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Old Jan 30, 2007, 1:41 PM   #11
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The picture you took with the 24-70 looks dull compared to your 50 1/8, i also have the 50 1/8 ll and for the price it's great but i believe the sigma 17-70 has better resolution than the 50 1/8.
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Old Feb 1, 2007, 6:38 PM   #12
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well, I got myself a sigma 17-70mm.
for some reason when I tried it at the store the focus felt faster but now I think that 17-70 and 24-70 have comparable focus speed. 24-70 feels a little bit more sure to lock the focus on the long end. Which is probably undrstandable. 24-70 is 2.8 at 70 and 17-70 is 4.5 at 70.

This weekend I will give my new lens a field test. My daughter competes again and I'll be there with 17-70mm on my 300d. I'll post a couple of pics for the comparison. If I like the lens I'll keep it if I don't I'll take it back.
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Old Feb 2, 2007, 5:50 AM   #13
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O.S. wrote:
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... for some reason when I tried it at the store the focus felt faster but now I think that 17-70 and 24-70 have comparable focus speed. 24-70 feels a little bit more sure to lock the focus on the long end. Which is probably undrstandable. 24-70 is 2.8 at 70 and 17-70 is 4.5 at 70.
A big factor in focusing speed is not the lens, but the camera! :idea:

The lens may differ slighly in their USM/HSM vs non- ultrasonic motors, but this is in order of 50-100 milliseconds which an average person can never detect (nor a stopwatch) - For comparison a quick push of the shutter release button down and up is at least several hundreds milliseconds long...
-> On the other hand the focusing speed of the camera varies greatly depending on lighting conditions (or contrast) using the same lens!!!

At the store (bright condition) any lens will feel fast - In the evening at home using most average ~100W bulb the autofocus will be slower. Of course in dimmer light any lens will have problem autofocusing, but that's because of the camera which hunts for focus and not the lens!
Of course a brighter f/2.8 lens will perform better than a dimmer f/5.6 lens feeding the camera in the dark
Also the camera focus is more precise when the f/2.8 AF sensors are enabled (just check the manual) - i.e. slower lens just don't use them... :?
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Old Feb 2, 2007, 7:03 AM   #14
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OS and others,

2.8 lenses are often just too slow for indoor sports work. As NHL pointed out, they don't let in enough light for the camera to focus.

However, I do disagree with downplaying the lens in the equation. Want to test it out? Shoot with the 85mm 1.2 mk I and 85mm 1.8. If we stick with the notion that the lens has little impact to focus speed beyond it's aperture then the 1.2 should be as fast or faster than the 1.8. But it's not the case. Or compare the 85mm 1.8 to the 50mm 1.8. Shoot indoor sports/dancing with both for an hour - you'll notice the difference.

A sports photog whose work I respect has owned both the sigma 24-70 and the canon 24-70. He loves the sigma for non sports work because it is so sharp for the money. And in good light he said it competes very well with it's more expensive canon counterpart. But in low light he said there's no contest - the canon is noticably faster to focus. Same camera, both 2.8 lenses. But the sigma hunted more. In the end he uses primes for indoors and kept the sigma for outdoors/good light.

It's why it's important to look beyond max aperture and MTF charts when choosing lenses for sports shooting. You want to make lens purchases based upon field tests of other sports shooters. Just like a wildlife photog should look to other wildlife shooters that have tested the lens in the same conditions they'll be using it in.
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Old Feb 2, 2007, 7:41 AM   #15
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thank you both,

I will be shooting an event this Sunday and that will tell me a lot about my new 17-70mm.
I am by no means a pro in terms of mastery, nor do I make any money on photography. I take pics of my daughter dancing for our ouwn use. I don't have a big budget, I don't think I'll be using primes other then my 50mm 1.8 as for me it is a pain in the butt to switch lens. So basically I am in the same boat as many other people - I am looking for a versatile enough lens that will stay on my camera 99% of times, day or night, indoors or out. I have a tougher proposition then most others as the lens I pick should be sharp, fast, fast focusing all the time especially in low light.
The only consolation I got is I can use flash. The problem sometimes is - I can not bounce it most of the time as the ceilings are high and sometimes very dark.

I am planning to upgrade my 300d to 40d when it comes out. I hate the noise of my 300d at ISO 400 and barely usable ISO 800. I hope the focus speed on the 40d is faster.

as I mentioned - I'll post the pics all who is interested to make your own judgement on the lens. I'll also tell you what it felt like to shoot with 17-70mm compared to sigma 24-70mm and canon 50mm 1.8

thanks again and I am actually going to take my lens to a photo store along with my 300d and compare it on my camera against 30d. I'll tell you about my experiences as well.
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Old Feb 2, 2007, 8:04 AM   #16
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JohnG

I don't think we disagree...

A non USM lens is always slower and I've indicated - Even though both lens will hunt in low light but if a camera has to do 4 pass to focus in low light then an additional 200ms (4 x 50ms) period is quite noticeable as compared to no hunting in full daylight (only one 50ms slower)

However when you're comparing f/1.8 and f/1.2 you're helping the camera by doubling/quadrupling the light for the camera to focus! You can shoot in an ambiance that is 2/4 times darker just as fast...

-> The 50mm f/1.8 again is like the Sigma which is not really a true USM lens like their other EX, and my older EF 85mm f/1.2 is actually quite slow to focus even though it's a true USM when compared to the Sigma HSM of recent vintages
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Old Feb 4, 2007, 8:22 AM   #17
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now back to the 17-70mm lens ... I got one but will be exchanging it today because it reboots my 300d, sometimes it gives me the err 99, and sometimes it stops focusing.
When it works - it produces soft images.

I'm shooting a dance competition tonight, I am really hoping that 17-70mm is up to the task.
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Old Feb 4, 2007, 10:29 AM   #18
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O.S. wrote:
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now back to the 17-70mm lens ... I got one but will be exchanging it today because it reboots my 300d, sometimes it gives me the err 99, and sometimes it stops focusing.
This is usually an early indication of the battery not holding its charge... and not neccessarily the lens with Err 99
-> Theses batteries do not last for ever - changing it (with a higher capacity) do wonders
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Old Feb 4, 2007, 7:28 PM   #19
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NHL - you could be right, the battery on my 300d is quite old and does not hold the charge as good as it used to.
The new 17-70mm that I exchanged for worked great today. I can not say that I am blown away by it but it does look better then 24-70mm.
the lighting was quite poor and I had to shoot with ISO 800 and shutter 100 which gotten me a bit worse results then ISO 400 and shutter 200 the last time. The ceilings were very high to bounce the flash. The direct flash did not really give me what I was looking for. I guess I need to make myself a "better bounce card" with some foam material.

this shot is with Canon 300d, Sigma 17-70mm at f4.5 (wide open), 70mm. ISO 800, shutter 1/100. No PP, just croped.

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Old Feb 4, 2007, 9:10 PM   #20
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well..... I have done some quick tests of my new 17-70mm and found it is not a good copy either. it is way too soft at 70mm. It is extremely soft on the left side especially in the top left corner and it backfocuses.
damit.

I'll exchange this one and give 17-70 another try.
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