Tamron 1.4X F AF4 out of 10 points and not recommendedCheapBad optics
I have used this TC with both a Tamron 70-300 and the Canon EF 28-135 on the Canon 300D Digital Rebel.reviewed January 4th, 2007 (purchased for $50)
Pictures taken from a stable tripod stopped down f/8 and low ISO are still somewhat blurred and have a noticable loss of contrast. In every instance where I have used this TC I later wished I did not when reviewing pictures
The last time I used it I setup a test where I used the 300mm with and without the TC and then compared uprezzing the non-TC shot to the same FofV as the TC shot and found that Photoshop does a much better job than this TC. Both sharpness and particularly contrast, suffer with the use of this TC.
The one pro for this TC is that it is cheap and built relatively solid. Additionally, it will give you the extra compression of the depth in a shot that a longer focal length provides. But that small benefit comes at a high cost.
My advice: don't use this TC. If you need a tighter shot just uprez in PS or buy a longer lens.
Sigma 70-300mm f/4-5.6 DG Macro6 out of 10 points and recommended
Overall, not a great performer compared to top quality lenses. In fact, I won't even use it at 300mm.reviewed January 5th, 2007
Shorter focals seem ok but it always seems to lack contrast ("punch"). It's always a bit soft however, at 300mm you'd be better off shooting with a good quality 150mm and just cropping; it's that bad. It's like shooting through fog.
Macro mode is a gimmick too. Closest focusing distance is nearly a meter, hardly macro. However, you do get 1:2 magnification which isn't too bad.
The other thing that has always bothered me about this lens is that you have to flip a mechanical switch to get into Macro mode which can only be done above 200mm and then proceed to focus into macro. Then, to get back you must focus on something further away than macro before you can flip the switch back. The focusing motor doesn't like you to do this manually (sounds like if you turn too fast it would strip the gears) and trying to do that on a camera is difficult if indoors.
Overall, mine is going on ebay and I'll just use my 135mm and crop down if necessary until I can get a different tele.
Sigma 28-70mm f/2.8-47 out of 10 points and not recommended
Replaced this with the Canon EF 28-135 due to softness all over and a general lack of contrast. The colors from this lens always looked washed out.reviewed January 5th, 2007
The close focusing distance was nice. This lens is nearly capable of macro work (albeit with a low magnification ratio)
One advantage is it is very light weight.
Canon EF 75-300mm f/4-5.6 III8 out of 10 points and recommendedBetter quality than most 3rd party near the same priceNot up to L standards (or price)
A very usable lens when stopped down and has much improved contrast and colors over the lower-end 3rd party lenses in this same range.reviewed January 5th, 2007
While it's not top-quality glass it doesn't cost or weight the same either.
Overall, for a buyer looking for a compromise, this is a good choice.
Canon EF 50mm f/1.8 II9 out of 10 points and recommendedVery fast, cheap, light weight, sharp stopped downcheap construction
I love to use this lens wide open at ISO 1600 as I can actually shoot (and get AF) by candlelight. I find it's also a good lens for night sky although the AF won't work anymore.reviewed January 5th, 2007 (purchased for $60)
* Tac sharp stopped down 2-3 stops
* Very fast wide open that gives a very shallow depth of field
* Unbelievably cheap
* Cheap construction although it does make it very light. Given the price this really isn't a problem because replacement is a non-issue.
* Focusing ring is too small making manual focus very difficult
* Quite soft at the corners when wide open.
Canon EF 28-135mm f/3.5-5.6 IS USM8 out of 10 points and recommendedIS works great, good pricelower price means some compromises, weight
This is my main walkaround lens although it's too long for most indoors use on crop-factor digital cameras.reviewed January 5th, 2007 (purchased for $450)
* Probably one of the best price/performance ratios in Canon's lineup if you don't mind paying for IS. It's not L glass but it's a big step up from the bargin lenses
* IS works as advertised. The only limition is motion blur if your subject is moving. For still lifes I have successfully shot 135mm @ 1/8 second!
* Very good range for a walkaround on full frame cameras although crop factor users will find it a bit long
* CA and sharpness are both good.
* Contrast is execellent compared to 3rd party lenses.
* Colors seem to have very good saturation and punch.
* Its heavy by comparison to non-L lenses. L users will probably not notice a difference
* Soft at the corners at 135mm even at f/8 even on a crop factor (at least my copy is)
* Slow. At 135mm its f/5.6 which rules out all but daylight shooting unless a strong flash/lighting is used.