What they've told me about my Sigma...

[Zoom Raider]

I didn't get a chance to take my brand new Sigma 70-300mm lens back yet, but I did talk to a technician about it having somewhat of a slow focus. Everytime I aim at something and press the shutter-button down halfway, it won't focus the very first time...it focuses the second time. But my Q-Ray 28-90mm focuses the very first time.

Well, he said it's`cos of the lens is much longer than the 28-90, that it takes a bit more time for the light to reach and so that's why it won't focus the very first time I press the SB. This makes some sense, but then again, light travels at 186,282.3969mps. So how could a couple more inches make it focus slow/er?

I get the feeling this Sigma is a dud. Am I right or is the tekkie right?:dunno

Thanks!

~ZR~

[leebase]

I didn't get a chance to take my brand new Sigma 70-300mm lens back yet, but I did talk to a technician about it having somewhat of a slow focus. Everytime I aim at something and press the shutter-button down halfway, it won't focus the very first time...it focuses the second time. But my Q-Ray 28-90mm focuses the very first time.

Well, he said it's`cos of the lens is much longer than the 28-90, that it takes a bit more time for the light to reach and so that's why it won't focus the very first time I press the SB. This makes some sense, but then again, light travels at 186,282.3969mps. So how could a couple more inches make it focus slow/er?

I get the feeling this Sigma is a dud. Am I right or is the tekkie right?:dunno

Thanks!

~ZR~
You are right...it's a very inadequate explaination. And besides....NO lens requires 2 presses to focus.

Lee

[Zoom Raider]

By the way, scientists have discovered that the speed of light is slowing down, and they don't understand why it is. (Doo, doo, doo, doo - Doo, doo, doo, doo)! It must have something to do with the nearing of the end of time, the returning of the Son of God.:): But, if the SOL is slowing down, this still couldn't slow down my Sigma's focus nor the focus of any lens...lol:rolleyes

~ZR~

[JHarris1984]

By the way, scientists have discovered that the speed of light is slowing down, and they don't understand why it is. (Doo, doo, doo, doo - Doo, doo, doo, doo)! It must have something to do with the nearing of the end of time, the returning of the Son of God.:): But, if the SOL is slowing down, this still couldn't slow down my Sigma's focus nor the focus of any lens...lol:rolleyes

~ZR~
You are farther away than the minimum focusing distance right? Does it still take 2 shutter presses to focus on something 100 feet away?

[Zoom Raider]

You are farther away than the minimum focusing distance right? Does it still take 2 shutter presses to focus on something 100 feet away?I can aim at something a foot away or at something in the horizon with dim light, no light or sunlight...and still it takes two presses to get it to focus.....everytime.:scratch

~ZR~

[david_h]

I have the same Sigma lens and it doesn't seem to have this problem.

It is a cheap lens so it isn't going to win any speed awards when it comes to focusing. With mine I have to hold the shutter button down for quite a while to allow the focus motion to finish and lock in.

A simple thing, but are you waiting until the focus is fully locked in before you try to take the shot? Mine sometimes has to hunt backwards and forwards a bit until it's happy. I think the main reason it's slow to focus is that the barrel of the lens often has to travel a long way to find focus, it's also only an f3.5 (or thereabouts) lens so it doesn't get as much light on the focus sensor as some of the wider appature lenses.

Personally, I do very little shooting that needs the range of the 70-300 or I would get something better and faster. I do find that the image quality I get from this lens is pretty good, especially considering the low price.

[Zoom Raider]

I have the same Sigma lens and it doesn't seem to have this problem.

It is a cheap lens so it isn't going to win any speed awards when it comes to focusing. With mine I have to hold the shutter button down for quite a while to allow the focus motion to finish and lock in.

A simple thing, but are you waiting until the focus is fully locked in before you try to take the shot? Mine sometimes has to hunt backwards and forwards a bit until it's happy. I think the main reason it's slow to focus is that the barrel of the lens often has to travel a long way to find focus, it's also only an f3.5 (or thereabouts) lens so it doesn't get as much light on the focus sensor as some of the wider appature lenses.

Personally, I do very little shooting that needs the range of the 70-300 or I would get something better and faster. I do find that the image quality I get from this lens is pretty good, especially considering the low price.Yeah, I wait everytime with either lens to get the focus to fully lock. Other wise, I suppose my shots would be blurry. Some say, "Not really", but I'm afraid it will be. I hope they will trade it in tomorrow, for it hasn't been 10 days yet. This is just day three.

It seems like with any lens, I can get it to focus better in MF than AF. But I still want the AF to work correctly. No sense spending $200 on a big lens and it just half a** works.:scratch

~ZR~

[Zoom Raider]

Well, I took the lens back today and was told the same things. They said that the greater the focal length, the slower the focus, unless I spend quite a bit more for a greater focal length lens...so if I wanna large lens to focus at the very first press of the shutter-button, I'd have to cough up the cash.:rolleyes

Then I tried out a Nikon 70-300mm that cost $20-$30 more and it was not much faster. Then there was a $500-$600 70-300mm lens that may have done the job as quickly as my Q-Ray 28-90mm, but I wasn't about to spend that yet.

So I saved several dollars buy getting a Q-Ray 70-300mm intead of keeping the Sigma 70-300mm since they're both the same in speed and not as fast as my 28-90mm. Maybe they're right about the focal length and the light trying to reach the sensor. I dunno.:dunno

I've noticed that all the Sigmas that I could afford to buy right now don't have the aspherical feature, (which I have no idea what that is anyway). All of the Q-Rays are aspherical. But the only problem I have with any of the affordable 70-300mm's, (whether it's Sigma, Q-ray or Nikon), is having to press the SB more than once to get it to focus.:rolleyes

As long as I get sharp pics and still pics of fast moving objects, such as a Humming Bird and a bee, I'll be happy with this camera system. After all, it's my first MSLR and second camera in my life. The first one was a digital, but I like this MSLR better.:):

~ZR~