Is this a good lens?

[Eggle]

SIGMA 18-200mm DC F/3.5-6.3 ZOOM LENS canon fit or this one..
Tamron AF 18-200 F/3.5-6.3 XR DI II LD Aspherical CANON
I am just about to buy a 20d and looking at lenses is confusing me. Ebay seems to have many options, but i'm not sure which are right for the 20d and which would be a poor choice.It is different from my vague memory of 35mm.
The sigma mentioned seems a good all round lens to get me going with. Talk me in or out of buying it over say a 18 - 55 kit lens and then say 55 - 100 and then say 8- - 200.
Mainly out door work, small amount of light tent work for product shots.

Edited by Eggle on Tuesday 13th April 14:37

[GetCarter]

With such a VAST range (18-200) Lenses are not great (or we'd all use them all the time). However, it saves lots of swapping and is cheap as chips. 90% of the time it'll do... but it'll never amaze.

Fine for snaps (probably bloody good).

Edited by GetCarter on Tuesday 13th April 15:30

[Simpo Two]

Eggle said:

say a 18 - 55 kit lens and then say 55 - 100 and then say 8- - 200.

18-70 and 70-300 is my recommended pairing for general purpose lenses (ie not fast)

[Eggle]

And am I right thinking the lower the F number the better?
I have narrowed the camera wanted down to the 20d, but the lenses are confusing me

[RichTbiscuit]

Yeah, the lower the F number the 'faster' the glass. The better Depth of Field you can achieve and faster the focus aquisition.

I planning on 3 lenses to cover the focal ranges I want to work with.

10-24
24-70
70-200

Have the first two and still deciding on the third. I can't see me needing much beyond these three for a long time. But it all depends on the budget you have.

[Simpo Two]

RichTbiscuit said:

Yeah, the lower the F number the 'faster' the glass. The better Depth of Field you can achieve

Shallower.

Fast lenses are often not necessary for beginners or normal use, and apart from 50mm lenses carry a big price tag. There's nothing wrong with 'normal' lenses for normal use.

[Eggle]

Again, looking on Ebay, the 18 - 200 would be £100 ish. Not a high budget to start with.
I could get the 18 - 55 kit lens for £40 ish and then see.
I am struggling with this a bit.

[4hero]

Eggle said:

Again, looking on Ebay, the 18 - 200 would be £100 ish. Not a high budget to start with.
I could get the 18 - 55 kit lens for £40 ish and then see.
I am struggling with this a bit.

No need to struggle, we are here to help Unless it's the budget you are struggling with, then sorry!

[GetCarter]

hey... it's £40! Half a tank of fuel, which you can re-sell on flee Bay. Get the kit lens and see how you get on. It might not be 'long' enough (bring stuff close enough), but you'll not know till you try.

[Lucas CAV]

I bought a Tamron 18-200mm on ebay the other day -- it was near the end of the auction and very cheap -- finishing time in the middle of the night...

Anyway -- I cannot get on with it - the flexibility is nice but for some reason it makes my camera (d200) do crackpot things with the metering - esp on centre-weighted. - Lots of images are coming out very very dark....

It will be going back on ebay asap..... and I will be sticking with my very cheap but surprisingly good Sigma 70-300

[Simpo Two]

Lucas CAV said:

for some reason it makes my camera (d200) do crackpot things with the metering - esp on centre-weighted. - Lots of images are coming out very very dark....

Sticking aperture blades?

[Lucas CAV]

Simpo Two said:

Lucas CAV said:

for some reason it makes my camera (d200) do crackpot things with the metering - esp on centre-weighted. - Lots of images are coming out very very dark....

Sticking aperture blades?

I'm not sure tbh -- you might be right -- but it is brand new as far as I can see -- noisy, clunky and cr@p at focussing within this year...

[rottie102]

Well, I have a 18-200 OS Sigma for my 450d.
And it's OK. That's exactly what it is.
I also have Canon 85MM f/1.8 prime and although it's a pain in the a... sometimes to get a good shot with a prime this long I've notice that since I've bought it I almost never use 18-200mmm.

Once you see pictures taken with a sharp lens there's no way back...

[miniman]

RichTbiscuit said:

Yeah, the lower the F number the 'faster' the glass. The better Depth of Field you can achieve and faster the focus aquisition.

Faster focus acquisition? Are you sure?

[RichTbiscuit]

miniman said:

RichTbiscuit said:

Yeah, the lower the F number the 'faster' the glass. The better Depth of Field you can achieve and faster the focus aquisition.

Faster focus acquisition? Are you sure?

As far as i was led to believe. The more light getting into the sensor the easier the software and lens has in getting to it's focal point. Or am I getting the wrong end of the stick again?

[miniman]

The woeful focus speed of my Sigma 24-70 f/2.8 would suggest otherwise Aside of that it is great; my most-used lens by far.

In my experience it is the inclusion of an ultrasonic motor (USM / HSM) that makes the focus speed improve.

[Simpo Two]

RichTbiscuit said:

miniman said:

RichTbiscuit said:

Yeah, the lower the F number the 'faster' the glass. The better Depth of Field you can achieve and faster the focus aquisition.

Faster focus acquisition? Are you sure?

As far as i was led to believe. The more light getting into the sensor the easier the software and lens has in getting to it's focal point. Or am I getting the wrong end of the stick again?

That's about right from my experience. Rather than 'speed' it helps accuracy and helps prevent hunting. As Miniman says the big difference in focusing speed is an ultrasonic motor as opposed to screw drive. That said, the more 'pro' the body the faster it turns the cogs. Hence for fast and accurate focusing performance you need a fast ultrasonic lens and a pro body. As ever Talbot's First Law applies: 'Yer gets what yer pays for'!

Edited by Simpo Two on Tuesday 13th April 20:02

[Eggle]

4hero said:

Eggle said:

Again, looking on Ebay, the 18 - 200 would be £100 ish. Not a high budget to start with.
I could get the 18 - 55 kit lens for £40 ish and then see.
I am struggling with this a bit.

No need to struggle, we are here to help Unless it's the budget you are struggling with, then sorry!

The understanding is the problem.
Terms I don't recognise, and features I don't know if I need.

[Simpo Two]

Eggle said:

The understanding is the problem. Terms I don't recognise, and features I don't know if I need.

The marketing departments have done their work well, unfortunately.

First thing - focal length. You know that: 18-200mm for example. Focal length controls the field of view/magnification- wide0angle, telephoto and all that.

Second: Aperture. I don't think you're in the fast lenses area here, so don't worry about aperture unduly.

Third: Focus - most lenses now have fast focusing systems called ultrasonic. Nikon call it AF-S, Canon call it USM and Sigma call it HSM. This is useful, so look for it - it's worth paying extra for

Fourth: Lots of acronyms like ED, XR, IF etc. You can look them up if you like but frankly you're likely just to confuse yourself and most of them are of only minor significance at this level.

Finally, don't buy very old lenses. Not only will Beano get upset (he collects them) but the older you go, the higher the chance they won't work fully with the camera.

That, in very general terms, is it

[Eggle]

Simpo Two said:

Eggle said:

The understanding is the problem. Terms I don't recognise, and features I don't know if I need.

The marketing departments have done their work well, unfortunately.

First thing - focal length. You know that: 18-200mm for example. Focal length controls the field of view/magnification- wide0angle, telephoto and all that.

Second: Aperture. I don't think you're in the fast lenses area here, so don't worry about aperture unduly.

Third: Focus - most lenses now have fast focusing systems called ultrasonic. Nikon call it AF-S, Canon call it USM and Sigma call it HSM. This is useful, so look for it - it's worth paying extra for

Fourth: Lots of acronyms like ED, XR, IF etc. You can look them up if you like but frankly you're likely just to confuse yourself and most of them are of only minor significance at this level.

Finally, don't buy very old lenses. Not only will Beano get upset (he collects them) but the older you go, the higher the chance they won't work fully with the camera.

That, in very general terms, is it

Thanks Simpo
Last question, how do I tell if the lens is specificity designed for digital, and not an old eos lens. I believe if I use an old lens, say 28 - 80, in digital terms it would be 18 - 55