Field Report
by Gary Gray
Available through online photo stores for approximately $360 (US), the
Tamron 28-75 f2.8 XR Di LD IF Aspherical AF lens is praised as one of the best budget
walkabout zooms available. I'll be giving the Tamron a Field Report and comparing it to the
venerable Canon EF 24-105mm f/4 L IS USM.
At about 1/3 the cost, I'll show you how the Tamron stacks up against what is
generally considered to be the best all-around general purpose lens for the Canon mount?
Tamron 28-75 f2.8 XR Di LD IF Aspherical AF
vs
Canon EF 24-105mm f/4 L IS USM
(by Gary Gray)
- Disclaimer -
I'm a photographer, not a camera tester or a lens tester. My camera testing and/or lens testing is normally limited to "in the field" where the rubber hits the pavement.
I use my photography gear every day and if it doesn't stack up to my demands, I shelve it or sell it. I'm not going to pixel peep or measurbate in this comparison. My intention is to show the average guy out there, what type of performance they can expect when they purchase a product. It's up to you to make a decision. My opinion is just that, my opinion. Your mileage may vary.
The test photos included below are for reference only. I didn't shoot any test charts, I took both lenses, a tripod and my 1DsMKII into my back yard on a sunny morning and shot some comparisons that I felt would illustrate the points I wanted to make. I concentrated on the extremes of these lenses and am not overly concerned with sweet spots and normal exposure conditions. Shoot either of these lenses at f8, at 50mm and you'll get roughly the same image. It's the ends and edges that interest me. These ends and edges make or break a shot more often than you'd realize. All photos were shot in JPG format using the 1DsMKII default settings at M1 quality. I loaded them in Adobe Lightroom, tweaked them slightly for color/exposure and didn't do any sharpening. What? They aren't in RAW and you tweaked them? Yep, that's right. That's what I do...I'm a photographer. I take photos, load them on to my computer and tweak them. If you disagree, get over it. This isn't a scientific test.
- The Review -
So, why compare these two lenses to one another? Answer...because they are there. It happens every day, informally, on the internet.
If you frequent any of the online camera forums, sooner or later you'll find somebody asking the question..."What is the best walk-about lens" for the Canon 5D, 30D, 400D or what-ever camera they have or intend to purchase. Read the replies and you'll invariably find these two lenses (amongst others) mentioned. I own both of these lenses and use them frequently. If I didn't like them, I wouldn't have them.
First, lets get the obligatory stuff out of the way.
It's not a fair comparison!
Yep, that's right. The Tamron 28-75 costs about 1/3 the price of the Canon 24-105L IS. I'll explain the differences in a bit more detail, but costs is a big one.
Focal Length: Well, c'mon...The Canon is wider and longer...duh. So what, it's not that much wider and not all that much longer. These are "walk-about" or "general purpose" lenses. Since they both fill a certain need and are often mentioned in the same discussions, this is a fair comparison.
Image Stabilization: The Canon 24-105L IS is image stabilized, the Tamron isn't...well duh. So what. The Canon costs 3 times more, it better have something extra.
Maximum Aperture: Well, surprise surprise. The Tamron is the faster of the two with a max aperture of f2.8 compared to the Canon's f4.0. This extra aperture is one advantage the Tamron has over the Canon.
Build Quality: The Tamron is a consumer lens at a consumer price, the Canon is a professional grade "L" lens at a premium price ($1,000 + US)...Double Dog Duh!! It's been my experience that you normally have to pay a steep price to get top glass. I've read numerous comments about the quality control on the Tamron lens not being that good and reportedly the Tamron lens suffers from copy-to-copy quality variation. I've no experience with this. My copies of each of these lenses meet my expectations and I'm fairly confident they represent as good a quality as can be expected from both manufacturers.
Auto Focus: I think the Canon lens is a little faster on the auto-focus. Both are quiet and quick though. I don't see much difference in most lighting conditions. One difference between the lenses; however, is the Canon lens can be manually focused while in auto focus mode. To manually focus the Tamron, you must unlock the auto focus by flipping the switch on the lens. There is also a little more play/slop in the Tamron focusing mechanism. Another reason the Canon is more expensive, it's better built and has more functionality.
Easy stuff
Center crop from both lenses at 50mm. Tamron on left, Canon on right.
So, what can you see? A bunch of boards from about 10 feet away, right? It's the gate to my back yard. What I see is that each of these lenses at 50mm are about equally sharp across the range. The Canon may be just a hair sharper than the Tamron wide open and stopped down, but you'll never notice the difference between these two lenses in prints up to 24 inches. Beside, a little post-processing and you can match them and not even I could tell you which lens was which. The Canon is a little more contrasty, which is my personal preference, but this too is subject to taste and tweaking in photoshop. I call it a draw, sharpness to Canon (barely) and aperture to Tamron.
- Wide Angle -
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
 |
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 |
 |
 |
| 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.
