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Old Jul 26, 2006, 12:35 AM   #1
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I currently have a 75-300mm f4.5 - 5.6 Canon lens on my 20D. Would it be worth spending the money on a 1.4 or 2.0 extender for daytime shots? I find that sometimes I am just a little short of zoom. I like to shoot wildlife and sports. If getting the extender is a waste then what lens would you suggest. Remember I am on a budget.
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Old Jul 26, 2006, 4:35 AM   #2
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You will lose autofucus putting an extender on this lens - a 2x would turn it into an f9-f11. Not much use for sport at this speed either as you will be getting long shutter times. This is not a good lens in the first place and I doubt you will get any better results with an extender than from cropping and enlarging.
There really aren't any budget lenses longer than 300mm though there are much better 70-300s than the one you have (lens technology has really advanced lately). In order to maintain auto-focus they need to be at least f5.6 and at 300mm+ even a f5.6 prime will be pretty large (and hence expensive). The only cheap long lenses are those gimicky things you see in tv magazines that look like plastic telescopes and have pin-hole apertures and reflecting lenses which have never been popular because of the weird bokeh they give.
The 'bigma' (sigma 50-500) is pretty good, very versatile and excellent value. A quality tele zoom such as one of the 70-200s or the Sigma 100-300f4 will take an extender and give you 400/420mm while keeping pretty good quality. You're looking at spending in the region of US$1000 though for any of these unless you can find second hand ones.
There are a few others. Try looking at the websites of 3rd party lens makers such as sigma and tamron as these tend to be a lot cheaper than canon.
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Old Jul 26, 2006, 5:18 AM   #3
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If I have to go with a better lens, what is it that I am looking for to know I am looking at a good fast lens. Is it the f-stop? If so what is good?
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Old Jul 26, 2006, 7:37 AM   #4
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Well for sports or action shots you'll need the faster aperture more than IS... to freeze the action with the shutter

However the 70-200 f/2.8's are already too short since you seem to need more reach than your 75-300mm -> This is the expensive lenses department I'm afraid:

An EF-300 f/4 IS prime will get you to 420mm with a 1.4x TC
So does the Sigma 100-300 f/4 EX which is a zoom instead but still quite comparable in optical quality
... and then the huge 120-300 f/2.8 EX which I often use with a 2X TC for shots @ 600mm with wildlife
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Old Jul 26, 2006, 7:51 AM   #5
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NHL is right on!

the optical quality with a TC will be too poor for that lens, you won't have autofocus so you'll get miserable results trying to shoot sports.

For wildlife, others can speak far better than me as to what is an appropriate lens. But for sports, the 'best' lens depends largely on what sport your shooting. What are you shooting (and from where) that the 300mm lens you're using is too short?
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Old Jul 26, 2006, 11:31 AM   #6
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You can try cheap tamron 1.4x TC. Maybe buy it used for $50 and see how well it works with your lens.

The AF should work fine (though slow) as this TC doesn't report correct aperture to the camera body. I use it all the time with my 400mm f5.6 prime for wildlife shots and can hardly tell the difference between shots taken with & without the TC.
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Old Jul 26, 2006, 8:06 PM   #7
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So other than price what is it that I am looking for to tell me I have found a good lens? I thought that a Canon lens would be good. 75-300mm with a 5.6aperture I thought was good or at least sounds good to me when I here all the other lenses that I am told are better have a lot of the same measurements? What is it that makes a good lens. What do I need to look for to tell the difference?:?

HELP I am so confused.
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Old Jul 26, 2006, 9:32 PM   #8
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RP33 wrote:
Quote:
... I thought that a Canon lens would be good. 75-300mm with a 5.6aperture I thought was good or at least sounds good to me when I here all the other lenses that I am told are better have a lot of the same measurements? What is it that makes a good lens. What do I need to look for to tell the difference?
You can read more about it here:
http://www.photozone.de/8Reviews/len...56is/index.htm
http://www.photozone.de/8Reviews/len...00_4/index.htm



... but basically:

o EF 75-300 f/4.5-5.6
1. Plastic built - poor construction
2. It extends and retracts when zoom (and the front element rotates) - poor design
3. Slower focus - i.e. micro USM with no full-time AF overide
4. f/5.6 @ 300mm
5. Not very sharp - measured MTF (1251 @ f/5.6 and 1182 @ f/8 )


o Sigma 100-300 f/4 EX
1. Full metal - excellent built (has anyone seen a plastic 'L'?)
2. Lens size stays constant when zoomed (front element is also fix) -> internal zooming and focus (faster mechanism and does not s_ucks air/dust inside)
3. Fast ultrasonic focus with full-time manual overide (HSM)
4. f/4 @ 300mm -> one full stop faster (twice the amount of incoming light)
5. Extremely sharp - measured MTF (1919 @ f/4, 1951 @ f/5.6, and 1827 @ f/8 )
-> even with a 1.4x TC on the sigma (i.e. @ 420mm) still beats the 75-300 by a wide margin!!! :idea:
(... and we've not even mention the Chromatic Aberrations yet)
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Old Jul 27, 2006, 4:45 AM   #9
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the 100-300 also beats the 75-300 in price by a large margin!:-)
But it really is a nice lens. If I had a reason to go for a long tele, I would consider the 100-300.

You got to be kidding, we can't type sucks?

oh, never mind. I thought you typed "s_ucks" to avoid censorship...:roll:
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Old Jul 27, 2006, 7:52 AM   #10
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BoYFrMSpC wrote:
Quote:
You got to be kidding, we can't type sucks?

oh, never mind. I thought you typed "s_ucks" to avoid censorship...:roll:
I did!

You typed "sucks?" - if you typed "sucks" without the "?" the big_brother software will filter it to "oops" instead! :-) :lol: :G

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