Sigma 70-200 f/2.8

[trying101]

Has anyone seen this lens yet? Comments?
I see it sports internal focus and zoom. Does Olympus's new 50-200 SWD have internal zoom and focus too?

Sigma's lens seems to have a better feature set and cheaper too.
I eagerly await a comparative review of the two lenses.


http://www.sigmaphoto.com/lenses/len...44&navigator=3

[spidey89]

Olympus new 50-200 SWD have internal focus but not internal zoom,i'm curious as to what better features does it have other than the constant f2.8?but I don't think the quality would be better than Zuiko wide open,no idea yet,haven't seen this lens,never even heard of it till today

[NMSS_2]

do take note that the sigma MTF is rated at 10 and 30 lp/mm whereas zuiko is rated at 50 lp/mm.

50-200 swd is more or less confirmed sharp wide open (if assuming it is optically unchanged from its older brother).

Unless your hand itchy then....... maybe buy the sigma and try then tell us the results!

[spidey89]

Originally Posted by NMSS_2 do take note that the sigma MTF is rated at 10 and 30 lp/mm whereas zuiko is rated at 50 lp/mm. 50-200 swd is more or less confirmed sharp wide open (if assuming it is optically unchanged from its older brother). Unless your hand itchy then....... maybe buy the sigma and try then tell us the results!

Ha ha ha,that i'm not sure,tempted,but I'd still prefer the wider end of Zuiko although the sigma's constant f2.8 is tempting,but nah

[viewwing]

Originally Posted by NMSS_2 do take note that the sigma MTF is rated at 10 and 30 lp/mm whereas zuiko is rated at 50 lp/mm.

Wah thats quite significant... where did u find the MTF file from?

[trying101]

Originally Posted by NMSS_2 do take note that the sigma MTF is rated at 10 and 30 lp/mm whereas zuiko is rated at 50 lp/mm.

Also take note that comparing MTF data from two different manufactures is not a true comparison as each manufacture produces their own charts. To get a true comparison, a third party chart must be used on both lenses. (For what it's worth).

I have Sigma lenses and Olympus lenses and I find the optical quality of the Olympus lenses to always be superior to that of Sigma's in the same range. IMHO

But, Sigma lenses are not bad lenses and they are less expensive too. You get what you pay for.

[NMSS_2]

Originally Posted by viewwing Wah thats quite significant... where did u find the MTF file from?

Originally Posted by trying101 Also take note that comparing MTF data from two different manufactures is not a true comparison as each manufacture produces their own charts. To get a true comparison, a third party chart must be used on both lenses. (For what it's worth).

you can check their rest of the lenses where normally they would put the mtf charts on the right side of the web page.

mtf charts are normally correct but they might just put the most favourable settings for the sharpness and contrast as they never really indicate which F-stop are they based on and on system are they using it to based on. As far as i know sigma lenses when used on sigma sensor (1.7x) produced fantastic results.

the current best way of looking at a mtf chart is to look at available DxO Analyzer (Diwa) in which Dpreview and some other reviewers are using. They do show sharpness differences at different Fstop and at different parts of the picture whether it is at centre or at border.

Originally Posted by trying101 I have Sigma lenses and Olympus lenses and I find the optical quality of the Olympus lenses to always be superior to that of Sigma's in the same range. IMHO But, Sigma lenses are not bad lenses and they are less expensive too. You get what you pay for.

Sigma lenses are very good if you are using =<1.7crop sensor. That is probably where they based the mtf from. They can beat other major camps on their own rights in terms of sharpness but i am not so sure about their micro contrast. For using these lenses on olympus is a different story as we need very high resolution lenses to resolve for the image.

However, i did hear there are some oly guys who have went down to re-calibrate their sigma lenses from the service centre and have great results, perhaps that is one of the alternatives we can look forward to and....... replace all the more expensive oly lenses to cheaper sigma alternatives. :P

another thing to take note is that they are not very telecentric in design .

[theITguy]

I dunno abt u, but to me the following factors are essential:

1. QC - spend more time taking photo or go servicing?
2. Build Quality - bring overseas to shoot or keep in dry cabinet?
3. Weight - 400g lighter or drag your way back home?
4. AF - snappy or slow but steady?
5. Weatherseal - Dancing in the rain or go for more servicing?


I dunno about you, but the purpose of 4/3 system is really to have the optical quality there corner to corner. Imagine the best zoom len from Canon lose out to Olympus', and Sigma can only (at best) match Canon, is it worth the money? Moreover, Sigma's len are build for film and slowly revised into digital, which I believe they are optically similar.

Just my opinion. If you are on a budget, then ok, else I rather you save up more to get something more reliable.

[trying101]

Originally Posted by theITguy Just my opinion. If you are on a budget, then ok, else I rather you save up more to get something more reliable.

I agree, the information provided answers my questions completely, I'll wait for the Oly 50-200.

Thanks again.

[bousozoku]

Originally Posted by NMSS_2 do take note that the sigma MTF is rated at 10 and 30 lp/mm whereas zuiko is rated at 50 lp/mm. 50-200 swd is more or less confirmed sharp wide open (if assuming it is optically unchanged from its older brother). Unless your hand itchy then....... maybe buy the sigma and try then tell us the results!

I just checked on the earlier Sigma in What Digital Camera magazine and the older model was rated better than the Olympus 50-200 by 1 %, 92 vs. 91 %. They, of course, didn't have a four-thirds sample.