualms using either on any camera body I own.
Happy shooting.



















