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09/07/2006 11:03:38 PM · #1 |
What is the difference? I know its an open question, let me be more specific.
what should be we consider when we buy either of the three lenses? I think canon lenses are bit costly as compare to other two. what else?
e.g. if I want to buy 28-90 IS lens then what should I consider and why?
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09/07/2006 11:13:53 PM · #2 |
I had the same question last month and went with the Tamron 28-75 and i am stoked with the lens. (cheap too!)
nick
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09/07/2006 11:40:21 PM · #3 |
The 24-70L is about $800 more than the Tamron 28-75, it also has better construction and possibly better optics, is 4mm wider on the wide end, and I think it has weather sealing.
I went with the Tamron version, but in the future if I have the funds might get the Canon. I don't think there's any advantages of going with the Tamron or Sigma version except price. |
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09/13/2006 10:31:30 AM · #4 |
You want to know which is the better of three lenses, but you didn't mention which three lenses you were looking at...
each different lens has its strengths and weaknesses.
The Canon 28-70 f/2.8 is fantastic, and the 24-70 f/2.8 is also exceptional.
On the other hand, the Tamron 28-75 f/2.8 is also very, very good.
Sigma also has a variant of these and it's probably quite good.
But we don't really know what you like to shoot.
The 28-70 and 24-70 are both ranges that are very popular because of the way they work on FULL FRAME and 35MM camera bodies... 24mm on full frame is very nice.
However, on a 20D it's not all that wide.
The current crop of equivalent lenses include the:
Sigma 18-50 f/2.8 (the first lens of this range that made it to market, a bit behind the others in refinement, but still pretty good)
Tamron 17-50 f/2.8 (sweeeet... almost as good as the Canon in most respects)
Tokina 16-50 f/2.8 (not yet available... grrrrrrr)
Canon 17-55 f/2.8 IS USM (MUCH more expensive)
Generally most people are recommending the Tamron 17-50, especially as the Tokina hasn't been released yet.
I've had a few very strong recommendations for that lens given to me. I will probably wait until the Tokina is released and reviewed though before making my own decision.
If the Tokina is around the same price, and has a better handle on the Chromatic Aberration, I will probably go with it because of the extra range... that wide end is USEFUL. If not, I will just go Tamron.
I had a look at your profile and you list a 28-90 USM f/4-5.6 lens... the biggest thing that you will notice when comparing that lens to the above mentioned lenses (either in the 28-70 range or the 17-50 range) is that the 28-90 has a comparitively slow aperture.
How can that affect the lens's performance?
- the 20D has a special focusing sensor which allows improved autofocus performance with lenses with f/2.8 max aperture or wider. It's about the angle of the light entering the lens and how it falls on the internals behind it, so whatever focal length you are at, if the max aperture is narrower than f/2.8, the light will not hit those special sensors. For this reason, even though the range is wider and the lens is exceptionally sharp, I have not included the Sigma 17-70 f/2.8-5.6 (or was it 4.5? sorry sigma if I got it wrong). That lens only provides this benefit when it is at 17mm focal length.
- the aperture range will greatly affect indoor performance of the lens. There's a 4 fold difference between f/2.8 and f/5.6. If you want to take some pics indoors and you are using an f/2.8 lens, you MIGHT (for example) find yourself shooting 1/40s. That's pretty slow, but if you are using 17mm, you should be mostly OK. On the other hand, f/4 would see you shooting at 1/20... That's pretty much guaranteed to smudge up most of your pics unless you use a flash (which adds a whole extra level of complication to many shots)... On the other hand, the 28-90 has a RANGE of apertures, meaning if you need to zoom in for some reason, you will jump to f/5.6 usually around half to 2/3 the way through the focal length of the lens. This would put you at 1/10 at an effective 80mm (approx) right up to 140mm (approx) and you would be in bad shape for indoors shooting... Try that on a 17-50 f/2.8 and you will be shooting 80mm equivalent, but still at f/2.8, meaning you would have the same shutter speed of 1/40. Hold your breath and you might actually get away with it! For a 1 stop difference, there's usually something that can be done too.. You could cheat by underexposing half a stop (risky, but doable if you know what you are doing and are shooting RAW) or using a subtle shift in ISO higher than your norm.
- another issue is general image quality. With higher quality glass, other aspects of the image tend to get better as well. Thing such as contrast and color accuracy often get missed in lens reviews but are a real issue when considering the quality of a lens. For example, the Sigma 18-50 is generally referred to as having somewhat inferior color response compared to more recent lenses... There is also Bokeh, which is far more complicated than simple sharpness or even contrast. I don't usually worry about this as this is also probably the most subjective area of consideration.
Those are probably the most significant areas of consideration for which lens to buy, but there is a veritable bottomless pit of issues by the time all is said and done.
If you want a budget lens with excellent quality, check the Tamron 17-50. You DO get what you pay for, but you can also get a lot of bang for your buck in that mid-range. |
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09/13/2006 10:54:41 AM · #5 |
I spent a few years as a motorsports and 'celebrity' photographer and used a set of Canon primes and zooms during that time, when someone else was footing the bill.
The extra money you pay is definately worth it if you are taking your kit into extremes. I had my gear covered in dust, mud and rain and it still kept on going again and again. The autofocus response was sharper in testing lighting conditions and I don't think anyone does Image Stabilization better than Canon in my opinion.
Sigma are getting close mind you and the differences between their lenses and Canon are difficult to judge especially when they can be 50% of the Canon pricetag. Build quality is also first rate.
I cannot speak about other lenses such as Tamron.
Kevin
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09/13/2006 11:35:32 AM · #6 |
You get what you pay for.
Also, remember there are different qualities of lenses - consumer type and pro type. Pro type are the canon L, tokina PRO, sigma EX and tamron SP lines. better build, better optics, and usually constant aperture.
FOr 90% of the shooting you may never notice a difference. It's that last 10% that you'll appreciate the Canon L difference (that 10% being tough environment, rough handling, large prints, super fast focus).
Only you can decide if the extra cost comes with an extra benefit for you. Check my lense, and you see my conclusion, but one day, when i have all I want I plan to upgrade to the canon lenses. A friend has done it and i've seen/used some of his lenses - yep, better IMO.
As to the whether sigma or tamron...i generally perfer tamron, BUT it is almost on an indivisual lens (focal lentgh) basis. I got the sigma 18-50 2.8 EX when it came out - i like it. not as sharp as i might like wider than f3.5, but i hear the tamron 17-50 is the same way, and the canon 17-40 F4 is more costly, less on the long end and 1 stop slower. Optically from F4 or 5.6 up all three lenses are excellent. I have no focusing issues, but I bet the canon is faster at it than the other two.
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